Renin-Angiotensin System (RAS) Blockade Reduces Proteinuria in Heart Transplant Recipients: An Observational, Longitudinal Analysis

Abstract

Purpose No data exist regarding the incidence of proteinuria and the impact of RAS blockade on proteinuria in heart transplant recipients. The International Society for Heart and Lung Transplantation does not address the evaluation or treatment of proteinuria following heart transplantation. We calculated the 3-year cumulative incidence of proteinuria in heart transplant recipients receiving and not receiving angiotensin converting enzyme inhibitor (ACE-I) or angiotensin receptor blocker (ARB) therapy, as well as, the risk of proteinuria in those receiving an ACE-I/ARB. Methods and Materials This study is as an observational, longitudinal analysis of heart transplant recipients managed at the University of Colorado Hospital Heart Transplant Program beginning January 1, 2000 with continued care for a minimum of three years. Proteinuria was defined as a urine albumin/creatinine ratio ≥ 30 mg/g. Data variables, including urine albumin/creatinine ratio and ACE-I/ARB use, were collected at baseline and at years 1, 2, and 3 post-transplant. Comparison between groups involved a t -test for normally distributed variables. A difference-in-differences estimator was used to account for temporal proteinuria trends between 1 and 3 years between groups. Kaplan-Meier analyses were used to compare time to proteinuria. Results 56 heart transplant recipients met inclusion criteria; 21 (37.5%) did not receive an ACE-I/ARB and 35 (62.5%) received an ACE-I/ARB. The cumulative 3-year incidence of proteinuria was 15%. In the unadjusted analysis, the rate of change in development of proteinuria at 1 to 3 years was lower with ACE-I/ARB therapy compared to those not receiving these therapies (5.5% vs 10%, p Conclusions RAS blockade appears to reduce the development of proteinuria in heart transplant recipients.