Association between endothelial function and early neurological improvement in atrial fibrillation-related ischemic stroke

Background Understanding the factors related to early neurological improvement (ENI) is crucial in managing atrial fibrillation-related ischemic stroke (AF-stroke), as ENI indicates better long-term outcomes. We investigated the association between endothelial function, measured via flow-mediated dilation (FMD), and the occurrence of ENI in patients with AF-stroke. Methods We reviewed patients with acute AF-stroke within 7 days of FMD between April 2019 and April 2025. ENI was defined as a ≥2-point decrease in National Institutes of Health Stroke Scale (NIHSS) or ≥1-point reduction in motor NIHSS items within 24 h in non-thrombolysis patients. For thrombolysis patients, ENI was a ≥8-point reduction or NIHSS 0–1 at 24 h. FMD was measured during hospitalization and expressed as %FMD = (peak diameter − baseline diameter) / Baseline diameter × 100. Multivariable analysis identified the factors associated with ENI and explored their relationship with FMD. Results Among the 169 patients diagnosed with AF-stroke, 77 (44.4%) experienced ENI. Those with ENI had higher NIHSS (7 [4–13] vs. 2 [1–5], p < 0.001), more confluent (38.7% vs. 25.5%) and scattered with confluent pattern (29.3% vs. 18.1%, p = 0.007), and higher %FMD (6.5% ± 2.5% vs. 5.3 ± 2.2%, p = 0.001). Multivariable analysis revealed a higher initial NIHSS score (adjusted odds ratio [aOR]: 1.329, p < 0.001) and a history of smoking (aOR: 4.532, p = 0.004), and higher %FMD score (aOR: 1.179; p = 0.043) were independently associated with ENI. Subgroup analysis demonstrated a stronger association between high %FMD and ENI in patients with concomitant vascular risk factors, such as hypertension and dyslipidemia. Conclusion Endothelial function was associated with ENI in patients with AF-stroke.