Indication for Acute Extracranial-Intracranial Arterial Bypass in Middle Cerebral Artery Occlusive Disease and its Results

The authors presented a retrospective analysis of 52 cases which underwent emergent superficial temporal artery-middle cerebral artery (STA-MCA) anastomosis for MCA occlusion in 45 cases and stenosis in 7 cases within 72 hours of onset. The neurological grade and its effect on preventing or limiting the development of cerebral infarction on computerized tomography (CT) scans after acute cerebral revascularization were assessed. As to the etiology of occlusion or stenosis, atherosclerotic origin accounted for 36 cases (69.2%), and embolic 16 cases (30.8%). Clinical presentation included progressive stroke in 16 cases and complete stroke in 36 cases, of which 8 were with mild,12 with moderate, and 16 with severe hemiparesis. Thirty-three (63.3%) of 52 cases had good neurological recovery, and 6 died in postoperative period : one from acute subdural hematoma and 5 from other complications. Postoperative CT scans showed no new infarction in 21 cases. Basal ganglia infarction occurred in 18 cases, of which 7 were embolic origin, and cortical infarction occurred in 13 cases, of which 8 were embolic origin. Hemorrhagic infarction was detected in 19 cases (36.5%) on CT scans with isodensity or minimally high density areas in 17 cases and small frank hematoma in 2 cases. Of these 19 cases, 15 presented complete stroke with moderate or severe hemiparesis,and 12 presented with embolic origin. Cerebral swelling and probable mass effect were detected in 10 cases on CT scans with definite mass effect in 2 cases. Of these 10 cases, 7 presented with embolic origin. Therefore, it was suggested that hemorrhagic infarction, cerebral swelling and mass effect after acute cerebral revascularization were apt to appear in severe ischemic patients such as major stroke and these could be reduced by excluding such patients from surgery. A clear distinction could be made between the good neurological grade without cortical infarction and the poor neurological grade with cortical infarction by the evaluation of clinical presentation such as conjugate deviation of eyes, angiographical collateral flow capacity and cerebral blood flow by single photon emission computed tomography (SPECT) using 133 Xe inhalation. In 10 embolic cases who had acute cerebral revascularizations within 3 to 6 hours of onset,good neurological recovery was obtained in 6 cases, but acute cerebral revascularization failed to prevent cortical infarction on CT scans in 7 cases with embolic origin. Therefore,it was indicated that acute cerebral revascularization failed to prevent cerebral infarction in the majority of the cases with embolic origin, even if the revascularization was performed within 3 to 6 hours of onset