Abstract 16617: Multimodality Imaging Approach in Delivery and Tracking of a Novel Imageable Hydrogel in a Chronic Porcine Infarct Model

Abstract

Introduction: Left ventricular (LV) remodeling is a known complication from myocardial infarction (MI). Intramyocardial hydrogel (HG) delivery can potentially prevent LV remodeling post MI. We evaluated the feasibility of using multimodality imaging approach to assess the delivery and response to an imageable HG in a chronic porcine MI model. Methods: Nine Yorkshire pigs subjected to 90 min balloon occlusion and reperfusion were randomized 5 days post MI to delivery of HG (n=5) or controls (n=4). 99m Tc-Tetrofosmin was injected during the occlusion to assess risk area (RA). The imageable HG (Hyaluronic Acid/Gelatin modified with Aldehydes and Hydrazides, with 100 mg/mL iohexol) was delivered intramyocardially in a 3x3 grid 5 days post-MI after assessing MI region with Hybrid 201 Tl SPECT/CT. Contrast cineCT angiography was performed at baseline, 5 days post MI and 1 hour and 1 week post thoracotomy to assess LV geometry, HG location and CT intensity expressed as Hounsfield units (HU). Results: The average RA was 16.7% LV with no difference between the groups (p=0.44). The HG was delivered to the MI region with guidance of SPECT/CT. The HG was visible with cineCT post-delivery within perfusion defect (MI: 154 ± 26 HU; remote 82 ± 20 HU, p<0.0001), but it was not visible 1 week post-delivery (MI: 79 ± 12 HU; remote 80 ± 14 HU, p=0.94). The wall thickening of the MI region dropped by 33% in both groups (p=0.99) at 5 days post MI. After HG delivery wall thickening increased by 33% in the HG group but decreased by 31% in the control group (HG: 2.42 ± 0.33 mm; Control: 1.25 ± 0.31 mm, p=0.041). After similar increase in end diastolic volume (EDV) 5 days post MI (p=0.43), the EVD was significantly reduced post HG delivery in the HG group (6.0 ± 2.0 ml reduction) compared to the control group (6.3 ± 4.4 ml increase, p=0.042). Conclusions: Multimodality imaging is a feasible method to guide and track the delivery of a novel imageable HG. Intramyocardial HG delivery was associated with decreased LV remodeling.