The relation between myocardial blush grade and myocardial contrast echocardiography: which one is a better predictor of myocardial damage?

Background. Myocardial blush grade (MBG) and myocardial contrast echocardiography (MCE) are both indices for myocardial perfusion in patients with ST-elevation acute myocardial infarction (STEMI). We aimed to compare MBG with MCE in the infarct-related artery segment for assessing infarct size in patients with STEMI treated with primary percutaneous coronary intervention (PCI).Methods. 43 patients underwent successful (postprocedural TIMI flow 3) primary PCI for STEMI. MBG was assessed at the end of the PCI procedure and MCE was assessed 1.7+/-1.8 days after PCI. Enzymatic infarct size was estimated by measurementof enzyme activities by using lactate dehydrogenase (LDH) as the referenceenzyme. Cumulative enzyme release (LDHQ(48)) from at least five serial measurements up to 48 hours after symptom onset was calculated. Also peak creatine kinase, CK-MB and peak LDH were measured.Results. MBG 0/1, 2 and 3 were observed in 14, 12 and 17 patients, respectively, and was compared with tertiles of MCE. We found a parallel correlation between both MBG and MCE and LDHQ(48). However, there was no correlation between MCE and MBG. Patients with both normal MCE and a normal MBG had least myocardial damage and those with both impaired MCE and an impaired MBG had most myocardial damage.Conclusion. Both MBG and MCE are good predictors of infarct size in STEMI patients treated with PCI. However, these markers are not mutually related, possibly due to time-related changes in myocardial perfusion. Combining these two markers may yield a more accurate prediction of final myocardial damage. (Neth Heart J 2010;18:25-30.).