[Evaluation of middle cerebral artery blood flow velocity with transcranial Doppler in carotid endarterectomy].
Thirty patients, submitted to 34 carotid endarterectomies, from September, 1992 to April, 1996, on Hospital Albert Einstein, São Paulo, have been studied. In these surgeries, Middle Cerebral Artery (MCA) was miniaturized with Transcranial Doppler (TCD). The purpose of this study were to verify the relationship between MCA blood flow velocity with postoperative neurologic complications: studying the velocity variations with risk of cerebral low perfusion and carotid stump back pressure, during carotid clamping; confirming that the TCD information, could show when it is necessary to use shunting, and its efficiency; and to know whether the method could detect intraoperative embolization. The equipment used was a Transpect TCD-EME 2000. During surgery, when carotid stump back pressure was bellow of 54.4 mmHg, Pruitt-Inahara shunt was applied. The flow velocity value observed with TCD was divided in 3 parts: phase 1, basal, since anesthesy induction until carotid clamping; phase 2, clamping, during the period when the carotid artery was occluded; phase 3, post-declamping, from the time the carotid artery was declamping until the end of surgery. The MCA flow velocity was available on three phases, in cm/s and percentually on phases 2 and 3, in relation to basal phase. The embolizations, detected by TCD, were classified in: a) a few embolizations in less than 10 second period, b) many embolizations in more than 10 second period. Based on the results obtained, its possible to conclude that the MCA flow velocity is related to the risk of cerebral low perfusion during carotid clamping; it was not possible to stablish any relation of MCA flow velocity to carotid stump back pressure; the TCD informs when the use of shunt is necessary and its efficiency; the postoperative neurologic complications were caused by embolizations. The conclusion is that the TCD is useful and easily applicated on carotid endarterectomy.
Waksman
H
H
Departamento de Cirurgia da Faculdade de Medicina da Universidade de São Paulo.
Aun
R
R
Kauffman
P
P
Puech-Leão
P
P
D000368:Aged; D000369:Aged, 80 and over; D001783:Blood Flow Velocity / Q000502:physiology; D002545:Brain Ischemia; D002536:Cerebral Arteries / Q000000981:diagnostic imaging / Q000502:physiology*; D016894:Endarterectomy, Carotid; D005260:Female; D006801:Humans; D020766:Intracranial Embolism; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D012307:Risk Factors; D017585:Ultrasonography, Doppler, Transcranial
Avaliação da velocidade de fluxo sangüíneo na artéria cerebral média, pelo Doppler transcraniano, na cirurgia de endarterectomia da carótida.