Intraluminal ultrasound assessment of vascular stent deployment

Abstract

This study assessed the utility of intraluminal ultrasound imaging during deployment of a self-expanding vascular stent and quantitated changes in arterial morphology produced by the stent. Cross-sectional images of arterial lumens (n=50) were obtained before stenting, in-vitro (n=35) from formalin-preserved human superficial femoral arteries and in-vivo (n=15) from canine iliac arteries containing laser-induced eccentric stenoses. Comparison of ultrasound-derived vessel dimensions (minimum and maximum diameter and cross-sectional area) with histological morphometric analysis of corresponding vessel sites showed good correlation by linear regression analysis (r=0.930–0.987, p=0.001–0.005). Following stent placement, 23 intraluminal ultrasound images were obtained from the stented vessel sites (in-vitro n=15, in-vivo n=8) and were compared to prestented cross-sectional areas. In the in-vitro vessels there was a small increase (p=0.023) in area, but there was no change in the in-vivo arteries (p=0.6). To assess the effect of stenting on luminal shape (ellipticity), minimum/ maximum diameter ratios were compared before and after stent deployment. There was an increase in this ratio in the in-vitro vessels (p=0.001) but no change in the in-vivo arteries (p=0.2). We conclude that intraluminal ultrasound produces clear and accurate images of the location, shape and degree of arterial pathology, ensuring good stent: vessel size matching and immediate quantitative assessment of the effects of arterial stent placement.