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Ischemic brain lesions after CAS may signal risk for future cerebrovascular events
In an imaging substudy of the International Carotid Stenting Study, ischemic brain lesions discovered on magnetic resonance diffusion-weighted imaging after carotid artery stenting were associated with increased risk for recurrent transient ischemic attack or stroke.
Previously reported data from the imaging substudy demonstrated that 62 (50%) patients who underwent carotid artery stenting (CAS) had periprocedural ischemic brain lesions on magnetic resonance diffusion-weighted imaging (MR-DWI) compared with 18 (16.8%) patients who underwent carotid endarterectomy (CEA).
Researchers for the new analysis of the substudy assessed whether risk for future cerebrovascular events was increased in the setting of periprocedural ischemic brain lesions on MR-DWI. In the substudy, 231 patients with symptomatic carotid stenosis were randomly assigned to undergo CAS or CEA. MR-DWI was performed 1 to 7 days before the intervention and 1 to 3 days after.
Median follow-up was 4.1 years. The primary endpoint was stroke/TIA in any territory on MR-DWI from 1 to 3 days after the intervention to the end of follow-up.
The cumulative incidence rate of recurrent stroke/TIA at 5 years was 22.8% among patients assigned CAS with new ischemic brain lesions on MR-DWI vs. 8.8% among patients assigned CAS with no ischemic brain lesions (unadjusted HR = 2.85; 95% CI, 1.05-7.72). Recurrent stroke/TIA occurred in 12 of 62 patients in the CAS group with periprocedural lesions vs. six of 62 patients in the CAS group with no lesions. Adjustment for baseline systolic BP did not affect the significant association between periprocedural lesions on MR-DWI and recurrent stroke/TIA risk (adjusted HR = 3.52; 95% CI, 1.21-10.22). Most of the recurrent cerebrovascular events occurred within 6 months after CAS.
The researchers reported no difference in the incidence of recurrent stroke/TIA during follow-up among patients assigned CEA with and without periprocedural lesions on MR-DWI.
In this substudy, 3-T scanners were used on 66 patients and 1.5 T scanners were used on 165 patients.
“Ischemic brain lesions discovered on DWI after CAS seem to be a marker of increased risk for recurrent cerebrovascular events. Patients with periprocedural DWI lesions might benefit from more aggressive and prolonged antiplatelet therapy after CAS,” the researchers concluded.
In an accompanying editorial, William A. Gray, MD, from the Center for Interventional Vascular Therapy and Columbia University Medical Center, noted that, “Although it is tempting to accept these conclusions in the quest for consequences in postprocedural MR-DWI lesions, the results warrant closer examination.”
Gray noted several limitations of the analysis, including atypical use of TIA as an endpoint for long-term follow-up after CAS and CEA; no reports or adjustments for atrial fibrillation, which may have confounded the results; and no specification of the sidedness of MR-DWI lesions.
“As a result of these issues, the mechanistic cause for the primary endpoint finding is called into question, as are any derivative suppositions regarding the duration of dual antiplatelet therapy,” Gray wrote. “Given the lack of differentiation between hard endpoints between the [two] therapies in the present study, along with the small but real increase in bleeding, extended dual antiplatelet therapy does not seem justified or advisable.”
Disclosure: The International Carotid Stenting Study was funded by grants from the European Commission, Medical Research Council, the Stroke Association and Sanofi-Synthelabo. Funding for the MRI scans in the substudy was provided by grants from the Mach-Gaensslen Foundation, the Netherlands Heart Foundation and the Stroke Association. Gensicke and Gray report no relevant financial disclosures. Please see the full study for a list of all other researchers’ relevant financial disclosures.