Assessment of the myocardial protective effect of antegrade warm blood cardioplegia by measuring the release of biochemical markers.

Intermittent warm blood cardioplegia has been reported as a valuable alternative for myocardial protection in cardiac surgery; however, conflicting experimental data have been published. To assess the clinical effectiveness of intermittent warm cardioplegia, we measured the release of troponin-T (Tn-T), a highly sensitive and specific marker of myocardial damage, and creatine kinase MB isoenzyme (CK-MB), in 12 patients who underwent elective coronary artery bypass grafting (CABG) with antegrade intermittent warm blood cardioplegia (37 degrees C) being the warm group, in comparison with 16 patients who underwent CABG with antegrade intermittent cold blood cardioplegia (4 degrees C) being the cold group. Blood samples were taken to determine the serum concentrations of CK-MB and Tn-T, at the induction of anesthesia, then 3, 6, 12, and 24h after the termination of cardiopulmonary bypass (CPB). The peak increase in serum CK-MB levels, 3h after CPB, was significantly lower in the warm group than in the cold group, at 27.8+/-7.8 IU/l vs. 40.8+/-12.6 IU/l, respectively (P = 0.0042). The serum Tn-T 12 h after CPB was significantly lower in the warm group than in the cold group, at 1.40+/-0.71 ng/ml vs. 2.06+/-0.95 ng/ml, respectively (P = 0.049). In conclusion, intermittent antegrade warm blood cardioplegia showed effective myocardial protection in elective CABG.