Angiotensin converting enzyme inhibitor therapy in severe postcardiotomy dysfunction: a prospective randomized study

Occurrence of severe postcardiotomy dysfunction requiring prolonged postoperative support with intra-aortic balloon counterpulsation (IABP) and inotropes, complicating surgery for coronary artery disease and valvular heart disease carries important hospital morbidity and mortality. This study evaluated the impact of angiotensin converting enzyme inhibitor (captopril) therapy in these patients in the early postoperative period.

During a 5-year period, 298 patients with prolonged diminished cardiac output required support (> 48 to 72 hours) with IABP plus two or three inotropes. This cohort was randomized to two groups, group A (195 patients) who were continued on IABP and inotropes alone and group B (103 patients) who were given an angiotensin converting enzyme (ACE) inhibitor, captopril 48 to 72 hours postoperatively and continued on IABP and inotropes.

Tissue perfusion and hemodynamic parameters improved (p < 0.0001) in group B with early termination of IABP (duration of support mean 86 hours in group B vs 169 hours in group A) and inotropes. Peak improvement in tissue perfusion and hemodynamic parameters correlated with decreased serum angiotensin converting enzyme levels. Hospital mortality occurred in 31% of patients in group A and 14.5% in group B. Morbidity complications developed in 37% of patients in group A and 20% in group B. The average length of hospital stay in group A was 27 days and 17 days in group B. Cardiac, pulmonary, infective, gastrointestinal, renal, and neurological complications were common in both groups.

Administration of ACE inhibitors in the early postoperative period to patients with severe postcardiotomy dysfunction caused improvement in tissue perfusion with decreases in mortality, morbidity, and length of hospital stay. These drugs, by effectively limiting physiological effects induced by renin angiotensin-aldosterone axis and other mechanisms, caused recovery of stunned myocardium. More randomized trials are needed before recommending these drugs for routine use in similar patients.