Outcomes of Combined Heart-Kidney Transplantation in Older Recipients

Abstract

<h3>Purpose</h3> The upper limit of recipient age for combined heart-kidney transplantation (HKT) remains controversial. This study evaluated trends and outcomes of HKT in patients aged 65 years or older. <h3>Methods</h3> The United Network of Organ Sharing (UNOS) registry was used to identify patients undergoing combined HKT from 2005-2021. Patients were stratified by age at the time of 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. <h3>Results</h3> There was a significant annual increase in frequency of HKT in recipients aged ≥65 from 5.6% of all HKT recipients in 2005 to 23.7% in 2021 (<i>p</i> = 0.002). Of 2,022 patients undergoing HKT in the study period, 372 (18.40%) were aged 65 or older. Older HKT recipients were more likely to be male and white and fewer required dialysis prior to HKT compared to younger recipients. 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], <i>p</i> =0.572). When modeled as a continuous variable, increasing age was also not associated with one-year mortality (HR 1.01 (95% CI [1.00-1.02], <i>p</i> = 0.236) per year). There was a trend for patients aged ≥65 to more frequently require new-onset dialysis after HKT prior to discharge (11.56% vs 7.82%, <i>p</i> = 0.051). Stroke and rejection rates were comparable between groups. <h3>Conclusion</h3> Combined HKT is being performed more frequently in older recipients in the United States. Although viewed by many programs as a contraindication, advanced age of 65 years or older should not preclude HKT as similar outcomes can be achieved as compared to younger recipients.