Between 1981 and 1990, superficial temporal artery-middle cerebral artery (STA-MCA) anastomosis was performed on 43 patients who had steno-occlusion of the internal carotid or middle cerebral artery. All of these patients were followed for an average of 6.5 years (range, 0.5 to 10 years). A follow-up study showed that 7 of these cases had a recurrence of an attack on the contralateral side or in the posterior circulation, but not on the ipsilateral side. Two of them had re-attacks on the contralateral side of EC/IC bypass, and 5 re-attacks took place in the posterior circulation. The symptoms of re-attack ware: 3 cases of TIA (vertigo, nausea), and 4 cases of stroke. The times of re-attacks were: immediately following surgery, 1 case; within 2 weeks following surgery, 1 case; 6 months or more following surgery, 5 cases. Fifteen out of 43 cases had 16 steno-occlusive lesions other than the operative side on preoperative angiography. Six of the 7 re-attack cases had steno-occlusive lesions on the re-attack sides. Positron emission tomography (PET) was performed on 18 cases before and after STA-MCA anastomosis. Five of these cases had re-attacks; 2 were in the form of misery perfusion on the contralateral side prior to surgery, and the re-attacks following surgery occurred on the same side. Another 2 cases who had cerebellar ischemias after postoperative PET study showed increasing of OEF on the cerebellar hemisphere postoperatively compared with the preoperative PET study.
In conclusion, bypass surgery is effective in preventing recurrence of ischemic symptoms on the operated side. But in cases with steno-occlusive lesions on the non-operated side, a follow-up study such as cerebral hemodynamics and metabolism is necessary for predicting the occurrence of the ischemic attack of that area following surgery.
