Patients with low stump pressure and possible pressure fall in the middle cerebral artery during carotid surgery may be identified preoperatively by transcranial Doppler.

Although it has now been established that surgery is the best way to treat patients with symptomatic tight carotid stenosis, the fact remains that perioperative risks are not negligible. Patients with significant contralateral stenosis and/or no collateral flow capacity through the anterior communicating artery are likely to be at higher risk during surgery. We examined a series of 52 patients pre- and postoperatively with transcranial Doppler (TCD) and compared the results to perioperative stump pressures. Our intention was to find out whether the results of the TCD examination of the circle of Willis could be correlated to the perioperative stump pressures, and whether TCD gives reliable information about the collateral flow. We found relatively high stump pressures in patients with potential function of any communicating artery, and in the group with no collateral function most patients had low stump pressures. We also found that preoperative flow velocity fall in the middle cerebral artery (MCA) on compression of the ipsilateral internal carotid artery correlated with perioperative stump-pressure indices. However, we were unable to predict stump pressures in individual patients by flow velocity measurements in the MCA preoperatively.