Abstract
BACKGROUND: Early infarct expansion after coronary occlusion compromises contractile function in perfused myocardial regions and promotes adverse long-term left ventricular (LV) remodeling. We hypothesized that injection of a tissue-expanding dermal filler material into a myocardial infarction (MI) would attenuate infarct expansion and limit LV remodeling. METHODS: Fifteen sheep were subjected to an anteroapical MI involving approximately 20% of the LV followed by the injection of 1.3 mL of a calcium hydroxyapatite-based dermal filler into the infarct. Real-time three-dimensional echocardiography was performed at baseline, 30 minutes after MI, and 15 minutes after injection to assess infarct expansion. Sixteen additional sheep were subjected to the same infarction and followed echocardiographically and hemodynamically for 4 weeks after MI to assess chronic remodeling. Eight animals had injection with dermal filler as described above immediately after MI, and 8 animals were injected with an equal amount of saline solution. RESULTS: All animals exhibited infarct expansion soon after coronary occlusion. The regional ejection fraction of the apex became negative after infarction, consistent with systolic dyskinesia. Injection of the dermal filler converted the apical wall motion from dyskinetic to akinetic and resulted immediately in significant decreases in global, regional, and segmental LV volumes. Chronically, relative to saline control, dermal filler injection significantly reduced LV end-systolic volume (62.2 +/- 3.6 mL versus 44.5 +/- 3.9 mL; p < 0.05) and improved global ejection fraction (0.295 +/- 0.016 versus 0.373 +/- 0.017; p < 0.05) at 4 weeks after infarction. CONCLUSIONS: Injection of an acellular dermal filler into an MI immediately after coronary occlusion reduces early infarct expansion and limits chronic LV remodeling.