The effect of kinking and residual plaque ulcers after carotid artery stenting: differences between closed stent design and double-layer stents

Background: Carotid stenting (CAS) is an established alternative to carotid endarterectomy for asymptomatic and symptomatic stenosis. However, morphological features possibly appearing after CAS, such as carotid tortuosity/kinking and plaque ulcers underneath the stent (PuUS) remain under investigated. This study evaluates the impact of these factors on postoperative neurological risks, according to the type of stent implanted, i.e. closed stent design (CSD) versus double-layer stents (DLS). Methods: A single center retrospective evaluation of all consecutive CAS from 2004 to 2022 was performed. Cerebral protection filters devices were routinely employed, and traditional CSD (Wallstents, Boston Scientific, Natick, MA, USA) until 2015, followed by DLSs (Roadsaver, Terumo Corp., Tokyo, Japan). Stroke rates at 30 days and 1 year were assessed, focusing on stent-determined carotid kinking (angle >90°) and the presence of residual plaque ulcers underneath the deployed stent. Results: A total of 644 CAS patients (27% symptomatic) were analyzed. The procedure achieved a technical success rate of 96%, with a significantly higher stroke rate in symptomatic compared to asymptomatic patients (5.8% vs. 2.1%, P=0.01). Post-stent carotid kinking (4.2%) and residual plaque ulcers (8.4%) were more frequent with DLS than CSD (P=0.04 and P=0.001). Residual ulcers increased 30-day stroke risk (13% vs. 2.2%, P<0.001) but not post-CAS kinking (2.7% vs. 3.1%, P=0.92). DLS showed no strokes with residual ulcers at 30 days and 1 year (P=0.0001 and P=0.03, respectively), differently from CSD (19%). Conclusions: DLS are associated with a higher rate of stent determined distal internal carotid kinking and residual plaque ulcers but demonstrate a protective effect, minimizing stroke risk from plaque ulcers compared to CSD. These findings support the use of DLS to reduce cerebral embolization.