Retrograde versus antegrade crystalloid cardioplegia in coronary surgery: value of troponin-I measurement

Background. The optimal route for delivery of cardioplegia is still in debate in patients with ischemic heart disease. Cardiac troponin-I is a new marker with the potential for detection of minor differences in myocardial ischemia. Methods. In a prospective randomized trial 58 patients undergoing elective coronary artery bypass grafting for two- or three-vessel coronary artery disease were divided into groups with antegrade (group A, N = 29) and retrograde (group R, N = 29) application of crystalloid cardioplegia (St. Thomas II). Patients with major risk factors were excluded. In addition to routine electrocardiogram monitoring, cardiac troponin-I and creatine kinase-MB activity were measured in all patients preoperatively at 2, 5, 8, 24, and 48 hours after aortic cross-clamp release, and at hospital discharge. Results. In both groups, there were no differences regarding operative parameters. A significantly higher cardiac troponin-I concentration was observed in the antegrade group at 24 hours after cross-clamp (8.2 ± 8.5 μg/L vs 3.2 ± 3.1 μg/L; p = 0.02). Patients with subtotal stenosis or occlusion of one or more main coronary arteries showed significantly lower cardiac troponin-I levels after retrograde application. Conclusions. Lower concentrations of the cardiac troponin-I marker after retrograde application of cardioplegia indicate advantages of myocardial protection in ischemic heart disease.