Perfusion Measures and Outcomes (PERForm) registry: First annual report.

BACKGROUND: The Perfusion Measures and Outcomes (PERForm) registry was established in 2010 to advance cardiopulmonary bypass (CPB) practices and outcomes. The registry is maintained through the Michigan Society of Thoracic and Cardiovascular Surgeons Quality Collaborative and is the official registry of the American Society of Extracorporeal Technology. METHODS: This first annual PERForm registry report summarizes patient characteristics as well as CPB-related practice patterns in adult (≥18 years of age) patients between 2019 and 2022 from 42 participating hospitals. Data from PERForm are probabilistically matched to institutional surgical registry data. Trends in myocardial protection, glucose, anticoagulation, temperature, anemia (hematocrit), and fluid management are summarized. Additionally, trends in equipment (hardware/disposables) utilization and employed patient safety practices are reported. RESULTS: A total of 40,777 adult patients undergoing CPB were matched to institutional surgical registry data from 42 hospitals. Among these patients, 54.9% underwent a CABG procedure, 71.6% were male, and the median (IQR) age was 66.0 [58.0, 73.0] years. Overall, 33.1% of the CPB procedures utilized a roller pump for the arterial pump device, and a perfusion checklist was employed 99.6% of the time. The use of conventional ultrafiltration decreased over the study period (2019 vs. 2022; 27.1% vs. 24.9%) while the median (IQR) last hematocrit on CPB has remained stable [27.0 (24.0, 30.0) vs. 27.0 (24.0, 30.0)]. Pump sucker termination before protamine administration increased over the study period: (54.8% vs. 75.9%). CONCLUSION: Few robust clinical registries exist to collect data regarding the practice of CPB. Although data submitted to the PERForm registry demonstrate overall compliance with published perfusion evidence-based guidelines, noted opportunities to advance patient safety and outcomes remain.

Advancing cardiotomy suction practices for coronary surgery via multidisciplinary collaborative learning.

Objective: Professional standards recommend stopping cardiotomy suction at the termination of cardiopulmonary bypass before protamine administration based on perceived safety concerns. This study evaluated a multidisciplinary collaborative quality-improvement intervention promoting this agreed-upon cardiotomy suction practice during coronary artery bypass grafting (CABG). Methods: A statewide intervention (eg, unblinded surgeon and perfusionist feedback, evidence-based lectures, evaluating barriers to change) involved 32 centers participating in the PERForm (ie, Perfusion Measures and Outcomes) Registry to standardize cardiotomy suction practices at cardiopulmonary bypass termination during CABG. Four non-Michigan registry participating centers were not exposed to collaborative learning. Cardiotomy suction practice was defined as the absence of or stopping cardiotomy suction before protamine administration. The practice changes attributed to the intervention, including Michigan and non-Michigan comparisons, were evaluated with the change of time effect modeled using splines. Multivariable regression was used to evaluate the intervention's associated impact (eg, mortality, reoperation, transfusion). Results: Among 10,394 patients undergoing CABG at Michigan centers, 80.7% achieved agreed-upon cardiotomy suction practices. The Michigan centers had nonsignificant changes in agreed-upon cardiotomy suction practices during the preintervention period (P = .24), with significant increased monthly change in practice thereafter, absent adjusted morbidity and mortality increases. The Michigan centers achieved a significantly greater adjusted monthly improvement in agreed-upon practices relative to non-Michigan centers within 7 months after the intervention (adjusted odds ratio for change of trends: 2.53, P < .001). Conclusions: This initiative demonstrates the effectiveness of multidisciplinary collaborative quality improvement in advancing agreed-upon cardiotomy suction practices without negatively impacting clinical outcomes.

del Nido versus blood cardioplegia in cardiac surgery: A multicenter analysis of over 40,000 patients.

OBJECTIVES: The use of del Nido cardioplegia in adult cardiac surgery is rising in popularity. The objective of this large multicenter study was to evaluate the use and associated outcomes of del Nido versus blood cardioplegia in adult cardiac surgery. METHODS: Patients undergoing coronary artery bypass grafting (CABG) and/or valve (mitral, aortic), and/or nondescending thoracic aortic surgery (July 2014 to March 2022) across 39 centers were extracted from the Perfusion Measures and Outcomes registry. Patients were stratified by cardioplegia type for unadjusted analysis and multivariable mixed-effects models were used for risk adjustment. RESULTS: Of 44,175 patients, 42.5% used del Nido, with use increasing 48% over time. Overall, the del Nido group had shorter median crossclamp time (74 minutes vs 87 minutes, P < .001) and lower median peak intraoperative glucose levels (161 mg/dL vs 180 mg/dL, P < .001). Use of del Nido was not associated with operative mortality (adjusted odds ratio [ORadj], 1.16; P = .075) nor major morbidity (ORadj, 1.05; P = .25). Findings for valve cases were similar, except crossclamp time differences were variable by type of valve procedure. Within the CABG subgroup there was a trend toward increased operative mortality with del Nido (ORadj, 1.24; P = .069), whereas the risk of renal failure approaches statistical significance in the aortic subgroup (ORadj, 1.54; P = .056). CONCLUSIONS: In this large, multicenter study, the use of del Nido was associated with variable crossclamp time differences, lower intraoperative glucose levels, and no significant difference in major morbidity or mortality. Efficiency benefits of del Nido may be limited in valve cases, whereas outcomes in CABG and aortic cases warrant further study.

The association of intraoperative and early postoperative events with risk of pneumonia following cardiac surgery.

BACKGROUND: Pneumonia, the most common infection following cardiac surgery, is associated with major morbidity and mortality. Although prior work has identified preoperative risk factors for pneumonia, the present study evaluated the role and associated impact of intraoperative and postoperative risk factors on pneumonia after cardiac surgery. METHODS: This observational cohort study evaluated 71,165 patients undergoing coronary and/or aortic valve surgery across 33 institutions between 2011 and 2021. Terciles of estimated pneumonia risk were compared between a validated preoperative model (Model One) and a model additionally accounting for significant intraoperative (eg, bypass duration) and postoperative (eg, extubation time) factors (Model Two). Logistic regression was used to develop and validate Model Two. RESULTS: Postoperative pneumonia occurred in 2.62% of the patients. A total of 9 significant intraoperative and early postoperative risk factors were identified. The absolute risk of pneumonia increased across Model One terciles: low (≤1.04%), medium (1.04%-2.40%), and high (>2.40%). Model two performed well (c-statistic = 0.771). Most patients (60.1%) had no change in their preoperative versus intraoperative/postoperative risk tercile. The 19.6% of patients who increased their risk tercile with Model Two accounted for 18.6% of all pneumonia events. CONCLUSIONS: This study identified 9 significant perioperative risk factors for pneumonia. Nearly 1 of every 5 patients moved into a higher pneumonia risk category based on their intraoperative and postoperative course. These findings may serve as the focus of future quality improvement efforts to reduce a patient's risk of postoperative pneumonia.

Determinants and Outcomes Associated With Skilled Nursing Facility Use After Coronary Artery Bypass Grafting: A Statewide Experience.

BACKGROUND: Skilled nursing facility (SNF) care is frequently used after cardiac surgery, but the patterns and determinants of use have not been well understood. The objective of this study was to evaluate determinants and outcomes associated with SNF use after isolated coronary artery bypass grafting. METHODS: A retrospective analysis of Medicare Fee-For-Service claims linked to the Society of Thoracic Surgeons clinical data was conducted on isolated coronary artery bypass grafting patients without prior SNF use in Michigan between 2011 and 2019. Descriptive analysis evaluated the frequency, trends, and variation in SNF use across 33 Michigan hospitals. Multivariable mixed-effects regression was used to evaluate patient-level demographic and clinical determinants of SNF use and its effect on short- and long-term outcomes. RESULTS: In our sample of 8614 patients, the average age was 73.3 years, 70.5% were male, and 7.7% were listed as non-White race. An SNF was utilized by 1920 (22.3%) patients within 90 days of discharge and varied from 3.2% to 58.3% across the 33 hospitals. Patients using SNFs were more likely to be female, older, non-White, with more comorbidities, worse cardiovascular function, a perioperative morbidity, and longer hospital lengths of stay. Outcomes were significantly worse for SNF users, including more frequent 90-day readmissions and emergency department visits and less use of home health and rehabilitation services. SNF users had higher risk-adjusted hazard of mortality (hazard ratio, 1.41 [95% CI, 1.26-1.57]; P<0.001) compared with non-SNF users and had 2.7-percentage point higher 5-year mortality rate in a propensity-matched cohort of patients (18.1% versus 15.4%; P<0.001). CONCLUSIONS: The use of SNF care after isolated coronary artery bypass grafting was frequent and variable across Michigan hospitals and associated with worse risk-adjusted outcomes. Standardization of criteria for SNF use may reduce variability among hospitals and ensure appropriateness of use.

Predictors and Variation in Cardiac Rehabilitation Participation After Transcatheter Aortic Valve Replacement.

Background: Cardiac rehabilitation (CR) is strongly recommended for a spectrum of cardiovascular conditions and procedures including aortic valve replacement. Objectives: The purpose of this study was to characterize patient and hospital factors associated with CR participation after transcatheter aortic valve replacement (TAVR) and determine which factors explain hospital-level variation in CR participation. Methods: We linked clinical and administrative claims data from patients who underwent TAVR at 24 Michigan hospitals between January 1, 2016 and June 30, 2020 and obtained rates of CR enrollment within 90 days of discharge. Sequential mixed models were fit to evaluate hospital variation in 90-day post-TAVR CR participation. Results: Among 3,372 patients, 30.6% participated in CR within 90-days after discharge. Several patient factors were negatively associated with CR participation after TAVR including older age, Medicaid insurance, atrial fibrillation/flutter, dialysis use, and slower baseline 5-m walk times. There was substantial hospital variation in CR participation after TAVR ranging from 5% to 60% across 24 hospitals. Patient case mix did not explain hospital variation in CR across hospitals with median OR numerically increasing from 2.11 (95% CI: 1.62-2.67) to 2.13 (95% CI: 1.61-2.68) after accounting for patient-level factors. Conclusions: Less than 1 in 3 patients who underwent TAVR in Michigan participated in CR within 90-days of discharge. Although several patient factors are associated with CR participation, hospital-level variation in CR participation after TAVR is not explained by patient case mix. Identifying hospital processes of care that promote CR participation after TAVR will be critical to improving CR participation after TAVR.

The Role of Race on Acute Kidney Injury After Cardiac Surgery.

BACKGROUND: 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. METHODS: 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. RESULTS: 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. CONCLUSIONS: 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.

Determinants of hospital variability in perioperative red blood cell transfusions during coronary artery bypass graft surgery.

OBJECTIVE: To identify to what extent distinguishing patient and procedural characteristics can explain center-level transfusion variation during coronary artery bypass grafting surgery. METHODS: 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. RESULTS: 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. CONCLUSIONS: 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.

Determinants of Hospital Variation in Cardiac Rehabilitation Enrollment During Coronary Artery Disease Episodes of Care.

BACKGROUND: Cardiac rehabilitation (CR) is associated with improved outcomes for patients with coronary artery disease (CAD). However, CR enrollment remains low and there is a dearth of real-world data on hospital-level variation in CR enrollment. We sought to explore determinants of hospital variability in CR enrollment during CAD episodes of care: medical management of acute myocardial infarction (AMI-MM), percutaneous coronary intervention (PCI), and coronary artery bypass grafting (CABG). METHODS: A cohort of 71 703 CAD episodes of care were identified from 33 hospitals in the Michigan Value Collaborative statewide multipayer registry (2015 to 2018). CR enrollment was defined using professional and facility claims and compared across treatment strategies: AMI-MM (n=18 678), PCI (n=41 986), and CABG (n=11 039). Hierarchical logistic regression was used to estimate effects of predictors and hospital risk-adjusted rates of CR enrollment. RESULTS: Overall, 20 613 (28.8%) patients enrolled in CR, with significant differences by treatment strategy: AMI-MM=13.4%, PCI=29.0%, CABG=53.8% (P<0.001). There were significant differences in CR enrollment across age groups, comorbidity status, and payer status. At the hospital-level, there was over 5-fold variation in hospital risk-adjusted CR enrollment rates (9.8%-51.6%). Hospital-level CR enrollment rates were highly correlated across treatment strategy, with the strongest correlation between AMI-MM versus PCI (R2=0.72), followed by PCI versus CABG (R2=0.51) and AMI-MM versus CABG (R2=0.46, all P<0.001). CONCLUSIONS: Substantial variation exists in CR enrollment during CAD episodes of care across hospitals. However, within-hospital CR enrollment rates were significantly correlated across all treatment strategies. These findings suggest that CR enrollment during CAD episodes of care is the product of hospital-specific rather than treatment-specific practice patterns.

Risk and Safety Perceptions Contribute to Transfusion Decisions in Coronary Artery Bypass Grafting.

Variability persists in intraoperative red blood cell (RBC) transfusion rates, despite evidence supporting associated adverse sequelae. We evaluated whether beliefs concerning transfusion risk and safety are independently associated with the inclination to transfuse. We surveyed intraoperative transfusion decision-makers from 33 cardiac surgery programs in Michigan. The primary outcome was a provider's reported inclination to transfuse (via a six-point Likert Scale) averaged across 10 clinical vignettes based on Class IIA or IIB blood management guideline recommendations. Survey questions assessed hematocrit threshold for transfusion ("hematocrit trigger"), demographic and practice characteristics, years and case-volume of practice, knowledge of transfusion guidelines, and provider attitude regarding perceived risk and safety of blood transfusions. Linear regression models were used to estimate the effect of these variables on transfusion inclination. Mixed effect models were used to quantify the variation attributed to provider specialties and hematocrit triggers. The mean inclination to transfuse was 3.2 (might NOT transfuse) on the survey Likert scale (SD: .86) across vignettes among 202/413 (48.9%) returned surveys. Hematocrit triggers ranged from 15% to 30% (average: 20.4%; SE: .18%). The inclination to transfuse in situations with weak-to-moderate evidence for supporting transfusion was associated with a provider's hematocrit trigger (p < .01) and specialty. Providers believing in the safety of transfusions were significantly more likely to transfuse. Provider specialty and belief in transfusion safety were significantly associated with a provider's hematocrit trigger and likelihood for transfusion. Our findings suggest that blood management interventions should target these previously unaccounted for blood transfusion determinants.

Quality Improvement: Arterial Grafting Redux, 2010:2019.

BACKGROUND: 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. METHODS: 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. RESULTS: 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). CONCLUSIONS: 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.

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.

Evaluating the Impact of Pneumonia Prevention Recommendations After Cardiac Surgery.

BACKGROUND: Pneumonia is the most prevalent healthcare-associated infection after coronary artery bypass grafting (CABG), but the relative effectiveness of strategies to reduce its incidence remains unclear. We evaluated the relationship between healthcare-associated infection recommendations and risk of pneumonia after CABG. METHODS: Pneumonia prevention practice recommendations were developed based on literature review and analysis of semistructured interviews with key health care personnel across centers with low (<5.9%), medium (5.9%-6.1%), and high (>6.1%) rates of pneumonia. These practices were implemented among 2482 patients undergoing CABG from 2016 to 2017 across 18 centers. The independent effect of each practice in reducing pneumonia was assessed using multivariable logistic regression, adjusting for baseline risk and center. A composite (bundle) score was calculated as the number of practices (0 to 4) each patient received. RESULTS: Recommended pneumonia prevention practices included lung protective ventilation management, early extubation, progressive ambulation, and avoidance of postoperative bronchodilator therapy. Pneumonia occurred in 2.4% of patients. Lung protective ventilation (adjusted odds ratio [ORadj], 0.45; 95% confidence interval [CI], 0.22-0.92), ambulation (ORadj, 0.08; 95% CI, 0.04-0.17), and postoperative ventilation of less than 6 hours (ORadj, 0.47; 95% CI, 0.26-0.87) were significantly associated with lower odds of pneumonia. Postoperative bronchodilator therapy (ORadj, 4.83; 95% CI, 2.20-10.7) was significantly associated with higher odds. Risk-adjusted rates of pneumonia, operative mortality, and intensive care unit length of stay were lower in patients with higher bundle scores (all P-trend < .01). CONCLUSIONS: These pneumonia prevention recommendations may serve as effective targets for avoiding postoperative healthcare-associated infections.

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 preintervention period (Q3/2011 through Q3/2012), there was no statistically significant difference in the adjusted odds of pneumonia for STS hospitals participating in the MI-Collaborative compared to the STS non-MI hospitals. However, during the intervention period (Q4/2012 through Q2/2017), there was a significant 2% reduction per quarter in the adjusted odds of pneumonia for MI-Collaborative hospitals (n=33) relative to the STS-nonMI hospitals. There was a significant 3% per quarter reduction in the adjusted odds of pneumonia for the MI-CollaborativeOnly (n=15) hospitals relative to the STS-nonMI hospitals. Over the course of the overall study period, the STS-nonMI hospitals had a 1.96% reduction in risk-adjusted pneumonia (pre- vs. intervention periods), which was less than the MI-Collaborative (3.23%, P=0.011). Over the same time period, the MI-CollaborativePlus (n=18) 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. CLINICAL TRIAL REGISTRATION: URL: https://www.clinicaltrials.gov . Unique identifier: NCT02068716.

Understanding the Association Between Frailty and Cardiac Surgical Outcomes.

BACKGROUND: 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. METHODS: 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. RESULTS: 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. CONCLUSIONS: 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.

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.

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.

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.

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.

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.