Evaluation of the Effectiveness of Surgical and Diagnostic Techniques in Patients With Steno-occlusive Diseases of the Cerebral Vessels

Patient selection. Patients with asymptomatic or symptomatic ICA occlusion undergoing STA-MCA bypass at the neurosurgical center will be prospectively enrolled between August 2025 and December 2027. Prior to registration, all participants will provide written informed permission in compliance of the Declaration of Helsinki's ethical guidelines.

Preoperative evaluation will include computed tomography angiography (CTA), magnetic resonance imaging (MRI), digital subtraction angiography (DSA), and comprehensive neurological and neuropsychological assessments. Magnetic Resonance Imaging also will be employed to exclude patients with extensive territorial infarctions. Only patients with radiologically confirmed ICA occlusion and arterial spin labeling (ASL) MRI-documented cerebral hypoperfusion in the affected vascular territory who undergo STA-MCA bypass will be included.

The study cohort will be recruited at the National Center for Neurosurgery in Astana through a multidisciplinary collaboration involving neurosurgeons, radiologists, neurologists, and neuropsychologists. All data will be collected using standardized case report forms and subsequently entered into a unified, secure database. Patient confidentiality will be ensured through strict coding and anonymization of personal identifiers and medical record identification numbers (MRINs).

Study variables. Data collection will include the following variables:

Demographic characteristics: Age, gender, birthplace, nationality, employment status, profession, and education level. Medical history: Past medical and surgical history, onset of TIA or stroke, vascular risk factors (hypertension, diabetes mellitus, dyslipidemia, atrial fibrillation), comorbidities (including genetic disorders), previous surgeries, ongoing follow-up care, current medications, and BMI. Clinical, neurological, and cognitive status: Baseline neurological examination findings, Modified Rankin Scale (mRS) and National Institutes of Health Stroke Scale (NIHSS) scores, history of seizures, quality-of-life measures, cognitive reserve indicators (educational attainment and occupational complexity), and engagement in cognitively stimulating activities will be assessed. Lifestyle factors: Smoking status, dietary habits, physical activity, alcohol consumption, sleep quality, vacation frequency, tobacco use, and other lifestyle factors. Radiological and hemodynamic parameters: Location and length of the internal carotid artery occlusion; collateral circulation patterns; Circle of Willis configuration; ASL perfusion metrics; cerebral blood flow (CBF) asymmetry indices; infarct burden; white matter hyperintensities; and postoperative bypass patency and the diameter of STA pre and postoperatively.