Left ventricular remodeling with preserved function after coronary microembolization: the effect of methylprednisolone

BACKGROUND: The objective of this study was to evaluate changes in left ventricular ejection fraction (LVEF) and left ventricular remodeling after coronary microembolization (CME) and to investigate the protective effects of methylprednisolone (MTP). METHODS: CME was induced by injection of microspheres (42 μm Dynospheres) into left anterior descending artery of mini swine. The animals were divided into two groups. Group 1 (n = 9) received 120,000 microspheres and Group 2 (n = 7) received 120,000 microspheres following intravenous administration of 30 mg/kg MTP. Contrast-enhanced magnetic resonance imaging (CeMRI) was performed at baseline, 6 h after intervention, and 1 week later. RESULTS: In Group 1, LVEF was significantly decreased at 6 h but recovered 1 week. This was accompanied by continuing left ventricular remodeling. In Group 2, LVEF remained unchanged at all assessment times. LVEF measured at 6 h and 1 week after CME in Group 1 and Group 2 was 0.39 ± 0.06 and 0.44 ± 0.04, and 0.44 ± 0.04 and 0.48 ± 0.03, respectively (Both P >0.05). Hyperenchancement at the anterior wall of the left ventricle was shown by MRI at 6 h in Group 1 but not in Group 2. The hyperenhanced area in Group 1 was 7.77 ± 1.49% of left ventricular mass. CONCLUSIONS: The consequence of CME is left ventricular dilation with preserved LVEF. Pretreatment with MTP appears to have a cardioprotective effect on left ventricular remodeling.