Does prosthetic covering of nitinol stents alter healing characteristics or hemodynamics?
PURPOSE: To evaluate placement of polyester (Dacron) coverings on nitinol stents implanted in the canine aorta to determine the effect on cross-sectional lumen area, development of intimal hyperplasia, device endothelialization, and flow hemodynamics. METHODS: Ten polyester-covered and 10 uncovered nitinol stents (60-mm length, 10- or 12-mm diameter) were deployed percutaneously in the normal infrarenal aorta of 20 adult mongrel dogs using random assignment. Angiography, intravascular ultrasound (IVUS), and duplex ultrasound performed at device deployment and before explantation at 6 weeks were used to measure aorta/device diameter and cross-sectional area. Pressure-perfusion-fixed aortic segments were compared for surface endothelialization (CD31 staining) and for thickness of neointimal formation. RESULTS: All 20 endoluminal devices were accurately positioned in the infrarenal aorta without early or delayed evidence of device thrombosis, significant lumen narrowing, or device deformi
