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Background Severe obesity (Body Mass Index (BMI) ≥40 kg/m2) is associated with a higher risk of developing severe symptoms and complications of coronavirus disease 19 (COVID-19), independent of other illnesses. Despite this, patients with severe obesity are less likely to receive Veno-Venous Extra Corporeal Membrane Oxygenation (VV-ECMO) support for severe Acute Respiratory Distress Syndrome (ARDS). Given this paradox, we examined the impact of severe obesity on outcomes of adult patients who underwent VV-ECMO implantation for ARDS at our center. Methods We reviewed our ECMO database from May 2013 through May 2020. Adults, who had received VV-ECMO, either in-house or through our mobile ECMO program, were included. We grouped patients into those with BMI ≥40 kg/m2 or not and compared survival at 48 hours, survival to hospital discharge, and hospital length of stay. We conducted multiple logistic and linear regression analyses to analyze the association with categorical and continuous variables, respectively, controlling for patient age, gender, and use of mobile ECMO. Results We identified 112 consecutive adult VV-ECMO patients; median age was 48 (34, 59) years, 61 (54.5%) were male, 56 (50%) were started on ECMO in-house, the median BMI was 31.7 (27.6, 38.8) Kg/ m2; and 23 (20.5%) had a BMI ≥40 kg/m2. Survival at 48 hours and hospital discharge were 69.6% and 61.6%, respectively; and, median hospital length of stay was 20 (9, 33) days. Logistic regression showed no evidence of an association between severe obesity and either 48-hour (OR 1.04, 95% CI 0.37-2.96) or hospital discharge survival (OR 1.06, 95% CI 0.38-2.93). There was, however, a significant correlation between increasing BMI and longer total hospital length of stay (R2 = 0.34; p = 0.0002) which remained significant in linear regression (p = 0.0002) (Figure). Conclusions We found no association between severe obesity and survival at 48-hour and hospital discharge in patients supported on VV-ECMO. Severe obesity was associated with a longer hospital stay, however. Our experience suggests that severe obesity alone should not exclude candidacy for VV-ECMO support.

Background A recent trend favoring donor allocation to sicker patients has led to a rise in the number of patients undergoing heart transplantation (HT) on Extracorporeal membrane oxygenation (ECMO) support. Traditionally, these sick patients in cardiogenic shock were managed with biventricular support while awaiting HT. In this context, we examined short-term survival in patients bridged with biventricular devices (BiVAD) or ECMO in the contemporary era of heart transplantation before the change in the donor allocation strategy. Methods We identified adult patients listed for HT who were bridged with an ECMO or BiVAD between 2000 and 2018 in the Scientific Registry of Transplant Recipients. We compared 30-day and 1-year survival with the Kaplan-Meier method. Using inverse propensity treatment weighting, we constructed doubly-robust Cox proportional hazards regression models to determine the risk-adjusted influence of support type on survival. Results Of the 1495 listings, 868 (58.1%) were bridged with BiVAD and 627 (41.9%) with ECMO. 730 underwent successful HT; 528 (72.3%) and 202 (27.7%) were bridged with BiVAD, or ECMO, respectively. The patients in ECMO group had higher prevalence of pre-transplant ventilator support (30.7% vs 6.3%, p Conclusions A minority of patients on BiVAD and ECMO support underwent HT. Besides, the transplantation rate was disproportionately lower in patients on ECMO support. Patients with heart failure bridged to HT with an ECMO experienced worse short-term post-transplant survival. This observation favors a relook into the current heart transplant allocation strategy.

Background Allosensitization as measured by presence of panel reactive antibodies (PRA) negatively impacts survival in adult heart transplant (HT) recipients. Questions remain whether these trends remain in more contemporary cohorts. We examined the interaction between long-term survival and pre-transplant PRA level in HT recipients from 2000-2018. Methods We identified adult HT recipients between 2000 and 2018 who had a pretransplant PRA in the Scientific Registry of Transplant Recipients. Study cohort was divided into groups with PRA levels; group with 0%, 1-10%, 11-24% and ≥25% PRA levels. We compared 3- and 5-year survival with the Kaplan-Meier method. We constructed Cox proportional hazards regression models to determine the risk adjusted influence of PRA category and PRA as a continuous value on survival. Results We included 24,655 HT recipients. PRA was 0% in 17,391 (70.5%) recipients, 1-10% in 3,331 (13.5%) recipients, 11-24% in 1,330 (5.4%) recipients, and ≥25% in 2,603 (10.6%) recipients. Patients with a PRA ≥25% were younger, had fewer comorbidities, and were more likely to be on ECMO or LVAD prior to HT. Unadjusted 3- and 5-year estimated survival was lower with increasing PRA category (Figure). After risk-adjustment, 5-year survival was higher for the 0% cohort compared to the 1-10% (HR 1.10, 95% CI 1.02-1.18), 11-24% (HR 1.20, 95%CI 1.08-1.34), and ≥25% (HR 1.16, 95% CI 1.07-1.26). When analyzed continuously, increasing PRA was associated with a lower survival (HR 1.003, 95% CI 1.002-1.005). Sensitivity analysis of those transplanted from 2013-2018 showed similar results. Conclusions In this contemporary cohort of HT recipients, increasing pretransplant PRA was associated with lower survival. Given the appreciable portion of HT recipients with elevated PRA, improvements in recipient selection and HT management may help improve outcomes.

Background Longer wait time and poor outcomes after heart transplant (HT) have been reported among blacks and minor ethnic groups. Whether racial disparity exists in the utilization of mechanical circulatory support, waitlist mortality, and HT rates is unknown. Methods We identified the adult patients listed for HT between 2000 and 2018 in the Scientific Registry of Transplant Recipients. Recipient characteristics, including hemodynamic and biochemical variables, are compared between racial groups-blacks, Asians, and others. The patients were followed until death, transplant, or end of data availability. Waitlist mortality and successful HT were compared between racial groups using a Fine and Gray competing risk regression model adjusted for known risk factors. Results Of the 57,285 listings; 43,485 (75.9%) were whites; 11,640 (20.3%) were blacks; 1,547 (2.7%) were Asians and 613 (1.1%) were listed as others. Blacks were significantly younger, had higher BMI, non-ischemic cardiomyopathy, hypertension, renal dysfunction, and dialysis (Table). Although more blacks were listed with LVAD bridge vs. whites, ECMO utilization was significantly lower. In the 37,164 patients who received a successful HT, the median wait time to transplant was lower (p Conclusions Overall, waitlist mortality and successful transplantation rates were similar across racial groups. Black HT candidates were less likely to be bridged with ECMO compared with Whites. Asians had higher transplantation rates while supported on ECMO or IABP.

Background The patients in cardiogenic shock supported with Extracorporeal Membrane oxygenation (ECMO) or non-dischargeable biventricular mechanical support (BiVAD) are more likely to receive heart transplantation (HT) since the donor allocation system was revamped in 2018, to favor sick patients and reduce waitlist mortality. However, the patients' characteristics and outcomes bridged with BiVAD or ECMO and listed for HT in the contemporary era before the policy changed are not explored. Methods We queried the Scientific Registry of Transplant Recipients database for adults listed for HT with BiVAD or ECMO between 2000 and 2018. Recipient characteristics, including hemodynamic and biochemical variables, are compared between groups. The patients were followed until death, transplant, or end of data availability. Waitlist mortality and successful HT were compared using a Fine and Gray competing risk regression model adjusted for known risk factors. Results Of the 1495 patients identified, 868 (58.1%) and 627 (41.9%) were bridged with BiVAD or ECMO. Since 2004, a more significant proportion of patients were on BiVAD, but that trend reversed over the past 5 years with more candidates on ECMO (pTrend Conclusions In recent years, there has been a rise in patients bridged to HT with ECMO. However, patients on ECMO suffered higher waitlist mortality and lower transplantation rates. This could, in part, be explained by the sicker profile of patients on ECMO.

Background Women continue to be under-represented as heart transplant (HT) recipients. Past studies on survival rates following HT and gender have suggested conflicting data. We compare long-term survival between male and female HT recipients in the contemporary heart transplantation era from 2000-2018 using novel methods. Methods We identified adult HT recipients between 2000 and 2018 in the Scientific Registry of Transplant Recipients. Men and women were matched using overlap propensity score weighting. We compared 10-year survival with the Kaplan-Meier method. We constructed doubly-robust Cox proportional hazards regression models to determine the risk-adjusted influence of gender on survival. Models were adjusted for recipient and donor characteristic including IMPACT score and donor-recipient predicted heart mass (PHM) ratio. The proportionality assumption was tested by inspection of Shoenfeld residuals with covariates being converted to time-varying if significant. Results We included 36,606 HT recipients. When compared with men, women tended to be younger, have fewer comorbidities, higher PRA, larger IMPACT score and donor-recipient PHM ratio. Unadjusted 10-year estimated survival was similar between men and women (Figure). After risk-adjustment, women had a similar risk of 10-year survival than men (HR 0.94, 95% CI 0.82-1.02; p=0.0974). When comparing between men and women at 1 (p Conclusions In this contemporary cohort of HT recipients, women had similar long-term survival to men despite an overall lower risk profile and greater likelihood to receive a size mismatched heart.

Purpose Calcineurin inhibitors are a cornerstone of immunosuppression post-orthotopic heart transplantation (OHT). The relationship of tacrolimus exposure, measured by time within therapeutic range (TTR), and level variability, measured by standard deviation (SD) of trough blood levels, to post-OHT acute rejection is unclear. We evaluated if tacrolimus TTR or variability in the 1-year post OHT impacted rejection. Methods This was a single-center, retrospective cohort study of consecutive adult OHT patients receiving standard immunosuppression with tacrolimus, MMF, and prednisone. Tacrolimus TTR was calculated up to 1 year using protocol goal ranges (10-15 ng/mL for months 0-2, 8-12 ng/mL for months 2-6 and 5-10 ng/mL for months 6-12) using the Rosendaal method. The primary outcomes included the association of TTR and level variability with 1-year clinical rejection (defined as any patient receiving ≥ 125 mg of IV methylprednisolone from post-op day 7-365). We analyzed categorical and continuous variables using chi-square and Mann Whitney-U respectively. Time-to-event analysis was conducted for 1-yr clinical rejection using both Kaplan-Meier and Cox Proportional Hazards methods, whereby TTR was calculated until event or censor date and reported using hazard ratio (HR) and 95% confidence interval (CI). Results 78 patients underwent OHT (age, 56.2 ± 12.7 years) with a median 1-yr TTR of 50.2%. Clinical rejection occurred in 31 (39.7%) patients. Those with clinical rejection had a significantly lower median TTR (45.9%) and higher level variability (5.8) than those without rejection (TTR 56.5%, variability 4.9; p=0.021 and p=0.005, respectively) (Figure A&B) . Time to therapeutic tacrolimus level (median 9 days) did not predict 1-year clinical rejection (p=0.274). In a univariable Cox Proportional Hazards Model (median TTR=40%), TTR Figure C ). Five (6.4%) patients died in the first year after OHT. TTR 50% (p=0.018, Figure D ). Conclusions Lower tacrolimus TTR and/or greater level variability predicts clinical rejection and death in the first year after OHT. TTR and and level variability should be monitored in addition absolute levels.