Angiographic Lumen Changes Associated with Oversized Intracranial Stent Implantation for Aneurysm Treatment

Abstract

The effect of oversized intracranial stent implantation, and potential excessive neointimal hyperplasia from the chronic outward radial force, has not been reported. We sought to compare the angiographic narrowing associated with implantation of oversized stents. We reviewed an aneurysm database and identified patients treated with stent-assisted embolization involving a vessel size transition. Demographics and lesion characteristics were extracted. The relationship between lumen diameter and stent oversizing was compared. Twenty vessels were identified in 18 patients, providing 80 paired data points. Mean follow-up time was 8 months (SD 6). The average oversizing in the smaller diameter parent vessel landing-zone was 1.75 mm. Mean change in lumen size from pre-stent implantation was not significantly different for any of the four sites. There was a significant difference in change of lumen size at the stent tines when compared with the respective mid-stent segment for both the proximal (P = 0.02) and distal (P = 0.0004) landing zones. A small significant lumen loss occurs at stent tines when compared to midstent struts. However, there is no overall significant stenosis from highly oversized stents. Persistent luminal gain from the oversized stent radial force likely predominates over any neointimal hyperplasia.