Angiotensin Converting Enzyme Inhibitors and Cardiopulmonary Bypass: Is ACE Inhibitor Safe for Heart Surgery?

Ischemia/reperfusion injury is unavoidable during cardiopulmonary bypass surgery because the surgery is conducted during ischemic arrest of the heart. Animal studies have shown that the administration of angiotensin converting enzyme (ACE) inhibitors can protect against lethal arrhythmias, preserve ventricular function, and improve coronary reserve after ischemia/reperfusion. Two factors to consider when using ACE inhibitors are their temperature dependency (because cardiopulmonary bypass surgery is usually done under hypothermic conditions) and their direct effect on the bypass material. In this paper, we review studies of ACE inhibitors and discuss both their temperature dependency and their effect on bypass material, especially on the coating of the circuit tube and artificial lung. Finally, we explore the potential clinical applications of ACE inhibitors in cardiopulmonary bypass surgery, taking into consideration the findings of our own preliminary clinical study.