The Effects of Trimetazidine on the Enhancement Pattern of Multi-detector Computed Tomography in a Porcine Myocardial Infarction Model

ABSTRACT

BACKGROUND AND OBJECTIVES: There is increasing evidence to suggest that trimetazidine (TMZ) has the ability to improve ischemic heart failure by way of optimizing the heart's energy metabolism. The aim of this study was to examine the changes of the myocardial enhancement pattern by using two-phase, contrast enhanced, ECG-gated, multi-detector computed tomography (MDCT) after the administration of TMZ in a porcine myocardial infarction model. SUBJECTS AND METHODS: The porcine myocardial infarction model was created by balloon occlusion of the left anterior descending coronary artery. We randomized the swine into two groups group I (n=7 aspirin only) and group II (n=7 aspirin plus 1 mg/kg TMZ for 4 weeks). Echocardiography and MDCT were performed and the ejection fraction (EF, %), end-systolic volume (ESV, mL) and end-diastolic volume (EDV, mL) were measured at 28 days after induction of myocardial infarction. Three enhancement patterns, including the early arterial phase defect (ED), the 4-min late enhancement (LE) and the residual defect (RD), were also investigated and those were described as class I [ED (-), RD (-), LE (+/-)], class II [ED (+), RD (-), LE (+)], and class III [ED (+), RD (+), LE (+)]. We performed histopathologic examination after sacrificing the animals. RESULTS: The baseline and follow-up echocardiography at 4 weeks after the induction of MI demonstrated no significant differences between the two groups. The LV indices by MDCT were also similar between the two groups (group I EF, ESV and EDV=46.0+/-12.5%, 35.9+/-23.0 mL and 69.0+/-40.2 mL, respectively, group II EF, ESV and EDV=49.8+/-13.2%, 43.8+/-23.1 mL and 82.8+/-24.6 mL, respectively, p=NS). The percent wall thickness was similar (69.1+/-19.6% vs. 64.9+/-10.5%, respectively, p=NS), but the enhancement pattern was different between the two groups (group I class I, II and III=0 (0%), 0 (0%) and 7 (100%) respectively, group II class I, II and III=0 (0%), 2 (28.6%) and 5 (71.4%), respectively, p<0.001). The volume of tissue that lacked triphenyl tetrazolium chloride was similar between two groups (8.4+/-1.9% vs. 7.3+/-2.6%, respectively, p=NS). CONCLUSION: TMZ administration produced different enhancement patterns on MDCT. This result suggests that TMZ administration can reduce the residual defect in a porcine myocardial infarction model. Although further experiments are needed for determining the effect of TMZ on reducing the irreversible area of infarcted myocardium, this is the first report that proved the beneficial effect of TMZ by performing MDCT.