Factors Associated with Proximal Carotid Axis Occlusion in Patients with Acute Stroke and Atrial Fibrillation

Abstract

Patients with atrial fibrillation (AF) are more likely to exhibit proximal carotid axis occlusion than those without AF. However, clinical characteristics associated with proximal arterial occlusion (PAO) in acute stroke patients with AF are not fully known. This study was aimed to elucidate the factors correlated with PAO. Consecutive patients with acute ischemic stroke developed in the middle cerebral artery (MCA) territory and AF who underwent magnetic resonance angiography (MRA) within 24h from onset were retrospectively enrolled. Prior users of warfarin were excluded. Patients were divided into 3 groups based on the site of arterial occlusion: occlusion at the internal carotid artery (ICA), at the horizontal segment of the MCA (M1), and at the MCA branch orno identifiable occlusion. Clinical characteristics were compared between the 3groups, and the factors associated with proximal vessel occlusion were evaluated with ordinal logistic regression analysis. All variables identified on univariable analyses with P values less than .1 were entered into the model. A total of 244 patients (124 women, median 80years old [interquartile range 72-87], median National Institutes of Health Stroke Scale [NIHSS] score 16 [7-22]) were studied. MRA was performed median 2.7 h (1.5-8.9) after stroke onset. Occlusion site was the ICA in 34 patients, M1 in 78, and MCA branch or no occlusion in the remaining 132. As the occlusion site was more proximal, patients were older and more female, the initial NIHSS score was higher, levels of d-dimer and brain natriuretic peptide (BNP) were higher, and histories of heart failure and systemic embolism were more common. On multivariable ordinal logistic regression analysis, female sex (odds ratio [OR] 1.83, 95% confidence interval [CI] 1.03-3.26), advanced age (OR 1.37, 95% CI 1.02-1.84 for every 10years), history of systemic embolism (OR 14.9, 95% CI 1.41-157.75), and higher BNP level (OR 1.03, 95% CI 1.01-1.07 for every 100pg/mL) were independent factors associated with the risk of occlusion at more proximal arteries. The risk was 2.68-fold higher (95% CI 1.28-5.61) in patients having 2 of the following factors: female sex, agemore than 80years, systemic embolism, and BNP greater than 250pg/mL; and 4.50-fold (2.11-9.59) higher in those having 3 or 4 of the 4 factors compared with those without any of these factors. Female sex, advanced age,history of systemic embolism, and higher BNP level were independently associated with more proximal carotid axis occlusion. Patients with AF having these factors may be prone to have relatively large thrombi in the heart.