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

BACKGROUND AND OBJECTIVES:The role of bypass surgery in intracranial atherosclerotic steno-occlusive diseases (ICADs) remains controversial. We aimed to analyze the surgical outcomes of bypass surgery in patients with the ICADs in a single tertiary institution. METHODS:Among 1018 cases of low-flow bypass surgery between 2003 and 2022, 215 patients with the ICAD refractory to medical treatment were finally enrolled in this study. Clinical and radiological outcomes were retrospectively evaluated, with survival analyses. RESULTS:All strokes, cerebral infarctions, and intracranial hemorrhages occurred in 12.1% (n = 26), 9.8% (n = 21), and 2.3% (n = 5), respectively, during the clinical follow-up of 54.6 ± 47.6 months (range, 0.6-237.8 months). Among all stroke events, 84.6% (n = 22) occurred within 30 postoperative days. The 2-year and 5-year cumulative risks of all strokes were 12.1% each. The mean modified Rankin Scale scores were 1.6 ± 1.1 (range, 0-5) preoperatively and 0.8 ± 1.2 (range, 0-6) at last (P < .01). The patency of direct bypass was 99.1% (n = 213) just before discharge and 96.3% (n = 184 of 191 patients with available tests) at the last angiographic follow-up of 27.0 ± 27.3 months (range, 2.3-97.3 months). All the patients with available data (n = 190) showed hemodynamic improvement on acetazolamide-challenged single-photon emission computed tomography with 99mTc-hexamethylpropyleneamine oxime during the follow-up of 38.6 ± 36.7 months (range, 2.3-158.6 months). CONCLUSION:Low-flow bypass surgery showed acceptable treatment outcomes in the prevention of recurrent stroke.