Cerebrovascular response time to a breath-holding challenge.
BACKGROUND
To evaluate the timecourse of cerebrovascular reserve response to breath-holding.


METHODS
Using simultaneous bilateral transcranial Doppler (TCD) recordings from the MCA during a breath-holding challenge, we measured the time interval between baseline and peak blood flow velocity values in 25 patients with critical unilateral internal carotid artery (ICA) stenosis (> 85% lumen diameter reduction), in 9 patients with a non-critical (70-85%) ICA-stenosis and in 27 normal controls.


RESULTS
Normal controls and patients with non-critical stenosis reached peak MCA velocities on both sides almost simultaneously. For the patients with critical stenosis the peak response time ipsilateral to the stenosis was delayed 2.40 +/- 3.43 sec compared to the opposite side. This delay resolved after carotid endarterectomy.


CONCLUSIONS
In response to a breath-holding challenge unilateral critical ICA stenosis is associated with a significant ipsilateral prolongation of the rise time from baseline to peak MCA velocity.
Gahn
G
G
Klinik und Poliklinik für Neurologie, Universitatsklinikum Carl Gustav Carus der Technischen Universität, Dresden, Germany. gahn@rcs.urz.tu-dresden.de
Hallmeyer-Elgner
U
U
Becker
S
S
Barrett
K M
KM
Ackermann
R H
RH
D000368:Aged; D001783:Blood Flow Velocity; D002343:Carotid Artery, Internal / Q000601:surgery; D016893:Carotid Stenosis / Q000000981:diagnostic imaging / Q000503:physiopathology* / Q000601:surgery; D002560:Cerebrovascular Circulation; D003097:Collateral Circulation; D016894:Endarterectomy, Carotid; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D020768:Middle Cerebral Artery / Q000000981:diagnostic imaging / Q000503:physiopathology*; D012119:Respiration; D012720:Severity of Illness Index; D013997:Time Factors; D016896:Treatment Outcome; D017585:Ultrasonography, Doppler, Transcranial