Surgical Outcomes of Low-Flow Bypass Surgery in Intracranial Atherosclerotic Steno-Occlusive Diseases

This is a report on a scholarly article regarding the treatment results of low-bypass surgery for 215 patients with intracranial atherosclerotic stenosis or occlusion at Seoul National University Hospital.

Background Introduction: Intracranial atherosclerotic disease (ICAD) causing stenosis or occlusion is one of the major causes leading to ischemic stroke. The optimal treatment for ICAD remains controversial, and it is unclear whether bypass surgery can improve the prognosis. This study aims to analyze the surgical outcomes of low-bypass surgery for ICAD patients.

Author’s Affiliation: The authors of the paper are from the Department of Neurosurgery, Seoul National University Hospital, including Yuwhan Chung, et al.

Research Methods: 1) Case selection criteria: From 2003 to 2022, a total of 1018 cases underwent low-bypass surgery, and 215 cases meeting the ICAD diagnostic criteria and ineffective with optimal medical treatment were included in the study. 2) Surgical approach: 44 cases (20.5%) with direct bypass surgery, 171 cases (79.5%) with direct combined indirect bypass surgery. 3) Pre- and post-operative management: Including standardized antiplatelet/anticoagulant therapy, risk factor control, etc. 4) Evaluation indicators: Clinical outcome (modified Rankin Scale), surgical complications, revascularization status (digital subtraction angiography), cerebral perfusion status (SPECT).

Key Research Findings: 1) After a follow-up of 54.6±47.6 months, the clinical condition was significantly improved compared to pre-operative status (decrease in modified Rankin Scale score). 2) In 98.1% of patients, the direct bypass pathway was patent after surgery, and 96.3% remained patent during the follow-up period. 33.7% showed indirect revascularization. All patients had improved cerebral perfusion. 3) The perioperative 30-day stroke rate was 10.2%, and the total stroke rate during the follow-up period was 12.1% (12.1% ischemic, 4.1% hemorrhagic). 4) The cumulative 2-year and 5-year stroke risk was 12.1%.

Research Significance: 1) ICAD patients receiving low-bypass surgery had good clinical prognosis, with successful revascularization in most patients and manageable ischemic and hemorrhagic complications after surgery. 2) It suggests that bypass surgery may still be a feasible treatment option for refractory ICAD patients. 3) For the first time, the possibility of indirect revascularization pathway formation after surgery in ICAD patients was observed.

Research Highlights: 1) Large case volume and extensive surgical experience. 2) Long-term systematic follow-up and evaluation of multiple clinical outcomes. 3) Exploration of the role of indirect bypass surgery in the treatment of ICAD.