Relation between plaque characteristics on MR imaging and distal protection devicein predicting risks of thromboembolic events during carotid artery stenting

Abstract

Objective: To evaluate risk in relation to plaque characteristics for estimating thromboembolic events during carotid artery stenting (CAS). Methods: MR imaging of 64 carotid artery stenotic lesions were reviewed retrospectively in patients for CAS with a balloon protection device (Guardwire) and filter (Angioguard XP). Magnetization-prepared rapid acquisition with gradient echo (MPRAGE) was used for MR plaque imaging. Lesions were classified into three types according to the intensities on MPRAGE: high-intensity, intermediate-intensity and isointensity groups. If the plaque displayed signal intensity of 200% compared to sternocleidomastoid muscle intensity, it was categorized as "high signal intensity." Results: Periprocedural adverse events occurred in 10 of 64 procedures (15.6%). Persistent neurological deficit was related to 3 procedures (5.1%). Transient neurological ischemic events occurred in 4 procedures (6.3%). Thromboembolic events of CAS for high-and intermediateintensity plaques on MPRAGE were 21.1% and 16.7%, respectively. Incidence of thromboembolic events for high-intensity plaques (21.1%) was significantly higher than that for iso-intensity plaque (0%) (P=0.013). Incidence of thromboembolic events for high-intensity plaques with use of a filter device (21.1%) was significantly higher than that with a balloon protection device (7%) (P=0.013). Although incidence of neurological ischemic event in CAS with a filter device (26.7%) was significantly higher than that with a balloon protection device (6.1%) (P=0.026), the morbidity rate was not significantly different between the two groups (0% vs 6.1%). Conclusions: High-intensity plaque on MPRAGE is related to a high rate of thromboembolic events during CAS. To avoid thromboembolic complications during CAS, an individual approach is needed for each case.

Two Patients with Reversible Cerebral Vasoconstriction after Carotid Artery Stenting

“…Tanaka et al 18) reported a patient in whom cerebral ischemic symptoms were more prominent than debris embolism on MRI after CAS; however, complete recovery was achieved. Regarding thromboembolism after CAS, Ishibashi et al 19) examined four patients with reversible cerebral ischemic complications a few hours after surgery. They stated that symptoms were more severe than the size of the high signal intensity area on diffusion-weighted imaging.…”