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

Background. The optimal route for delivery of cardioplegia is still in deba te in patients with ischemic heart disease. Cardiac troponin-I is a new mar ker with the potential for detection of minor differences in myocardial isc hemia. Methods. In a prospective randomized trial 58 patients undergoing elective coronary artery bypass grafting for two- or three-vessel coronary artery di sease were divided into groups with antegrade (group A, n = 29) and retrogr ade (group R, n = 29) application of crystalloid cardioplegia (St. Thomas I I). Patients with major risk factors were excluded. In addition to routine electrocardiogram monitoring, cardiac troponin-I and creatine kinase-MB act ivity were measured in all patients preoperatively at 2, 5, 8, 24, and 48 h ours after aortic cross-clamp release, and at hospital discharge. Results. In both groups, there were no differences regarding operative para meters. A significantly higher cardiac troponin-I concentration was observe d in the antegrade group at 24 hours after cross-clamp (8.2 +/- 8.5 mug/L v s 3.2 +/- 3.1 mug/L; p = 0.02). Patients with subtotal stenosis or occlusio n 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 re trograde application of cardioplegia indicate advantages of myocardial prot ection in ischemic heart disease.