Engineering of Small-Diameter Vessels

Several approaches are employed to treat atherosclerotic cardiovascular disease of small-caliber arteries (<6 mm). One of the approaches is balloon angioplasty or percutaneous transluminal coronary angioplasty, a procedure used to dilate narrowed arteries. Coronary artery bypass graft operation is an invasive procedure that is done to reroute, or “bypass,” blood around occluded arteries and improve the supply of blood and oxygen to the heart. Grafts commonly used include the great saphenous vein from the leg, internal thoracic artery from the chest, radial artery from the arms, and sometimes arteries from the stomach. Small-diameter tissue-engineered grafts are typically composed of cells and a scaffold. The scaffold serves as a temporary template that provides the required geometry and has such properties to allow the cells to remodel the scaffold and deposit their own extracellular matrix (ECM) proteins. Three major components that need to be considered in the design and fabrication of a tissue-engineered small-diameter vascular graft include cells, scaffolds, and environmental stimuli. The design of an appropriate scaffold in fabricating a cellularized tubular construct is crucial as the scaffold provides the initial spatial templating and structural support for the developing tissue and it must support cell adhesion, proliferation, and matrix synthesis. There are three broad classes of scaffold that are employed, which include synthetic polymer scaffolds, hydrogels or biopolymer scaffolds, and decellularized tissues.