ABSTRACT
After an arteriotomy, vascular surgeons typically close medium-diameter arteries with patches to avoid significant luminal narrowing that can occur after primary closure. We developed a small animal model of patch angioplasty applicable to both arteries (arterioplasty) and veins (venoplasty). Both arterioplasty and venoplasty heal via neointima formation and accumulation of endothelial progenitor cells, smooth muscle cells, and macrophages. However, these studies show that neointimal formation is different in arteries and veins, with thicker neointima in arteries compared to veins; in addition, neointimal endothelial cells expressed the arterial markers Ephrin-B2 and notch-4 in the arterial system, whereas they expressed the venous markers Eph-B4 and COUP-TFII in the venous system. Tissue-engineered vascular patches show decreased neointimal hyperplasia in both arterioplasty and venoplasty. In the rat model, patch arterioplasty is associated with pseudoaneurysm formation after 30 days. TGF-β1 plays a mechanistic role in this process, and patches covalently bonded with nanoparticles that elute TGF-β1 effectively decrease the occurrence of pseudoaneurysm formation. Vascular patch angioplasty has broad application in surgical techniques and a unique role in vascular biomaterial research.
