901-56 Contrast Echocardiography Detects the Development Coronary Collateral Blood Flow: Validation in a Porcine Model of Gradual Coronary Occlusion

Abstract

Few data exist directly documenting the ability of contrast echo (CE) to demonstrate the presence and development of coronary collaterals. Therefore, we performed serial CE in 5 closed chest awake pigs in whom an ameroid constrictor placed around the proximal LCx produced total occlusion and development of collateral flow gradually over 3 weeks. A second inflatable cuff constrictor was placed distal to the ameroid for acute occlusion. Short axis echos during left atrial injections of 1 gram of SHU 504 (Levovist) were performed with and without inflation of the acute occluder at baseline, 5, 10, 20, and 25 days. Ameroid occlusion produced only a transient contractile abnormality: posterolateral wall thickening was 71, 39, and 67% at BASE, 10, and 25 days. With the acute cuff occluder open. interventricular septum (IVS) opacification was dense during all studies. while posterolateral wall (PLW) intensity was dense at BASE, decreased markedly at 10 days, and increased again at 25 days as collaterals developed. Acute inflation of the cuff resulted in a clear PLW perfusion deficit during BASE to day 10, which improved significantly at day 25. We measured videointensity (gray levels) from a 0.3 cm 2 region of interest in the mid IVS and PLW. The ratio of IVS/PLW intensity increased on day 10 as the constrictor occluded, and then decreased on day 25 as collaterals developed, even with the acute cuff inflated (Figure). Thus, in a porcine model in which gradual coronary occlusion induces collaterals. CE demonstrates opacification of the involved myocardium. These data document the ability of CE to identify and track the development of coronary collateral flow.