Risk factors and outcomes of patients with early spontaneous recanalization after acute middle cerebral artery occlusion.

Background: Several studies have shown that spontaneous recanalization after acute intracranial arterial occlusion is not uncommon. This study aimed to investigate the predictive factors and outcomes of early spontaneous recanalization following acute middle cerebral artery occlusion. Methods: We conducted an analysis of 116 patients with acute middle cerebral artery occlusion from a prospective cohort (January 2021-December 2023). Patients aged 18-85 years with confirmed middle cerebral artery occlusion within 7 days of stroke onset who did not receive thrombolysis or thrombectomy were included. Early spontaneous recanalization was assessed by the Arterial Occlusive Lesion Scale after admission within 7 days. Outcomes included 90-day modified Rankin Scale (mRS) scores, symptomatic intracranial hemorrhage within 90 days, and mortality within 90 days. According to the degree of recanalization, early spontaneous recanalization was categorized into complete recanalization and noncomplete recanalization. The baseline characteristics and therapeutic regimen were compared between the patients with no-recanalization and early spontaneous recanalization. Outcomes were compared between the early spontaneous recanalization and no-recanalization groups and between the noncomplete recanalization and complete recanalization groups. Multivariate logistic regression analysis was conducted to identify risk factors of early spontaneous recanalization and complete recanalization. Results: Early spontaneous recanalization occurred in 20.7% of patients (24/116). The independent predictors of early spontaneous recanalization were nonatherosclerotic etiology [adjusted odds ratio (OR) 10.40; P=0.03] and higher National Institutes of Health Stroke Scale (NIHSS) score (adjusted OR 1.31; P<0.01). Complete early spontaneous recanalization occurred in 8.6% (10/116) of patients. Atrial fibrillation was an independent predictor of complete early spontaneous recanalization (OR 21.70; P=0.01). Patients with early spontaneous recanalization (n=24) did not differ significantly from those without recanalization (n=92) in terms of median 90-day mRS (3 Conclusions: Early spontaneous recanalization after acute middle cerebral artery occlusion is independently associated with nonatherosclerotic etiology and higher baseline NIHSS score. Spontaneous complete recanalization after acute middle cerebral artery occlusion is independently associated with atrial fibrillation. The absence of benefit or harm indicates that spontaneous recanalization is a neutral phenomenon after acute middle cerebral artery occlusion.