Attenuation of left ventricular adverse remodeling with epicardial patching after myocardial infarction.

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.