Cardioplegic arrest with L-arginine improves myocardial protection: results of a prospective randomized clinical trial.

Abstract

Blood cardioplegic arrest remains the method of choice for myocardial protection. L-arginine has been suggested to improve protection through an increase in nitric oxide production. A prospective, randomized, double-blinded clinical trial comparing standard blood cardioplegic solution to L-arginine-enriched solution (7.5 g/500 mL) enrolled 200 patients undergoing coronary artery bypass grafting. Clinical data and biochemical markers of ischemia were recorded. Warm blood cardioplegia (33 degrees C) was administered in 74% of patients and cold blood (20 degrees C) was used in 26% of patients. Both groups averaged three grafts per patient. There were two (2%) deaths in both groups. There were four (4%) myocardial infarctions (MI) in the control group and six (6%) infarctions in the L-arginine group (p = 0.5). For the 190 patients without MI, serum levels of troponin T averaged 0.40+/-0.43, 0.38+/-0.42, and 0.39+/-0.50 microg/L in control patients compared with 0.28+/-0.22, 0.24+/-0.18, and 0.27+/-0.20 microg/L in L-arginine patients, respectively, 12, 24 and 48 hours after coronary artery bypass grafting (p = 0.03). The cardiac index averaged 2.7+/-0.8 L x min(-1) x m(-2) in control patients and 2.9+/-0.7 L x min(-1) x m(-2) in arginine patients immediately after surgery (p = 0.09). Intensive care unit and hospital length of stay averaged 3.5+/-5 days and 7.3+/-6 days in control patients compared with 2.5+/-3 days and 6.1+/-4 days in arginine patients (p = 0.09). L-arginine-supplemented blood cardioplegic solution is associated with reduced release of biochemical markers of myocardial damage, suggesting improved myocardial protection.