Abstract 10957: Six Month Patency of Bioengineered Human Acellular Vessels in a Primate Model of Coronary Artery Bypass Grafting

Abstract

Introduction: Limitations of coronary artery bypass grafting (CABG) include the availability, quality, and long-term patency of autologous saphenous vein grafts. An “off-the-shelf” human acellular vessel (HAV) bioengineered from banked human vascular cells, decellularized before implantation, and capable of host cellular regeneration may address these issues. Therefore, we assessed early patency and tolerability of a small diameter HAV as a CABG conduit in a baboon surgical model. Methods: Adult male, non-immunosuppressed baboons (n = 3; 30.5 - 37.0 kg) underwent CABG via sternotomy with cardiopulmonary bypass. The right coronary artery (RCA) was ligated and bypassed with a 3.5 mm inner diameter HAV. Intraoperative blood flow was determined by transit-time flow measurement (TTFM). HAV patency was assessed by computed tomography angiography (CTA) at 1, 3 and 6 months, and confirmed by left heart catheterization at the 6 month study endpoint. Explanted tissues were processed for histological analysis of host cellular repopulation and HAV remodeling. Results: Three animals were successfully bypassed with a 3.5 mm HAV as aorta-RCA CABG conduits with resulting TTFM blood flow rates of 22 ± 7.7 mL/min. CTA at 1, 3 and 6 months demonstrated patency of the HAV with no significant stenosis or dilatation. There were no HAV related adverse events for the duration of the study. Histological staining of 6 month explanted tissues showed recellularization and remodeling of the HAV with a microcapillary-containing neo-adventitial layer, alpha smooth muscle actin expressing cells within the HAV wall, and endothelialization of the HAV lumen. Conclusion: A small diameter, readily available HAV was successfully implanted in a primate model of CABG and remained patent up to 6 months with no evidence of dilatation. In addition, the HAVs were thoroughly recellularized and remodeled by host cells. These bioengineered vessels may prove to be durable long-term conduit options in CABG.