Long-term Follow-up of EC/IC Bypass

Abstract

Between 1973 and 1985, superficial temporal artery-middle cerebral artery (STA-MCA) anastomosis was performed in 125 patients with steno-occlusion of the internal carotid or middle cerebral artery. Patients with moyamoya disease were excluded. One hundred twenty patients were followed for an average of 5.1 years (range, 0 to 12.5 years). The patients were divided into four groups according to the degree of neurological deficit. Mild neurological deficit (MiND) was observed in nine patients with transient ischemic attacks, six with reversible ischemic neurological deficits, nine with minor stroke who underwent surgery within 3 weeks of onset, and 37 with minor completed stroke. The moderate neurological deficit (MoND) group consisted of five patients with major stroke who were operated within 3 weeks and 12 with major completed stroke who had incomplete hemiparesis. Among the patients with severe neurological deficit (SND) were seven with major stroke and 19 with major completed stroke and, complete hemiparalysis. The fourth group included 16 patients with acute progressing stroke (APS). The results of follow-up in the MiND group were consistent with those of the International Cooperative Study of Extracranial/Intracranial (EC/IC) Arterial Anastomosis. Drug-induced electroencephalography and evoked potential test was performed in 60 cases. Hemodynamic competence was confirmed by means of induced hypotension in seven MiND patients, none of whom had further cerebral ischemic attacks. Reversibility of neurological deficits (ischemic penumbra) was demonstrated during induced hypertension in eight cases (two of MiND, three of MoND, and three of APS). In all of these cases the neurological status improved. Cerebral blood flow (CBF) was measured under induced hypotension in 13 cases, and two patients in the MiND group showed reduced CBF and had no further cerebral ischemic attacks. These results suggest that it is essential to document hemodynamic competence and reversibility of functional deficits (ischemic penumbra) in patients being considered for EC/IC bypass.