Research into in-stent intimal hyperplasia of carotid artery stenting followed by carotid duplex ultrasound

Abstract

With the increasing use of carotid artery stenting (CAS), carotid duplex ultrasound (CDU) is important for post-stented patients to check the patency of CAS. In our institute, stented patients were treated with dual antiplatelet therapy for 3 months after CAS. Follow-up on 3-dimensional computed tomography (3D-CT) angiography was performed around 2 years after CAS. Some patients were also followed up annually with CDU. Although the major complication of CAS is reportedly in-stent restenosis (ISR), definitions of ISR have not been standardized. From the perspective of long-term follow-up of stented vessels, we considered in-stent intimal hyperplasia (ISH) as more important for patients than ISR. We therefore studied the clinical features of ISH in comparison with normal stented vessels. CAS was performed for 158 vessels (117 patients) in our hospital from 2009 to 2013. Patients who underwent simple balloon angioplasty, experienced CAS failure or arterial dissection, or had no data available from CDU were excluded. We defined ISH from CDU as a maximum in-stent plaque thickness >1.1 mm during follow-up. Subjects were divided into an ISH group (n=43) and normal stented group (n=79). The ISH group showed significantly lower age and higher concentration of LDL than the normal group. Next we studied changes over time for in-stent plaque thickness. ISH was uniformly <2.0 mm during the first 2 years, but 3 cases showed increases to ≤3.0 mm by 4 years after CAS. In conclusion, attention must be paid to increments in ISH during long-term follow-up.