EC-IC direct bypass revascularization for intracranial atherosclerosis. Insights beyond the COSS trial

Despite the results of the EC-IC Bypass International Trial and the Carotid Occlusion Surgery Study (COSS), high-volume centers continue to treat symptomatic intracranial atherosclerotic patients with bypass revascularization. This study aimed to analyze our data and assess whether patient characteristics and outcomes differ from those in EC-IC Bypass and COSS trials. Patients with intracranial atherosclerotic occlusions treated by EC-IC bypass from January 2012 to June 2022 were included. Inclusion criteria were: (1) intracranial atherosclerotic occlusion >70 %, (2) transient or permanent ischemic events in the affected territory, and (3) impaired cerebrovascular reactivity demonstrated by acetazolamide-challenged SPECT. Forty-nine patients were included. Half presented bilateral occlusions, and 53.1 % had hemodynamic symptoms. Most were asymptomatic or had mild strokes preoperatively. Postoperatively, mRS worsened in 34.78 % of patients without hemodynamic symptoms, compared to 15 % of symptomatic patients. No significant differences in NIHSS or mRS were observed between pre- and postoperative evaluations. The 30-day complication rate was 20.4 %, with one procedure-related death. High rates of bypass patency (97.95 %) and SPECT improvement (87.75 %) were achieved. Long-term ipsilateral ischemic stroke rate was 2 %. EC-IC bypass remains a viable option in carefully selected patients with symptomatic intracranial stenosis and impaired cerebrovascular reserve. Patient selection based on clinical and functional criteria is essential. Our results contrast with those of the COSS trial, showing lower recurrence of ipsilateral ischemic stroke, neurological stability in most patients, and favorable outcomes in individuals with hemodynamic symptoms and contralateral stenosis.