Prognostic implications of inactive status in highest urgency categories among heart transplantation recipients in the new donor heart allocation system.

BACKGROUND

Patients on the waiting list for heart transplantation (HT) can become inactive or made status seven because of medical reasons, such adverse events, complications, or psychosocial circumstances. If the condition that caused the inactivation is resolved, patients are re- activated. Information about the prognostic implications of Status 7 in the new donor heart allocation system has not been described. To bridge this knowledge gap, we performed an analysis of the United Network of Organ Sharing (UNOS) registry.

METHODS

Data on adult patients who underwent HT between October 18th, 2018 and October 2021, were queried from the UNOS registry. The main outcomes were post- transplant all-cause mortality, 1-year all-cause mortality and treated acute rejection. Since re-transplantation is a competing event for all-cause mortality, we performed competing risk survival analysis and reported sub distribution hazard ratios (SHR) from the Fine and Gray model to examine the relationship between inactive status and all-cause mortality.

RESULTS

A total of 5267 adult patients underwent HT and were previously listed as Status 1 or Status 2 in the new allocation system. We identified 946 HT recipients temporarily inactivated while on HT list (18%). The number of temporarily inactive patients remained stable since the implementation of the new donor allocation system (p = .37). Approximately, two-thirds of temporarily inactive patients (65.9%) were inactivated for being too sick, whereas other frequent justifications for inactivity included left ventricular assist device implantation (7.8%) and insurance related issues (4.8%). Temporarily inactive HT recipients were more likely to be African Americans, males, have a higher body mass index (BMI) and significantly longer waiting time (391.6 ± 600 vs. 72.3 ± 223 days, p < .001) compared with never inactivated patients. In the unadjusted analyses 30-day mortality did not differ between groups, but both 1-year and overall all-cause mortality was significantly higher in temporarily inactive patients (1-year: SHR: 1.3; 95% confidence intervals [CI]: 1.03, 1.64; p = .028, overall mortality SHR: 1.31; 95% CI: 1.06, 1.64; p = .014). After adjustment for donor and recipient characteristics, a trend towards higher 1-year and overall mortality remained (1-year: SHR 1.32; 95% CI .99, 1.76, p = .006, overall mortality SHR: 1.29; 95% CI: .98-1.68, p = .065). No differences in treated acute allograft rejection at 1 year were found between groups.

CONCLUSIONS

Temporary inactive status while waiting for HT occurs in approximately one in five HT recipients listed in higher urgency categories after the implementation of the new allocation system. A signal of adverse long-term outcomes was found, and this could be explained by differences in recipient characteristics. Further research is required to elucidate pathways involved and possible implications for clinical practice.