Outcomes of donation after brain death heart transplantation from older donors: A contemporary analysis of the UNOS database

Background

The effect of older donor age on heart transplant outcomes remains controversial, with traditional views that older donors lead to worse post-transplant survival. However, in the modern era, the use of extended donor criteria has included older donors in efforts to expand the donor pool. In this study, we examine the effects of older donor age (≥50 years) on post-transplant outcomes in donation after brain death (DBD) heart transplants in the post-allocation change era.

Methods

This United Network for Organ Sharing (UNOS) database study included adult heart transplants from October 18, 2018 to June 30, 2023. We excluded circulatory death donors, prior heart and multiorgan transplants, and loss to follow-up. Propensity-matching was performed with 3:1 matching. Primary outcome was overall survival. Secondary outcomes included acute rejection, coronary vasculopathy (CAV), 30-day and 1-year mortality.

Results

A total of 12,802 patients were included, 11,936 who received hearts from standard donors (age <50 years), and 866 from older donors (age ≥50 years). Recipients of older hearts were older (median age 61 vs 56 years, p < 0.001), more likely to have durable left ventricular assist devices (LVADs) (30.1% vs 24.3%, p = 0.001) and less likely to be hospitalized (49.1% vs 71.4%, p < 0.001). Older donors were more likely male (71.6% vs 64.7%, p < 0.001) with history of smoking (25.0% vs 11.7%, p < 0.001), diabetes (9.1% vs 3.7%, p < 0.001), and hypertension (42.9% vs 13.9%, p < 0.001). The majority of older organs were received by recipients at waitlist status 4 (31.2%), while younger hearts were primarily transplanted into status 2 recipients (51.9%, p < 0.001).

On unadjusted analysis, recipients of older hearts had worse overall survival (p = 0.0062, Figure 1A), but after propensity-matching, this difference was no longer significant (p = 0.32). Multivariable Cox regression demonstrated no difference in graft failure, risk stratifying donor age by decade. Subgroup analysis on donors with preoperative coronary angiograms demonstrated worse survival in older donors with coronary artery disease (CAD), which remained significant after adjusting for donor and recipient characteristics.

Recipients of older hearts were more likely to develop coronary vasculopathy (12.9% vs 9.5%, p = 0.002) at a median follow-up of 32 months, which persisted after propensity-matching (Table 1). On multivariable regression, donor age was an independent risk factor for coronary vasculopathy with increased risk per decade compared to donor age <30 years (all p < 0.05).

Conclusion

Older donor hearts (age ≥50 years) may achieve comparable perioperative outcomes and survival with careful selection. CAD in older donors worsens overall survival, and expanded preoperative evaluation in these donors is warranted. Further investigation is required into higher rates of CAV, but this did not affect long-term graft survival.