The role of cinefluoroscopy and intravascular ultrasonography in evaluating the deployment of experimental endovascular prostheses

Abstract

This study compares the utility of cineangiography and real-time intravascular ultrasonography (IVUS) in achieving successful deployment of endovascular prostheses. Five types of 5 cm long, 8 mm internal diameter polyester vascular grafts were secured in the infrarenal aorta of mongrel dogs by 18 mm long Palmaz balloon expandable vascular stents sutured to each end of the prostheses. The endovascular prostheses were delivered by crimping the stents at the ends of the grafts onto a 10 mm outside diameter, 8 cm long polyethylene balloon-dilation catheter. Real-time IVUS of the procedure was provided by a 0.035-inch, 20 MHz imaging element passed through the guide wire lumen in the balloon catheter. Two prostheses of each type were implanted, with one removed at 30 days and the other at 60 days for analysis. At implantation, both angiography and IVUS provided information regarding the choice of site for placement of the device and sizing of the aortic lumen. Real-time IVUS enhanced the information obtained by cineangiography by displaying tomographic views of the vessel anatomy, enabling determination of cross-sectional areas, assessing full stent expansion, and providing information regarding surface topography along the length of the prostheses. Several critical observations were apparent only on IVUS, including incomplete initial stent expansion during two procedures evidenced by pulsation of the aortic wall independent of the stent and movement of unstented segments of thin-walled grafts. Some of these observations led to further interventions at the time of deployment. At death, a comparison of cineangiography, IVUS, and ultrafast computed tomography outlined lumenal continuity and areas of irregularity, thrombus, or narrowing, with IVUS being more sensitive than cineangiography or computed tomography for determining most parameters. We conclude that IVUS is a promising alternative method for precise placement of intravascular grafts.