Comparative study on the clinical factors and collateral circulation compensation in acute and chronic middle cerebral artery occlusion

Abstract

Background and objectives: Middle cerebral artery (MCA) occlusion may lead to acute large-area cerebral infarction with severe clinical symptoms and signs. Some cases may present with mild symptoms or even be clinically asymptomatic in conditions such as chronic MCA occlusion benefit due to effective collateral circulation compensation. This study investigated the related factors and collateral circulation compensation mechanisms in acute and chronic MCA occlusion. Methods: A total of 223 patients with unilateral M1-segment MCA occlusion confirmed by imaging (magnetic resonance angiography, computed tomography angiography, or digital subtraction angiography [DSA]) were enrolled. Based on clinical features, patients were categorized into acute MCA occlusion (AMCAO) and chronic MCA occlusion (CMCAO) groups. DSA was performed in 129 patients. We collected baseline clinical data, anterior cerebral artery (ACA), and posterior cerebral artery (PCA) collateral compensation scores, cerebral ischemic compensation status, and corresponding PCA branch vascular excursion phenomena on cranial CT perfusion imaging. We summarized the associated clinical factors affecting the pattern of large-vessel occlusion and disease severity and analyzed the primary compensatory mechanisms and pathways after unilateral AMCAO and CMCAO. Results: Patients in the AMCAO group (95/223) had a significantly higher prevalence of comorbid alcohol use history than those in the CMCAO group (128/223). The CMCAO group had a better level of ACA compensation, whereas PCA compensation was more prominent in the AMCAO group. The proportion of PCA branches showing deviation of the inferior temporal artery on the affected side was much higher in the cerebral ischemia compensation group than in the non-compensation group. Conclusions: In AMCAO, PCA showed a higher degree of collateral circulation opening than ACA, whereas in CMCAO, compensation was predominantly mediated by MCA-ACA floppy collateral branch, with ACA providing better collateral supply. The proportion of patients with a history of alcohol abuse was significantly higher in the AMCAO group than in the CMCAO group, suggesting that alcohol may, to some extent, influence clinical symptoms and prognosis of patients with MCA occlusion.