Plaque Protrusion Detected by Intravascular Ultrasound during Carotid Artery Stenting

Background Stroke is a major complication of carotid artery stenting (CAS) that can occur during the procedure and for up to 30 days after the procedure in the late phase. Although the cause of late stroke after CAS is unknown, plaque protrusion may be one of the potential causes. This study aims to assess the rate of plaque protrusion during CAS by intravascular ultrasound (IVUS). Methods We performed 77 consecutive CAS procedures using IVUS between May 2008 and December 2012. The rate of plaque protrusion was assessed at the end of the procedure using IVUS and angiography. Results Mean age of patients was 72.5 ± 7.5 years. Sixty-eight patients were male and 42 had diabetes mellitus. In all, 65 PRECISE stents and 12 Carotid Wall stents were used. All cases were distally protected with filter devices. Six plaque protrusions (7.8%) through the stent struts were detected by IVUS but only 2 (2.6%) by angiography. A predictor of plaque protrusion was preprocedural severe stenosis with flow delay. Additional postdilations (n = 6) and stent-in-stent implantations (n = 4) were performed to correct the plaque protrusions. No remaining plaque protrusion was observed in the final IVUS. Overall stroke rate was 2.6% (major 0%, minor 2.6%), and these occurred in the catheterization laboratory, but no late stroke was observed at 30 days after procedure. Conclusions IVUS can detect plaque protrusion better than angiography. Because adequate management of plaque protrusion may reduce stroke complications, IVUS usage is worth considering.