Donor utilization in heart transplant with donation after circulatory death in the United States.

Heart transplantation using donation after circulatory death (DCD) was recently adopted in the United States. This study aimed to characterize organ yield from adult (≥18 years) DCD heart donors in the United States using the United Network for Organ Sharing registry. The registry does not identify potential donors who do not progress to circulatory death, and only those who progressed to death were included for analysis. Outcomes included organ recovery from the donor operating room and organ utilization for transplant. Multiple logistic regression was used to identify predictors of heart recovery and utilization. Among 558 DCD procurements, recovery occurred in 89.6%, and 92.5% of recovered hearts were utilized for transplant. Of 506 DCD procurements with available data, 65.0% were classified as direct procurement and perfusion and 35.0% were classified as normothermic regional perfusion (NRP). Logistic regression identified that NRP, shorter agonal time, younger donor age, and highest volume of organ procurement organizations were independently associated with increased odds for heart recovery. NRP independently predicted heart utilization after recovery. DCD heart utilization in the United States is satisfactory and consistent with international experience. NRP procurements have a higher yield for DCD heart transplantation compared with direct procurement and perfusion, which may reflect differences in donor assessment and acceptance criteria.

Trends and Outcomes of Combined Heart-Kidney and Heart-Lung Transplantation Over the Past Two Decades.

INTRODUCTION: Combined heart-kidney transplantation (HKTx) and combined heart-lung transplantation (HLTx) remain the definitive therapy for patients with end-stage heart failure with concomitant end-stage renal or lung failure. We sought to study trends and outcomes of HKTx and HLTx over the last two decades. METHODS: The United Network for Organ Sharing registry was used to identify all adult patients (aged >18 y) who underwent HKTx and HLTx between 2001 and 2021. Patients were divided into 5-y groups by the year of transplantation (2001-2006, 2007-2011, 2012-2016, and 2017-2021). Primary outcome was 1-y posttransplantation mortality. Kaplan-Meier and multivariable Cox proportional hazards models were used for unadjusted and risk-adjusted survival analyses, respectively. RESULTS: A total of 2301 HKTx and 567 HLTx patients were included. Between 2001 and 2021, HKTx volume increased from 25 to 344 patients (P < 0.001) and centers performing HKTx increased from 19 to 76 (P < 0.001). On unadjusted analysis, 1-y survival after HKTx improved from 86.7% in 2001-2006 to 89.0% in 2017-2021 (log-rank, P = 0.005). On risk-adjusted analysis, the hazard ratio of 1-y mortality for 2017-2021 was 0.62 (0.39-1.00, P = 0.048) compared with that for 2001-2006. Between 2001 and 2021, HLTx volume increased from 21 to 43 patients (P < 0.001) and centers performing HLTx increased from 12 to 20 (P = 0.047). On unadjusted analysis, 1-y survival after HLTx improved from 68.9% in 2001-2006 to 83.9% in 2017-2021 (log-rank, P = 0.600). On risk-adjusted analysis, the hazard ratio of 1-y mortality for 2017-2021 was 0.37 (0.21-0.67, P = 0.001) compared with that for 2001-2006. CONCLUSIONS: Over the last two decades, HKTx volume substantially increased and HLTx experienced resurgent growth. One-year survival persistently improved for both procedures, especially over the past 5 y.

Heart Transplantation for Adults With Congenital Heart Disease Can Be Performed at Adult or Pediatric Hospitals With Comparable Outcomes.

INTRODUCTION: The goal of this study was to evaluate the relationship between hospital-related factors and hospital type on outcomes of heart transplantation for patients with adult congenital heart disease (ACHD). METHODS: Patients with ACHD who underwent heart transplant between 2010 and 2021 were identified using the United Network for Organ Sharing data registry. The primary outcome was post-transplant mortality. Kaplan-Meier unadjusted survival curves were compared using the log-rank test. Multivariable Cox proportional hazard models were used for risk-adjustment in evaluating the independent effect of hospital type on post-transplant mortality. RESULTS: Of 70 centers, 54 (77.1%) adult centers performed 415 (87.0%) heart transplants and 16 (22.9%) pediatric centers performed 62 (13.0%) heart transplants. Patients transplanted at pediatric centers were younger, had lower creatinine levels, and had lower body mass index. The unadjusted 1-y and 5-y survival was comparable in pediatric versus adult centers, respectively: 93.4% versus 86.6% (log-rank P = 0.16) and 87.4% versus 73.9% (log-rank P = 0.06). These findings persisted after risk-adjustment. One-year mortality hazard ratio for pediatric hospitals: 0.64 (0.22-1.89, P = 0.416) and 5-y mortality hazard ratio for pediatric hospitals: 0.53 (0.21-1.33, P = 0.175). Rates of acute rejection, postoperative stroke, and new-onset postoperative dialysis were also comparable. CONCLUSIONS: Heart transplantation for patients with ACHD can be performed safely in adult centers. The majority of heart transplant for ACHD in the United States are performed at adult hospitals. However, further research is needed to delineate the impact of individual surgeon characteristics and hospital-related factors on outcomes.

Waitlist and Transplant Outcomes in Organ Donation After Circulatory Death: Trends in the United States.

OBJECTIVES: To summarize waitlist and transplant outcomes in kidney, liver, lung, and heart transplantation using organ donation after circulatory death (DCD). BACKGROUND: DCD has expanded the donor pool for solid organ transplantation, most recently for heart transplantation. METHODS: The United Network for Organ Sharing registry was used to identify adult transplant candidates and recipients in the most recent allocation policy eras for kidney, liver, lung, and heart transplantation. Transplant candidates and recipients were grouped by acceptance criteria for DCD versus brain-dead donors [donation after brain death (DBD)] only and DCD versus DBD transplant, respectively. Propensity matching and competing-risks regression was used to model waitlist outcomes. Survival was modeled using propensity matching and Kaplan-Meier and Cox regression analysis. RESULTS: DCD transplant volumes have increased significantly across all organs. Liver candidates listed for DCD organs were more likely to undergo transplantation compared with propensity-matched candidates listed for DBD only, and heart and liver transplant candidates listed for DCD were less likely to experience death or clinical deterioration requiring waitlist inactivation. Propensity-matched DCD recipients demonstrated an increased mortality risk up to 5 years after liver and kidney transplantation and up to 3 years after lung transplantation compared with DBD. There was no difference in 1-year mortality between DCD and DBD heart transplantation. CONCLUSIONS: DCD continues to expand access to transplantation and improves waitlist outcomes for liver and heart transplant candidates. Despite an increased risk for mortality with DCD kidney, liver, and lung transplantation, survival with DCD transplant remains acceptable.

Impact of Donor Hemodynamics on Recipient Survival in Heart Transplantation.

BACKGROUND: Heart transplantation is the gold-standard therapy for end-stage heart failure, but rates of donor-heart use remain low due to various factors that are often not evidence based. The impact of donor hemodynamics obtained via right-heart catheterization on recipient survival remains unclear. METHODS: The United Network for Organ Sharing registry was used to identify donors and recipients from September 1999-December 2019. Donor hemodynamics data were obtained and analyzed using univariate and multivariable logistical regression, with the primary endpoints being 1- and 5-year post-transplant survival. RESULTS: Of the 85,333 donors who consented to heart transplantation during the study period, 6573 (7.7%) underwent right-heart catheterization, of whom 5531 eventually underwent procurement and transplantation. Donors were more likely to undergo right-heart catheterization if they had high-risk criteria. Recipients who had donor hemodynamic assessment had 1- and 5-year survival rates similar to those without donor hemodynamic assessment (87% vs 86%, 1 year). Abnormal hemodynamics were common in donor hearts but did not impact recipient survival rates, even when risk-adjusted in multivariable analysis. CONCLUSIONS: Donors with abnormal hemodynamics may represent an opportunity to expand the pool of viable donor hearts.

Outcomes in Patients With LVADs Undergoing Simultaneous Heart-Kidney Transplantation.

BACKGROUND: Multiple studies have shown better outcomes for simultaneous heart-kidney transplant (sHKT) than for isolated orthotopic heart transplant (iOHT) in recipients with chronic kidney disease (CKD). However, outcomes in patients supported by durable left ventricular assist devices (LVADs) have not been well studied. METHODS: Patients with durable LVADs and stage 3 or higher CKD (eGFR < 60 mL/min/1.73 m2) undergoing iOHT or sHKT between 2008 and 2020 were identified from the United Network for Organ Sharing registry. A Kaplan-Meier survival analysis with associated log-rank test was conducted to compare post-transplant survival rates. Multivariable modeling was used to identify risk-adjusted predictors of 1 year post-transplant mortality. RESULTS: We identified 4375 patients; 366 underwent sHKT, and 4009 underwent iOHT. The frequency of sHKT increased during the study period. The 1-year post-transplant survival rate was worse in patients after sHKT than in patients after iOHT (80.3% vs 88.3%; P < 0.001) and persisted up to 5 years post-transplant (P = 0.001). sHKT recipients were more likely to require dialysis after transplantation and had longer hospital lengths of stay (P < 0.001). Multivariable analysis showed that sHKT remained an independent risk factor for mortality at 1 year (OR 1.58; P = 0.002). CONCLUSIONS: sHKT is becoming more common in patients with durable LVADs. Compared with iOHT, patients with sHKTs have worse short- and long-term survival rates and are more likely to require post-transplant dialysis.

Revascularization Strategies for Multivessel Coronary Artery Disease in the Elderly Population.

BACKGROUND: Prospective trials comparing coronary artery bypass grafting (CABG) with percutaneous coronary intervention (PCI) for the treatment of multivessel coronary disease (MVCAD) have included mostly younger patients. We compared treatment strategies in the elderly population. MATERIALS AND METHODS: We performed a propensity-score-matched comparison of patients ≥75 y who underwent isolated CABG or PCI for MVCAD between 2011 and 2018, excluding those with prior cardiac surgery and/or significant left main disease. The primary outcome was 5-year Kaplan Meier survival, and secondary outcomes included readmissions and major adverse cardiovascular and cerebrovascular events (MACCE). RESULTS: Propensity-matching yielded 536 patients (266 PCI and 266 CABG). Rates of complete revascularization of all stenotic lesions were higher in the CABG arm (86.8% versus 21.8%; P < 0.001). Thirty-d mortality was similar between cohorts, though PCI recipients had shorter hospital stay and greater likelihood of discharge to home. Unadjusted one- (89.1% versus 88.4%) and 5-year (73.8% versus 60.1%) survival were both higher in patients who underwent CABG (P = 0.0332). Patients undergoing CABG had reduced, but nonsignificant cumulative incidence of all-cause hospital readmission and MACCE at 5 y. Subgroup analysis of patients 80 y or older revealed similar late survival benefit with CABG when compared to PCI. Among patients undergoing CABG, there did not appear to be any 5-year benefits from multi-arterial grafting. CONCLUSIONS: Despite longer hospitalization and higher rate of nonhome discharge, CABG was associated with improved late survival over PCI in the elderly population. Cardiac surgeons should be included in the multidisciplinary evaluation of older patients with MVCAD.

Midterm Outcomes of Isolated Coronary Artery Bypass Grafting in the Setting of Moderate Ischemic Mitral Regurgitation.

INTRODUCTION: Although randomized trial data exist for 2-y outcomes comparing isolated coronary artery bypass grafting (CABG) versus CABG with concomitant mitral valve repair (CABG + MVr) for the treatment of moderate ischemic mitral regurgitation (IMR), longer term outcomes are unclear. This study evaluated the longitudinal outcomes of isolated CABG for moderate IMR. METHODS: Patients with moderate IMR undergoing isolated CABG from January 2010 to February 2018 at a single institution were included. Outcomes included longitudinal freedom from heart failure readmission, survival, rates of persistent mitral regurgitation (MR), and freedom from mitral valve reinterventions. A subanalysis was conducted comparing CABG versus CABG + MVr. Multivariable Cox regression was used for risk adjustment. RESULTS: A total of 528 patients with moderate IMR underwent isolated CABG. Postoperatively, 26% of patients had at least moderate MR at 1-mo follow-up, although at 5 y progression to severe MR was rare (2.2%) as were mitral valve reinterventions (0.2%). Survival at 30 d (95.8%), 1 y (89.6%), and 5 y (76.6%) was acceptable. Furthermore, the freedom from readmission for heart failure was also acceptable at 30 d (92.6%), 1 y (79.9%), and 5 y (65.0%) postoperatively. In a subanalysis comparing CABG versus CABG + MVr, unadjusted and risk-adjusted survival, freedom from heart failure readmissions, mitral valve reinterventions, and degrees of MR were comparable between the groups at all intervals (all P > 0.05). CONCLUSIONS: The majority of patients with moderate IMR can undergo isolated CABG with acceptable rates of heart failure readmissions, survival, progression to severe MR, and the need for subsequent mitral interventions. These data support the use of isolated CABG in patients with moderate IMR.

Charlson Comorbidity Index is Associated With Longer-Term Mortality and Re-Admissions Following Coronary Artery Bypass Grafting.

INTRODUCTION: The Charlson Comorbidity Index (CCI) is widely utilized for risk stratification by providers, payors, and administrative database researchers for non-cardiac surgical patients. CCI scores have not been validated in cardiac surgical patients. We hypothesize that the CCI will predict mid-term mortality and re-admissions, but performance may be different than purpose-built cardiac surgery risk calculators. METHODS: Patients undergoing isolated CABG between 2011 and 2017 were reviewed. Age-adjusted CCI scores were calculated based on clinical status at a time of index operation using prospectively captured data from institutional databases. Primary endpoint was 5-year mortality and 1-year re-admissions. The CCI, STS predicted mortality, and ASCERT 5-year mortality scores were compared in a sub-cohort of 500 patients. Patients underwent analysis using Cox Proportional Hazard ratios, Kaplan-Meier analysis, and ROC comparisons. RESULTS: Average CCI score for the overall population (n = 6064) was 3.40 ± 1.75. Kaplan-Meier analysis revealed significant difference in mortality stratified by CCI. Hazard ratio for 5-year mortality increased with each interval increase in CCI score value (HR 1.38 [1.33-1.43], P < 0.001), as did the risk of 1-year re-admission (HR 1.19 [1.15-1.22], P < 0.001). ROC curves for CCI, STS mortality, and ASCERT 5-year mortality risk demonstrate that all three scores are predictive at 5 y, but the ASCERT score performs best (ROC 0.76 versus 0.69, P = 0.004). CONCLUSIONS: The CCI can serve as a useful mid-term risk stratification tool in patients undergoing CABG when variables for the purpose-built STS and ASCERT scores are unavailable. However, the ASCERT score performs better at 5-year mortality calculation.

Fate of the Kidneys in Patients with Post-Operative Renal Failure After Cardiac Surgery.

BACKGROUND: This study evaluates the clinical and renal-related outcomes in patients with acute renal failure (ARF) following cardiac surgery. METHODS: Index adult cardiac operations at a single institution from 2010-2018 were reviewed. Patients requiring dialysis pre-operatively were excluded. ARF was stratified as either creatinine rise (≥3-times baseline or ≥4.0 mg/dL) or post-operative dialysis. Outcomes included mortality, rates of progression to dialysis, and renal recovery. Multivariable Cox regression was used for risk-adjustment. RESULTS: A total of 10,037 patients, including 6,275 (62.5%) isolated coronary artery bypass grafting (CABG), 2,243 (22.3%) isolated valve, and 1,519 (15.1%) CABG plus valve cases, were included. Post-operative ARF occurred in 346 (3.5%) patients, with 230 (66.5%) requiring dialysis. Survival was significantly reduced in patients with ARF at 30-days (97.9 versus 70.8%, P <0.001), 1-year (94.9 versus 48.0%, P <0.001), and 5-years (86.2 versus 38.2%, P <0.001) with more profound reductions in those requiring dialysis, findings which persisted after risk-adjustment. Progression to subsequent dialysis in the creatinine rise group was rare (n = 1). The median time to dialysis initiation in the dialysis group was 5 days (IQR 2-12 days) with a median time of dialysis dependence of 72 days (IQR 38-1229 days). Of those patients requiring postoperative dialysis, 30.9% demonstrated renal recovery. CONCLUSIONS: Post-operative ARF and in particular the need for dialysis are associated with substantial reductions in survival that persist during longitudinal follow-up. This occurs despite the finding that patients experiencing creatinine rise only rarely progress to dialysis, and that nearly one-third of patients requiring post-operative dialysis recover renal function.

National trends and outcomes of heart-kidney transplantation using hepatitis C positive donors.

BACKGROUND: This study evaluated the outcomes of combined heart-kidney transplantation in the United States using hepatitis C positive (HCV+) donors. METHODS: Adults undergoing combined heart-kidney transplantation from 2015 to 2020 were identified in the United Network for Organ Sharing registry. Patients were stratified by donor HCV status. Kaplan-Meier curves with multivariable Cox regression models were used for risk-adjustment in a propensity-matched cohort. RESULTS: A total of 950 patients underwent heart-kidney transplantation of which 7.8% (n = 75) used HCV+ donors; 68% (n = 51) were viremic and 32% (n = 24) were non-viremic donors. Unadjusted 1-year recipient survival was similar between HCV+ versus HCV- donors (84% vs 88%, respectively; P = .33). Risk-adjusted analysis in the propensity-matched cohort showed HCV+ donor use did not confer increased risk of 1-year mortality (hazard ratio .63, 95% CI .17-2.32; P = .49). Sub-group analysis showed viremic and non-viremic HCV+ donors had similar 1-year survival as well (84% vs 84%; P = .95). CONCLUSIONS: Compared with recipients of HCV- donor dual heart-kidney transplants, recipients of HCV+ organs had comparable 1-year survival and clinical outcomes after combined transplantation. Although future studies should evaluate other outcomes related to HCV+ donor use, this practice appears safe and should be expanded further in the heart-kidney transplant population.

HVAD versus heartmate III bridge to heart transplantation: Waitlist and posttransplant outcomes.

BACKGROUND: This study compared outcomes of patients bridged with either the Heartware HVAD or Heartmate 3 (HM3) device to orthotopic heart transplantation (OHT). METHODS: The United Network of Organ Sharing registry was queried to perform two separate analyses of adult, isolated OHT candidates bridged with HVAD or HM3. First, waitlist outcomes were compared among patients waitlisted 1/1/2015-3/20/2020. Second, posttransplant survival was compared among those transplanted 1/1/2015-3/20/2020. RESULTS: Two thousand two hundred fifty-five candidates were waitlisted within the study period, 1587 (70.4%) bridged with HVAD and 668 (29.6%) with HM3. At 1 year from waitlisting, cumulative incidence of OHT higher in the HVAD cohort (p < .001). During the same time period, 2643 patients underwent OHT, 2154 (81.5%) with prior HVAD and 489 (18.5%) with HM3. Yearly proportions of patients bridged with HM3 increased across the study period and decreased for HVAD (p < .001). HM3-bridged recipients had shorter waitlist times, longer graft cold ischemic times, and experienced a higher rate of posttransplant dialysis requirement. Unadjusted and risk-adjusted posttransplant mortality rates were similar between both groups. CONCLUSIONS: Posttransplant survival is equivalent regardless of device type used for bridging. However, HM3 patients had lower likelihood of reaching transplantation, which may be a reflection of the recent heart allocation policy changes.

Preventing driveline infection during left ventricular assist device support by the HeartMate 3: A survey-based study.

PURPOSE: Driveline infection (DLI) is a significant source of morbidity and mortality during left ventricular assist device (LVAD) support yet limited studies are available to describe the center-level prevalence, preventive practices, and their potential effectiveness. METHODS: We surveyed LVAD centers in the United States to determine program burden and preventive practices for DLI during HeartMate (HM) 3 support. An online, anonymous, question-based survey was sent to expert providers at implanting centers. Only a single respondent completed the survey for each center. As an exploratory analysis, we compared specific DLI preventive practices between centers with low (≤10%) and high (>10%) reported prevalence of DLI. RESULTS: Seventy-eight centers responded to the survey (response rate: 50%). Respondents were comprised of 37 (47%) heart failure cardiologists, 27 (35%) LVAD coordinators, and 14 (18%) cardiothoracic surgeons. The prevalence of DLI during HM3 was reported as ≤10% by 27 (35%), 11%-25% by 36 (46%), and >25% by 16 (19%) centers. Thirteen (17%) centers had a body mass index threshold for device placement, 29 (37%) utilized a counter incision, 66 (81%) placed an anchor stitch, and 69 (88%) used an external device to stabilize the DL. Proportionally, more centers with a low DLI prevalence used a wound vacuum 6 (22%) versus 3 (6%, p = 0.03) than those with high DLI. CONCLUSION: Variation exists in reported prevalence and practices of preventing and managing driveline infections across centers during HM3 support. Further studies are warranted to develop and assess the effectiveness of standardized preventive strategies.

Infectious complications following contemporary left ventricular assist device implantation.

BACKGROUND: The aim of this study is to evaluate the source of infectious complications following contemporary left ventricular assist device (LVAD) implantation and to determine the impact of infections on patient outcomes. METHODS: All patients who underwent centrifugal LVAD implantation between 2014 and 2020 at a single center were retrospectively reviewed. Postimplant infections were categorized as VAD-specific, VAD-related, or non-VAD according to previously published definitions. Postoperative survival and freedom from readmission were assessed using Kaplan-Meier analysis. Univariable and multivariable analyses were performed to determine the risk factors for postoperative infectious complications. RESULTS: A total of 212 patients underwent centrifugal LVAD implantation (70 HeartMate 3, 142 HeartWare HVAD) during the study period. One hundred and two patients (48.1%) developed an infection, including 34 VAD-specific, 11 VAD-related, and 57 non-VAD. Staphylococcus species were the most common source of postoperative infection (n = 57, 33.7%). In multivariable analysis, diabetes significantly impacted overall postoperative infection rate. At 12 and 24 months, respectively, Kaplan-Meier survival was 81.1% and 61.6% in the infection group and 83.4% and 78.1% in the noninfection group (p = 0.006). Within the total cohort, 12- and 24-month freedom from infection were 46.2% and 31.9%, respectively. Patients with infectious complication had significantly lower rate of transplantation (16.4% vs. 43.6%; p < 0.001), increased overall mortality (46.3% vs. 17.3%, p < 0.001), and increased rates of noncardiac readmission (58.2% vs. 37.3%, p = 0.007). CONCLUSIONS: Infections are common following contemporary LVAD implantation and are most commonly non-VAD related. Patients with postoperative infectious complications have significantly reduced rates of transplantation, survival, and freedom from noncardiac readmission.

Less invasive durable management of postoperative ventricular tachycardia storm after LVAD insertion.

BACKGROUND: Ventricular tachycardia (VT) can be a challenging problem in patients following durable left ventricular device (LVAD) implantation, and can lead to significant morbidity and mortality. Both the etiology and management of VT in this population can also vary substantially. CASE PRESENTATION: We herein report a case of a patient with preoperative VT who developed a drug resistant VT storm postoperatively that was ultimately controlled durably with a bedside stellate ganglion block. CONCLUSION: This case illustrates that stellate ganglion block can be an effective and durable intervention for terminating refractory VT in LVAD patients. This method is attractive because it can be performed at the bedside in relatively unstable patients, and is less invasive than other alternatives such as VT ablation and thoracic sympathectomy.

Waitlist and transplant outcomes for patients bridged to heart transplantation with Impella 5.0 and 5.5 devices.

BACKGROUND: Impella devices are increasingly utilized as a bridge to heart transplantation (BTT) and are now prioritized as Status 2 under the current heart allocation policy. This study evaluated waitlist and post-transplant outcomes of patients supported with Impella 5.0/5.5 devices. METHODS: The United Network of Organ Sharing registry was used to identify adults waitlisted or transplanted with Impella 5.0 or 5.5 devices from 2010 to 2021. Separate analyses were performed for waitlist and transplantation outcomes for patients supported by Impella 5.0/5.5 devices. Competing outcomes for the waitlist analysis included rates of transplantation, recovery, and death or clinical deterioration. Among patients undergoing transplantation, the primary outcome was 1-year survival. Secondary outcomes included rates of rejection, new postoperative dialysis, stroke, and pacemaker implantation after transplantation. RESULTS: There were 344 patients waitlisted and 394 patients transplanted with an Impella 5.0 (n = 212 and 251) or 5.5 (n = 132 and 143) device. Competing risk regression demonstrated similar likelihood of transplant (subhazard ratio [SHR], 1.33 (0.98-1.81, p = 0.067)) and similar likelihood of death or clinical deterioration (SHR, 0.67 [0.27-1.69, p = 0.400]) for Impella 5.5 patients. In the transplanted cohort, unadjusted 1-year post-transplant survival was comparable at 91.3% versus 94.6% (log-rank p = 0.661) for patients supported by Impella 5.0 or 5.5 device, respectively, a finding that persisted after risk-adjustment (HR 1.22, p = 0.699). Post-transplant complication rates were also comparable between 5.0 and 5.5 patients. CONCLUSIONS: Impella devices can be used as a BTT with excellent survival and minimal post-transplant morbidity. Outcomes were comparable for Impella 5.0 and 5.5 devices.

Trends and outcomes following total artificial heart as bridge to transplant from the UNOS database.

INTRODUCTION: Bridge to transplantation (BTT) with a SynCardia Total Artificial Heart (TAH) has been gaining momentum as a therapy for patients with biventricular heart failure. Recent transplant waitlist and posttransplant outcomes with this strategy have not been comprehensively characterized. We reviewed the United Network for Organ Sharing (UNOS) database to examine BTT outcomes for the TAH system since approval. METHODS: Adult patients listed for heart transplantation in the UNOS system between 2004 and 2020 who underwent BTT therapy with a TAH were included in the study. Trends in utilization of TAH compared with other durable mechanical support strategies were examined. The primary outcome was 1-year survival following heart transplantation following BTT with TAH. Secondary outcomes included waitlist deterioration and risk factors for waitlist or posttransplant mortality. RESULTS: During the study 433 total patients underwent TAH implant as BTT therapy; 236 (54.4%) were listed with the TAH, while the remaining patients were upgraded to TAH support while on the waitlist. Waitlist mortality was 7.4%, with 375 patients (86.6%) ultimately being transplanted. Age, cerebrovascular disease, functional status, and ventilator dependence were risk factors for waitlist mortality. One-year survival following successful BTT was 80%. Risk factors for mortality following BTT included age, body mass index, and underlying diagnosis. CONCLUSIONS: Patients undergoing BTT with TAH demonstrate acceptable waitlist survival and good 1-year survival. While utilization initially increased as a BTT therapy, there has been a plateau in relative utilization. Individual patient and transplantation center factors deserve further investigation to determine the ideal population for this therapy.

A machine learning approach to model for end-stage liver disease score in cardiac surgery.

OBJECTIVE: Model for end-stage liver disease (MELD) likely has nonlinear effects on operative outcomes. We use machine learning to evaluate the nonlinear (dependent variable may not correlate one to one with an increased risk in the outcome) relationship between MELD and outcomes of cardiac surgery. METHODS: Society of Thoracic Surgery indexed elective cardiac operations between 2011 and 2018 were included. MELD was retrospectively calculated. Logistic regression models and an imbalanced random forest classifier were created on operative mortality. Cox regression models and random forest survival models evaluated survival. Variable importance analysis (VIMP) ranked variables by predictive power. Linear and machine-learned models were compared with receiver operator characteristic (ROC) and Brier score. RESULTS: We included 3872 patients. Operative mortality was 1.7% and 5-year survival was 82.1%. MELD was the fourth largest positive predictor on VIMP analysis for operative long-term survival and the strongest negative predictor for operative mortality. MELD was not a significant predictor for operative mortality or long-term survival in the logistic or Cox regressions. 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 than the Cox regression starting at 2 years and continuing throughout the study period. Bootstrap estimation on linear regression demonstrated machine-learned models were superior. CONCLUSIONS: MELD and mortality are nonlinear. MELD was insignificant in the Cox multivariable regression but was strongly important in the random forest survival model and when using bootstrapping, the superior utility was demonstrated of the machine-learned models.

Recipient-surgeon racial concordance in orthotopic heart transplantation outcomes.

BACKGROUND: Prior studies have demonstrated deleterious outcomes for physician-patient racial discordance. We explored recipient-surgeon racial concordance and short-term postoperative survival in adults undergoing orthotopic heart transplantation (OHT). METHODS: The United Network for Organ Sharing (UNOS) database was queried to identify White and Black adult (≥18 years) patients undergoing isolated OHT between 2000 and 2020. Surgeon race was obtained from publicly available images. All non-White and non-Black recipients and surgeons were excluded. Linear probability models were utilized to explore the relationship between recipient-surgeon racial concordance and 30-, 60-, and 90-day post-transplant mortality using a fixed effects approach. RESULTS: A total of 26,133 recipients were identified (mean age 52.79 years, 74.4% male) with 77.65% (n = 20,292) being White and 22.35% (n = 5841) being Black. A total of 662 White surgeons performed 25,946 (97.56%) OHTs during the study period while 17 Black surgeons performed 437 (1.67%) OHTs. Although some evidence of differences across groups was observed in cross-tabular specifications, these differences became insignificant after the inclusion of controls (i.e., comorbidities and fixed effects). This suggests that recipient race and physician race are not correlated with post-OHT survival at 30, 60, or 90 days. CONCLUSIONS: Recipient-surgeon racial concordance and discordance among adults undergoing OHT do not appear to impact post-transplant survival. Nor do we observe significant penalties accruing for Black patients overall once controls are accounted for. Given that worse outcomes have historically been demonstrated for Black patients undergoing OHT, further work will be necessary to improve understanding of racial disparities for patients with end-stage heart failure.

The HeartMate 3 left ventricular assist device as a strategy to bridge to transplant.

PURPOSE: Recent changes in the market for left ventricular assist devices have resulted in the HeartMate 3 (HM3) being the only commercially-available device. This study evaluates the outcomes of patients with a HM3 waitlisted for and undergoing orthotopic heart transplantation (OHT). METHODS: Patients waitlisted for isolated OHT with a HM3 or undergoing OHT after bridge-to-transplant (BTT) with a HM3 between 2015 and 2021 were identified from the UNOS registry and included in this study. Propensity matching was used to compare outcomes of BTT-HM3 versus primary OHT. RESULTS: A total of 1321 patients supported with a HM3 underwent OHT during our study period. Unadjusted 30-day, 90-day, and 1-year survival following OHT in the BTT-HM3 cohort was 96.5%, 94.4%, and 90.7%, respectively. In propensity-matched analysis, 1103 BTT-HM3 patients were compared with 1103 primary OHT patients. Rates of post-OHT stroke were higher in the BTT-HM3 group (4.4% vs. 2.0%, p = .001). The BTT-HM3 group had lower 30-day survival (96.2% vs. 97.4%, p = .033) although 90-day (94.2% vs. 95.3%, p = .103) and 1-year survival (90.4% vs. 91.7%, p = .216) were comparable. A total of 1251 patients were supported with a HM3 at the time of OHT listing during the study period. At the time of this analysis, 60 (4.5%) remained on the waitlist, 991 (75.0%) underwent OHT, and 119 (9.0%) died or clinically deteriorated with waitlist removal. CONCLUSIONS: The HM3 is a viable method for BTT with acceptable waitlist outcomes. Although 1-year survival is comparable to primary OHT, early outcomes are worse, suggesting that refinement of patient selection and perioperative management is prudent to optimizing outcomes.