[Postoperative evaluation of EC/IC bypass surgery--long-term follow up study by donor artery compression test]

Focal cerebral vascular dependency of donor arteries was evaluated in 45 patients who had undergone EC/IC bypass surgery. During EEG recording, digital compression was applied to the anastomosed donor superficial temporal artery (STA) at the preauricular region. The appearance of slow waves on the EEG recording suggests hypofunction of the local brain. In cases showing positive response to the STA compression test, we suggest that the blood supply via STA is an essential collateral route to the ischemic brain. The test was periodically repeated in the postoperative follow-up period for a mean of seven years. Eleven cases (24%) showed positive results in the STA compression test during the long-term postoperative follow-up period.