Bypass surgery in patients with intracranial stenotic lesions. Postoperative morbidity and angiographic findings.

Postoperative morbidity in patients with intracranial stenotic lesions following extracranial-intracranial arterial (EC-IC) bypass is not well defined. A high rate of neurological complications associated with occlusion of the stenotic arteries after surgery has recently been reported. In the period June, 1976, to March, 1984, the authors performed EC-IC bypass procedures in 19 patients with intracranial stenotic arteries. Most of the patients were initially treated pharmacologically (usually by anticoagulant therapy). Surgery was performed if the symptoms recurred while the patients were under pharmacological treatment and if angiography confirmed arterial stenosis. Antiplatelet therapy was given until the day of surgery and during the entire follow-up period. No permanent postoperative morbidity was observed in the series. One patient, with stenosis of the left siphon, the A1 segment of the anterior cerebral artery, and the M1 segment of the middle cerebral artery, had a transient dysphasia and right hemiparesis (lasting 3 days) in the presence of an unchanged arterial stenosis. In five patients early postoperative angiography (at 5 to 21 days) revealed occlusion of previously stenotic arteries. In one patient the occlusion was disclosed only on a later angiographic study, 2 months after surgery. Although EC-IC bypass is generally not a very high-risk operation in patients with intracranial arterial stenosis, there is a high percentage of immediate postoperative occlusion, and the authors suggest caution in determining indication for surgical treatment.