Left ventricular assist device bridging to heart transplantation: Comparison of temporary versus durable support

Optimizing outcomes in heart transplantation: multidisciplinary Heart Teams and mechanical circulatory support for primary graft dysfunction

Heart transplantation (HTx) is a definitive treatment for selected patients with advanced heart failure. However, primary graft dysfunction (PGD), a severe early complication, is a major cause of post-HTx morbidity and mortality. This paper explores the pathophysiology, diagnostic approaches, and management strategies for PGD, with a particular focus on temporary mechanical circulatory support (MCS) devices such as venoarterial extracorporeal membrane oxygenation and Impella. It also highlights the essential role of the multidisciplinary Heart Team in optimizing outcomes through patient-tailored MCS selection and timely intervention.

Durable left ventricular assist device in donation after circulatory death heart transplantation

BACKGROUND

This study evaluates outcomes following donation after circulatory death (DCD) heart transplantation in recipients with a durable left ventricular assist device (LVAD).

METHODS

The UNOS registry was queried to analyze adult recipients of isolated DCD heart transplantation between 1/1/2019-3/31/2023. The recipients were stratified by durable LVAD use as a bridge to transplantation. The primary outcome was 1-year post-transplant survival. Sub-group analyses were conducted to evaluate the effects of transplant status, device type, and donor type on 1-year survival.

RESULTS

A total of 703 recipients were included, of which 219 (31.2%) recipients were bridged with a durable LVAD. The recipients of DCD hearts with durable LVADs had significantly lower 1-year post-transplant survival compared to those without durable LVADs (88.4% vs. 93.6%, p=0.017). Among the recipients bridged with durable LVADs, status 4 recipients had significantly improved 1-year survival compared to statuses 2 and 3 recipients, similar to those without durable LVADs. Furthermore, the recipients with HeartMate II and HeartMate 3 had improved survival compared to those with the HeartWare HVAD, similar to those without durable LVADs. Lastly, the DCD and DBD recipients with durable LVADs had comparable 1-year survival (88.4% vs. 89.0%, p=0.763).

CONCLUSIONS

Recipients of DCD hearts bridged to transplantation with a durable LVAD exhibit reduced early post-transplant survival compared to those without a durable LVAD. However, clinical acuity and device type significantly influence post-transplant outcomes in this vulnerable population. Despite this, candidates with a durable LVAD can safely undergo DCD heart transplantation, achieving early post-transplant survival comparable to those of DBD heart transplantation.

Changes in Donor Utilization and Outcomes for Patients Bridged With Durable Left Ventricular Assist Device

We studied the impact of the 2018 heart allocation policy change on donor characteristics and posttransplant outcomes of left ventricular assist device (LVAD)-bridged heart transplant (HT) recipients. Left ventricular assist device-bridged adult HT recipients from October 2014 to October 2022 in the United Network for Organ Sharing database were categorized into old allocation policy (OAP) and new allocation policy (NAP) cohorts. Baseline characteristics, posttransplant outcomes, and subgroup analyses of unstable and stable LVAD-bridged recipients were assessed. The study included 7,384 HT recipients; 4,345 (58.8%) were transplanted in the OAP era and 3,039 (41.2%) in the NAP era. Old allocation policy recipients were most frequently status 1A at transplantation (71.1%), whereas NAP recipients were most frequently status 3 (40.0%), and status 4 (31.9%). Median donor sequence number (DSN) was higher in the NAP versus OAP era (9 vs. 3, p < 0.001). On multivariable analysis, NAP recipients had 20% higher 1 year mortality compared to OAP (adjusted hazard ratio [aHR] = 1.20 [95% confidence interval {CI}: 1.04-1.40], p = 0.01). Status 1 or 2 recipients had 28% higher 1 year mortality compared to status 1A (aHR = 1.28 [95% CI: 1.01-1.63], p = 0.04). Status 1 and 2 LVAD-supported recipients had higher mortality following the 2018 allocation change, indicating the need for closer surveillance of LVAD-bridged patients who may decompensate on the waitlist.

Donation after circulatory death improves probability of heart transplantation in waitlisted candidates and results in post-transplant outcomes similar to those achieved with brain-dead donors

OBJECTIVE

To quantitate the impact of heart donation after circulatory death (DCD) donor utilization on both waitlist and post-transplant outcomes in the United States.

METHODS

The United Network for Organ Sharing database was queried to identify all adult waitlisted and transplanted candidates between October 18, 2018, and December 31, 2022. Waitlisted candidates were stratified according to whether they had been approved for donation after brain death (DBD) offers only or also approved for DCD offers. The cumulative incidence of transplantation was compared between the 2 cohorts. In a post-transplant analysis, 1-year post-transplant survival was compared between unmatched and propensity-score-matched cohorts of DBD and DCD recipients.

RESULTS

A total of 14,803 candidates were waitlisted, including 12,287 approved for DBD donors only and 2516 approved for DCD donors. Overall, DCD approval was associated with an increased sub-hazard ratio (HR) for transplantation and a lower sub-HR for delisting owing to death/deterioration after risk adjustment. In a subgroup analysis, candidates with blood type B and status 4 designation received the greatest benefit from DCD approval. A total of 12,238 recipients underwent transplantation, 11,636 with DBD hearts and 602 with DCD hearts. Median waitlist times were significantly shorter for status 3 and status 4 recipients receiving DCD hearts. One-year post-transplant survival was comparable between unmatched and propensity score-matched cohorts of DBD and DCD recipients.

CONCLUSIONS

The use of DCD hearts confers a higher probability of transplantation and a lower incidence of death/deterioration while on the waitlist, particularly among certain subpopulations such as status 4 candidates. Importantly, the use of DCD donors results in similar post-transplant survival as DBD donors.

Use of mechanical circulatory support and survival for heart and heart-kidney transplant recipients in the new allocation system

Background

The 2018 United Network for Organ Sharing organ allocation change aimed to distribute donor hearts to the sickest patients on the waitlist. Whether this change differentially affected outcomes in heart-only vs heart-kidney transplant recipients is unknown.

Methods

This study used the Scientific Registry of Transplant Recipients to compare outcomes, including survival, of heart-only and heart-kidney transplant recipients from 2015 to 2021, from the old vs new allocation system, including use of mechanical circulatory support (MCS), prior to transplant.

Results

During the study period, 16,696 patients underwent heart transplant alone (9,320 in the old and 7,376 in the new system) and 1,156 patients underwent heart-kidney transplant (529 in the old and 627 in the new system). For both heart and heart-kidney transplant populations, there was a 3- to 5-fold increase in the use of temporary MCS. Heart-only recipients had worse survival when temporary MCS was used in the old allocation system. Heart-only recipients with durable MCS had worse survival both in the old and the new allocation system. There was no difference in survival in heart-kidney recipients in the old vs new allocation system, regardless of MCS use.

Conclusions

The new heart allocation system was associated with increased use of temporary MCS in both heart and heart-kidney recipients. However, this change only differentially affected survival in heart-only recipients with improved survival if on temporary MCS, but worse survival if on durable MCS. Unlike prior studies, heart-kidney recipients did not have different outcomes after the heart allocation change, which may reflect outcomes in more current times.

Heart Transplantation

Heart transplantation (HTx) remains the last therapeutic resort for patients with advanced heart failure. The present work is a clinically focused review discussing current issues in heart transplantation. Several factors have been associated with the outcome of HTx, such as ABO and HLA compatibility, graft size, ischemic time, age, infections, and the cause of death, as well as imaging and laboratory tests. In 2018, UNOS changed the organ allocation policy for HTx. The aim of this change was to prioritize patients with a more severe clinical condition resulting in a reduction in mortality of people on the waiting list. Advanced heart failure and resistant angina are among the main indications of HTx, whereas active infection, peripheral vascular disease, malignancies, and increased body mass index (BMI) are important contraindications. The main complications of HTx include graft rejection, graft angiopathy, primary graft failure, infection, neoplasms, and retransplantation. Recent advances in the field of HTx include the first two porcine-to-human xenotransplantations, the inclusion of hepatitis C donors, donation after circulatory death, novel monitoring for acute cellular rejection and antibody-mediated rejection, and advances in donor heart preservation and transportation. Lastly, novel immunosuppression therapies such as daratumumab, belatacept, IL 6 directed therapy, and IgG endopeptidase have shown promising results.

The Year in Cardiothoracic and Vascular Anesthesia: Selected Highlights From 2023

This special article is the 16th in an annual series for the Journal of Cardiothoracic and Vascular Anesthesia. The authors thank the editor-in-chief, Dr. Kaplan, and the editorial board for the opportunity to continue this series, namely the research highlights of the past year in the specialty of cardiothoracic and vascular anesthesiology. The major themes selected for 2023 are outlined in this introduction, and each highlight is reviewed in detail in the main article. The literature highlights in the specialty for 2023 begin with an update on perioperative rehabilitation in cardiothoracic surgery, with a focus on novel methods to best assess patients in the preoperative and postoperative periods, and the impact of rehabilitation on outcomes. The second major theme is focused on cardiac surgery, with the authors discussing new insights into inhaled pulmonary vasodilators, coronary revascularization surgery, and discussion of causes of coronary graft failure after surgery. The third theme is focused on cardiothoracic transplantation, with discussions focusing on bridge-to-transplantation strategies. The fourth theme is focused on mechanical circulatory support, with discussions focusing on both temporary and durable support. The fifth and final theme is an update on medical cardiology, with a focus on outcomes of invasive approaches to heart disease. The themes selected for this article are only a few of the diverse advances in the specialty during 2023. These highlights will inform the reader of key updates on various topics, leading to improved perioperative outcomes for patients with cardiothoracic and vascular disease.

Impact of 2018 allocation system change on outcomes in patients with durable left ventricular assist device as bridge to transplantation: A UNOS registry analysis

BACKGROUND

This study compared outcomes of patients waitlisted for orthotopic heart transplantation with durable left ventricular assist devices (LVAD) before and after the October 18, 2018 heart allocation policy change.

METHODS

The United Network of Organ Sharing database was queried to identify 2 cohorts of adult candidates with durable LVAD listed within seasonally-matched, equal-length periods before (old policy era [OPE]) and after the policy change (new policy era [NPE]). The primary outcomes were 2-year survival from the time of initial waitlisting, as well as 2-year post-transplant survival. Secondary outcomes included incidence of transplantation from the waitlist and de-listing due to either death or clinical deterioration.

RESULTS

A total of 2,512 candidates were waitlisted, 1,253 within the OPE and 1,259 within the NPE. Candidates under both policies had similar 2-year survival after waitlisting, as well as a similar cumulative incidence of transplantation and de-listing due to death and/or clinical deterioration. A total of 2,560 patients were transplanted within the study period, 1,418 OPE and 1,142 within the NPE. Two-year post-transplant survival was similar between policy eras, however, the NPE was associated with a higher incidence of post-transplant stroke, renal failure requiring dialysis, and a longer hospital length of stay.

CONCLUSIONS

The 2018 heart allocation policy has conferred no significant impact on overall survival from the time of initial waitlisting among durable LVAD-supported candidates. Similarly, the cumulative incidence of transplantation and waitlist mortality have also been largely unchanged. For those undergoing transplantation, a higher degree of post-transplant morbidity was observed, though survival was not impacted.