The goal of this observational study is to learn about the protein heterogeneity in extracellular vesicles (EVs) derived from different human blood circulatory regions of patients with ruptured or unruptured intracranial aneurysms. The main objectives are:

Reveal the proteomic heterogeneity of EVs in different blood circulatory regions of the human body。 Reveal the proteomic differences of EVs in cerebral feeding arteries and draining veins between patients with aneurysmal subarachnoid hemorrhage and those without hemorrhage.

Explore EV-derived protein biomarkers that reflect the diagnosis and prognosis of subarachnoid hemorrhage

Extracellular vesicles (EVs) are small lipid bilayer-enclosed vesicles that are widely secreted by almost all types of cells into the extracellular microenvironment. They carry biomolecules such as proteins, lipids, mRNA, and miRNA, and play important roles in intercellular communication and disease regulation. Due to their stability and specificity, EVs have become a research hotspot for the diagnosis and prognosis of various diseases.

Currently, existing studies on blood-derived EVs mostly rely on samples collected from peripheral veins, such as the brachial vein. However, there is a lack of research investigating the heterogeneity of EV contents across different vascular regions of the human body, such as arteries and deep veins in the head and neck.

Neurointerventional surgery is a minimally invasive, imaging-guided medical technique that utilizes microcatheters, micro guidewires, and other instruments to access target vessels through the vascular system for the diagnosis and treatment of cerebrovascular diseases. This technique allows for the collection of blood samples from arteries or veins in the head and neck during the surgical procedure.

This project proposes to collect blood samples from the femoral vein, internal jugular vein, and internal carotid artery of patients with ruptured or unruptured intracranial aneurysms undergoing neurointerventional procedures under general anesthesia. EVs will be extracted for proteomic differential analysis, aiming to characterize the heterogeneity of EVs across different vascular regions in the human body and to explore potential diagnostic and prognostic protein biomarkers for aneurysmal subarachnoid hemorrhage.

Inclusion Criteria:

• 1. Aged between 18 and 60 years, regardless of gender; 2. Diagnosed with intracranial aneurysm confirmed by MRA, CTA, or DSA; 3. Patients with aneurysmal subarachnoid hemorrhage must have CT imaging evidence of hemorrhage, and blood collection must occur within 3 days of symptom onset; 4. Scheduled to undergo neurointerventional surgery for intracranial aneurysm under general anesthesia, with the procedure starting between 8:00 AM and 12:00 PM; 5. Willing to comply with the study protocol and data collection procedures; 6. Able to understand and sign the informed consent form.

Exclusion Criteria:

• 1. Patients with a pre-onset (in hemorrhagic cases) or preoperative (in non-hemorrhagic cases) Modified Rankin Scale (MRS) score ≥ 2; 2. Presence of other neurological disorders such as Parkinson's disease, Alzheimer's disease, cerebral infarction, brain tumors, epilepsy, etc.; 3. Presence of other systemic diseases such as diabetes, coronary artery disease, cancer, infections, hematological diseases, or severe metabolic disorders that may significantly affect the evaluation of blood EVs; 4. History of severe hepatic or renal dysfunction (ALT > 3 times the upper limit of normal; creatinine > 225 μmol/L); 5. Patients who cannot tolerate anesthesia, anticoagulant therapy, or who have coagulation disorders; 6. History of severe allergic reactions to contrast agents; 7. Pregnant women; 8. Patients participating in other clinical trials who have not yet completed follow-up.

This is an exploratory study, and to date, there have been no similar reports in the literature. The primary outcome will be differences in proteomic profiles, which may yield hundreds of differential results. Based on the planned budget and clinical experience, we preliminarily aim to enroll 60 patients with aneurysmal subarachnoid hemorrhage and 60 patients with unruptured intracranial aneurysms. Proteomic analysis of extracellular vesicles from the first 30 patients will be used to identify intergroup differential markers of interest, which will then guide further adjustments to the sample size in the subsequent phase of the study.