Shankar Kumar Biswas

Discrepancy between myocardial perfusion and fatty acid metabolism following acute myocardial infarction for evaluating the dysfunctional viable myocardium.

OBJECTIVE Following acute myocardial infarction (AMI) the area of myocardial perfusion and metabolism mismatch is designated as dysfunctional viable myocardium. (123)I-beta-methyl iodophenyl pentadecanoic acid (BMIPP) is clinically very useful for evaluating myocardial fatty acid metabolism, and (99)mTc-Tetrofosmin (TF) is a widely used tracer for myocardial perfusion. This study was designed to evaluate the degree of discrepancy between BMIPP and TF at the subacute state of AMI. METHODS Fifty-two patients (aged 59 ± 10 years; mean 46 years) with AMI were enrolled, and all of them underwent percutaneous coronary intervention (PCI). Patients were classified according to ST-T change and PCI timing. (123)I-beta-methyl iodophenyl pentadecanoic acid and TF cardiac scintigraphy were performed on 7 ± 3.5 days of admission using a dual headed gamma camera. Perfusion and fatty acid metabolism defect were scored on a 17 segments model. RESULTS The mean BMIPP defect score on early and delayed images were 16.67 ± 10.19 and 16.25 ± 10.40, respectively. The mean TF defect score was 10 ± 7.69. Defect score of BMIPP was significantly higher than that of the TF (P < 0.0001; 95% CI 4.32-7.02), and there was a strong correlation between perfusion and metabolism defect score (r = 0.89, P < 0.00001). Forty-seven (90%) patients showed mismatched defect (BMIPP > TF), and 5 (10%) patients showed matched defect (BMIPP = TF). Mismatched defect score (MMDS) was significantly higher in patients with ST-segment elevation myocardial infarction (STEMI) than that of non-ST-segment elevation myocardial infarction (NSTEMI) (P < 0.041; 95% CI 0.11-5.19). CONCLUSION At the subacute state of AMI, most of the patients showed perfusion-metabolism mismatch, which represents the dysfunctional viable myocardium, and patients with STEMI showed higher mismatch.

P-115 Diastolic Stunning Following Acute Myocardial Infraction: Role of Conventional Echocardiography

Some studies have shown that predischarge stress perfusion imaging after AMI gives incremental prognostic information. On the other hand, I-123-BMIPP at rest has been actively applied to patients with AMI. However, no data are available in comparison between long-term prognosis assessment with early rest I-123-BMIPP and predischarge stress perfusion imaging. The aim of this study was to investigate incremental prognostic values of early rest I-123-BMIPP imaging after AMI compared to predischarge stress perfusion imaging established. Data from 107 consecutive patients with AMI who had undergone both early rest I-123-BMIPP and predischarge stress perfusion imaging were analysed. Tracer uptake was graded using a 17-segment model and the total defect score (TDS) was calculated. Patients were followed up for 60 months with primary end points (cardiac death, nonfatal AMI) as hard events and with secondary end points (late revascularization, recurrent angina and heart failure) as soft events. For overall cardiac events (11 hard and 29 soft events), Kaplan-Meier analysis revealed significantly lower event rates in subgroups with I-123-BMIPP and perfusion tracer with TDS of <18, or absence of diabetes mellitus when compared to each counterpart. For the prediction of primary hard events, the stepwise elimination with I-123BMIPP TDS forced in the first step was performed. In conclusion, impaired I-123-BMIPP uptake are related to high probability of cardiac events, suggesting prognostic value to differentiate “vulnerable patients” on impaired fatty acid metabolism following AMI.