Evaluation of EC-IC bypass for patients with atherosclerotic occlusive cerebrovascular disease: clinical and positron emission tomographic studies.

The authors report clinical evaluations of extracranial-intracranial (EC-IC) bypass surgery for patients presenting with misery perfusion on positron emission tomography (PET) due to atherosclerotic occlusive cerebrovascular disease. Seven patients underwent PET both before and after undergoing EC-IC bypass surgery. Three of the 7 patients had transient ischaemic attacks (TIAs) and 4 had minor strokes. Five of the 7 had unilateral superficial temporal-middle cerebral artery (STA-MCA) anastomosis, one had bilateral STA-MCA anastomoses and one had STA-MCA anastomosis on one side and carotid endarterectomy on the other side. PET showed postoperative improvement in regional cerebral blood flow and metabolism in 5 of the 7 patients. In the remaining 2 patients, one showed no remarkable changes on PET and the other showed exacerbation on PET due to postoperative cerebral infarction. All three patients who had TIAs had no further TIAs after surgery. Two of the 3 patients postoperatively showed improvement in misery perfusion on PET. In the 4 patients who had minor strokes, 2 showed clinical improvements. One of the 2 showed improvement not only in motor function but also in the higher cortical functions such as verbal and performance intelligence quotients. Changes on PET correlated to the clinical improvement in 4 of 7 patients. The EC-IC bypass is therefore effective in patients with haemodynamic hypoperfusion syndromes by improving the state of low perfusion.