Contralateral cerebral blood flow velocity changes after intracarotid amobarbital injection.

BACKGROUND AND PURPOSE: The intracarotid amobarbital procedure (IAP) leads to a prompt decrease in ipsilateral middle cerebral artery (MCA) mean blood flow velocity (MFV). Little is known about contralateral MFV changes.

METHODS

The authors investigated bilateral MCA MFV using transcranial Doppler sonography (TCD) in 8 patients with epilepsy undergoing IAP. Measurements were excluded from analysis if angiography revealed any signs of interhemispheric cross-flow.

RESULTS

With in 64 seconds after amobarbital injection, ipsilateral MFV decreased to a mean of 44.4% +/- 7.5% of baseline value (P < .01). In the absence of interhemispheric cross-flow and within 68 seconds, contralateral MFV decreased to 83.1% +/- 7.9% (P < .01).

CONCLUSIONS

The observed decrease of contralateral MFV was not caused by amobarbital cross-perfusion. A possible underlying mechanism may be interhemispheric deafferentation.