EFFECTS OF HUMAN ATRIAL-NATRIURETIC-PEPTIDE IN PATIENTS AFTER CORONARY-ARTERY BYPASS-SURGERY

Objectives: To determine the effects of synthetic human atrial natriur etic peptide (ANP) on renal function, hemodynamics, and levels of vaso active peptides when infused in the immediate postoperative period aft er coronary bypass surgery in patients with normal kidney function. De sign: A prospective, randomized, double-blind, placebo-controlled stud y. Setting: The Department of Cardiothoracic Anaesthetics and Intensiv e Care of a university hospital. Participants: Thirty patients with no rmal kidney function scheduled for elective coronary bypass surgery. I nterventions: During the first 3 hours postoperatively, patients recei ved an infusion of either ANP 7.5 pMol/Kg/min (ANP) or vehicle alone ( C). Measurements and Main Results: No differences were found between t he two groups in respect to sex, degree of coronary disease, preoperat ive medical treatment, or duration of cardiopulmonary bypass and aorti c occlusion. Plasma ANP levels increased nearly 10-fold from a mean of 7.0 +/- 1.1 pMol/L in ANP and remained at baseline levels in C, (p < 0.001). In ANP, there occurred significant increases in urine flow (p< 0.001), inulin clearance (p < 0.001), filtration fraction (p = 0.007), and fractional clearance of sodium (p < 0.001) and of osmoles (p < 0. 001) compared with C. During the study, no differences in mean arteria l pressure, heart rate, and right atrial pressure, heart rate, and rig ht atrial or pulmonary capillary wedge pressure were detected between the groups. Cqrdiac index decreased by 5% in ANP compared with a 9% in crease in C (p = 0.027). Vasopressin levels significantly increased in C but remained at baseline levels in ANP (p = 0.031). There were no c hanges in levels of catecholamines or angiotensin II. Conclusions: The results of this study show that ANP increases diuresis, natriuresis, and glomerular filtration in the immediate postoperative period after coronary bypass surgery. Copyright (C) 1996 by W.B. Saunders Company