Cardiac troponin T and creatine kinase MB isoenzyme as biochemical markers of ischemia after heart preservation and transplantation.

An ischemic preservation period of less than 4 to 6 hours for the donor heart is considered safe in heart transplantation. To determine the severity of myocardial cell damage, we measured serum creatine kinase MB isoenzyme activity, creatine kinase MB isoenzyme mass concentration, and troponin T release in 14 patients during the first 48 hours after heart transplantation. All donors had normal cardiac function at echocardiographic evaluation. The heart was arrested with cold crystalloid cardioplegic solution and preserved in a hypothermic solution. All patients survived the first week after transplantation. Total ischemic time averaged 126 +/- 33 minutes (range 88 to 195 minutes). Maximal creatine kinase MB isoenzyme activity, creatine kinase MB isoenzyme mass concentration, and troponin T serum values after transplantation averaged 130 +/- 44 IU/L, 140 +/- 121 ng/ml, and 3.3 +/- 1.4 ng/ml, respectively. No significant correlation was found between ischemic time and peak levels of creatine kinase MB isoenzyme activity (r = 0.22), creatine kinase MB isoenzyme mass (r = 0.37) and troponin T (r = 0.12). A moderate correlation between ischemic time and the initial slope of time-activity curve of creatine kinase MB isoenzyme mass (r = 0.66, p = 0.01) and of troponin T release (r = 0.55, p = 0.03) was observed. Ischemic time and donor age were significantly related to creatine kinase MB isoenzyme mass (R2 = 0.61) and to troponin T (R2 = 0.47) initial release slopes. In conclusion, during a short period of ischemic preservation, myocardial cell damage appears to be mild and best reflected by the elevation and the time-activity curves of release of cardiac troponin T and creatine kinase MB isoenzyme mass.