Correlation between Thrombolysis in Myocardial Infarction, the Myocardial Perfusion Grade and the Myocardial Viability Indices after Primary Percutaneous Coronary Intervention in ST Segment Elevation Myocardial Infarction

Abstract

Background and Objectives: The thrombolysis in myocardial infarction (TIMI) myocardial perfusion grade (TMPG) is associated with the long term clinical outcomes. This study compared the TMPG with the myocardial viability as determined by 18F-fluorodeoxyglucose positron emission tomography (FDG-PET), and with improvement of the left ventricular (LV) function on echocardiography.

Subjects and Methods: We enrolled 44 consecutive patients (37 men: age 56±11 years) who underwent primary percutaneous coronary intervention (PCI) for ST segment elevation myocardial infarction (STEMI). We assessed the coronary flow reserve (CFR), the diastolic deceleration time (DDT), the coronary wedge pressure (Pcw) and the coronary wedge pressure/mean aortic pressure (Pcw/Pa). All the patients underwent FDG-PET scans on the 7th day after primary PCI. The patients were divided into 3 groups according to the TMPG (TMPG 0/1: n=18, TMPG 2: n=14, TMPG 3: n=12).

Results: There was a significant correlation between the TMPG and the CFR, DDT, Pcw and Pcw/Pa (r=0.367, p=0.017; r=0.587, p<0.001; r=-0.513, p<0.001; r=-0.614, p<0.001, respectively). There was a significant correlation between the TMPG and the % of FDG uptake (r=0.587, p<0.001) and the patients with TMPG 3 had the most favorable % of FDG uptake (TMPG 0/1 vs TMPG 2 vs TMPG 3; 42.0±12.3% vs 53.9±11.2% vs 59.3±13.3%, p=0.001). On echocardiography, the patients with TMPG 3 revealed an improvement of the LV ejection fraction (53.4±9.9% vs 60.0±7.0%, p=0.004) and the patients with TMPG 2 and TMPG 3 revealed improvement of their regional wall motion abnormality (RWMA) index (1.44±0.26 vs 1.24±0.18, p=0.022; 1.35±0.26 vs 1.15±0.18, p=0.018, respectively).

Conclusion: The angiographically determined TMPG might be clinically useful for the assessment of myocardial viability and it might be a useful predictor for improvement of the LV function in patients suffering with STEMI.