Comparative Effects of Angiotensin Receptor BlockadeandACE Inhibition on the Fibrinolytic and Inflammatory Responses to Cardiopulmonary Bypass

The effects of angiotensin-converting enzyme (ACE) inhibition and angiotensin II type 1 receptor blockade (ARB) on fibrinolysis and inflammation following cardiopulmonary bypass (CPB) are uncertain. This study tested the hypothesis that ACE inhibition enhances fibrinolysis and inflammation to greater extent than ARB in patients undergoing CPB.One week to five days prior to surgery, patients were randomized to ramipril 5mg/day,candesartan 16mg/day or placebo.ACE inhibition increased intraoperative bradykinin and tissue-type plasminogen activator (t-PA) concentrations compared to ARB. Both ACE inhibition and ARB decreased plasma transfusion compared to placebo, but only ACE inhibition decreased length of stay. Neither ACE inhibition nor ARB significantly affectedplasminogen activator inhibitor-1 (PAI-1), interleukin (IL)-6, IL-8, or IL-10 concentrations. ACE inhibition enhanced intraoperative fibrinolysis without increasing red cell transfusion risk. In contrast, neither ACE inhibition nor ARB affected the inflammatory response. ACE inhibitors and ARB may be safely continued until the day of surgery.