Evaluation of maximum neointima proliferation and plaque morphology in iliac self-expanding nitinol stents with intravascular sonography.

Abstract

The purpose of this study was to use intravascular sonography to evaluate neointima formation, plaque location, and the performance of self-expanding nitinol (Memotherm) stents in iliac arteries. Seventeen patients (mean age, 64+/-9.4 years) with stenoses or occlusions of the common (n = 12) or external (n = 5) iliac artery were treated with 21 Memotherm stents (mean diameter +/- SD, 8.9+/-1.3 mm; mean length, 53+/-20.9 mm). Four patients had two stents each. Intravascular sonography was performed 13+/-6 months after stent implantation. Maximum thickness of neointima and maximum cross-sectional plaque area were measured. Qualitative analysis of plaque composition and lesion topography were also assessed. Intravascular sonography revealed 22.1%+/-17.3% maximum percentage of restenosis, and maximum plaque area was found to be 11.2+/-10 mm2. Only hypoechogenic in-stent lesions (soft plaques) were found. Seven (33%) incomplete stent expansions and two (10%) incomplete appositions of the stent to the vessel wall were revealed by intravascular sonography. Iliac artery Memotherm stents generally showed moderate in-stent restenosis with uniform neointima distribution. Incomplete stent expansion was detected in one third of all implanted stents.