Regional cerebral blood flow studies following superficial temporal-middle cerebral artery anastomosis

Regional cerebral blood flow (rCBF) studies were performed during the postoperative period on 16 patients with internal carotid occlusions and inaccessible stenoses, and middle cerebral artery occlusion and stenoses, who underwent superficial temporal artery-middle cerebral artery (STA-MCA) anastomoses. The intra-arterial xenon method with selective application of the xenon bolus through the internal carotid and the newly established superficial temporal channel has allowed comparison of the flow provided by the pathological input with flow through the new input. The results show that initial rCBF (rCBF1) was globally reduced in all patients to a mean of 28.4 +/- 11.9 ml/100 gm/min at a mean pCO2 of 29.6 +/- 9.55 mm Hg. Patients with transient ischemic attacks (TIA) and minor strokes with minimal residua (RIND) had a mean rCBF1 of 30.4 +/- 11.6 ml/100 gm/min at a mean pCO2 of 30 +/- 10 mm Hg, while patients with completed strokes had a mean rCBF1 of 25.0 +/- 12.4 ml/100 gm/min at a mean pCO2 of 29.1 +/- 8.8 mm Hg. There was no significant difference between these two groups. This finding suggests that in this small group of patients with TIA's and RIND's, the cause of the stroke is probably related more to decreased perfusion than embolus, and may explain why these patients' symptoms improve after STA-MCA anastomosis. The results of this study suggest that in addition to an inaccessible lesion, global or focal decreased rCBF is a necessary criterion in the definition of indications for intracranial revascularization procedures.