Attenuation of Left Ventricular Adverse Remodeling With Epicardial Patching After Myocardial Infarction

Abstract

Background: Previous studies suggested that epicardial patch applied to the infarcted site after acute myocardial infarction (MI) can alleviate left ventricular (LV) remodeling and improve cardiac performance; however, the effects of regional epicardial patch on chronic phase of LV remodeling remain unclear. Methods and Results: We studied 20 pigs with MI induced by distal embolization and impaired LV ejection fraction (LVEF <45%) as detected by gadolinium-enhanced cardiac magnetic resonance imaging (MRI). Eight weeks post-MI, all animal underwent open chest procedure for sham surgery (control, n = 12) or patch implantation over the infarcted lateral LV wall (patch group, n = 12). In the patch group, +dP/dt increased and LV end-diastolic pressure decreased at 20 weeks compared with immediately post-MI and at 8 weeks (P < .05), but not in the control group (P > .05). As determined by cardiac MRI, LV end-diastolic and end-systolic volumes increased at 20 weeks compared with 8 weeks in both groups (P < .05). However, the increase in LV end-diastolic volume (+14.1 ± 1.8% vs. +6.6 ± 2.1%, P = .015) and LV end-systolic volume (+12.1 ± 2.4% vs. -4.7 ± 3.7%, P = .0015) were significantly greater in the control group compared with the patch group. Furthermore, the percentage increase in LVEF (+17.3 ± 4.9% vs. +4.1 ± 3.9%, P = .048) from 8 to 20 weeks was significantly greater in the patch group compared with the control group. Histological examination showed that LV wall thickness at the infarct region and adjacent peri-infarct regions were significantly greater in the patch group compared with the control group (P < .05). Conclusion: Regional application of a simple, passive synthetic epicardial patch increased LV wall thickness at the infarct region, attenuated LV dilation, and improved LVEF and +dP/dt in a large animal model of MI. © 2010 Elsevier Inc. All rights reserved.