Pressure-Directed Embolization of Hepatic Arteries in a Porcine Model Using a Temporary Occlusion Balloon Microcatheter: Proof of Concept

Abstract

The purpose of this project was to test the hypothesis that temporary hepatic artery balloon occlusion would favorably alter the distribution of particle emboli within the targeted and nontargeted downstream vascular compartments. Five Yorkshire pigs underwent transfemoral placement of balloon microcatheters into selected segmental hepatic arteries. A collection catheter was surgically introduced into a downstream hepatic artery branch. Blood pressures at the femoral artery sheath and the collection catheter were obtained with the microcatheter balloon deflated and inflated. Identical quantities of calibrated 250- and 400-µm microspheres were injected via the balloon microcatheter when inflated, then deflated. Each animal underwent up to four paired microsphere embolizations. Microspheres collected from the intrahepatic collection catheter were counted manually by light microscopy. Inflation of the balloon microcatheter in the segmental hepatic artery resulted in a consistent and significant decrease in blood pressure (mean: 30mmHg; range 23-43mmHg; p<0.05) in the downstream vascular compartment. The number of microspheres selectively delivered to the targeted intrahepatic collection catheter was significantly greater when the balloon microcatheter was inflated rather than deflated in all 20 paired embolic deliveries (by 2.4-fold, mean; p=0.0002), despite delivery of the same total number of microspheres. Balloon occlusion significantly reduces blood pressure in the downstream vascular compartment, resulting in increased delivery of emboli to a targeted intrahepatic arterial collection catheter relative to other portions of the embolized vascular compartment, likely due to blood flowing into this compartment from neighboring hepatic and extrahepatic arteries.