Abstract 17441: Non-Invasive Quantification of Peripheral Angioplasty-Induced Vascular Inflammation in a Porcine Model Using PET/CT Imaging

Abstract

Background: Similarities in peripheral vascular anatomy between swine and humans make this animal an ideal model for evaluating the effects of lower extremity angioplasty procedures commonly performed to improve limb blood flow in peripheral artery disease (PAD). Hypothesis: We hypothesized that PET/CT imaging would provide a non-invasive strategy for quantifying the inflammatory response to balloon overdilation injury in a swine model of peripheral angioplasty. Methods: Five Yorkshire pigs (weight = 25 kg) underwent overdilation of the right femoral artery. A balloon catheter (7 mm x 40 mm) was introduced via the carotid artery and guided to the femoral artery under fluoroscopy. The balloon was then inflated to a pressure 1.5 times greater the recommended nominal pressure to induce arterial injury. 18 F-fluorodeoxyglucose (FDG) PET/CT imaging was performed 14 days after angioplasty to quantify in vivo inflammation in the injured and control femoral arteries, which was expressed as the maximum standardized uptake value (SUV max ). Pigs were euthanized 14 days post-angioplasty and arteries were harvested and sectioned for gamma counting ( 18 F-FDG uptake), and stained with hematoxylin and eosin histology (H&E), Masson’s trichrome, and alpha-smooth muscle actin (α-SMA) for evaluation of intimal remodeling and smooth muscle cell proliferation. Results: 18 F-FDG PET/CT imaging quantified a significant increase in inflammation for the injured versus control femoral artery 14 days post-angioplasty (p=0.04). Gamma counting confirmed a significant increase in 18 F-FDG uptake in the injured artery (p=0.02). H&E revealed a significant increase in intimal thickening in the injured artery (p=0.03). α-SMA expression was also significantly increased in the injured versus control femoral artery (p=0.01), demonstrating an increase in smooth muscle cell proliferation. Conclusions: 18 F-FDG PET/CT quantifies arterial inflammation resulting from overdilation injury that is associated with intimal remodeling and smooth muscle cell proliferation. PET/CT imaging may provide a non-invasive strategy for in vivo testing of the efficacy of emerging drug-coated endovascular peripheral devices.