Effect of corrugated structure on the collapsing of the small-diameter vascular scaffolds

Major barriers to the development of a desirable small-diameter vascular scaffold are the compliance mismatch between natural and artificial vessels and low long-term patency. In the present study, the electrospinning technique was performed to fabricate three different structures, i.e. non-corrugated, radial corrugated, and axial corrugated, for small-diameter vascular graft. The compliance measurement shows that the value of dynamic compliance for the crimping structures is lower than that of the simple structure and decreases in the order: non-corrugated structure > radial corrugated structure > axial corrugated structure. The crimping in the axial direction decreases the more than requirement compliance of Thermoplastic polyurethane (TPU) scaffolds. The scaffolds should maintain its tubular shape during the grafting to avoid any collapsing, hence, the setup for measuring the resistance of scaffold against radial compression was designed and the result was reported as the dimensionless collapse coefficient. For non-corrugated, radial corrugated, and axial corrugated structures at constant intraluminal pressure, the required external pressure corresponding to the collapse coefficients equal to 0.5 were 140.92 ± 3.43, 136.51 ± 2.53, and 152.26 ± 3.08 mmHg, respectively. The reinforcing role of the axial crimping shifts the collapsing threshold to higher external pressure. Besides, the fabricated scaffolds provided the burst strength very close to those of the native blood vessels.