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

Background. 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. Methods. 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 (33degreesC) was administered in 74% of patients and cold blood (20degreesC) was used in 26% of patients. Both groups averaged three grafts per patient. Results. 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 mug/L in control patients compared with 0.28 +/- 0.22, 0.24 +/- 0.18, and 0.27 +/- 0.20 mug/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 (.) min(-1.) m(-2) in control patients and 2.9 +/- 0.7 L (.) min(-1) (.) 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). Conclusions. L-arginine-supplemented blood cardioplegic solution is associated with reduced release of biochemical markers of myocardial damage, suggesting improved myocardial protection. (C) 2002 by The Society of Thoracic Surgeons.