Introduction: There are no guidelines regarding the use of bovine pericardial or porcine valves for aortic valve replacement, and prior studies have yielded conflicting results. The current study sought to compare short- and long-term outcomes in propensity-matched cohorts of patients undergoing isolated AVR with bovine versus porcine valves. Methods: This was a retrospective study utilizing an institutional database of all isolated bioprosthetic surgical aortic valve replacements performed at our center from 2010 to 2020. Patients were stratified according to type of bioprosthetic valve (bovine pericardial or porcine), and 1:1 propensity-score matching was applied. Kaplan-Meier survival estimation and multivariable Cox regression for mortality were performed. Cumulative incidence functions were generated for all-cause readmissions and aortic valve reinterventions. Results: A total of 1,502 patients were identified, 1,090 (72.6%) of whom received a bovine prosthesis and 412 (27.4%) of whom received a porcine prosthesis. Propensity-score matching resulted in 412 risk-adjusted pairs. There were no significant differences in clinical or echocardiographic postoperative outcomes in the matched cohorts. Kaplan-Meier survival estimates were comparable, and, on multivariable Cox regression, valve type was not significantly associated with long-term mortality (HR 1.02, 95% CI: 0.74, 1.40, p=0.924). Additionally, there were no significant differences in competing-risk cumulative incidence estimates for all-cause readmissions (p=0.68) or aortic valve reinterventions (p=0.25) in the matched cohorts. Conclusion: The use of either bovine or porcine bioprosthetic aortic valves yields comparable postoperative outcomes, long-term survival, freedom from reintervention, and freedom from readmission.

Background: While prior data have suggested worse outcomes in women after acute type A aortic dissection (ATAAD) repair when compared to men, results have been inconsistent across studies over time. This study sought to evaluate the impact of sex on short- and long-term outcomes after ATAAD repair. Methods: This was a retrospective study utilizing an institutional database of ATAAD repairs from 2007 to 2021. Patients were stratified according to sex. Kaplan-Meier survival estimation and multivariable Cox regression were performed. Supplementary analysis using propensity score matching was also performed. Results: Of the 601 patients who underwent ATAAD repair, 361 were males (60.1%) and 240 (39.9%) were females. Females were significantly older, more likely to have hypertension, and more likely to have chronic lung disease. Females were also significantly more likely than males to undergo hemiarch replacement, while males were significantly more likely than females to undergo total arch replacement and frozen elephant trunk. Operative mortality was 9.4% among males and 13.8% among females, though this was not a statistically significant difference (p=0.098). Postoperative complications were comparable between groups. Kaplan-Meier survival estimates were similar for men and women, and, on multivariable Cox regression, sex was not significantly associated with long-term survival (HR 1.00, 95% CI: 0.73, 1.37, p=0.986). Outcomes remained comparable after supplementary propensity score matched analysis. Conclusion: ATAAD repair can be performed with comparable short-term and long-term outcomes in both men and women.

Introduction Thoracic endovascular aortic repair (TEVAR) became the standard of care for treating type B aortic dissections and descending thoracic aortic aneurysms. We aimed to describe the racial/ethnic differences in TEVAR utilization and outcomes. Methods The National Inpatient Sample was reviewed for all TEVARs performed between 2010 and 2017 for Type B aortic dissection and descending thoracic aortic aneurysm (DTAA). We compared groups stratifying by their racial/ethnicity background in whites, black, Hispanic, and others. A mixed-effects logistic regression was performed to assess the relationship between race/ethnicity and the primary outcome, in-hospital mortality. Results A total of 25,260 admissions for TEVAR during 2010–2017 were identified. Of those, 52.74% (n= 13,322) were performed for aneurysm and 47.2% (n= 11,938) were performed for type B dissection. 68.1% were white, 19.6% were black, 5.7% Hispanic, and 6.5% were classified as others. White patients were the oldest (median age 71 years; <0.001), with TEVAR being performed electively more often for aortic aneurysm (58.8% vs. 34% vs. 48.3% vs. 48.2%; p<0.001). In contrast, TEVAR was more likely urgent or emergent for type B dissection in black patients (65.6% vs 41.1% vs 51.6% vs 51.7%; p<0.001). Finally, the black population showed a relative increase in the incidence rate of TEVAR over time. The adjusted multivariable model showed that race/ethnicity was not associated with in-hospital mortality. Conclusion Although there is a differential distribution of thoracic indication and comorbidities between race/ethnicity in TEVAR, racial disparities do not appear to be associated with in-hospital mortality after adjusting for covariates.

Objective The Model for End- Stage Liver Disease (MELD) score is a composite number of physiologic parameters and likely has non-linear effects on operative outcomes. . We use machine learning to evaluate the relationship between MELD score and outcomes of cardiac surgery. Methods All STS indexed elective cardiac surgical procedures at our institution between 2011 and 2018 were included. MELD score was retrospectively calculated. Logistic regression models and an imbalanced random forest classifier was created on operative mortality using 30 preoperative characteristics. Cox regression models and random forest survival models were created for long-term survival. Variable importance analysis (VIMP) was conducted to rank variables by predictive power. Linear and machine learned models were compared with their receiver operating characteristic (ROC) and Brier score respectively. Results The patient population included 3,872 individuals. Operative mortality was 1.7% and 5-year survival was 82.1%. MELD score was the 4th largest positive predictor on VIMP analysis for both operative long-term survival and the strongest negative predictor for operative mortality. The logistic model ROC area was 0.762, compared to the random forest classifier ROC of 0.674. The Brier score of the random forest survival model was larger (worse) than the cox regression starting at 2 years and continuing throughout the study period. Conclusions MELD score and other continuous variables had high degrees of non-linearity to mortality. This is demonstrated by the fact that MELD score was not significant in the cox multivariable regression but was strongly important in the random forest survival model.

Background: The introduction of integrated thoracic surgery residency programs has led to increased recruitment efforts of medical students to pursue a career in cardiac surgery. With little representation of cardiac surgery in medical school curriculum, we assessed a cardiac surgery mini-elective’s efficacy in improving perceived knowledge among medical students. Methods: Preclinical medical students were offered the opportunity to participate in a cardiac surgery mini-elective, which consisted of five 2-hour sessions. These sessions consisted of didactic and simulation components and covered topics including cardiopulmonary bypass (CPB) and extracorporeal membrane oxygenation (ECMO), aortic disease, aortic valve replacement (AVR), transplant and left ventricular assist devices (LVAD), and coronary artery bypass grafting (CABG). Students completed pre- and post-session survey’s describing their perceived knowledge in these topics. Results: Overall, 22 students completed at least one session of the mini-elective. Fourteen (73.7%) of the students were male. Fifteen (68.2%) students completed at least three out of five sessions. The post-session survey responses showed significantly higher perceived knowledge compared to pre-session responses for all survey prompts of all five sessions. The CPB/ECMO and aortic disease sessions showed the greatest increase in post-session familiarity and perceived knowledge after the session (p<0.001) compared to the CABG, AVR, and transplant/LVAD sessions (p<0.05). Conclusions: Beyond developing interest in cardiac surgery, these data indicate that a well-planned didactic and surgical simulation program may build confidence in students’ knowledge of various cardiac surgical topics. Further studies will need to address how this increase in perceived ability lasts over time and impacts career selection.

Background: This study investigated the impact of transplanting center donor acceptance patterns on usage of extended-criteria donors (ECDs) and posttransplant outcomes following orthotopic heart transplantation (OHT). Methods: The Scientific Registry of Transplant Recipients was queried to identify heart donor offers and adult, isolated OHT recipients in the United States from 1/1/2013-10/17/2018. Centers were stratified into 3 equal-size terciles based on donor heart acceptance rates (<13.7%, 13.7%-20.2%, >20.2%). Overall survival was compared between recipients of ECDs (≥40 years, left ventricular ejection fraction <60%, distance ≥500 miles, hepatitis B, hepatitis C or human immunodeficiency virus, or ≥50 offers) and recipients of traditional-criteria donors, and among transplanting terciles. Results: A total of 85,505 donor heart offers were made to 133 centers with 15,264 (17.9%) accepted for OHT. High-acceptance programs (>20.2%) more frequently accepted donors with LVEF <60%, HIV, HCV, and/or HBV, ≥50 offers, or distance >500 miles from the transplanting center (each p<0.001). Posttransplant survival was comparable across all three terciles (p=0.11). One- and five-year survival were also similar across terciles when examining recipients of all five ECD factors. Acceptance tier and increasing acceptance rate were not found to have any impact on mortality in multivariable modeling. Of ECD factors, only age ≥40 years was found to have increased hazards for mortality (HR 1.33, 95% CI 1.22-1.46, p<0.001). Conclusions: Of recipients of ECD hearts, outcomes are similar across center-acceptance terciles. Educating less aggressive programs to increase donor acceptance and ECD utilization may yield higher national rates of OHT without major impact on outcomes.

Background: This study evaluated the impact of various sizing metrics on outcomes of female donor to male recipient orthotopic heart transplantation (OHT). Methods: We queried the United Network of Organ Sharing database to analyze all isolated, primary adult OHTs from 1/12010-3/20/2020. Patients were stratified by donor-recipient sex pairing. Logistic regression was used to investigate risk-adjusted effects of current size matching criteria (weight ratio, body mass index (BMI) ratio, predicted heart mass (pHM) ratio) on one-year post-transplant mortality. Kaplan-Meier analysis was used to compare posttransplant survival among cohorts. Results: A total of 22,450 patients were analyzed, of which 3,019 (13.4%) underwent female-to-male transplantation. Of sex-matched pairs, female-to-male donation had the lowest proportion of undersized hearts using weight and BMI ratio metrics (10.5% and 5.2%) but had the highest proportion of undersizing using pHM metrics (48.1%) (all P<0.001). Female-to-male recipients had the lowest rate of unadjusted one-year survival (90.0%, P = 0.0169), and increased hazards of mortality after risk adjustment (OR 1.17, 95% CI 1.01-1.36, P=0.034)). Undersizing using pHM (donor-recipient ratio < 0.85) was the only metric found to be associated in increased mortality after risk adjustment (OR 1.32, 95% CI 1.02 to 1.71, P=0.035). Conclusions: Female-to-male heart transplantation has the worst survival of all sex-matching combinations. Although female donors in this cohort are appropriately sized using traditional metrics, half are under-sized using pHM. This, combined with its strong association with mortality, underscores the importance of routine pHM assessment when evaluating female donors for male recipients.

Background: This study evaluated outcomes of cardiac operations with very prolonged cardiopulmonary bypass (CPB) times. Methods: This was a retrospective study of cardiac surgical procedures with very-long CBP times (≥300 minutes) performed at a single institution. Primary outcomes of operative (≤30-day) and one-year mortality were evaluated, and secondary outcomes included use of mechanical support and postoperative complications. A probability analysis was also conducted to identify the correlation between operative mortality and CPB time. Results: 293 patients were included with a Society of Thoracic Surgeons predicted risk of mortality of 2.51% (IQR 1.32%- 4.70%), and median CPB time of 340 minutes (IQR 315.0-385.0). Preoperative mechanical support included intra-aortic balloon pump (IABP, n=4, 1.4%), Impella (n=0), or extracorporeal membrane oxygenation (ECMO, n=2, 0.7%). Intraoperative and operative mortality were 5.1% and 22.5%, respectively. Intraoperative or postoperative mechanical support were utilized in 90 (30.7%) cases, including IABP (n=65, 22.2%), Impella (n=2, 0.68%), or ECMO (n=23, 7.8%). Postoperative complications included prolonged mechanical ventilation (n=121, 41.3%), renal failure (n=71, 24.2%), stroke (n=20, 6.8%), and reoperation (n=95, 32.4%). One-year survival for the overall cohort was 61.4%. Probability analysis identified a CPB time of 446 minutes to be associated with 50% odds of operative mortality. Conclusions: Cardiac operations requiring very-long CPB times are associated with high rates of operative mortality and morbidity, with a 50% operative mortality rate predicted for those with a CPB time of 446 minutes or longer. Nonetheless, the majority of patients survive at least 1 year, and these cases should not be considered futile.

Background: This study evaluates the impact of peak preoperative troponin level on outcomes of coronary artery bypass grafting (CABG) for non-ST-elevation myocardial infarction (NSTEMI). Methods: This was a retrospective review of patients undergoing isolated CABG from 2011-2018 with presentation of NSTEMI. Patients were stratified into low- and high-risk groups based on median preoperative peak troponin (1.95ng/dL). Major cardiac and cerebrovascular events (MACCE) and mortality were compared. Multivariable analysis was performed to model risk factors for MACCE and mortality. Results: This study included 1,211 patients, 607 low- (≤1.95ng/dL) and 604 high-risk (>1.95ng/dL). Patients were well-matched with respect to age and comorbidity. High-risk patients had lower median preoperative ejection fraction (46.5% [IQR 35.0%-55.0%] vs 53.0% [IQR 40.0%-58.0%]) and higher incidence of preoperative intra-aortic balloon pump (15.9% vs 8.73%). Intensive care unit (47 hours [IQR 26-82] vs 43 hours [IQR 25-69]) and hospital lengths of stay (10 days [IQR 8-13] vs 9 days [IQR 8-12]) were longer in the high-risk group (each P<0.05). Postoperative complications and thirty-day, one- and five-year rates of both MACCE and survival were similar between groups. Peak troponin >1.95ng/dL was not associated with increased hazards for MACCE, mortality, or readmission in multivariable modeling. In sub-analyses, neither increasing troponin as a continuous variable nor peak troponin >10.00ng/mL were associated with increased hazards for these outcomes. Conclusions: Higher preoperative troponin levels are associated with longer lengths of stay but not MACCE or mortality following CABG. Dictating timing of CABG for NSTEMI based on peak troponin does not appear to be warranted.

Background: Cardiogenic shock is a known risk factor for early mortality following conventional cardiac surgery, however its impact on longitudinal outcomes is less established. This study evaluated longer-term outcomes of conventional cardiac surgery in patients with cardiogenic shock. Methods: This was a retrospective review of conventional cardiac operations performed in patients presenting with cardiogenic shock between 2010 and 2020. The primary outcome was survival, and secondary outcomes included postoperative complications, and rates of heart failure readmission. Multivariable Cox proportional hazards modeling was conducted to identify risk-adjusted predictors of mortality. Results: 604 patients were included, representing 4% of all cardiac cases. Median follow up was 4.3 (IQR 0.3-6.8) years. Aortic root repair/replacement (31.6%) was most commonly performed. 11.1% of patients required preoperative cardiopulmonary resuscitation. Bridging modalities included intravenous inotropes (35.4%), intra-aortic balloon pump (33.4%), Impella (0.5%), or venoarterial extracorporeal membrane oxygenation (3.3%). Operative mortality was 21.5%. Complications included reoperation (24.3%), stroke (15.9%) renal failure (19.2%), and prolonged ventilation (47.9%). Unadjusted 1- and 5-year survival were 71.7% and 62.1%. Risk-adjusted preoperative predictors for mortality included peripheral vascular disease (HR 1.75, 95% CI 1.23-2.49), dialysis dependency (HR 6.30, 95% CI 3.77–10.51) and increasing age (HR 1.02, 95% CI 1.02–1.04). Three patients eventually underwent ventricular assist device implantation and no patients underwent heart transplantation. Conclusions: Despite high initial rates of morbidity and mortality following conventional cardiac surgery in patients presenting with cardiogenic shock, 62% survive to 5 years and most do not require heart failure readmission or advanced heart failure surgical therapy.

Background: This study compared outcomes of patients bridged with extracorporeal membrane oxygenation (ECMO) to orthotopic heart transplantation (OHT) following the recent heart allocation policy change. Methods: The United Network of Organ Sharing Registry (UNOS) database was queried to examine OHT patients between 2010-2020 that were bridged with ECMO. Waitlist outcomes and one-year posttransplant survival were compared between patients waitlisted and/or transplanted before and after the heart allocation policy change. Secondary outcomes included posttransplant stroke, renal failure, and one-year rejection. Results: 285 waitlisted patients were included, 173 (60.7%) waitlisted under the old policy and 112 (39.3%) under the new policy. New policy patients were more likely to receive OHT (82.2% vs 40.6%), and less likely to be removed from the waitlist due to death or clinical deterioration (15.0% vs 41.3%) (both P<0.001). 165 patients bridged from ECMO to OHT were analyzed, 72 (43.6%) transplanted during the old policy and 93 (56.3%) under the new. Median waitlist time was reduced under the new policy (4 days [IQR 2-6] vs 47 days [IQR 10-228]). Postoperative renal failure was higher in the new policy group (23% vs 6%; P=0.002), but rates of stroke and one-year acute rejection were equivalent. One-year survival was lower the new policy but was not significant (79.8% vs 90.3%; P=0.3917). Conclusions: The UNOS heart allocation policy change has resulted in decreased waitlist times and higher likelihood of transplant in patients supported with ECMO. Posttransplant one-year survival has remained comparable although absolute rates are lower.

Objectives: Though guidelines are set by the American Board of Thoracic Surgery for the operative cases that cardiothoracic surgery residents must perform to be board-eligible, no such recommendations exist to assess competency for the wide range of high-risk bedside procedures. Our department created and implemented a multi-disciplinary developed course designed to standardize common high-risk bedside procedures and credential our residents. The aim of this study was to survey the attitudes of residents to and query the efficacy of such a course. Methods: The course was designed with the goal of standardizing endotracheal intubation, arterial line insertion (radial and femoral), central venous line insertion, pigtail tube thoracostomy and nasogastric tube placement. The course consisted of an online module followed by a 4-hour hands on simulation session. Knowledge based pre and post evaluations were administered as well as Likert based survey regarding multiple aspects of the residents’ perceptions of the course and the procedures. Results: Twenty-three (7 traditional and 16 integrated) cardiothoracic surgical residents participated in the course. Residents reported that 48% of the time, bedside procedures were historically taught by other trainees rather than faculty. All residents endorsed increased standardization of all procedures after the course. Likewise, residents showed increased confidence in all procedures except for pigtail and thoracentesis as well as nasogastric tube placement. 43.5% of the participants demonstrated improvement in the pre and post-test knowledge-based evaluations. ConclusionCardiothoracic residents have favorable attitudes towards standardization and credentialing for high risk bedside procedures and utilizing such courses may help standardize procedural techniques.