MSTCVS Quality Collaborative Publications
The Role of Lung Cancer Surgical Technique on Lymph Node Sampling and Pathologic Nodal Upstaging
Stanley Kalata, MD, MS; Nathan M. Mollberg, DO; Chang He, MS; Melissa Clark, MSN; Patricia Theurer, BSN; Andrew C. Chang, MD; Robert J. Welsh, MD; Kiran H. Lagisetty, MD
The role of operative approach in surgical lymphadenectomies and pathologic nodal upstaging for lung cancer remains unclear.
This study retrospectively reviewed patients who underwent lobectomy for non-small cell lung cancer from January 2015 to December 2020 at 16 centers within a statewide quality improvement collaborative in Michigan. Patients were stratified by operative approach, and our primary end points were number of LN recovered, number of LN stations sampled, and rates of nodal upstaging with nodal upstaging defined as a higher final pathologic nodal stage compared with preoperative clinical nodal staging.
A total of 3036 patients were included: 608 (20.0%) with open lobectomies, 1362 (41.3%) with video-assisted thoracoscopic surgery (VATS), and 1233 (37.4%) with robot-assisted thoracoscopic surgery (RATS) lobectomies. Using multivariable logistic regression, study investigators found that VATS was associated with lower rates of nodal upstaging (odds ratio [OR], 0.71; 95% CI, 0.54-0.94; P = .015) and harvesting ≥10 LNs (OR, 0.40; 95% CI, 0.31-0.50; P < .001) as compared with open surgery, whereas no significant difference was found between RATS and open techniques. Compared with open surgery, VATS had lower rates of sampling at ≥5 nodal stations (OR, 0.66; 95% CI, 0.53-0.84; P = .001), whereas RATS rates were higher (OR, 2.38; 95% CI, 1.85-3.06; P < .001).
VATS lobectomies were associated with lower rates of harvesting ≥10 LNs, sampling ≥5 LN stations, and pathologic nodal upstaging compared with open and RATS lobectomies. Compared with open procedures, RATS lobectomies were associated with higher rates of sampling ≥5 LN stations, but there was no significant difference between open and RATS approaches in rates of nodal upstaging or harvesting ≥10 LNs.
Risk Factors for Readmission After Pulmonary Lobectomy for Lung Cancer: A Quality Collaborative Study
Nathan M. Mollberg, DO, Chang He, MS, Melissa J. Clark, MSN, RN, Robert Welsh, MD, Andrew C. Chang, MD
Previous studies identified postoperative complications as being associated with readmission after lobectomy. However, these studies inadequately account for timing of complication and have not accounted for institutional effects. Our objectives were to examine readmission rates after lobectomy and identify factors associated with readmission.
Patients >18 undergoing lobectomy for lung cancer from 2015-2019 were identified from a statewide database. Patients with in-hospital mortality, missing data regarding discharge status, 30-day readmission status, and discharge location were excluded. Data regarding STS postoperative complications were abstracted by hospital data managers to determine timing of occurrence (index admission vs. readmission). Logistic mixed model with hospitals as random intercept to account for clustering data structure and assess hospital-specific effect on readmission was performed.
Overall readmission rate was 6.9% (184/2686). The most common complication was air leak ≥ 5 days 17.4% (467/2686). Variables significantly predictive of more readmission were pre-discharge postoperative complications and Zubrod score ≥ 1. Variables predictive of less readmission were increasing length of stay, and having been operated on at institutions with higher cumulative volume or having post discharge follow-up visit protocol ≤7 days from discharge. The c statistic for the final model was 0.80.
Patients who experience postoperative complications are at increased risk for readmission, while follow-up ≤ 7 day was predictive of less risk for readmission. Efforts at reducing readmissions should focus on decreasing postoperative complication rates, the timing of discharge for patients experiencing complications, as well as decreasing length of time between discharge and clinic follow-up.
Adequate Lung Cancer Surgery Lymphadenectomy within a Statewide Quality Collaborative
In January 2016, our statewide quality improvement collaborative focused on three metrics of adequate lymph node harvest during lung cancer surgery: 1) rates of pathologic examination of ≥10 lymph nodes, 2) sampling ≥5 lymph node stations within the hilum and/or mediastinum, and 3) pathologic nodal upstaging (pathologic nodal stage higher than clinical nodal stage). Unblinded, hospital-level outcomes were presented at biannual meetings and opportunities for education or improvement were discussed. We set out to describe this quality improvement initiative and the subsequent impact on surgical lymphadenectomies statewide.
We retrospectively reviewed patients undergoing lobectomy for stage IA-IIIA non-small-cell lung cancer from July 2015-December 2020 at the 16 participating centers.
The study cohort included 3,753 patients. The rates of examining ≥10 lymph nodes statewide increased from 215 lobectomies (44.0%) in 2015 to 522 lobectomies (78.9%) in 2020 (p<.001). Similar trends were noted statewide for ≥5 lymph node stations which increased from 193 lobectomies (39.6%) to 531 lobectomies (80.3%) in 2020 (p<.001). The overall rate of nodal upstaging was more variable year-to-year and generally declined over time (p=.004).
Our statewide quality improvement initiative improved rates of appropriate lymph node staging for surgically treated non-small cell lung cancer compared to national rates. This work demonstrates the power that a “community of practice” philosophy can have on surgical treatment of lung cancer. Quality improvement interventions including transparent data-driven discussions and collaboration can help guide future quality improvement initiatives and should be readily transferrable to other clinical domains.
The Effect of Direct Oral Anticoagulants on Outcomes Following Urgent or Emergent Cardiac Surgery
Objective: To determine the safety of performing urgent or emergent cardiac surgery within 5 days of a patient taking a direct oral anticoagulant (DOAC).
Design: Multicenter retrospective registry study
Setting: 33 hospitals in a quality collaborative from 2017 to 2019
Participants: Patients were included if they underwent urgent or emergent coronary artery bypass grafting (CABG). Patients were excluded if they received any anticoagulant or antiplatelet agent besides DOACs, heparin or aspirin.
Interventions: Patients were stratified based upon the receipt of a DOAC within 5 days of their operation. Patient cohorts included DOAC within 2 days, DOAC within 3-5 days, and no anticoagulation. Data was unavailable on the specific DOAC agent taken prior to admission.
Measurements and Main Results: There were 7201 patients included with 94 on DOACs. Intraoperative blood transfusion was required in 23.9% of patients on no anticoagulant, 26.2% on a DOAC within 3-5 days of surgery (OR 0.98; 95% CI 0.46 – 2.11), and 30.3% on a DOAC within 2 days (OR 0.99; 95% CI 0.37 – 2.67). Five or more intraoperative blood products were required in 4.4% on no anticoagulant, 1.7% on DOAC within 3-5 days (OR 0.33; 95% CI 0.04 – 2.71), and 6.1% on DOAC within 2 days (OR 0.47; 95% CI 0.06 – 4.05). No difference in mortality was observed amongst the 3 groups (2.9% vs. 3.3% vs. 3.0%; p=0.67).
Conclusions: For urgent or emergent CABGs no significant differences in minor bleeding, major bleeding, or mortality were observed in patients taking a DOAC within 5 days of surgery. This study is hypothesis generating for performing urgent or emergent operations sooner than 5 days after holding DOACs.
Understanding Racial Differences in Lung Cancer Surgery Through a Statewide Quality Collaborative
Persistent racial disparities in lung cancer incidence, treatment, and survival are well documented. Given the importance of surgical resection for lung cancer treatment, racial disparities in surgical quality were investigated using a statewide quality collaborative.
This retrospective study used data from the Michigan Society of Cardiothoracic Surgeons General Thoracic database, which includes data gathered for the Society of Thoracic Surgeons General Thoracic Surgery Database at 17 institutions in Michigan. Adult patients undergoing resection for lung cancer between 2015 and 2021 were included. Propensity score-weighting methodology was used to assess differences in surgical quality, including extent of resection, adequate lymph node evaluation,
30-day mortality, and 30-day readmission rate between white and black patients.
The cohort included 5073 patients comprising 357 (7%) black and 4716 (93%) white patients. The black patients had significantly higher unadjusted rates of wedge resection than the white patients, but after propensity score weighting for clinical factors, wedge resection did not differ from lobectomy (odds ratio [OR], 1.07; 95% confidence interval [CI], 0.78–1.49; P = 0.67). The black patients had fewer lymph nodes collected (incidence rate ratio [IRR], 0.77; 95% CI, 0.73–0.81; P \ 0.0001) and lymph node stations sampled (IRR, 0.89; 95% CI, 0.84–0.94; P\0.0001). The black patients did not differ from the white patients in terms of mortality (OR, 0.65; 95% CI, 0.19–2.34; P = 0.55) or readmission (OR, 0.79; 95% CI, 0.49–1.27; P = 0.32). The black patients had longer hospital stays (OR, 1.08; 95% CI, 1.02–1.14; P = 0.01).
In a statewide quality collaborative that included high-volume centers, black patients received a less extensive lymph node evaluation, with fewer nonanatomic wedge resections performed, and a more limited lymph node evaluation with lobectomy.
Determinants of hospital variability in perioperative red blood cell transfusions during coronary artery bypass graft surgery
To identify to what extent distinguishing patient and procedural characteristics can explain center-level transfusion variation during coronary artery bypass grafting surgery.
Observational cohort study using the Perfusion Measures and Outcomes Registry from 43 adult cardiac surgical programs from July 1, 2011, to July 1, 2017. Iterative multilevel logistic regression models were constructed using patient demographic characteristics, preoperative risk factors, and intraoperative conservation strategies to progressively explain center-level transfusion variation.
Of the 22,272 adult patients undergoing isolated coronary artery bypass surgery using cardiopulmonary bypass, 7241 (32.5%) received at least 1 U allogeneic red blood cells (range, 10.9%-59.9%). When compared with patients who were not transfused, patients who received at least 1 U red blood cells were older (68 vs 64 years; P < .001), were women (41.5% vs 15.9%; P < .001), and had a lower body surface area (1.93 m2 vs 2.07 m2; P < .001), respectively. Among the models explaining center-level transfusion variability, the intraclass correlation coefficients were 0.07 for model 1 (random intercepts), 0.12 for model 2 (patient factors), 0.14 for model 3 (intraoperative factors), and 0.11 for model 4 (combined). The coefficient of variation for center-level transfusion rates were 0.31, 0.29, 0.40, and 0.30 for models 1 through 4, respectively. The majority of center-level variation could not be explained through models containing both patient and intraoperative factors.
The results suggest that variation in center-level red blood cells transfusion cannot be explained by patient and procedural factors alone. Investigating organizational culture and programmatic infrastructure may be necessary to better understand variation in transfusion practices.
Predictors of Discharge Home Without Opioids After Cardiac Surgery: A Multicenter Analysis
Whether all patients will require an opioid prescription after cardiac surgery is unknown. We performed a multicenter analysis to identify patient predictors of not receiving an opioid prescription at the time of discharge home after cardiac surgery.
Opioid-naïve patients undergoing coronary artery bypass grafting and/or valve surgery through a sternotomy at 10 centers from January to December 2019 were identified retrospectively from a prospectively maintained data set. Opioid-naïve was defined as not taking opioids at the time of admission. The primary outcome was discharge without an opioid prescription. Mixed-effects logistic regression was performed to identify predictors of discharge without an opioid prescription, and postdischarge opioid prescribing was monitored to assess patient tolerance of discharge without an opioid prescription.
Among 1924 eligible opioid-naïve patients, mean age was 64 ± 11 years, and 25% were women. In total, 28% of all patients were discharged without an opioid prescription. On multivariable analysis, older age, longer length of hospital stay, and undergoing surgery during the last 3 months of the study were independent predictors of discharge without an opioid prescription, whereas depression, non-Black and non-White race, and using more opioid pills on the day before discharge were independent predictors of receiving an opioid prescription. Among patients discharged without an opioid prescription, 1.8% (10 of 547) were subsequently prescribed an opioid.
Discharging select patients without an opioid prescription after cardiac surgery appears well tolerated, with a low incidence of postdischarge opioid prescriptions. Increasing the number of patients discharged without an opioid prescription may be an area for quality improvement.
The Role of Race on Acute Kidney Injury After Cardiac Surgery
Acute kidney injury (AKI) frequently complicates cardiac surgery and is more common among Black patients. We evaluated determinants of race-based differences in AKI rates.
Serum creatinine-based criteria were used to identify adult cardiac surgical patients having postoperative AKI in the Perfusion Measures and Outcomes (PERForm) Registry (July 1, 2014, to June 30, 2019). Patient characteristics, operative details, and outcomes were compared by race (Black vs White) after excluding patients with preoperative dialysis, missing preoperative or postoperative creatinine, or other races. A mixed effects model (adjusting for demographics, comorbidities, surgical factors) used hospital as a random effect to predict postoperative stage 2 or 3 AKI. Propensity score analyses were conducted to evaluate robustness of the primary analyses.
The study cohort included 34 520 patients (8% Black). More Black patients than White patients were female (43% vs 27%, P < .001), and had hypertension (93% vs 87%, P < .001) and diabetes mellitus (51% vs 41%, P < .001). Acute kidney injury of stage 2 or greater occurred in 1697 patients (5%), more often among Black than White patients (8% vs 5%, P < .001). Intraoperatively, Black patients had lower nadir hematocrits (23 vs 26, P < .001), and were more likely to be given transfusions (22% vs 14%, P < .001). After adjustment, Black race (compared with White) independently predicted odds for postoperative AKI (adjusted odds ratio 1.50; 95% confidence interval, 1.26 to 1.78). The multivariable findings were similar in propensity score analyses.
Despite accounting for differences in risk factors and intraoperative practices, Black patients had a 50% increased odds for having moderate-severe postoperative AKI compared with White patients. Additional evaluations are warranted to identify potential targets to address racial disparities in AKI outcomes.
Establishment and Implementation of Evidence-Based Opioid Prescribing Guidelines in Cardiac Surgery
Despite the risk of new persistent opioid use after cardiac surgery, postdischarge opioid use has not been quantified and evidence-based prescribing guidelines have not been established.
Opioid-naive patients undergoing primary cardiac surgery via median sternotomy between January and December 2019 at 10 hospitals participating in a statewide collaborative were selected. Clinical data were linked to patient-reported outcomes collected at 30-day follow-up. An opioid prescribing recommendation stratified by inpatient opioid use on the day before discharge (0, 1-3, or ≥4 pills) was implemented in July 2019. Interrupted time-series analyses were performed for prescription size and post discharge opioid use before (January to June) and after (July to December) guideline implementation.
Among 1495 patients (729 prerecommendation and 766 postrecommendation), median prescription size decreased from 20 pills to 12 pills after recommendation release (P < .001), while opioid use decreased from 3 pills to 0 pills (P < .001). Change in prescription size over time was +0.6 pill/month before and -0.8 pill/month after the recommendation (difference = -1.4 pills/month; P = .036). Change in patient use was +0.6 pill/month before and -0.4 pill/month after the recommendation (difference = -1.0 pills/month; P = .017). Pain levels during the first week after surgery and refills were unchanged. Patients using 0 pills before discharge (n = 710) were prescribed a median of 0 pills and used 0 pills, while those using 1 to 3 pills (n = 536) were prescribed 20 pills and used 7 pills, and those using greater than or equal to 4 pills (n = 249) were prescribed 32 pills and used 24 pills.
An opioid prescribing recommendation was effective, and prescribing after cardiac surgery should be guided by inpatient use.
High Socioeconomic Deprivation and Coronary Artery Bypass Grafting Outcomes: Insights From Michigan
Cardiovascular outcomes are worse among individuals from areas with limited socioeconomic resources. This study evaluated the relationship between high socioeconomic deprivation and isolated coronary artery bypass grafting (CABG) outcomes.
We linked statewide Society of Thoracic Surgeons Adult Cardiac Surgery Database data to Medicare Fee-for-Service records for 10 423 Michigan residents undergoing isolated CABG between January 2012 and December 2018. High socioeconomic deprivation was defined as residing in the highest decile of the ZIP Code-level area deprivation index (ADI). Multivariable logistic regression estimated the relationship between top ADI decile and major morbidity, in-hospital mortality, and operative mortality. Survival analyses evaluated long-term survival comparing patients in the top vs not in the top ADI decile.
A total of 1036 patients were in the top decile of ADI (ADI >82.4), and they were more likely to be female, Black, and have a higher predicted risk of mortality. Patients in the top ADI decile had significantly higher rates of major morbidity (17.4% vs 11.4%; adjusted odds ratio, 1.26; 95% CI, 1.04-1.54; P = .021) and in-hospital mortality (3.2% vs 1.3%, adjusted odds ratio, 1.84; 95% CI, 1.18-2.86, P = .007) but not operative mortality. The adjusted hazard of mortality was 16% higher for patients residing in the top ADI decile (95% CI, 1.01-1.33; P = .032).
Isolated CABG patients residing in the highest areas of socioeconomic deprivation differed with respect to demographic and clinical characteristics and experienced worse short- and long-term outcomes compared with those not in the top ADI decile.
Failure to rescue: variation in mortality after cardiac surgery
Measures to prevent surgical complications are critical components of optimal patient care, and adequate management when complications occur is equally crucial in efforts to reduce mortality. This study aims to elucidate clinical realities underlying in-hospital variations in failure to rescue (FTR) after cardiac surgery.
Using a statewide database for a quality improvement program, we identified 62 450 patients who had undergone adult cardiac surgery between 2011 and 2018 in 1 of the 33 Michigan hospitals performing adult cardiac surgery. The hospitals were first divided into tertiles according to their observed to expected (O/E) ratios of 30-day mortality: low-mortality tertile (O/E 0.46–0.78), intermediate-mortality tertile (O/E 0.79–0.90) and high-mortality tertile (O/E 0.98–2.00). We then examined the incidence of 15 significant complications and the rates of death following complications among the 3 groups.
A total of 1418 operative deaths occurred in the entire cohort, a crude mortality rate of 2.3% and varied from 1.3% to 5.9% at the hospital level. The death rates also diverged significantly according to mortality score tertiles, from 1.6% in the low-mortality group to 3.2% in the high-mortality group (P < 0.001). Hospitals ranked in a high- or intermediate-mortality tertile had similar rates of overall complications (21.3% and 20.7%, P = 0.17), while low-mortality hospitals had significantly fewer complications (16.3%) than the other 2 tertiles (P < 0.001). FTR increased in a stepwise manner from low- to high-mortality hospitals (8.3% vs 10.0% vs 12.7%, P < 0.001, respectively). Differences in FTR were related to survival after cardiac arrest, multi-system organ failure, prolonged ventilation, reoperation for bleeding and severe acute kidney disease that requires dialysis.
This study demonstrates that timely recognition and appropriate treatment of complications are as important as preventing complications to further reduce operative mortality in cardiac surgery. FTR tools may provide vital information for quality improvement initiatives.
Barriers to atrial fibrillation ablation during mitral valve surgery
Nearly 40% of patients with atrial fibrillation (AF) undergoing mitral valve surgery do not receive concomitant ablation despite societal guidelines. We assessed barriers to implementation of this evidence-based practice through a survey of cardiac surgeons in 2 statewide quality collaboratives.
Adult cardiac surgeons across 2 statewide collaboratives were surveyed on their knowledge and practice regarding AF ablation. Questions concerning experience, clinical practice, case scenarios, and barriers to implementation were included.
Among 66 respondents (66 of 135; 48.9%), the majority reported “very comfortable/frequently use” cryoablation (53 of 66; 80.3%) and radiofrequency (55 of 66; 83.3%). Only 12.1% (8/66) were not aware of the recommendations. Approximately one-half of the respondents reported learning AF ablation in fellowship (50.0%; 33 of 66) or attending courses (47.0%; 31 of 66). Responses to clinical scenarios demonstrated wide variability in practice patterns. One-half of the respondents reported no barriers; others cited increased cross-clamp time, excessive patient risk, and arrhythmia incidence as obstacles. Desired interventions included cardiology/electrophysiology support, protocols, pacemaker rate information, and education in the form of site visits, videos and proctors.
Knowledge of evidence-based recommendations and practice patterns vary widely. These data identify several barriers to implementation of concomitant AF ablation and suggest specific interventions (mentorship/support, protocols, research, and education) to overcome these barriers.
The influence of tobacco load versus smoking status on outcomes following lobectomy for lung cancer in a statewide quality collaborative
Collaborative quality consortia can facilitate implementation of quality measures arising from clinical databases. Our statewide general thoracic surgery (GTS) collaborative investigated the influences of cigarette smoking status on mortality and major morbidity following lobectomy for lung cancer.
Society of Thoracic Surgeons General Thoracic Surgery Database records were identified from 14 institutions participating in a statewide thoracic surgical quality collaborative between 2012 and 2017. We excluded patients with nonelective procedures, stage 0 tumors, American Society of Anesthesiologists class VI disease, and missing clinical characteristics. Outcomes analysis included the combined mortality and major postoperative morbidity rates and the influence of patient characteristics, including smoking status, on composite rate and on postoperative complications.
The study cohort included 2267 patient records for analysis. Overall combined mortality and major morbidity rate was 10.2% (n = 231). Postoperative 30-day mortality was 1.5%, and major morbidity 9.6%. Significant predictors of the combined outcome included male sex (P = .004), body mass index (P < .001), Zubrod score (P = .02), smoking pack-years (P = .03), and thoracotomy (P < .001). Higher American Society of Anesthesiologists disease class and advanced tumor stage were marginally associated with worse combined outcome (P = .06). Smoking status; that is, current, past (no smoking within 30 days), or never smoked, was not associated with worse combined outcome (P = .56) and had no significant influence on major complications.
Smoking status was not associated with worse outcomes; however, smoking dose (pack-years) was associated with worse combined mortality and major morbidity. A statewide quality collaborative provides constructive feedback for participating institutions and surgeons, promoting quality improvement in perioperative patient care strategies and improved outcomes.
Quality Improvement: Arterial Grafting Redux, 2010:2019
The evidence base favoring utilization of multiple arterial conduits in coronary artery bypass grafting has strengthened in recent years. Nevertheless, utilization of arterial conduits in the US lags behind that of many European peers. We describe a statewide collaborative based approach to improving utilization.
Four metrics of arterial revascularization were devised. These were displayed and discussed at quarterly statewide quality collaborative meetings from January 2016 onwards, integrated with an educational program regarding attendant benefits. We undertook retrospective review of isolated coronary artery bypass grafting statewide from 2012-2019 to assess impact.
A total of 38,523 cases met inclusion/exclusion criteria. Statewide incidence of multiple arterial grafting increased from 7.4% at baseline to 21.7% in 2019 (P < .001), implementation across hospitals varied widely, ranging from 67.6% to 0.0%. Utilization of total arterial revascularization increased 1.9% to 4.4% (P < .001) between time frames. Utilization of both radial artery and bilateral internal thoracic artery conduit increased significantly from 5.3% to 13.2% (P < .001) and 2.1% to 8.5% (P < .001), respectively; radial artery utilization was significantly higher than bilateral internal thoracic artery for each year (P < .001 for all comparisons).
Our statewide quality improvement initiative improved rates of utilization of multiple arterial grafting by all metrics. Barriers to current utilization were identified to guide future quality improvement efforts. This reproducible approach is readily transferable to improve quality of care in other domains and geographical areas.
Sources of Hospital Variation in Post-Acute Care Spending After Cardiac Surgery
Postacute care is a major driver of cardiac surgical episode spending, but the sources of variation in spending have not been explored. The objective of this study was to identify sources of variation in postacute care spending within 90-days of discharge following coronary artery bypass grafting (CABG) and aortic valve replacement (AVR) and the relationship between postacute care spending and other postdischarge utilization.
Methods and Results
A retrospective analysis was conducted of public and private administrative claims for Michigan residents insured by Medicare fee-for-service and Blue Cross Blue Shield of Michigan/Blue Care Network commercial and Medicare Advantage plans undergoing CABG (n=11 208) or AVR (n=6122) in 33 nonfederal acute care Michigan hospitals between January 1, 2015 and December 31, 2018. Postacute care use was present in 9662 (86.2%) CABG episodes and 4242 (69.3%) AVR episodes, with respective mean (SD) 90-day spending of $4398±$6124 and $3465±$5759. Across hospitals, mean postacute care spending ranged from $3280 to $8186 for CABG and $2246 to $7710 for AVR. Inpatient rehabilitation and skilled nursing facility care accounted for over 80% of the variation spending between low and high postacute care spending hospitals. At the hospital-level, postacute care spending was modestly correlated across procedures and payers. Spending associated with readmissions, emergency department visits, and outpatient facility care was significantly different between low and high postacute care spending hospitals in CABG and AVR episodes.
There was wide hospital variation in postacute care spending after cardiac surgery, which was primarily driven by differential use and intensity in facility-based postacute care. Optimizing facility-based postacute care after cardiac surgery offers unique opportunities to reduce potentially unwarranted care variation.
Determinants of Value in Coronary Artery Bypass Grafting
Over 180 000 coronary artery bypass grafting (CABG) procedures are performed annually, accounting for $7 to $10 billion in episode expenditures. Assessing tradeoffs between spending and quality contributing to value during 90-day episodes has not been conducted but is essential for success in bundled reimbursement models. We, therefore, identified determinants of variability in hospital 90-day episode value for CABG.
Medicare and private payor admissions for isolated CABG from 2014 to 2016 were retrospectively linked to clinical registry data for 33 nonfederal hospitals in Michigan. Hospital composite risk-adjusted complication rates (≥1 National Quality Forum-endorsed, Society of Thoracic Surgeons measure: deep sternal wound infection, renal failure, prolonged ventilation >24 hours, stroke, re-exploration, and operative mortality) and 90-day risk-adjusted, price-standardized episode payments were used to categorize hospitals by value by defining the intersection between complications and spending. Results Among 2573 total patients, those at low- versus high-value hospitals had a higher percentage of prolonged length of stay >14 days (9.3% versus 2.4%, P=0.006), prolonged ventilation (17.6% versus 4.8%, P<0.001), and operative mortality (4.8% versus 0.6%, P=0.001). Mean total episode payments were $51 509 at low-compared with $45 526 at high-value hospitals (P<0.001), driven by higher readmission ($3675 versus $2177, P=0.005), professional ($7462 versus $6090, P<0.001), postacute care ($7315 versus $5947, P=0.031), and index hospitalization payments ($33 474 versus $30 800, P<0.001). Among patients not experiencing a complication or 30-day readmission (1923/2573, 74.7%), low-value hospitals had higher inpatient evaluation and management payments ($1405 versus $752, P<0.001) and higher utilization of inpatient rehabilitation (7% versus 2%, P<0.001), but lower utilization of home health (66% versus 73%, P=0.016) and emergency department services (13% versus 17%, P=0.034).
To succeed in emerging bundled reimbursement programs for CABG, hospitals and physicians should identify strategies to minimize complications while optimizing inpatient evaluation and management spending and use of inpatient rehabilitation, home health, and emergency department services.
Evaluating Changes in del Nido Cardioplegia Practices in Adult Cardiac Surgery
There has been a rapid adoption of the use of del Nido cardioplegia (DC) among adults undergoing cardiac surgery. We leveraged a multicenter database to evaluate differences over time in the choice and impact of cardioplegia type (DC vs. blood) among patients undergoing cardiac surgery. We evaluated 26,373 patients undergoing non-emergent coronary artery bypass and/or valve surgery between 2014-2015 (early period) and 2017-2018 (late period) at 31 centers. DC was compared with blood-based cardioplegia (BC: 1:1, 2:1, 4:1, 8:1, and variable ratio). We evaluated whether treatment choice differed across prespecified patient characteristics, procedure type, and perfusion practices by time period. We evaluated increased DC use with clinical outcomes (major morbidity and mortality, prolonged intubation, and renal failure), after adjusting for baseline characteristics, procedure type, center, and year. DC use increased from 19.6% in 2014-2015 to 41.5% in 2017-2018, p < .001. Increased DC use occurred among coronary artery bypass grafting (CABG), valve, and CABG + valve procedures, all p < .001. Differences in median procedural duration increased over time (DC vs. BC): 1) bypass duration was 11.0 minutes shorter with DC in the early period and 27.0 minutes shorter in the late period, and 2) cross-clamp duration was 7.0 minutes shorter with DC in the early period and 17.0 minutes shorter in the late period, all p < .001. There were no statistical differences in adjusted odds of major morbidity and mortality (odds ratio [OR]adj: 1.01), prolonged intubation (ORadj: .99), or renal failure (ORadj: .80) by DC use (p > .05). In this large multicenter experience, DC use increased over time and was associated with reduced bypass and ischemic time absent any significant differences in adjusted outcomes.
The Role of Regional Collaboratives in Quality Improvement: Time to Organize, and How?
Over the last 12 years, surgeon representatives from the 33 participating hospitals of the Michigan Society of Thoracic and Cardiovascular Surgeons Quality Collaborative (MSTCVS-QC), along with data specialists, surgical and quality improvement (QI) teams, have met at least 4 times a year to improve health-care quality and outcomes of cardiac and general thoracic surgery patients. The MSTCVS-QC nature of interactive learning has allowed all members to examine current data from each site in an unblinded manner for benchmarking, learn from their findings, institute clinically meaningful changes in survival and health-related quality of life, and carefully follow the effects. These meetings have resulted in agreement on various interventions to improve patient selection, periprocedural strategies, and adherence with evidence-based directed medication regimens, Factors contributing to the quality movement across hospitals include statewide-recognized clinicians who are eager to involve themselves in QI initiatives, dedicated health-care professionals at the hospital level, trusting environments in which failure is only a temporary step on the way toward achieving QI goals, real-time analytics of accurate data, and payers who strongly support QI efforts designed to improve outcomes.
Effect of sex on nadir hematocrit and rates of acute kidney injury in coronary artery bypass
Findings from a large multicenter experience showed that sex influenced the relationship between low nadir hematocrit and increased risk of acute kidney injury after cardiac surgery. We explored whether sex-related differences persisted among patients undergoing isolated coronary artery bypass grafting.
We undertook a prospective, observational study of 17,363 patients without dialysis (13,137 male: 75.7%; 4226 female: 24.3%) undergoing isolated coronary artery bypass grafting between 2011 and 2016 across 41 institutions in the Perfusion Measures and Outcomes registry. Odds ratios between nadir hematocrit and stage 2 or 3 acute kidney injury were calculated, and the interaction of sex with nadir hematocrit was tested. The multivariable, generalized, linear mixed-effect model adjusted for preoperative and intraoperative factors and institution.
Median nadir hematocrit was 22% among women and 27% among men (P < .001). Women were administered a greater median net prime volume indexed to body surface area (407 vs 363 mL/m2) and more red blood cell transfusions (55.5% vs 24.3%; both P < .001). Acute kidney injury was higher among women (6.0% vs 4.3%, P < .001). There was no effect of sex on the relationship between nadir hematocrit and acute kidney injury (P = .67). Low nadir hematocrit was inversely associated with acute kidney injury (adjusted odds ratios per 1-unit increase in nadir hematocrit 0.96; 95% confidence interval, 0.93-0.98); this effect was similar across sexes and independent of red blood cell transfusions.
We found no sex-related differences in the effect of nadir hematocrit on acute kidney injury after isolated coronary artery bypass grafting. However, the strong inverse relationship between anemia and acute kidney injury across sexes suggests the importance of reducing exposure to low nadir hematocrit.
Transcatheter Versus Surgical Aortic Valve Replacement Episode Payments and Relationship to Case Volume
Transcatheter aortic valve replacement (TAVR) has increased in volume as an alternative to surgical aortic valve replacement (SAVR). Comparisons of total episode expenditures, although largely ignored thus far, will be key to the value proposition for payers.
We evaluated 6,359 Blue Cross Blue Shield of Michigan and Medicare fee-for-service beneficiaries undergoing TAVR (17 hospitals, n = 1,655) or SAVR (33 hospitals, n = 4,704) in Michigan between 2012 and 2016. Payments through 90 post-discharge days between TAVR and SAVR were price-standardized and risk-adjusted. Centers were divided into terciles of procedural volume separately for TAVR and SAVR, and payments were compared between lowest and highest terciles.
Payments (± SD) were higher for TAVR than SAVR ($69,388 ± $22,259 versus $66,683 ± $27,377, p < 0.001), while mean hospital length of stay was shorter for TAVR (6.2 ± 5.6 versus 10.2 + 7.5 days, p < 0.001). Index hospitalization payments were $4,374 higher for TAVR (p < 0.001), whereas readmission and post-acute care payments were $1,150 (p = 0.001) and $739 (p = 0.004) lower, respectively, and professional payments were similar. For SAVR, high-volume centers had lower episode payments (difference: 5.0%, $3,255; p = 0.01) and shorter length of stay (10.0 ± 7.5 versus 11.1 ± 7.9 days, p = 0.002) than low volume centers. In contrast, we found no volume–payment relationship among TAVR centers.
Episode payments were higher for TAVR, despite shorter length of stay. Although not a driver for TAVR, center SAVR volume was inversely associated with payments. These data will be increasingly important to address value-based reimbursement in valve replacement surgery.
Understanding the Association Between Frailty and Cardiac Surgical Outcomes
Previous work identified a direct relationship between frailty and adverse outcomes in cardiac surgery, but assessment of the effect across subgroups of patients has largely been ignored. This study identified whether the association of frailty (measured by gait speed) with adverse outcomes differed across subgroups of patients.
The study evaluated 53,932 patients who underwent cardiac operations between 2011 and 2016 across 33 Michigan institutions. Five-meter gait speed (in seconds) was divided into groups: faster (<5.0 seconds), intermediate (5.0 to 5.99 seconds), and slower (≥6.0 seconds). The study used mixed logistic regression to estimate the relationship between increasing gait speed time and a patient’s odds of major morbidity or mortality, by adjusting for patient-related demographics, disease characteristics, surgeon, and hospital. Effect modification by subgroup of patients and gait speed test time was tested with interaction terms. The study’s secondary end point was an analysis of discharge disposition.
Nearly one fourth (22.7%) of patients had at least one gait speed test. Slower (34% of patients) versus faster (28%) patients were older (72.5 years vs 62.6 years), had more comorbidities, and had the primary outcome (16.6% vs 9.5%) (p < 0.0001). Significant interactions with gait speed existed for patients’ comorbidities (chronic lung disease, atrial fibrillation, p < 0.05), although marginal interactions existed for patients’ age (p = 0.059) and diabetes (p = 0.063). Slower patients were more often discharged to a facility rather than home.
Slower gait speed was associated with increased odds of major morbidity or mortality. This effect was amplified among patients with preexisting comorbidities. Future studies should evaluate the impact of preprocedural interventions on frailty, including those aimed at addressing comorbidities.
Collaborative Quality Improvement Reduces Postoperative Pneumonia After Isolated Coronary Artery Bypass Grafting Surgery
Background: To date, studies evaluating outcome improvements associated with participation in physician-led collaboratives have been limited by the absence of a contemporaneous control group. We examined post cardiac surgery pneumonia rates associated with participation in a statewide, quality improvement collaborative relative to a national physician reporting program.
Methods and Results: We evaluated 911 754 coronary artery bypass operations (July 1, 2011, to June 30, 2017) performed across 1198 hospitals participating in a voluntary national physician reporting program (Society of Thoracic Surgeons [STS]), including 33 that participated in a Michigan-based collaborative (MI-Collaborative). Unlike STS hospitals not participating in the MI-Collaborative (i.e., STSnonMI) that solely received blinded reports, MI-Collaborative hospitals received a multi-faceted intervention starting November 2012 (quarterly in-person meetings showcasing unblinded data, webinars, site visits). Eighteen of the MI-Collaborative hospitals received additional support to implement recommended pneumonia prevention practices (“MI-CollaborativePlus”), whereas 15 did not (“MI-CollaborativeOnly”). We evaluated rates of postoperative pneumonia, adjusting for patient mix and hospital effects. Baseline patient characteristics were qualitatively similar between groups and time. During the pre-intervention period, there was a 2.53% per quarter reduction in the adjusted neumonia odds ratio for STS hospitals not participating in the MI-Collaborative ( P<0.001), which was equivalent to the MI-Collaborative ( P>0.05). During the intervention period, there was a significant 2% reduction in the adjusted odds ratio for pneumonia for MI-Collaborative hospitals relative to the STS hospitals not participating in the MI-Collaborative, although was 3% significantly lower among the MI-CollaborativeOnly hospitals. The STS hospitals not participating in the MI-Collaborative had a 1.96% reduction in risk-adjusted pneumonia, which was less than the MI-Collaborative (3.23%, P=0.011). The MI-CollaborativePlus reduced adjusted pneumonia rates by 10.29%, P=0.001.
Conclusions: Participation in a physician-led collaborative was associated with significant reductions in pneumonia relative to a national quality reporting program. Interventions including collaborative learning may yield superior outcomes relative to solely using physician feedback reporting.
Association Between Postoperative Pneumonia and 90-Day Episode Payments and Outcomes Among Medicare Beneficiaries Undergoing Cardiac Surgery
Background: Postoperative pneumonia is the most common healthcare-associated infection in cardiac surgical patients, yet their impact across a 90-day episode of care remains unknown. Our objective was to examine the relationship between pneumonia and 90-day episode payments and outcomes among Medicare beneficiaries undergoing cardiac surgery.
Methods and Results: Medicare claims were used to identify beneficiaries with episodes of coronary artery bypass grafting (CABG; n=56 728) and valve surgery (n=56 377) across 1045 centers between April 2014 and March 2015. Using a published diagnosis code-based algorithm, we identified pneumonia in 6.4% CABG episodes and 6.6% of valve surgery episodes. We compared price-standardized 90-day episode payments and outcome measures (postoperative length of stay, discharge to postacute care, mortality, and readmission) between beneficiaries with and without pneumonia using hierarchical regression models, adjusting for patient factors and hospital random effects. Pneumonia was associated with 24.5% higher episode payments for CABG ($46 723 versus $37 496; P<0.001) and 26.5% higher episode payments for valve surgery ($61 544 versus $48 549; P<0.001). For both cohorts, pneumonia was significantly associated with longer postoperative length of stay (CABG: +4.1 days, valve: +5.6 days), more frequent discharge to postacute care (CABG: odds ratio [OR]=1.99, valve: OR=2.17), and higher rates of 30-day mortality (CABG: OR=2.42, valve: OR=2.57) and 90-day readmission (CABG: OR=1.20, valve: OR=1.25), all P<0.001. We compared episode payments and outcomes across terciles of pneumonia rates and found that high pneumonia rate hospitals had higher episode payments and poorer outcomes compared with episodes at low pneumonia rate hospitals in both CABG and valve surgery cohorts.
Conclusions: Postoperative pneumonia was associated with significantly higher 90-day episode payments and inferior outcomes at the patient and hospital level. Future work should examine whether reducing pneumonia after cardiac surgery reduces episode spending and improves outcomes, which could facilitate hospital success in value-based reimbursement programs.
Development of a Risk Prediction Model and Clinical Risk Score for Isolated Tricuspid Valve Surgery
Background: Although tricuspid valve operations remain associated with high mortality (approximately 8% to 10%), no robust prediction models exist to support clinical decision making. We developed a preoperative clinical risk model with an easily calculable clinical risk score (CRS) to predict mortality and major morbidity after isolated tricuspid valve surgery.
Methods: The Society of Thoracic Surgeons database records were evaluated for 2,050 isolated TV repair and replacement operations for any etiology performed at 50 hospitals (2002 to 2014) in a number of states. Parsimonious preoperative risk prediction models were developed using multiple-level mixed effects regression to estimate mortality and composite major morbidity risk. Model results were utilized to establish a novel CRS for patients undergoing tricuspid valve operations. Models were evaluated for discrimination and calibration.
Results: Operative mortality and composite major morbidity rates were 9% and 42%, respectively. Final regression models performed well (both p < 0.001; areas under the receiver-operating characteristics curve 0.74 and 0.76) and included preoperative factors: age, sex, stroke, hemodialysis, ejection fraction, lung disease, New York Heart Association class, reoperation, and urgent or emergency status (all p < 0.05). A simple CRS from 0 to 10+ was highly associated (p < 0.001) with incremental increases in predicted mortality and major morbidity. Predicted mortality risk ranged from 2% to 34% across CRS categories, and predicted major morbidity risk ranged from 13% to 71%.
Conclusions: Mortality and major morbidity after isolated tricuspid valve surgery can be predicted using preoperative patient data from The Society of Thoracic Surgeons National Adult Cardiac Database. A simple clinical risk score predicts mortality and major morbidity after isolated tricuspid valve surgery. This score may facilitate perioperative counseling and identification of suitable patients for tricuspid valve surgery.
Evolving trends in aortic valve replacement: A statewide experience
Background: Transcatheter aortic valve replacement (TAVR) is an alternative to surgical aortic valve replacement (SAVR) for the treatment of aortic stenosis in patients at intermediate, high, and extreme risk for mortality from SAVR. We examined recent trends in aortic valve replacement (AVR) in Michigan.
Methods: The Michigan Society of Thoracic and Cardiovascular Surgeons Quality Collaborative (MSTCVS-QC) database was used to determine the number of SAVR and TAVR cases performed from January 2012 through June 2017. Patients were divided into low, intermediate, high, and extreme risk groups based on STS predicted risk of mortality (PROM). TAVR patients in the MSTCVS-QC database were also matched with those in the Transcatheter Valve Therapy Registry to determine their Heart Team-designated risk category.
Results: During the study period 9517 SAVR and 4470 TAVR cases were performed. Total annual AVR volume increased by 40.0% (from 2086 to 2920), with a 13.3% decrease in number of SAVR cases (from 1892 to 1640) and a 560% increase in number of TAVR cases (from 194 to 1280). Greater than 90% of SAVR patients had PROM≤8%.
While >70% of TAVR patients had PROM ≤ 8%, they were mostly designated as high or extreme risk by a Heart Team.
Conclusions: During the study period, SAVR volume gradually declined and TAVR volume dramatically increased. This was mostly due to a new group of patients with lower STS PROM who were designated as higher risk by a Heart Team due to characteristics not completely captured by the STS PROM score.
Association Between Medicaid Expansion and Cardiovascular Interventions in Michigan
Michigan is one of several states that expanded Medicaid coverage under the Affordable Care Act. The “Healthy Michigan Plan,” implemented in April 2014, provides coverage through Medicaid to adults with incomes up to 138% of the federal poverty level and requires a health risk assessment and cost sharing by enrollees.
Early results suggest that the Michigan Plan has been successful. Within 1 year of expansion, 600,000 new adults had enrolled (1). Primary care service utilization increased 6% following expansion, and participation in health risk assessments are more than double that of private health insurance plans (2). Less well known is the association between Medicaid expansion and the use and outcomes of cardiovascular revascularization.
Determinants of Variation in Pneumonia Rates After Coronary Artery Bypass Grafting
Background: Although conventional wisdom suggests that differences in patient risk profiles drive variability in postoperative pneumonia rates after coronary artery bypass grafting (CABG), this teaching has yet to be empirically tested. We determined to what extent patient risk factors account for hospital variation in pneumonia rates.
Methods: We studied 324,085 patients undergoing CABG between July 1, 2011, and December 31, 2013, across 998 hospitals using The Society of Thoracic Surgeons Adult Cardiac Database. We developed 5 models to estimate our incremental ability to explain hospital variation in pneumonia rates. Model 1 contained patient demographic characteristics and admission status, while Model 2 added patient risk factors. Model 3 added measures of pulmonary function, Model 4 added measures of cardiac anatomy and function and medications, and Model 5 further added measures of intraoperative and postoperative care.
Results: Although 9,175 patients (2.83%) experienced pneumonia, the median estimated distribution of pneumonia rates across hospitals was 2.5% (25th to 75th percentile: 1.5% to 4.0%). Wide variability in pneumonia rates was evident, with some hospitals having rates more than 6 times higher than others (10th to 90th percentile: 1.0% to 6.1%). Among all five models, Model 2 accounted for the most variability at 4.24%. In total, 2.05% of hospital variation in pneumonia rates was explained collectively by traditional patient factors, leaving 97.95% of variation unexplained.
Conclusions: Our findings suggest that patient risk profiles only account for a fraction of hospital variation in pneumonia rates; enhanced understanding of other contributory factors (eg, processes of care) is required to lessen the likelihood of such nosocomial infections.
Drivers of Payment Variation in 90-Day Coronary Artery Bypass Grafting Episodes
Importance: Coronary artery bypass grafting (CABG) is scheduled to become a mandatory Medicare bundled payment program in January 2018. A contemporary understanding of 90-day CABG episode payments and their drivers is necessary to inform health policy, hospital strategy, and clinical quality improvement activities. Furthermore, insight into current CABG payments and their variation is important for understanding the potential effects of bundled payment models in cardiac care.
Objective To examine CABG payment variation and its drivers.
Design, Setting, and Participants This retrospective cohort study used Medicare and private payer claims to identify patients who underwent nonemergent CABG surgery from January 1, 2012, through October 31, 2015. Ninety-day price-standardized, risk-adjusted, total episode payments were calculated for each patient, and hospitals were divided into quartiles based on the mean total episode payments of their patients. Payments were then subdivided into 4 components (index hospitalization, professional, postacute care, and readmission payments) and compared across hospital quartiles. Seventy-six hospitals in Michigan representing a diverse set of geographies and practice environments were included.
Main Outcomes and Measures Ninety-day CABG episode payments.
Results: A total of 5910 patients undergoing nonemergent CABG surgery were identified at 33 of the 76 hospitals; of these, 4344 (73.5%) were men and mean (SD) age was 68.0 (9.3) years. At the patient level, risk-adjusted, 90-day total episode payments for CABG varied from $11 723 to $356 850. At the hospital level, the highest payment quartile of hospitals had a mean total episode payment of $54 399 compared with $45 487 for the lowest payment quartile (16.4% difference, P < .001). The highest payment quartile hospitals compared with the lowest payment quartile hospitals had 14.6% higher index hospitalization payments ($34 992 vs $30 531, P < .001), 33.9% higher professional payments ($8060 vs $6021, P < .001), 29.6% higher postacute care payments ($7663 vs $5912, P < .001), and 35.1% higher readmission payments ($3576 vs $2646, P = .06). The drivers of this variation are diagnosis related group distribution, increased inpatient evaluation and management services, higher utilization of inpatient rehabilitation, and patients with multiple readmissions.
Conclusions and Relevance Wide variation exists in 90-day CABG episode payments for Medicare and private payer patients in Michigan. Hospitals and clinicians entering bundled payment programs for CABG should work to understand local sources of variation, with a focus on patients with multiple readmissions, inpatient evaluation and management services, and postdischarge outpatient rehabilitation care.
Impact of Medicaid Expansion on Cardiac Surgery Volume and Outcomes
Background: Thirty-one states approved Medicaid expansion after implementation of the Affordable Care Act. The objective of this study was to evaluate the effect of Medicaid expansion on cardiac surgery volume and outcomes comparing one state that expanded to one that did not.
Methods: Data from the Virginia (nonexpansion state) Cardiac Services Quality Initiative and the Michigan (expanded Medicaid, April 2014) Society of Thoracic and Cardiovascular Surgeons Quality Collaborative were analyzed to identify uninsured and Medicaid patients undergoing coronary bypass graft or valve operations, or both. Demographics, operative details, predicted risk scores, and morbidity and mortality rates, stratified by state and compared across era (preexpansion: 18 months before vs postexpansion: 18 months after), were analyzed.
Results: In Virginia, there were no differences in volume between eras, whereas in Michigan, there was a significant increase in Medicaid volume (54.4% [558 of 1,026] vs 84.1% [954 of 1,135], p < 0.001) and a corresponding decrease in uninsured volume. In Virginia Medicaid patients, there were no differences in predicted risk of morbidity or mortality or postoperative major morbidities. In Michigan Medicaid patients, a significant decrease in predicted risk of morbidity or mortality (11.9% [8.1% to 20.0%] vs 11.1% [7.7% to 17.9%], p = 0.02) and morbidities (18.3% [102 of 558] vs 13.2% [126 of 954], p = 0.008) was identified. Postexpansion was associated with a decreased risk-adjusted rate of major morbidity (odds ratio, 0.69; 95% confidence interval, 0.51 to 0.91; p = 0.01) in Michigan Medicaid patients.
Conclusions: Medicaid expansion was associated with fewer uninsured cardiac surgery patients and improved predicted risk scores and morbidity rates. In addition to improving health care financing, Medicaid expansion may positively affect patient care and outcomes.
Organizational Contributors to the Variation in Red Blood Cell Transfusion Practices in Cardiac Surgery: Survey Results From the State of Michigan
Background: While large volumes of red blood cell transfusions are given to preserve life for cardiac surgical patients, indications for lower volume transfusions (1–2 units) are less well understood. We evaluated the relationship between center-level organizational blood management practices and center-level variability in low volume transfusion rates.
Methods: All 33 nonfederal, Michigan cardiac surgical programs were surveyed about their blood management practices for isolated, nonemergent coronary bypass procedures, including: (1) presence and structure of a patient blood management program, (2) policies and procedures, and (3) audit and feedback practices. Practices were compared across low (N = 14, rate: 0.8%–10.1%) and high (N = 18, rate: 11.0%–26.3%) transfusion rate centers.
Results: Thirty-two (97.0%) of 33 institutions participated in this study. No statistical differences in organizational practices were identified between low- and high-rate groups, including: (1) the membership composition of patient blood management programs among those reporting having a blood management committee (P= .27–1.0), (2) the presence of available red blood cell units within the operating room (4 of 14 low-rate versus 2 of 18 high-rate centers report that they store no units per surgical case, P= .36), and (3) the frequency of internal benchmarking reporting about blood management audit and feedback practices (low rate: 8 of 14 versus high rate: 9 of 18; P= .43).
Conclusions: We did not identify meaningful differences in organizational practices between low- and high-rate intraoperative transfusion centers. While a larger sample size may have been able to identify differences in organizational practices, efforts to reduce variation in 1- to 2-unit, intraoperative transfusions may benefit from evaluating other determinants, including organizational culture and provider transfusion practices.
For a more on this article, please go to Anesthesia & Analgesia
Prediction of Transfusions After Isolated Coronary Artery Bypass Grafting Surgical Procedures
Background: Although blood transfusions are common and have been associated with adverse sequelae after cardiac surgical procedures, few contemporaneous models exist to support clinical decision making. This study developed a preoperative clinical decision support tool to predict perioperative red blood cell transfusions in the setting of isolated coronary artery bypass grafting.
Methods: We performed a multicenter, observational study of 20,377 patients undergoing isolated coronary artery bypass grafting among patients at 39 hospitals participating in the Michigan Society of Thoracic and Cardiovascular Surgeons Quality Collaborative’s PERFusion measures and outcomes (PERForm) registry between 2011 and 2015. Candidates’ preoperative risk factors were identified based on previous work and clinical input. The study population was randomly divided into a 70% development sample and a 30% validation sample. A generalized linear mixed-effect model was developed to predict perioperative red blood cell transfusion. The model’s performance was assessed for calibration and discrimination. Sensitivity analysis was performed to assess the robustness of the model in different clinical subgroups.
Results: Transfusions occurred in 36.8% of patients. The final regression model included 16 preoperative variables. The correlation between the observed and expected transfusions was 1.0. The risk prediction model discriminated well (receiver operator characteristic [ROC]development, 0.81; ROCvalidation, 0.82) and had satisfactory calibration (correlation between observed and expected rates was r = 1.00). The model performance was confirmed across medical centers and clinical subgroups.
Conclusions: Our risk prediction model uses 16 readily obtainable preoperative variables. This model, which provides a patient-specific estimate of the need for transfusion, offers clinicians a guide for decision making and evaluating the effectiveness of blood management strategies.
The Relationship between Intra-Operative Transfusions and Nadir Hematocrit on Post-Operative Outcomes after Cardiac Surgery
Abstract: Uncertainty exists regarding the optimal strategy for the management of anemia in the setting of cardiac surgery. We sought to improve our understanding of the role of intra-operative hematocrit (HCT) and transfusions on peri-operative outcomes following cardiac surgery. A total of 18,886 patients undergoing on-pump cardiac surgery were identified from a multi-institutional registry including surgical and perfusion data. Patients were divided into four groups based on their intra-operative nadir HCT (<21 or ≥21) and whether or not they received intra-operative red blood cell (+RBC or −RBC) transfusions. Outcomes were adjusted for the Society of Thoracic Surgeons predicted risk of mortality (PROM), pre-operative HCT, and medical center. Regardless of nadir HCT cohort, those who received a transfusion had higher PROM relative to patients who did not receive a transfusion. The mean PROM was significantly higher among those HCT ≥21 + RBC (5.3%) vs. HCT ≥ 21 − RBC (1.9%), p < .001. Similarly, the PROM was significantly higher among HCT <21 + RBC (5.1%) vs. those HCT <21 − RBC (3.1%), p < .001. Adjusted outcomes demonstrated an increased impact of RBC transfusions on adverse outcomes irrespective of nadir HCT including stroke (p < .001), renal failure (p < .001), prolonged ventilation (p < .001), and mortality (p< .001). This study demonstrates that transfusions have a more profound effect on post-operative cardiac surgery outcomes than anemia.
Aortic Valve Replacement in the Moderately Elevated Risk Patient: A Population-Based Analysis of Outcomes
Background: As transcatheter aortic valve replacement (TAVR) therapy transitions from inoperable or high-risk patients to those considered moderate risk, a contemporary evaluation of AVR in this latter group is warranted
Methods: Using the Michigan Cardiothoracic Surgical Quality Collaborative Database, we analyzed outcomes and identified predictors of a composite end point (30-day death, stroke, and dialysis) for 2,979 patients (2007 to 2015) undergoing AVR (n = 1,196) or AVR and coronary artery bypass grafting (n = 1,783) with a preoperative The Society of Thoracic Surgeons predicted risk of mortality (PROM) of 4% to 8% (mean, 5.5%; interquartile range, 4.5% to 6.3%).
Results: The 30-day mortality was 3.9%. Independent predictors of death included stage 4 chronic kidney disease and the presence of pulmonary hypertension (both p < 0.05), but not year of procedure, despite a significant trend in decreased PROM during the study period (p = 0.003). Morbidity included stroke in 2.3%, and renal failure, defined as Acute Kidney Injury Network stage 1 to 3, in 43.7%, although only 5.4% required dialysis. Prolonged ventilator support was required by 21.0%. After a mean length of stay of 10 days (interquartile range 6 to 11 days), 36.4% were discharged to extended care facilities. Independent predictors of the composite outcome included the Society of Thoracic Surgeons PROM (p < 0.001 for trend) and pulmonary hypertension (p < 0.001). Compared with those presenting with pure aortic stenosis, mixed aortic stenosis and aortic insufficiency was independently protective of the composite outcome (odds ratio, 0.58; p < 0.001), whereas pure aortic insufficiency was not (odds ratio, 0.87; p = 0.58). The composite end point frequency was not significantly different in the 17 hospitals developing TAVR programs (TAVR 9.6% vs non-TAVR 9.6%, p = 0.98).
Conclusions: This population-based contemporary assessment suggests moderate-risk patients undergoing AVR experience favorable outcomes. Although increasing PROM is important in preoperative evaluation of risk, preexisting pulmonary hypertension and indication for operation are among other factors that should be considered as TAVR expands into this group of patients.
A Preoperative Risk Model for Postoperative Pneumonia After Coronary Artery Bypass Grafting
Background: Postoperative pneumonia is the most prevalent of all hospital-acquired infections after isolated coronary artery bypass graft surgery (CABG). Accurate prediction of a patient’s risk of this morbid complication is hindered by its low relative incidence. In an effort to support clinical decision making and quality improvement, we developed a preoperative prediction model for postoperative pneumonia after CABG.
Methods: We undertook an observational study of 16,084 patients undergoing CABG between the third quarter of 2011 and the second quarter of 2014 across 33 institutions participating in the Michigan Society of Thoracic and Cardiovascular Surgeons Quality Collaborative. Variables related to patient demographics, medical history, admission status, comorbid disease, cardiac anatomy, and the institution performing the procedure were investigated. Logistic regression through forward stepwise selection (p < 0.05 threshold) was utilized to develop a risk prediction model for estimating the occurrence of pneumonia. Traditional methods were used to assess the model’s performance.
Results: Postoperative pneumonia occurred in 3.30% of patients. Multivariable analysis identified 17 preoperative factors, including demographics, laboratory values, comorbid disease, pulmonary and cardiac function, and operative status. The final model significantly predicted the occurrence of pneumonia, and performed well (C-statistic: 0.74). These findings were confirmed through sensitivity analyses by center and clinically important subgroups.
Conclusions: We identified 17 readily obtainable preoperative variables associated with postoperative pneumonia. This model may be used to provide individualized risk estimation and to identify opportunities to reduce a patient’s preoperative risk of pneumonia through prehabilitation.
The Midterm Impact of Transcatheter Aortic Valve Replacement on Surgical Aortic Valve Replacement in Michigan
Background: We characterized the midterm impact of transcatheter aortic valve replacement (TAVR) on surgical aortic valve replacement (SAVR) volume, patient profiles, and outcomes in Michigan.
Methods: We analyzed data obtained after SAVR (n =15,288) and TAVR (n= 1,783) using the Michigan Society of Thoracic and Cardiovascular Surgery Quality Collaborative from 2006 to 2015. During this period, 17 of 33 hospitals developed TAVR programs.
Results: Annual SAVR volume increased by 38.1% at TAVR hospitals and by 20.4% at non-TAVR hospitals, (ptrend < 0.001). In TAVR hospitals, the Society of Thoracic Surgeons (STS) Predicted Risk of Mortality (PROM) decreased before (4.7% 5.1%) and after (3.5% 3.6%) initiation of TAVR (p < 0.001). Rates of 30-day mortality (pre-TAVR, 3.9% vs post-TAVR, 2.7%; p < 0.001) and renal failure (pre-TAVR, 5.2% vs post-TAVR, 3.3%; p < 0.001) butnot stroke (pre-TAVR, 1.9% vs post-TAVR, 1.7%; p= 0.47) were lower after TAVR implementation. Length of stay decreased from 9.0 to 8.5 days (p < 0.001). When analyzing high-risk patients undergoing SAVR (ie, PROM >8%), neither mortality, stroke, nor renal failure was different (all p > 0.15). Despite a reduction in the STS-PROM, non-TAVR hospitals did not display changes in mortality, stroke, or renal failure for either the entire or the high-risk SAVR cohorts after initiation of TAVR in Michigan.
Conclusions: TAVR implementation in Michigan has dramatically increased overall SAVR volume. This phenomenon has occurred with a concomitant decrease in preoperative risk profile and has improved early SAVR outcomes, particularly at TAVR hospitals, but surprisingly not in patients considered at high preoperative risk. As TAVR use increases, these issues may be further clarified and elucidated.
Impact of institutional culture on rates of transfusions during cardiovascular procedures: The Michigan experience
Background: Red blood cell (RBC) transfusions have been associated with morbidity and mortality in both coronary artery bypass grafting (CABG) and percutaneous coronary interventions (PCI). As a mechanism for identifying determinants of RBC practice, we quantified the relationship between a center’s PCI and CABG transfusion rate.
Methods: We identified all patients undergoing CABG (n = 16,568) or PCI (n = 94,634) at each of 33 centers from 2010 through 2012 in the state of Michigan and compared perioperative RBC transfusion rates for CABG and PCI at each center. Crude and adjusted transfusion rates were modeled separately. We adjusted for common preprocedural risk factors (12 for CABG and 23 for PCI) and reported Pearson correlation coefficients based on the crude and risk-adjusted rates.
Results: As expected, RBC transfusion was more common after CABG (mean 46.5%) than PCI (mean 3.3%), with wide variation across centers for both (CABG min:max 26.5:71.3, PCI min:max 1.6:6.0). However, RBC transfusion rates were significantly correlated between CABG and PCI in both crude, 0.48 (P = .005), and adjusted, 0.53 (P = .001), analyses. These findings were consistent when restricting to nonemergent cases (radj = 0.44, P = .001).
Conclusions: Red blood cell transfusion rates were significantly correlated between the CABG and PCI at individual hospitals in Michigan, independent of patient case mix. Future work should explore institutional practice patterns philosophies, and guidelines for RBC transfusions.
Greater Volume of Acute Normovolemic Hemodilution May Aid in Reducing Blood Transfusions After Cardiac Surgery
Background: Perioperative red blood cell transfusions (RBC) are associated with increased morbidity and mortality after cardiac surgery. Acute normovolemic hemodilution (ANH) is recommended to reduce perioperative transfusions; however, supporting data are limited and conflicting. We describe the relationship between ANH and RBC transfusions after cardiac surgery using a multi-center registry.
Methods: We analyzed 13,534 patients undergoing cardiac surgery between 2010 and 2014 at any of the 26 hospitals participating in a prospective cardiovascular perfusion database. The volume of ANH (no ANH, <400 mL, 400 to 799 mL, ≥800 mL) was recorded and linked to each center’s surgical data. We report adjusted relative risks reflecting the association between the use and amount of ANH and the risk of perioperative RBC transfusion. Results were adjusted for preoperative risk factors, procedure, body surface area, preoperative hematocrit, and center.
Results: The ANH was used in 17% of the patients. ANH was associated with a reduction in RBC transfusions (RRadj [adjusted risk ratio] 0.74, p < 0.001). Patients having 800 mL or greater of ANH had the most profound reduction in RBC transfusions (RRadj 0.57, p < 0.001). Platelet and plasma transfusions were also significantly lower with ANH. The ANH population had superior postoperative morbidity and mortality compared with the no ANH population.
Conclusions: There is a significant association between ANH and reduced perioperative RBC transfusion in cardiac surgery. Transfusion reduction is most profound with larger volumes of ANH. Our findings suggest the volume of ANH, rather than just its use, may be an important feature of a center’s blood conservation strategy.
Sources of Variation in Hospital-Level Infection Rates After Coronary Artery Bypass Grafting: An Analysis of The Society of Thoracic Surgeons Adult Heart Surgery Database
Background: Patients undergoing coronary artery bypass grafting (CABG) are at risk for a variety of infections. Investigators have focused on predictors of these adverse sequelae, but less attention has been focused on characterizing hospital-level variability in these outcomes.
Methods: Between July 2011 and December 2013, The Society of Thoracic Surgeons Adult Cardiac Surgery Database shows 365,686 patients underwent isolated CABG in 1,084 hospitals. Hospital-acquired infections (HAIs) were defined as pneumonia, sepsis/septicemia, deep sternal wound infection/mediastinitis, vein harvest/cannulation site infection, or thoracotomy infection. Hospitals were ranked by their HAI rate as low (10th percentile), medium (10th to 90th percentile), and high (>90th percentile). Differences in perioperative factors and composite morbidity and mortality end points across these groups were determined using the Wilcoxon rank sum and tests.
Results: HAIs occurred among 3.97% of patients overall, but rates varied across hospital groups (low: <0.84%, medium: 0.84% to 8.41%, high: >8.41%). Pneumonia (2.98%) was the most common HAI, followed by sepsis/septicemia (0.84%). Patients at high-rate hospitals more often smoked, had diabetes, chronic lung disease, New York Heart Association Functional Classification III to IV, and received blood products (p < 0.001); however, they less often were prescribed the appropriate antibiotics (p < 0.001). Major morbidity and mortality occurred among 12.3% of patients, although this varied by hospital group (low: 8.6%, medium: 12.3%, high: 17.9%; p < 0.001).
Conclusions: Substantial hospital-level variation exists in postoperative HAIs among patients undergoing CABG, driven predominantly by pneumonia. Given the relatively small absolute differences in comorbidities across hospital groups, our findings suggest factors other than case mix may explain the observed variation in HAI rates.
Nadir Hematocrit on Bypass and Rates of Acute Kidney Injury: Does Sex Matter?
Background: Reports have associated nadir hematocrit (Hct) on cardiopulmonary bypass with the occurrence of renal dysfunction. Recent literature has suggested that women, although more often exposed to lower nadir Hct, have a lower risk of postoperative renal dysfunction. We assessed whether this relationship held across a large multicenter registry.
Methods: We undertook a prospective, observational study of 15,221 nondialysis-dependent patients (10,376 male, 68.2%; 4,845 female, 31.8%) undergoing cardiac surgery between 2010 and 2014 across 26 institutions in Michigan. We calculated crude and adjusted OR between nadir Hct during cardiopulmonary bypass and stage 2 or 3 acute kidney injury (AKI), and tested the interaction of sex and nadir Hct. The predicted probability of AKI was plotted separately for men and women.
Results: Nadir Hct less than 21% occurred among 16.6% of patients, although less commonly among men (9.5%) than women (31.9%; p < 0.001). Acute kidney injury occurred among 2.7% of patients, with small absolute differences between men and women (2.6% versus 3.0%, p = 0.20). There was a significant interaction between sex and nadir Hct (p = 0.009). The effect of nadir Hct on AKI was stronger among male patients (adjusted odds ratio per 1 unit decrease in nadir Hct 1.10, 95% confidence interval: 1.05 to 1.13) than female patients (adjusted odds ratio 1.01, 95% CI: 0.96, 1.06).
Conclusions: Lower nadir Hct was associated with an increased risk of AKI, and the effect appears to be stronger among men than women. Understanding of the mechanism underlying this association remains uncertain, although these results suggest the need to limit exposure to lower nadir Hct, especially for male patients.
Impact of Ultrafiltration on Kidney Injury After Cardiac Surgery: The Michigan Experience
Background: This study examines the relationship between the use and volume of conventional ultrafiltration (CUF) and the risk of acute kidney injury (AKI) after isolated on-pump coronary artery bypass graft surgery.
Methods: A total of 6,407 consecutive patients underwent isolated on-pump coronary artery bypass graft surgery between 2010 and 2013 at 21 medical centers participating in the PERFusion Measures and Outcomes (PERForm) registry. We assessed the effect of CUF use on AKI and other postoperative sequelae using a generalized linear mixed-effect model with a logit link. We also modeled the effect of increasing volume of CUF per weight on AKI, and tested for any modification by a patient’s preoperative kidney function.
Results: Patients having CUF were more likely to have diabetes, vascular disease, chronic obstructive pulmonary disease, congestive heart failure, history of a myocardial infarction, or an intraaortic balloon pump (p < 0.05). They had lower preoperative and nadir hematocrits, creatinine clearance, and ejection fraction (p < 0.05). Patients exposed to CUF had higher adjusted risk of AKI (adjusted odds ratio, 1.36; p = 0.002), although similar rates of death, stroke, and reoperation for bleeding (p > 0.05). The risk of AKI was modified by a patient’s preoperative kidney function (p < 0.0004). Among patients with a creatinine clearance of less than 99.6 mL/min (95% confidence interval, 67.6 to 137.5), increasing volume of CUF was associated with a higher risk of AKI.
Conclusions: Patients exposed to CUF had a higher adjusted risk of AKI. Clinical teams should consider lower volumes of CUF among patients with low creatinine clearance to minimize the risk of AKI.
Red Blood Cell Transfusions Impact Pneumonia Rates After Coronary Artery Bypass Grafting
Background: Pneumonia, a known complication of coronary artery bypass grafting (CABG), significantly increases a patient’s risk of morbidity and mortality. Although not well characterized, red blood cell (RBC) transfusions may increase a patient’s risk of pneumonia. We describe the relationship between RBC transfusion and postoperative pneumonia after CABG.
Methods: A total of 16,182 consecutive patients underwent isolated CABG between 2011 and 2013 at 1 of 33 hospitals in the state of Michigan. We used multivariable logistic regression to estimate the relative odds of pneumonia associated with the use or number of RBC units (0, 1, 2, 3, 4, 5, and ≥ 6). We adjusted for predicted risk of mortality, preoperative hematocrit values, history of pneumonia, cardiopulmonary bypass duration, and medical center. We confirmed the strength and direction of these relationships among selected clinical subgroups in a secondary analysis.
Results: Five hundred seventy-six (3.6%) patients had pneumonia and 6,451 (39.9%) received RBC transfusions. There was a significant association between any RBC transfusion and pneumonia (adjusted odds ratio [ORadj], 3.4; p < 0.001). There was a dose response between number of units and odds of pneumonia, with a ptrend less than 0.001. Patients receiving only 2 units of RBCs had a 2-fold (ORadj, 2.1; p < 0.001) increased odds of developing pneumonia. These findings were consistent across clinical subgroups.
Conclusions: We found a significant volume-dependent association between an increasing number of RBCs and the odds of pneumonia, which persisted after risk adjustment. Clinical teams should explore opportunities for preventing a patient’s risk of RBC transfusions, including reducing hemodilution or adopting a lower transfusion threshold in a stable patient.
The Society of Thoracic Surgeons Adult Cardiac Surgery Database Version 2.73: More Is Better
Background: With the introduction of version 2.73, several new patient risk factors are now captured in The Society of Thoracic Surgeons’ (STS) Adult Cardiac Surgery Database. We sought to evaluate the potential association of these risk factors with mortality.
Methods: We reviewed all patients with an STS predicted risk of mortality in our statewide quality collaborative database from July 2011 to September 2013 (N = 19,743). Univariate analyses were used to determine significant associations between mortality and the new risk factors in version 2.73. We then performed multivariable analysis, incorporating the STS predicted risk of mortality into our regression.
Results: In the univariate model, patients with illicit drug use, syncope, unresponsive neurologic state, cancer within the last 5 years, current smoking history, other tobacco use, or sleep apnea had no significant difference in mortality (p > 0.05). Patients with liver disease, elevated Model for End-Stage Liver Disease score, mediastinal radiation, prolonged 5-meter walk test, home oxygen use, inhaled medications or bronchodilator therapy, decreased forced expiratory volume, and history of recent pneumonia had significant increases in operative mortality (p < 0.05). In multivariable analysis incorporating the STS predicted risk models, liver disease, elevated Model for End-Stage Liver Disease score, prolonged 5-meter walk test, home oxygen use, bronchodilator therapy, and abnormal pulmonary function tests were independently predictive of mortality.
Conclusion: Several of the new STS data variables were significantly associated with operative mortality after cardiac surgery. The addition of these patient factors improves our understanding of evolving patient demographics and comorbid conditions and their impact on perioperative risk. This will improve both shared decision making and assessments of provider performance.
Red Blood Cells and Mortality After Coronary Artery Bypass Graft Surgery: An Analysis of 672 Operative Deaths
Background: Prior studies have implicated transfusion as a risk factor for mortality in coronary artery bypass graft surgery (CABG). To further our understanding of the true association between transfusion and outcome, we specifically analyzed the subgroup of patients who died after undergoing CABG.
Methods: A total of 34,362 patients underwent isolated CABG between January 2008 and September 2013 and were entered into a statewide collaborative database; 672 patients (2.0%) died and form the basis for this study. Univariate analysis compared preoperative and intraoperative variables, as well as postoperative outcomes, between those with and without transfusion in both unadjusted cohorts and those matched by predicted risk of mortality (PROM). Mortality was further evaluated with phase of care analysis.
Results: Of the 672 deaths, 566 patients (84.2%) received a transfusion of red blood cells. The PROM was 7.5% for the transfused patients versus 4.3% for those not transfused (p < 0.001). Transfused patients were older, more often female, had more emergency, on-pump, and redo procedures, and had a lower preoperative and on-bypass nadir hematocrit. Most other demographics were similar between the groups. Postoperatively, transfused patients were ventilated longer, had more renal and multisystem organ failure, and were more likely to die of infectious and pulmonary causes after longer intensive care unit and overall lengths of stay.
Conclusion: Significant differences in PROM and the postoperative course leading to death between those with and without transfusion suggest the role of transfusion may be secondary to other patient-related factors. Recognizing that the relationship between transfusion and outcome after CABG remains incompletely understood, these findings are suggestive of a complex interaction of many variables.
Center-level Variation in Infection Rates after Coronary Artery Bypass Grafting
Background: Health-care-acquired infections (HAIs) are a leading cause of morbidity and mortality after cardiac surgery. Prior work has identified several patient-related risk factors associated with HAIs. We hypothesized that rates of HAIs would differ across institutions, in part attributed to differences in case mix.
Methods and Results: We analyzed 20 896 patients undergoing isolated coronary artery bypass grafting surgery at 33 medical centers in Michigan between January 1, 2009, and June 30, 2012. Overall HAIs included pneumonia, sepsis/septicemia, and surgical site infections, including deep sternal wound, thoracotomy, and harvest/cannulation site infections. We excluded patients presenting with endocarditis. Predicted rates of HAIs were estimated using multivariable logistic regression. Overall rate of HAI was 5.1% (1071 of 20 896; isolated pneumonia, 3.1% [n=644]; isolated sepsis/septicemia, 0.5% [n=99]; isolated deep sternal wound infection, 0.5% [n=96]; isolated harvest/cannulation site, 0.5% [n=97]; isolated thoracotomy, 0.02% [n=5]; multiple infections, 0.6% [n=130]). HAI subtypes differed across strata of center-level HAI rates. Although predicted risk of HAI differed in absolute terms by 2.8% across centers (3.9-6.7%; min:max), observed rates varied by 18.2% (0.9-19.1%).
Conclusion: There was a 18.2% difference in observed HAI rates across medical centers among patients undergoing isolated coronary artery bypass grafting surgery. This variability could not be explained by patient case mix. Future work should focus on the impact of other factors (eg, organizational and systems of clinical care) on risk of HAIs.
Morbidity But Not Mortality Is Decreased After Off-Pump Coronary Artery Bypass Surgery
Background: Off-pump coronary bypass surgery (CABG) has been advocated to avoid the physiologic perturbations related to cardiopulmonary bypass and improve outcomes compared with on-pump CABG. Previous reports have been inconsistent, and thus its benefits remain uncertain. This retrospective study compared outcomes between on-pump and off-pump CABG from a large multicenter cohort of propensity-matched patients.
Methods: The study consisted of 21,640 patients (19,639 [90.8%] on-pump, 2,001 [9.2%] off-pump) who underwent isolated CABG between January 1, 2008, and June 30, 2011, and were entered into a statewide collaborative database. Univariate analysis compared 37 baseline characteristics between on-pump and off-pump procedures. Patients were matched 1:1 based on similarities in propensity scores derived from statistically significant baseline characteristics. Propensity scores and surgery type were used in conditional logistic regression models for predicting each of 14 postoperative outcomes using the sample of 3,898 matched procedures.
Results: Patients undergoing off-pump CABG had significantly fewer complications overall, including decreased red blood cell transfusion, stroke, intensive care unit and ventilator time, reoperation for bleeding, and length of stay. There was no difference in renal failure, wound infection, discharge location, or 30-day readmission rate. Although off-pump patients received fewer bypass grafts per patient (2.5 1.2 versus 3.0 1.1; p < 0.001), operative mortality was similar for the two groups (1.8% on-pump versus 2.3% off-pump; p = 0.30).
Transfusion of 1 and 2 Units of Red Blood Cells Is Associated With Increased Morbidity and Mortality
Background: This study examined the relationship between transfusion of 1 or 2 units of red blood cells (RBCs) and the risk of morbidity and mortality after isolated onpump coronary artery bypass grafting (CABG). Methods. A total of 22,785 consecutive patients underwent isolated on-pump CABG between January 1, 2008, and December 31, 2011 in Michigan. We excluded 5,950 patients who received three or more RBC units. Twenty-one preoperative variables significantly associated with transfusion by univariate analysis were included in a logistic regression model predicting transfusion, and propensity scores were calculated. Transfusion and the propensity score covariate were included in additional logistic regression models predicting mortality and each of 11 postoperative outcomes.
Results: Operative mortality for the study cohort of 16,835 patients was 0.8% overall, 0.5% for the 10,884 patients with no transfusion, and 1.3% for the 5,951 patients who received transfusion of 1 or 2 units (odds ratio 2.44; confidence interval 1.74 to 3.42; p < 0.0001). The association between transfusion and mortality lessened after propensity adjustment but remained highly significant (odds ratio 1.86; confidence interval 1.21 to 2.87; p = 0.005). Of the 11 postoperative outcomes studied, all but sternal wound infection and need for dialysis were also significantly associated with transfusion.
Conclusions: Transfusion of as little as 1 or 2 units of RBCs is common and is significantly associated with increased morbidity and mortality after on-pump CABG. The relationship persists after adjustment for preoperative risk factors. These results suggest that aggressive attempts at blood conservation and avoidance of even small amounts of RBC transfusion may improve outcomes after CABG.
Aortic Valve Replacement: Using a Statewide Cardiac Surgical Database Identifies a Procedural Volume Hinge Point
Background: Expanding therapies for aortic stenosis have focused on high-risk and inoperable patients, suggesting that an evaluation of outcomes of conventional aortic valve replacement (AVR) or AVR and coronary artery bypass grafting (CABG) is timely and warranted.
Methods: Outcomes for 6,270 AVR (3,487) or AVR/CABG (2,783) procedures performed in Michigan (2008-2011) were analyzed using a statewide cardiothoracic surgical database. Hospital and surgeon volumeoutcome relationships were assessed.
Results: Independent predictors of early mortality (all p < 0.05) included age, female sex, predicted risk of mortality, and hospital volume, with a hinge point of a 4-year volume of 390 procedures (high-volume hospital [HVH], 2.41% versus low-volume hospital [LVH], 4.34%; p < 0.001). At this hinge point, observed to expected ratio (O/E) for operative mortality after AVR was lower inHVHs for patients with a predicted risk of mortality (PRoM) greater than 4.7%. In contrast, no surgeon-volume outcome relationship was identified, even when stratified by preoperative patient-risk profile. With respect to other measures, HVHs reported lower rates of prolonged ventilation (24.9% versus LVH, 30.9%; p < 0.001), postoperative transfusion (46.1% versus LVH, 59.0%; p < 0.001), pneumonia (6.6% versus LVH, 9.0%; p=0.01), and multisystem organ failure (0.7% versus LVH, 1.8%; p =0.012).
Transfusion Rate as a Quality Metric: Is Blood Conservation a Learnable Skill?
Background: Between January 2008 and December 2012, a multicenter quality collaborative initiated a focus on blood conservation as a quality metric, with educational presentations and quarterly reporting of institutional-level perioperative transfusion rates and outcomes. This prospective cohort study was undertaken to determine the effect of that initiative on transfusion rates after isolated coronary artery bypass grafting (CABG).
Methods: Between January 1, 2008, and December 31, 2012, 30,271 patients underwent isolated CABG in Michigan. Evaluated were annual crude and adjusted trends in overall transfusion rates for red blood cells (RBCs), fresh frozen plasma (FFP), and platelets, and in operative death.
Results: Transfusion rates continuously decreased for all blood products. RBC use decreased from 56.4% in 2008 (baseline) to 38.3% in 2012, FFP use decreased from 14.8% to 9.1%, and platelet use decreased from 20.5% to 13.4% (ptrend < 0.001 for all). A significant reduction occurred in deep sternal wound infection, reoperation for bleeding, renal failure, prolonged ventilation, initial ventilator time, and intensive care unit duration. The percentage ofpatients discharged home significantly increased (ptrend<0.001). Mortality rates did not differ significantly (ptrend= 0.11).
Analyzing “Failure to Rescue”: Is This an Opportunity for Outcome Improvement in Cardiac Surgery?
Background: In the setting of a statewide quality collaborative approach to the review of cardiac surgical mortalities in intensive care units (ICUs), variations in complication-related outcomes became apparent. Utilizing “failure to rescue” methodology (FTR; the probability of death after a complication), we compared FTR rates after adult cardiac surgery in low, medium, and high mortality centers from a voluntary, 33-center quality collaborative.
Methods: We identified 45,904 patients with a Society of Thoracic Surgeons predicted risk of mortality who underwent cardiac surgery between 2006 and 2010. The 33 centers were ranked according to observedto-expected ratios for mortality and were categorized into 3 equal groups. We then compared rates of complications and FTR.
Results: Overall unadjusted mortality was 2.6%, ranging from 1.5% in the low-mortality group to 3.6% in the high group. The rate of 17 complications ranged from 19.1% in the low group to 22.9% in the high group while FTR rates were 6.6% in the low group, 10.4% in the medium group, and 13.5% in the high group (p < 0.001). The FTR rate was significantly better in the low mortality group for the majority of complications (11 of 17) with the most significant findings for cardiac arrest, dialysis, prolonged ventilation, and pneumonia.
Validation of a Perfusion Registry: Methodological Approach and Initial Findings
Abstract: Although regional and national registries exist to measure and report performance of cardiac surgical programs, few registries exist dedicated to the practice of cardiopulmonary bypass (CPB). We developed and implemented a cardiovascular perfusion registry (Perfusion Measures and outcomes [PERForm] Registry) within the structure of the Michigan Society of Thoracic and Cardiovascular Surgeons (MSTCVS) to improve our understanding of the practice of CPB. The PERForm Registry comprises data elements describing the practice of CPB. Fourteen medical centers within MSTCVS have voluntarily reported these data on procedures in which CPB is used. We validated the case count among procedures performed between January 1, 2011 to December 31, 2011, and validated the values among 20 fields at three medical centers. We queried database managers at all 14 medical centers to identify the infrastructure that contributed to best overall data collection performance. We found that 98% of all records submitted to the PERForm and 95% of those submitted to the Society of Thoracic Surgeons (STS) matched. We found quite favorable agreement in our audit of select fields (95.8%). Those centers with the most favorable performance in this validation study were more likely to use electronic data capture, have a perfusionist as the STS database manager, and have involvement of the STS database manager in the PERForm or STS databases. We successfully and accurately collected data concerning cardiovascular perfusion among 14 institutions in conjunction with the MSTCVS. Future efforts will focus on expanding data collection to all MSTCVS participating institutions as well as more broadly outside of Michigan.
Preoperative predicted risk does not fully explain the association between red blood cell transfusion and mortality in coronary artery bypass grafting
Objective: Perioperative red blood cell transfusion is associated with increased morbidity and mortality after coronary artery bypass grafting (CABG). Whether transfusion is a cause of these outcomes or serves as a surrogate for a high-risk patient population remains uncertain. This retrospective study tested the hypothesis that increased preoperative risk profile of patients receiving transfusion would explain the relationship between red blood cell transfusion and operative mortality in isolated CABG.
Methods: A total of 31,818 patients undergoing isolated CABG were entered into a statewide collaborative database between January 2006 and June 2010. With the Society of Thoracic Surgeons risk calculator, patient cohorts were stratified into 4 groups by predicted risk of mortality (PROM) of less than 2%, 2% to 5%, more than 5% to 10% and more than 10%. The association between blood transfusion and mortality was tested at each stratum with a x2 test. A Breslow-Day test for homogeneity of odds ratios was used to test whether the 4 odds ratios of the strata were similar, and a Cochran-Mantel-Haenszel test was used to test the association between blood transfusion and mortality while controlling for predicted risk mortality strata.
Results: In all, 17,720 (55.7%) of all patients were transfused during the hospitalization. Incidence of transfusion increased stepwise with risk level; 93.3% of patients with PROM greater than 10% received blood. Operative mortality was 2.1% overall, 0.6% among the 44.3% of patients who were not transfused, and 3.3% in the transfused group (odds ratio, 6.19; P<.0001). The association between blood transfusion and mortality was significant within each predicted risk stratum. Increased mortality associated with transfusion was statistically equivalent across all predicted risk strata (P =.1778). The association between blood transfusion and mortality for all patients lessened somewhat when controlling for PROM (odds ratio, 2.99 vs 6.19), yet remained highly significant (P<.0001).
A Method to Evaluate Cardiac Surgery Mortality: Phase of Care Mortality Analysis
Background: This is a study of a method of mortality review, adopted by the Michigan Society of Thoracic and Cardiovascular Surgeons, to enhance understanding of mortality and potentially avoidable deaths after cardiac surgery, utilizing a voluntary statewide database.
Methods: A system to categorize mortality was developed utilizing a phase of care mortality analysis approach as well as providing criteria to classify mortality as potentially “avoidable.” For each mortality, the operating surgeon categorized a cardiac surgery mortality trigger into 1 of 5 time frames: preoperative, intraoperative, intensive care unit (ICU), postoperative, and discharge.
Results: A total of 53,674 adult cardiac operations were performed from January 1, 2006 to June 30, 2010 with a crude mortality of 3.5% (1,905 of 53,674). Of the mortalities analyzed, 35% (618 of 1,780) were preoperative, 25% (451 of 1,780) were ICU, 19% (333 of 1,780) were intraoperative, 11% (198 of 1,780) were floor, and 10% (180 of 1,780) were discharge phase. “Avoidable” mortality triggers occurred in 53% (174 of 333) of the intraoperative, 41% (253 of 618) and (184 of 451) of the preoperative and ICU phases, 42% (83 of 198) of the floor, and 19% (35 of 180) of the discharge phase. Overall potentially avoidable mortality was 41% (729 of 1780). Thirty-six percent (644 of 1,780) of the mortalities were coronary artery bypass grafting patients and 29% (188 of 644) of these were in the preoperative phase, with a mean predicted risk of 16%.
How A Regional Collaborative Of Hospitals And Physicians In Michigan Cut Costs And Improved The Quality Of Care
Abstract: There is evidence that collaborations between hospitals and physicians in particular regions of the country have led to improvements in the quality of care. Even so, there have not been many of these collaborations. We review one, the Michigan regional collaborative improvement program, which was paid for by a large private insurer, has yielded improvements for a range of clinical conditions, and has reduced costs in several important areas. In general and vascular surgery alone, complications from surgery dropped almost 2.6 percent among participating Michigan hospitals—a change that translates into 2,500 fewer Michigan patients with surgical complications each year. Estimated annual savings from this one collaborative are approximately $20 million, far exceeding the cost of administering the program. Regional collaborative improvement programs should become increasingly attractive to hospitals and physicians, as well as to national policy makers, as they seek to improve health care quality and reduce costs.
Statewide Quality Collaborative for Process Improvement: Internal Mammary Artery Utilization
Background: The Michigan Society of Thoracic and Cardiovascular Surgeons (MSTCVS) Quality Collaborative is a voluntary, surgeon-directed quality initiative involving all cardiac surgery programs in Michigan. Understanding that internal mammary artery (IMA) use during coronary artery bypass grafting is an important process measure associated with improved outcomes, this analysis reviews our methodology to understand IMA use and increase appropriate IMA use statewide.
Methods: Adult cardiac Society of Thoracic Surgeons data were collected at each Michigan site and submitted quarterly to the Duke Clinical Research Institute and the MSTCVS. Seven cardiac surgery programs with IMA use less than 90% in isolated coronary artery bypass grafting were identified as low IMA users. An improvement plan was adopted at the state level and included quarterly monitoring of IMA use, documenting the rationale for IMA exclusion, evidence-based lectures, feedback letters to sites, and physician-led site visits if no improvement was noted.
Results: From 2005 through 2008, 29,114 patients underwent coronary artery bypass grafting in Michigan. Internal mammary artery utilization varied widely at the beginning of this investigation, ranging from 66.2% to 98.4%. Seven Michigan programs were identified as low IMA users. Using the MSTCVS Quality Collaborative’s process-improvement plan, collectively the seven low IMA users increased IMA grafting from 82.0% to 92.7% (p < 0.0001). Michigan IMA use increased from 91.9% to 95.8% (p < 0.0001) and is now higher than The Society of Thoracic Surgeon’s average.
Cardiac Surgeons and the Quality Movement: the Michigan Experience
The Michigan Society of Thoracic and Cardiovascular Surgeons (MSTCVS) was founded in 1965 during an era when many national, regional, and state speciality societies were beginning. The first meeting of what was initially called the Michigan Society of Thoracic Surgeons was held on September 21, 1965 in Detroit in conjunction with the Michigan State Medical Society (personal communication, Allen Silbergleit, MD, PhD, Historian, Michigan Society of Thoracic and Cardiovascular Surgeons, August 2008). The initial meeting was attended by 17 of the 60 board certified thoracic surgeons in Michigan. Dr Cameron Haight, Head of the Section of Thoracic Surgery at the University of Michigan in Ann Arbor, was the President of the society.
As one of the first state thoracic organizations, plans were implemented for an annual meeting, which in the initial years often occurred in conjunction with the American College of Surgeons Michigan Chapter meeting. In the mid-1980s the Michigan Society of Thoracic Surgeons created its own meeting time and moved the annual meeting to resort areas in northern Michigan in late summer. Recognizing the evolution of the speciality of Thoracic Surgery, in 1988 the name of the organization was changed from the Michigan Society of Thoracic Surgeons to the Michigan Society of Thoracic and Cardiovascular Surgeons. Today, the Society has over 100 board-certified thoracic surgeon members, as well as associate members, including data managers, physician assistants, and perfusionists.
Since its inception in 1965 the society has had yearly meetings with the initial focus of these meetings on case presentations, as well as providing an opportunity for house officers from Michigan programs in general surgery, and the two thoracic surgical residency programs to present scientific papers. Presentations from invited cardiac and thoracic surgeon guests with expertise in various areas have become a part of the meeting programs in recent years.
Partnering with payers to improve surgical quality: The Michigan plan
With growing recognition that surgical outcomes vary widely across providers, employers and payers are becoming more actively involved in strategies for improving the quality of surgical care. Employers have obvious interests in minimizing productivity losses from employees undergoing surgical procedures. With ever-rising health care costs, purchasers and payers are also increasingly aware of the financial implications of surgical complications. According to one recent analysis, major complications add over $11,000 to the baseline cost of a surgical procedure.
Payers are using a variety of tactics to improve surgical outcomes. Some are focusing on selective referral strategies. For example, the Leapfrog Group is using public reporting, selective contracting, and a variety of financial incentives to steer patients to hospitals or surgeons likely to have the best results. However, many payers are shifting their focus to “pay-for-performance”(P4P) strategies, using direct financial incentives to motivate quality improvement. With P4P, hospitals are rewarded for meeting specific performance benchmarks, as determined by process of care or direct outcome measures. For example, in a new P4P initiative launched by the Center for Medicare and Medicaid Services, hospitals scoring in the top decile of performance (based on a composite of quality indicators) for coronary artery bypass will receive a 2% bonus on their Medicare payments for this procedure. Similarly, both Centers for Medicare & Medicaid Services (CMS) and many private payers are implementing P4P plans focused on the appropriate use of perioperative antibiotics.
Recent Journal Publications
Review recent syndicated publications of interest from The Journal of Cardiac Surgery, The Journal of Cardiothoracic Surgery, The European Journal of Cardio-Thoracic Surgery and more.