Comparative Effects of Angiotensin Receptor Blockade and ACE 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 after cardiopulmonary bypass (CPB) are uncertain. This study tested the hypothesis that ACE inhibition enhances fibrinolysis and inflammation to a greater extent than ARB in patients undergoing CPB. One week to 5 days before surgery, patients were randomized to ramipril 5 mg/day, candesartan 16 mg/day, or placebo. ACE inhibition increased intraoperative bradykinin and tissue-type plasminogen activator (t-PA) concentrations as compared to ARB. Both ACE inhibition and ARB decreased the need for plasma transfusion relative to placebo, but only ACE inhibition decreased the duration of hospital stay. Neither ACE inhibition nor ARB significantly affected concentrations of plasminogen activator inhibitor-1 (PAI-1), interleukin (IL)-6, IL-8, or IL-10. ACE inhibition enhanced intraoperative fibrinolysis without increasing the likelihood of red-cell transfusion. By contrast, neither ACE inhibition nor ARB affected the inflammatory response. ACE inhibitors and ARBs may be safely continued until the day of surgery.