DIAGNOSIS OF PERIOPERATIVE MYOCARDIAL NECROSIS FOLLOWING CORONARY-ARTERY SURGERY - A REAPPRAISAL OF ISOENZYME ANALYSIS

Although the routine determination of CK-MB activity is widely used after coronary artery bypass grafting (CABG), the diagnosis of a perioperative myocardial necrosis remains arbitrary. The intention of the present study was to develop discriminative enzymatic parameters of CK-MB activity in a collective of 710 patients following CABG. Patients were grouped according to their postoperative electrocardiogram (ECG). For each patient, the time activity curve of CK-MB was determined. The total amount of CK-MB was calculated by integrating the area beneath the CK-MB activity curve. Patients presenting with an unchanged postoperative ECG (group I) or a new bundle branch block with uncompromiscd hacmodynamics (group II a) had an uniform and low profile of CK-MB activity. Serial CK-MB activities as well as the integrated CK-MB area of these two collectives were significantly different (P < 0.001) from values determined for patients with bundle branch block and low cardiac output (group II b) or patients with new Q waves (group III). After 24 h, the 90th percentile of serial CK-MB activities of group I had declined to 18 U/l and was clearly exceeded by 90% of all patients that belonged to either group II b or III. The 90th percentile of CK-MB areas for group I showed a value of 801 U/l × h. CK-MB areas above 801 U/l × h were seen in about 50% of all patients of group II a. The uncomplicated course, the fast reversibility of the bundle branch block and the low range of CK-MB areas between 801 and 1470 U/l × h, however, showed the benign character of this fascicular conduction disturbance in patients of group II a. On the other hand, 2 patients (8.6%) in group II b and 5 patients (12.5%) in group Ill had falsenegative CK-M B areas below 801 U/l × h. In conclusion. limit values of serial CK-MB or integrated CK-MB areas derived from a large collective of patients with unchanged postoperative electrocardiogram can be used to identify patients with perioperative myocardial necrosis. © Springer-Verlag 1990.