Background Data on the relative contribution of clinical and neuroimaging risk factors to
acute ischemic stroke (AIS) versus
intracerebral hemorrhage (ICH) occurring on oral
anticoagulant treatment are scarce. Methods and Results Cross-sectional study was done on consecutive oral
anticoagulant-treated patients presenting with AIS,
transient ischemic attack (TIA), or ICH from the prospective observational NOACISP (Novel-Oral-
Anticoagulants-In-
Stroke-Patients)-Acute registry. We compared clinical and neuroimaging characteristics (small vessel disease markers and
atherosclerosis) in ICH versus AIS/TIA (reference) using logistic regression. Among 734 patients presenting with
stroke on oral
anticoagulant treatment (404 [55%] direct oral
anticoagulants, 330 [45%]
vitamin K antagonists), 605 patients (82%) had AIS/TIA and 129 (18%) had ICH. Prior AIS/TIA,
coronary artery disease,
dyslipidemia, and worse renal function were associated with AIS/TIA (adjusted odds ratio [aOR] [95% CI] 0.51 [0.32-0.82], 0.48 [0.26-0.86], 0.55 [0.34-0.89], and 0.82 [0.75-0.90] per 10 mL/min). Prior ICH, older age, higher admission blood pressure, and
statin treatment were associated with ICH (aOR [95% CI] 6.33 [2.87-14.04], 1.37 [1.04-1.81] per 10 years, 1.19 [1.10-1.29] per 10 mm Hg, and 1.81 [1.09-3.03]). Cerebral microbleeds and moderate-to-severe white matter hyperintensities contributed more to ICH (aOR [95% CI] 2.77 [1.34-6.18], and 2.62 [1.28-5.63]). Aortic arch, common and internal carotid artery
atherosclerosis, and
internal carotid artery stenosis ≥50% contributed more to AIS/TIA (aOR [95% CI] 0.54 [0.31-0.90], 0.29 [0.05-0.97], 0.48 [0.30-0.76], and 0.32 [0.13-0.67]). Conclusions In patients presenting with
stroke on oral
anticoagulant, AIS/TIA was 5 times more common than ICH. A high atherosclerotic burden (indicated by cardiovascular comorbidities and extracranial
atherosclerosis) and prior AIS/TIA contributed more to AIS/TIA, while small vessel disease markers and prior ICH were stronger determinants for ICH. Registration URL: https://www.clinicaltrials.gov; Unique identifier: NCT02353585.