Cerebral border zone infarctions: An etiologic study

Background: Cerebral border zone infarctions (BZIs) are a subtype of acute ischemic stroke that occur at the junction between two major cerebral arterial territories. Internal and external BZIs are defined based on the known patterns in brain magnetic resonance imaging (MRI). However, the etiology and pathophysiology of these two types of BZI are still debated. This study aimed to determine the etiologic differences of two types of BZI to guide tailor appropriate treatment strategies for these patients. Methods: In this prospective study, patients with BZIs were enrolled from patients with acute ischemic stroke admitted to the hospitals affiliated with Tabriz University of Medical Sciences, Tabriz, Iran, from 2017 to 2019. Appropriate clinical and laboratory workups were applied to determine possible etiologies of ischemic stroke according to the Trial of Org 10172 in Acute Stroke Treatment (TOAST) classification system. Results: The study included 106 patients with BZI, 53 patients in each group. Both types of BZI were more frequent in males. However, there was no significant difference between the two types concerning sex, age, and profile of major stroke risk factors. The results showed no correlation between the type of BZI and hemodynamic factors (P = 0.086). However, large artery atherosclerosis (LAA) was the most frequent etiology within each subtype of BZI; LAA in internal (P = 0.016) and cardioembolism (P = 0.046) in external BZI were more frequent etiologic subtypes of cerebral infarction. Conclusion: LAA might be the most common etiology for internal and external cerebral BZIs. Cardioembolism might have a more important etiologic role in the external subtype.