Abstract 2804: Relationship between Tissue Level Perfusion Parameters and Infarct Size in Patients with Acute Myocardial Infarction
Background: Despite its prognostic importance, accurate assessment of microvascular perfusion in patients with acute myocardial infarction (AMI) is difficult. Relations between the methods which have been suggested to evaluate status of microcirculation and infarct size are unknown. In this study we interrogated microvascular integrity with multiple invasive and non-invasive indices and sought their relations with infarct size.
Methods and Results: Forty-one patients with AMI who underwent primary percutaneous intervention were included. ST segment resolution (STR) was calculated from surface ECG. At 48 hours patients were recatheterized to evaluate microvascular integrity. Myocardial blush grades (MBG), corrected TIMI frame counts (TFC), coronary flow reserve (CFR), pressure derived collateral flow index (CFIp), coronary wedge pressure (CWP), and index of microvascular resistance (IMR) were determined. Diastolic deceleration time (DDT) of diastolic flow of infarct related artery was measured echocardiographically. Infarct size was measured in patients with single photon emission tomography using Bull’s eye method at six month. Multivariate analysis models including diabetes mellitus, peak troponin T, pain to balloon time, preinfarction angina, anterior AMI location and each of the microvascular perfusion indices were built. Infarct size was found to be significantly and independently related with CFR (r = -0,50; p = 0,002), IMR (r = 0,48; p = 0,003), CWP (r = 0,461; p = 0,005), DDT (r = −0,45, p = 0,02), CFIp (r = 0,422; p = 0,007), MBG (r = − 0,411; p = 0,014) and TFC (r = 0,40; p = 0,01) respectively. No correlation was found between infarct size and STR (r = 0, 23; p =0, 20).
Conclusion: Extend of microvascular damage after AMI correlates well with infarct size. The correlations of infarct size with invasive and quantitative indices (IMR, CFR, CWP, CFIp) were stronger than the correlations with noninvasive (DDT) or semi-quantitative (MBG, TFC) indices. STR was not found to be correlated with infarct size.