[Hyperperfusion syndrome following bilateral aorto-carotid bypass--a study of transcranial Doppler].

A 22-year old female with Takayasu disease, who underwent bilateral aorto-carotid bypass surgery developed hyperperfusion syndrome postoperatively. Following the operation, convulsion and headache developed and mean velocity in the middle cerebral artery, measured by transcranial doppler, elevated. Mean velocity gradually decreased on the 10th postoperatively day and became a plateau at 200% of preoperative value. Pulsatility index as a index of cerebral vascular resistance was low just after the operation, became normal the following day and gradually increased 10 days after the operation. These changes seem to be recovery of cerebral autoregulation. On the 20th postoperative day, computed tomography scan was examined and multiple low density areas were found in the basal ganglia regions, but these changes disappeared 2 months after the operation. These reversible changes of CT scan might show ischemic changes or cerebral edema induced by cerebral vasospasm.