Indirect revascularization after bypass surgery for intracranial atherosclerotic steno-occlusive disease

Indirect revascularization after bypass surgery for intracranial atherosclerotic steno-occlusive disease (ICAD) remains controversial. We aimed to evaluate indirect revascularization after direct bypass surgery in patients with ICAD.

Among 245 patients with ICAD who underwent direct bypass surgery between 2003 and 2022, 191 patients were ultimately enrolled in this study. Treatment outcomes were compared between combined bypass (n = 162 [84.8 %]) and direct bypass alone (n = 29) groups. Multivariable analyses were performed to identify significant predictors of indirect revascularization and favorable clinical outcomes.

There were no significant differences in overall baseline characteristics or treatment outcomes between the two groups. At the last angiographic follow-up at 27.1 ± 27.1 months (range, 5.0-97.3 months), the rate of indirect revascularization was significantly higher in the combined bypass group than in the direct bypass alone group (39.5 % versus 17.2 %, P = .022). Significant predictors of indirect revascularization included combined bypass (OR 3.175, 95 % CI 1.142-8.826; P = .027) rather than direct bypass alone, and significant stenosis and occlusion in the middle cerebral artery rather than the internal carotid artery (OR 1.961, 95 % CI 1.022-3.763; P = .043). An additional analysis revealed that a good preoperative clinical status (OR 0.141, 95 % CI 0.066-0.302, P < .001) and indirect revascularization (OR 5.508, 95 % CI 1.003-30.245, P = .050) were independent predictors of favorable clinical outcomes.

Indirect revascularization was more pronounced after combined bypass than direct bypass alone and was a significant predictor of favorable clinical outcomes.