Haemodynamic and renal effects of intravenous enalaprilat during coronary artery bypass graft surgery in patients with ischaemic heart dysfunction

Abstract

Renal dysfunction occurring after open heart surgery is multifactorial in origin but activation of the renin-angiotensin system may have a prominent role. Fourteen patients with ischaemic heart dysfunction scheduled for elective coronary artery bypass graft (CABG) surgery were allocated to a treatment group [enalaprilat for 2 days; ACEI (angiotensin-converting enzyme inhibitor) group, n=7] or a control group (n=7). The cardiac index was significantly higher in ACEI-treated patients than in the controls before and after cardiopulmonary bypass (CPB) (P<0.05) and on postoperative day 2 (P<0.05). The systemic vascular resistance was significantly lower in the ACEI-treated patients than in the controls before and after CPB (P<0.05). Renal plasma flow, measured as [131I]orthoiodohippuran clearance (ClH), was higher in the ACEI group than in the control group before CPB, as was endogenous creatinine clearance after CPB (P<0.05). On post-operative day 7, ClH was significantly higher in the ACEI group than in the control group (P<0.05). Plasma renin activity and vasopressin concentration increased in both groups during CPB (P<0.05). The study demonstrates that administration of an i.v. ACEI, enalaprilat, improves cardiac output during CABG surgery in patients with ischaemic heart dysfunction. Moreover, renal perfusion was better maintained during surgery, and this effect was sustained up to post-operative day 7.