ESTIMATION OF ENZYMATIC INFARCT SIZE - DIRECT COMPARISON OF THE MARKER ENZYMES CREATINE-KINASE AND ALPHA-HYDROXYBUTYRATE DEHYDROGENASE

Background Estimation of infarct size with serum-time activity curves of creatine kinase (CK) (or CKMB) or alpha-hydroxybutyrate dehydrogena se (HBDH) is widely used in clinical trials. However, an independent v ariable such as left ventricular function has not been directly compar ed with CK and HBDH infarct size measurements in the same group of pat ients. Methods and Results Infarct size was calculated by the CK area under the curve (AUG) and by the cumulative release of HBDH in 90 pati ents with acute myocardial infarction undergoing early thrombolysis. I nfarct size estimates by CK AUC and HBDH release were closely correlat ed (r = 0.88, p < 0.0001). HBDH release was significantly better (p < 0.001) correlated to angiographically assessed election fraction 8 day s after infarction (r = 0.74) than to CK AUC (r = 0.60), as was maximu m HBDH (r = 0.71) compared with CK maximum (r = 0.59). In contrast to CK, maximum levels of HBDH only slightly overestimate myocardial damag e in patients with early reperfusion. Data reanalyzed from the former placebo-controlled Intravenous Streptokinase in Acute Myocardial Infar ction (ISAM) study revealed significant differences in favor of strept okinase for CK and CKMB AUC and for HBDH maximum, but no difference fo r CK and CKMB maximums. Conclusions For comparative clinical trials HB DH appears to be the preferable marker enzyme for estimates of infarct size and measure of reperfusion effectiveness. In clinical practice o ne routine measure of HBDH serum activity on the second day after infa rction may be a useful approximate value of infarct size.