Pretransplantation Patient Characteristics and Survival Following Combined Heart and Kidney Transplantation An Analysis of the United Network for Organ Sharing Database

Hypothesis: Pretransplantation patient characteristics determine survival following combined heart and kidney transplantation (HKT). Design: Time-to-event analysis. Setting: Academic research. Patients: The United Network for Organ Sharing provided deidentified patient-level data. Analysis included 19 373 heart transplant recipients from January 1, 1995, to December 31, 2005. Main Outcome Measures: Multivariate Cox proportional hazards regression analysis was performed to identify pretransplantation recipient characteristics associated with improved long-term survival following HKT. Kaplan-Meier survival functions and Cox proportional hazards regression were used for time-to-event analysis. Using the relative risks calculated in regression analysis, weights were assigned for each risk factor, allowing for the construction of a risk score. Results: Among heart transplant recipients, 264 (1.4%) underwent HKT. Factors associated with diminished survival included peripheral vascular disease, recipient age older than 65 years, nonischemic etiology of heart failure, dialysis dependence at the time of transplantation, and bridge to transplantation using a ventricular assist device. After stratification by risk score, 1-year survival was 93.2% and 61.9% in the lowest-and highest-risk HKT groups, respectively. Further stratification by estimated glomerular filtration rate (eGFR) was performed based on a previous study showing decreased survival of patients undergoing orthotopic heart transplantation with a preoperative eGFR of less than 33 mL/min. Low-risk patients with an eGFR of less than 33 mL/min undergoing HKT constituted the only group that had significantly better survival compared with isolated patients undergoing orthotopic heart transplantation with eGFRs and risk scores in the same range (P=.006). Conclusions: When patients were stratified by risk score and by diminished eGFR (<33 mL/min), low-risk HKT recipients with a diminished eGFR had improved survival following HKT over isolated heart transplant recipients. Only low-risk patients with combined kidney failure (eGFR, <33 mL/min) and heart failure seem to gain a survival benefit from HKT.