The Risk of Stroke and TIA in Nonstenotic Carotid Plaques: A Systematic Review and Meta-Analysis.

BACKGROUND Severe carotid stenosis carries a high risk of stroke. However, the risk of stroke with nonstenotic carotid plaques ( 10 patients with 50% were extracted if reported. DATA SYNTHESIS We identified 31 studies reporting on the risk of ipsilateral stroke/TIA in patients with nonstenotic carotid plaques. Twenty-five studies (n = 13,428 participants) reported on first-ever stroke/TIA and 6 studies (n = 122 participants) reported on the recurrence of stroke/TIA. DATA ANALYSIS The incidence of first-ever ipsilateral stroke/TIA was 0.5/100 person-years. The risk of recurrent stroke/TIA was 2.6/100 person-years and increased to 4.9/100 person-years if intraplaque hemorrhage was present. The risk of progression to severe stenosis (>50%) was 2.9/100 person-years (8 studies, n = 448 participants). LIMITATIONS Included studies showed heterogeneity in reporting stroke etiology, the extent of stroke work-up, imaging modalities, and classification systems used for characterizing carotid stenosis. CONCLUSIONS The risk of recurrent stroke/TIA in nonstenotic carotid plaques is not negligible, especially in the presence of high-risk plaque features. Further research is needed to better define the significance of nonstenotic carotid plaques for stroke etiology.