Incremental Prognostic Value of Carotid Plaque-RADS Over Stenosis Degree in Relation to Stroke Risk.

Background: Recently, a standardized classification system for carotid atherosclerotic plaques, known as Carotid Plaque-RADS (Reporting and Data System), has been introduced. However, its capacity to improve stroke risk stratification beyond traditional stenosis degree assessment has not been extensively explored.

Objectives: This study aimed to determine the incremental prognostic value of Carotid Plaque-RADS over stenosis degree for stroke risk.

Methods: A retrospective analysis was performed on data from January 2010 to December 2021, involving subjects who underwent magnetic resonance imaging, computed tomography angiography, and ultrasound evaluations of the carotid artery. Disease-free survival (DFS) and recurrence-free survival (RFS) rates were compared across different stenosis degrees, Carotid Plaque-RADS categories, and their combination, using the Kaplan-Meier and net reclassification improvement formula.

Results: The study enrolled 1,378 subjects. During a follow-up period of 57 ± 25 months, 4.6% of 987 asymptomatic individuals and 16.9% of 391 subjects with stroke history experienced initial and recurrent strokes, respectively. Significant differences in DFS and RFS rates were found between subjects with mild/moderate and severe stenosis (P < 0.001). Significant differences in DFS rates were observed across Carotid Plaque-RADS categories (P < 0.001), with a notable decrease in DFS rates as Carotid Plaque-RADS categories increased from 1 to 4. This trend was similar in subjects with a history of stroke (P < 0.001). For patients with mild/moderate stenosis, significant differences in DFS and RFS rates were found between those with Carotid Plaque-RADS of ≥3 vs <3 (P < 0.001). Correct reclassification was achieved for 3.3% (32 of 979) of asymptomatic individuals and 9.7% (37 of 381) of subjects with a stroke history initially identified with mild/moderate stenosis. Incorporating Carotid Plaque-RADS with stenosis grading markedly improved risk assessment, resulting in net reclassification improvement of 63.8% for initial stroke and 47.8% for recurrent stroke prediction. The likelihood ratio test demonstrated that Carotid Plaque-RADS scores significantly enhanced the prognostic accuracy of stenosis degrees for both asymptomatic individuals and patients with a history of stroke (both P < 0.001).

Conclusions: Carotid Plaque-RADS significantly improves stroke risk stratification over traditional stenosis grading, especially in mild/moderate stenosis cases.