Multicenter analysis of embolic complications during carotid artery stenting using Angioguard XP filter wire - predicting high risk patients by MR plaque image and length of stenosis

Objective: Objectives: To investigate embolic complications related to carotid artery stenting (CAS) under Angioguard XP filter protection, and analyze the relationship between several potential risk factors and complications. Methods: Forty-eight patients with 49 carotid stenoses, that underwent MR plaque imaging before CAS under Angioguard XP filter protection, were retrospectively reviewed. Embolic complications during CAS and MR plaque images, including signal ratio of the plaque to posterior cervical muscle (P/M ratio) and submandibular gland (P/S ratio) on T1 and T2 weighted images, were reviewed. Relationships between embolic complications and P/M, P/S ratios, and length of lesions were analyzed. Results: Ten slow flow (20.4%), 3 embolism (6.1%), and 4 spasm (8.1%) incidents occurred during the procedures. All embolisms occurred concurrently with slow flow. T1 P/M ratio and T1 P/S ratio in patients with an embolism tended to be higher than those without (2.33 vs 1.62, p=0.107, 1.78 vs 1.19, p=0.092, respectively). T2 P/M ratio and T2 P/S ratio in patients with slow flow tended to be lower than those without (1.60 vs 2.49,p=0.259, 0.68 vs 0.96, p=0.328, respectively). Mean length of the stenosis was longer in cases with an embolism or slow flow, compared to cases without an embolism or slow flow (27.3 vs 20.2mm, p=0.153, 24.2 vs 19.7, p=0.130, respectively). Cases with plaque length ≧25mm and T1 P/M ratio ≧1.5 showed a statistically significant high risk of an embolism (p=0.003). Conclusion: Plaque imaging findings and plaque length appeared to be related to embolic complications. Patients with plaques showing a high T1 P/M ratio ≧1.5 with long stenosis ≧25mm have a greater risk of an embolic complication. Techniques to be applied and indications for CAS need careful consideration in such cases.