Low Lymphocyte-to-Monocyte Ratio Predicts Plaque Instability and Stroke Recurrence in Intracranial Atherosclerotic Stenosis.

Background and Purpose: While our previous cross-sectional study linked the lymphocyte-to-monocyte ratio (LMR) to symptomatic ICAS and plaque inflammation, its prospective value for predicting stroke recurrence remained unexplored. This study aimed to validate the association between LMR and plaque instability in a larger cohort and, critically, to determine whether baseline LMR predicts future ischemic events. Methods: We prospectively enrolled adult patients with radiologically confirmed ICAS from April 2018 to July 2024 at our tertiary cerebrovascular center. Comprehensive datasets, including clinical characteristics, laboratory markers (LMR and full inflammatory profiles), and neuroimaging features, were systematically collected and analyzed. Hematologic markers were compared between patients with ICAS with and without plaque enhancement and between those with and without symptoms. Receiver operating characteristic analysis was used to assess the discriminative value of LMR for plaque instability and determine optimal cutoff points. A follow-up was conducted to record stroke recurrence and evaluate the predictive role of baseline LMR. Results: We included 132 patients with confirmed ICAS. LMR emerged as an independent predictor of both plaque enhancement and symptomatic ICAS. An LMR cutoff of 4.0 effectively distinguished symptomatic from asymptomatic plaques. In 120 patients with ICAS with follow-up data, those with LMR of ≤ 4.0 had significantly higher recurrence (32.1% vs 15.6%, P = 0.026) and shorter median recurrence time ( Conclusion: A low LMR is associated with plaque instability in ICAS, and an LMR ≤ 4.0 may serve as a practical and accessible hematologic marker that could help identify patients at increased short-term risk of stroke recurrence.