Acellular Tissue Engineered Vessels as Coronary Artery Bypass Grafts

Abstract

Coronary artery bypass graft (CABG) uses the patient's internal mammary artery and saphenous vein; however, unavailable or poor quality autologous vessels limit revascularization. This study addresses the critical need for alternative CABG conduits by evaluating a small diameter acellular tissue-engineered vessel ([sdATEV], 3.5 mm) in a primate model. Adult baboons (n = 5) underwent CABG to the right coronary artery (RCA) with an sdATEV. Patency, diameter, and cardiac function were longitudinally assessed by computed tomography angiography. All sdATEVs remained patent throughout the 6-month study. Computed tomography angiography demonstrated that the distal sdATEV diameter gradually remodeled to approximate the smaller baboon RCA. Histology and spatial transcriptomics revealed that sdATEVs recellularized with host endothelial and smooth muscle cells including a quiescent neomedia layer with gene expression patterns similar to the RCA, indicating that host cell ingrowth from the bypassed coronary artery regulates sdATEV diameter. These results suggest that the sdATEV is a durable alternative CABG conduit.

Keywords: coronary artery bypass graft; coronary computed tomography angiography; regenerative medicine; spatial genomics; tissue engineering; vascular biology.