Angiotensin in Cardiac Surgery: Efficacy in Patients on Angiotensin Converting Enzyme Inhibitors

BACKGROUND: Patients presenting for cardiac surgery are often treated with angiotensin converting enzyme inhibitors (ACEIs), either for heart failure or hypertension. Control of systemic vascular resistance (SVR) during surgery can be difficult in such patients. Angiotensin II has been available as an unlicensed vasoconstrictor, but there is concern about renal damage and its use. AIM: This study compared a standard vasoconstrictor with angiotensin II and examined the effect on renal function after cardiac surgery. METHOD: Twenty consecutive, consenting patients scheduled for cardiac surgery that had been taking ACEIs for at least 6 months, were randomly assigned to receive either phenylephrine or angiotensin II for the control of SVR during and for 24 h after cardiac surgery. A pulmonary artery catheter was used to guide therapy. Creatinine clearance was measured before, 24 and 48 h after surgery. RESULTS: Low SVR and blood pressure requiring intervention was seen in all patients, particularly during cardiopulmonary bypass. One patient in the control group failed to respond to P, but responded normally to angiotensin II. Neither drug caused renal impairment. CONCLUSION: Angiotensin II is a safe alternative to phenylephrine in patients on ACEIs and should be considered in patients who fail to respond to conventional vasoconstrictors.