Atrial Natriuretic Peptide in the Prevention of Postoperative Acute Renal Dysfunction in Patients Undergoing Heart Transplantation - An Investigator-Driven, Single-Center, Blinded, Randomized and Placebo-Controlled Trial

Abstract

Purpose The development of acute kidney injury (AKI) and renal dysfunction is a common complication after heart transplantation (HTx) that is associated with increased morbidity and mortality. When used for treatment of AKI, infusion of atrial natriuretic peptide (ANP) has been shown to increase renal blood flow and glomerular filtration rate (GFR) after complicated cardiac surgery and in cyclosporine-induced AKI after HTx. Furthermore, it was shown that ANP reduced the probability of dialysis in cardiac surgery-associated AKI. The aim of this investigation was to evaluate whether ANP infusion could prevent or mitigate acute renal dysfunction after HTx. Methods After approval of Ethical Review Board and the Swedish Medical Products Agency, 72 adult patients undergoing HTx were included after informed consent. The patients were randomized to receive either ANP or placebo (saline) by a web-based computerized random-number generator. The anesthesia/intensive staff and physicians were blinded to the allocated treatment throughout the entire study. After induction of anesthesia, a continuous intravenous infusion of either ANP (HANP1000®, Daichii Sankyo Propharma, Japan) at a dose of 50 ng/kg/min or the equivalent volume of placebo (saline) was started. The administration of the study drugs continued for five postop days, or until the patient died or treatment with dialysis was started. Inclusion has been completed. Endpoints The primary end-point was measured mGFR at day five. mGFR was assessed by the infusion clearance of 52Cr-EDTA. The difference in mGFR between groups was estimated using intention-to-treat and per-protocol analyses. To detect a 30% higher mGFR in the ANP group, 31 patients per group would be required, assuming a 80% power and a two-sided error of 0.05. To compensate for drop-outs and for the use of nonparametric tests, we included 35 randomised patients per group. Secondary end-points were: the incidence of postoperative AKI (KDIGO criteria), daily postoperative serum creatinine, need for dialysis, intra- and postoperative diuresis, the use of diuretics, length of ICU and hospital stay, ICU mortality and 30-days mortality, length of mechanical ventilation, incidence of hypotension and arrhythmias and inotropic score.