Prophylactic Vasopressin in Patients Receiving the Angiotensin-Converting Enzyme Inhibitor Ramipril Undergoing Coronary Artery Bypass Graft Surgery

ObjectiveThe purpose of this study was to compare the effects of continuation versus discontinuation of the angiotensin-converting enzyme (ACE) inhibitor ramipril and assess the efficacy of prophylactic vasopressin infusion on hemodynamic stability and vasoactive drug requirements in patients undergoing coronary artery bypass graft (CABG) surgery.DesignA prospective, randomized, double-blinded, single-center clinical study.SettingTertiary care hospital.ParticipantsForty-seven patients on the ACE inhibitor ramipril for 6 weeks before undergoing elective primary CABG surgery on cardiopulmonary bypass (CPB).InterventionsPatients were randomly divided into 3 groups: group A (n = 16), patients discontinued ramipril 24 hours before surgery; group B (n = 16), patients continued ramipril until the morning of surgery; and group C (n = 15), patients continued ramipril until the morning of surgery and received vasopressin infusion (0.03 U/min) from the onset of rewarming until the hemodynamics were stable without vasopressor agents. The anesthetic technique and conduct of CPB were standardized for all the groups. Hemodynamic parameters and vasoactive drug requirements were recorded for 3 days postoperatively.Measurements and Main ResultsPatients in group A maintained stable mean arterial pressure (MAP) and systemic vascular resistance (SVR). In group B, MAP and SVR decreased after the induction of anesthesia and remained so throughout surgery (p < 0.05). In group C, MAP and SVR decreased upon the induction of anesthesia (p < 0.05) but normalized after CPB.ConclusionsPreoperative ACE inhibitor continuation predisposed to hypotension upon the induction of anesthesia and in the post-CPB period. Prophylactic low-dose vasopressin infusion prevented post-CPB hypotension. Low-dose vasopressin can be considered as potential therapy in these patients.