Cerebral Small Vessel Disease Burden for Bleeding Risk during Antithrombotic Therapy: Bleeding with Antithrombotic Therapy 2 Study.

Objective: This study was undertaken to determine the excess risk of antithrombotic‐related bleeding due to cerebral small vessel disease (SVD) burden. Methods: In this observational, prospective cohort study, patients with cerebrovascular or cardiovascular diseases taking oral antithrombotic agents were enrolled from 52 hospitals across Japan between 2016 and 2019. Baseline multimodal magnetic resonance imaging acquired under prespecified conditions was assessed by a central diagnostic radiology committee to calculate total SVD score. The primary outcome was major bleeding. Secondary outcomes included bleeding at each site and ischemic events. Results: Of the analyzed 5,250 patients (1,736 women; median age = 73 years, 9,933 patient‐years of follow‐up), antiplatelets and anticoagulants were administered at baseline in 3,948 and 1,565, respectively. Median SVD score was 2 (interquartile range = 1–3). Incidence rate of major bleeding was 0.39 (per 100 patinet‐years) in score 0, 0.56 in score 1, 0.91 in score 2, 1.35 in score 3, and 2.24 in score 4 (adjusted hazard ratio [aHR] for score 4 vs 0 = 5.47, 95% confidence interval [CI] = 2.26–13.23), that of intracranial hemorrhage was 0.11, 0.33, 0.58, 0.99, and 1.06, respectively (aHR = 9.29, 95% CI = 1.99–43.35), and that of ischemic event was 1.82, 2.27, 3.04, 3.91, and 4.07, respectively (aHR = 1.76, 95% CI = 1.08–2.86). In addition, extracranial major bleeding (aHR = 3.43, 95% CI = 1.13–10.38) and gastrointestinal bleeding (aHR = 2.54, 95% CI = 1.02–6.35) significantly increased in SVD score 4 compared to score 0. Interpretation: Total SVD score was predictive for intracranial hemorrhage and probably for extracranial bleeding, suggesting the broader clinical relevance of cerebral SVD as a marker for safe implementation of antithrombotic therapy. ANN NEUROL 2024;95:774–787 [ABSTRACT FROM AUTHOR]