Outcomes of Combined Heart-Kidney Transplantation in Older Recipients

Abstract

Objectives. The upper limit of recipient age for combined heart-kidney transplantation (HKT) remains controversial. This study evaluated the outcomes of HKT in patients aged ≥65 years. Methods. The United Network of Organ Sharing (UNOS) was used to identify patients undergoing HKT from 2005 to 2021. Patients were stratified by age at transplantation: <65 and ≥ 65 years. The primary outcome was one-year mortality. Secondary outcomes included 90-day and 5-year mortality, postoperative new-onset dialysis, postoperative stroke, acute rejection prior to discharge, and rejection within one-year of HKT. Survival was compared using Kaplan–Meier analysis, and risk adjustment for mortality was performed using Cox proportional hazards modeling. Results. HKT in recipients aged ≥65 significantly increased from 5.6% of all recipients in 2005 to 23.7% in 2021 ( $p=0.002$ ). Of 2,022 HKT patients in the study period, 372 (18.40%) were aged ≥65. Older recipients were more likely to be male and white, and fewer required dialysis prior to HKT. There were no differences between cohorts in unadjusted 90-day, 1-year, or 5-year survival in Kaplan–Meier analysis. These findings persisted after risk-adjustment, with an adjusted hazard for one-year mortality for age ≥65 of 0.91 (95% CI (0.63–1.29), $p=0.572$ ). As a continuous variable, increasing age was not associated with one-year mortality (HR 1.01 (95% CI (1.00–1.02), $p=0.236$ ) per year). Patients aged ≥65 more frequently required new-onset dialysis prior to discharge (11.56% vs. 7.82%, $p=0.051$ ). Stroke and rejection rates were comparable. Conclusion. Combined HKT is increasing in older recipients, and advanced age ≥65 should not preclude HKT.