Abstract 334: Collateral Development in Swine after Ligation of Native Leg Arteries

Abstract

Introduction: The development of collateral vasculature is a key mechanism compensating for arterial occlusions in patients with Peripheral Artery Disease (PAD). We aimed to examine the development of collateral pathways after ligation of native vessels in a porcine model of PAD. Methods: Right hindlimb ischemia was induced in domestic swine (N=11, male, 26-57 kg) using two different versions of arterial ligation. Version 1 (N=6) consisted of ligation/division of the right external iliac, profunda femoral (RPFA) and superficial femoral arteries (RSFA). Version 2 (N=5) consisted of the ligation of Version 1 with additional ligation/division of the right internal iliac artery (RIIA). Development of collateral pathways was evaluated with standard angiography at baseline (prior to arterial ligation) and at termination (4-8 weeks later). Relative luminal diameter of the arteries supplying the ischemic right hindlimb were determined by 2D angiography, as percent of the size of the distal aortic diameter. Results: The pathway connecting the RIIA to the RPFA and RSFA/popliteal artery of the ischemic limb was the dominant collateral pathway in version 1. Mean luminal diameter (± standard error) of the RIIA at termination increased by 39.4± 5.5% (P<0.01) compared to baseline. There were two co-dominant collateral pathways in version 2. The first pathway connected the common internal iliac trunk and left internal iliac artery to the reconstituted RIIA which then supplied the RPFA and RSFA/popliteal arteries. The second pathway connected the left profunda artery to the reconstituted RPFA. Mean diameter (± standard error) of the common internal iliac trunk and left profunda artery increased at termination by 23.7± 7.6% and 24.8± 7.4%, respectively (p < 0.05). Conclusion: Two versions of hindlimb ischemia induction (right ilio-femoral artery ligation with and without right internal iliac artery ligation in swine produced differing collateral pathways along with changes to the diameter of the inflow vessels. Radiographic and anatomical data of the collateral formation in this porcine model has value in investigation of the pathophysiology of hindlimb ischemia, and assessment of angiogenic therapies as potential treatments for PAD.