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.