Abstract 14327: Intramyocardial Delivery of an Imageable Theranostic Hydrogel Post Myocardial Infarction Alters Regional Strain and Reduces Remodeling in Chronic Porcine Model

Abstract

Introduction: Myocardial infarction (MI) causes acute regional changes in stiffness and strain, resulting in pathological remodeling in the left ventricle (LV). Intramyocardial injection of hydrogel (HG) into the MI region may alter deformation and improve LV remodeling. Using high resolution cineCT (CCT) we evaluated changes in regional strain, global function, and geometry in chronic porcine MI model. Methods: Yorkshire pigs (n=12) subjected to 90 min balloon occlusion and reperfusion were randomized 5 days post MI to intramyocardial delivery of MI+HG (n=6) or MI only (n=6). Imageable HG was delivered in a 3x3 grid after assessing MI region with hybrid 201 Tl SPECT/CT. Contrast CCT was performed at baseline, day 5 (post MI before HG delivery), and day 12 (7 days post HG delivery) to assess end diastolic volume (EDV) and ejection fraction (EF). Custom software was used to calculate 3D myocardial Lagrangian strains on 6 HG animals and 3 MI only animals in remote, border (>50% normal) and MI regions (<50% normal). Results: At day 5 in both groups, EDV increased by 13.2% (p=0.016), LVEF decreased by 15.7% (p=0.008), and radial strain (E rr ) decreased in MI region by -0.11 (p=0.007). On day 12, EDV decreased by 8.3% in the MI+HG group but increased by 10.4% in the MI only group (p=0.003). LVEF increased significantly in the MI+HG group by 8.96% and was significantly greater than in MI only group (p=0.027) which had no significant changes. Average change in E rr between baseline and day 12 was not different between groups within the MI (p=0.13) or border region (p=0.67). However, average E rr did not decline in the MI+HG group (+0.029) but significantly declined in MI only group (-0.14, p=0.017) (MI+HG vs MI only; p=0.003), mirroring EDV changes. Conclusions: Intramyocardial delivery of HG 5 days post-MI resulted in greater improvement in E rr in remote region and global LVEF and a decrease in EDV suggesting reduced LV remodeling compared to MI only controls.