Long-term evaluation of cerebral blood flow, transient ischemic attacks, and stroke after STA-MCA anastomosis.

A group of 107 consecutive patients with patent extracranial-intracranial bypasses were followed an average of 25.2 months to determine the long-term results on regional cerebral blood flow (rCBF), transient ischemic attacks (TIAs), and stroke incidence. Average mean rCBF initially rose to 110% at 1 week, then gradually fell to 105% at 6 months, and 85% at 2 years. Maximum increase in cerebral blood flow occurred in patients with middle cerebral artery stenosis or those in the preoperative low flow group, i.e., less than 50 ml/100 gm/min. In the group with TIAs plus mild stroke, the mean rCBF rose to 122% at 1 week, compared to the group with TIAs only who showed a mean increase to 107% at one week. Clinical improvement was excellent or good in 82% of those with TIAs only; in those with TIAs plus mild stroke, 77% had excellent or good relief of TIAs; and in those with mild stroke only, 70% recovered from their neurological deficits. In the 25.2 months of average follow-up, stroke occurred in only 1 patient on the side of the anastomosis, and in 2 patients on the side opposite the anastomosis, giving an average stroke incidence of 1.5% per year.