Assessment of coronary reperfusion after thrombolysis with a model combining myoglobin, creatine Kinase-MB, and clinical variables

Background Several biochemical markers have been investigated for the noninvasive assessment of reperfusion after myocardial infarction. Because myoglobin is released very soon after myocardial injury and clears rapidly after reperfusion, it may prove to be an excellent marker of occlusion and reperfusion. Methods and Results We examined the relation between various myoglobin measures and Thrombolysis In Myocardial Infarction (TIMI) flow grade in 96 patients enrolled in a study of front-loaded thrombolysis who underwent 90-minute angiography. We also combined myoglobin measures with models that include clinical and creatine kinase-MB variables. The myoglobin level measured within 10 minutes of acute angiography showed the best overall performance and was used for later analyses. Of the clinical variables examined, only time from symptom onset to thrombolysis and chest pain grade at angiography discriminated among TIMI flow grades. Combining the 90-minute myoglobin level and these clinical variables showed a significant difference (P<.0001) between both TIMI 3 versus TIMI 0 through 2 and TIMI 2 or 3 versus TIMI 0 or 1 flow. When the 90-minute myoglobin level was added to an established predictive model containing clinical variables and creatine kinase-MB measures, its contribution remained significant (P=.044). The area under the receiver operator characteristic curve for this combined model was .88. Conclusions A single myoglobin measurement obtained 90 minutes after the start of thrombolysis, combined with select clinical variables and creatine kinase-MB levels, enhances the noninvasive prediction of reperfusion after myocardial infarction.