Geographic Variation in Heart Transplant Extended Criteria Donors in the United States

The Year in Cardiothoracic Transplant Anesthesia: Selected Highlights From 2022 Part II: Cardiac Transplantation

These highlights focus on research published in the year 2022 and is divided into preoperative, intraoperative, and postoperative sections. The preoperative section includes research on the assessment and optimization of candidates for heart transplantation; donor optimization and the use of extended donors; organ protection systems; donation after circulatory death allografts; recipient factors including cannabis use, sex, race, and comorbidities such as obesity, diabetes mellitus, and peripartum cardiomyopathy; the effects of the 2018 heart allocation policy change on waitlist and postoperative mortality; updates on heart transplantation in patients with coronavirus disease 2019; in pediatric patients; and those who require a bridge to transplant. The intraoperative section includes the use of a multidisciplinary team, a proposed transfusion algorithm, bench surgery on the allograft, and size matching. The postoperative section focuses on the research on the development and management of tricuspid regurgitation, echocardiography, arrhythmia management, and, finally, xenotransplantation.

Extended Donor Criteria Outcomes in Adult Congenital Heart Disease Patients Undergoing Heart Transplantation in the United States

Background: There are very few published outcomes for the use of extended criteria donor (ECD) organs in adult congenital heart disease (ACHD) patients undergoing cardiac transplantation. We investigated outcomes with the use of ECD organs in this population. We hypothesized that ECD organs may be safely used in this population in patients who are younger and carry less vascular and renal disease than the general cardiac transplant population. Methods: United Network of Organ Sharing data from all ACHD heart transplant recipients between October 18, 2018, and September 30, 2023, was analyzed. Patients were grouped by ECD transplantation. The primary outcome of interest was one-year survival. Secondary outcomes included length of stay, posttransplant stroke, retransplantation, kidney transplantation, dialysis, pacemaker implantation, and rejection. Results: Extended criteria donor organs were utilized in 39.1% (200/512) of ACHD heart transplantation cases. There was marked regional variation in the use of ECD organs. Extended criteria donor criteria in this population were solely met by ischemic time ≥4 h in 89.5% (179/200) of cases. Transplantation with ECD donors was associated with lower survival (one-year survival 82.76% vs 90.62%). A multivariate Cox regression analysis suggested a hazard ratio of 1.96 with the use of these organs. Conclusion: Compared with organs accepted under traditional donor criteria, ECD organs appear to compromise short- and long-term survival in ACHD transplant candidates.

Impact of prolonged cardiopulmonary resuscitation on outcomes in heart transplantation with higher risk donor heart

OBJECTIVES

To evaluate the influence of prolonged cardiopulmonary resuscitation (CPR) on outcomes in heart transplantation with higher risk donor hearts (HRDHs).

METHODS

Patients transplanted in our hospital between May 2006 and December 2019 were divided into 2 groups, HRDH recipients and non HRDH recipients. HRDH was defined as meeting at least one of the following criteria: (1) donor left ventricular ejection fraction ≤ 50%, (2) donor-recipient predicted heart mass ratio < 0.8 or > 1.2, (3) donor age ≥ 55 years, (4) ischemic time > 4 h and (5) catecholamine index > 20. Recipients of HRDHs were divided into 3 groups according to the time of CPR (Group1: non-CPR, Group 2: less than 30 min-CPR, and Group 3: longer than 30 min CPR).

RESULTS

A total of 125 recipients were enrolled in this study, composing of HRDH recipients (n = 97, 78%) and non HRDH recipients (n = 28, 22%). Overall survival and the rate of freedom from cardiac events at 10 years after heart transplantation were comparable between two groups. Of 97 HRDH recipients, 54 (56%) without CPR, 22 (23%) with CPR < 30 min, and 21 (22%) with CPR ≥ 30 min were identified. One-year survival rates were not significantly different among three groups. The 1-year rate of freedom from cardiac events was not also statistically different, excluding the patients with coronary artery disease found in early postoperative period, which was thought to be donor-transmitted disease. Multivariate logistics regression for cardiac events identified that the CPR duration was not a risk factor even in HRDH-recipients.

CONCLUSION

The CPR duration did not affect the outcomes after heart transplantation in HRDH recipients.

Non-inferior outcomes in lower urgency patients transplanted with extended criteria donor hearts

BACKGROUND

Recent work has suggested that outcomes among heart transplant patients listed at the lower-urgency (United Network for Organ Sharing Status 4 or 6) status may not be significantly impacted by donor comorbidities. The purpose of this study was to investigate outcomes of extended criteria donors (ECD) in lower versus higher urgency patients undergoing heart transplantation.

METHODS

The United Network for Organ Sharing (UNOS) database was queried for all adult patients undergoing heart transplantation from October 18, 2018 through December 31, 2021. Patients were stratified by degree of urgency (higher urgency: UNOS 1 or 2 vs lower urgency: UNOS 4 or 6) and receipt of ECD hearts, as defined by donor hearts failing to meet established acceptable use criteria. Outcomes were compared using propensity score matched cohorts.

RESULTS

Among 9,160 patients included, 2,320 (25.4%) were low urgency. ECD hearts were used in 35.5% of higher urgency (HU) patients and 39.2% of lower urgency (LU) patients. While ECD hearts had an impact on survival among high-urgency patients (p < 0.01), there was no difference in 1- and 2-year survival (p > 0.05) found among low urgency patients receiving ECD versus standard hearts. Neither ECDs nor individual ECD criteria were independently associated with mortality in low urgency patients (p > 0.05).

CONCLUSIONS

Post-transplant outcomes among low urgency patients are not adversely affected by receipt of ECD vs. standard hearts. Expanding the available donor pool by optimizing use of ECDs in this population may increase transplant frequency, decrease waitlist morbidity, and improve postoperative outcomes for the transplant community at large.

Utilization of the percutaneous left ventricular support as bridge to heart transplantation across the United States: In-depth UNOS database analysis

BACKGROUND

Intra-aortic balloon pump (IABP) and Impella device utilization as a bridge to heart transplantation (HTx) have risen exponentially. We aimed to explore the influence of device selection on HTx outcomes, considering regional practice variation.

METHODS

A retrospective longitudinal study was performed on a United Network for Organ Sharing (UNOS) registry dataset. We included adult patients listed for HTx between October 2018 and April 2022 as status 2, as justified by requiring IABP or Impella support. The primary end-point was successful bridging to HTx as status 2.

RESULTS

Of 32,806 HTx during the study period, 4178 met inclusion criteria (Impella n = 650, IABP n = 3528). Waitlist mortality increased from a nadir of 16 (in 2019) to a peak of 36 (in 2022) per thousand status 2 listed patients. Impella annual use increased from 8% in 2019 to 19% in 2021. Compared to IABP, Impella patients demonstrated higher medical acuity and lower success rate of transplantation as status 2 (92.1% vs 88.9%, p < 0.001). The IABP:Impella utilization ratio varied widely between regions, ranging from 1.77 to 21.31, with high Impella use in Southern and Western states. However, this difference was not justified by medical acuity, regional transplant volume, or waitlist time and did not correlate with waitlist mortality.

CONCLUSIONS

The shift in utilizing Impella as opposed to IABP did not improve waitlist outcomes. Our results suggest that clinical practice patterns beyond mere device selection determine successful bridging to HTx. There is a critical need for objective evidence to guide tMCS utilization and a paradigm shift in the UNOS allocation system to achieve equitable HTx practice across the United States.