Importance of cerebral collateral pathways during carotid endarterectomy.

Abstract

Before surgery, we evaluated major intracranial collateral pathways using transcranial Doppler ultrasonography (TCD) in 50 patients who then underwent carotid endarterectomy with concurrent multimodality cerebral monitoring. Patients were grouped with respect to collateral pathways demonstrated preoperatively by TCD: Group 1, good collateralization with an anterior and/or a posterior communicating artery ipsilateral to the operative carotid lesion (29 patients, 58%); Group 2, collateral pathways present but impeded by other proximal stenoses (nine patients, 18%); and Group 3, no collateralization identified (nine patients, 18%). Three patients (6%) could not be classified. TCD identified major collateral pathways with a sensitivity of 89% and a specificity of 80% when compared with arteriography. During carotid endarterectomy mean middle cerebral artery velocity, pulsatility index, and stump pressure were higher and the decrease in middle cerebral artery velocity with extracranial carotid artery cross clamping was significantly less among Group 1 patients than among Group 2 and 3 patients (p<0.Q5 for both groups). Group 1 patients required fewer intraoperative carotid artery shunts and developed fewer ischemic electroencephalographic abnormalities than did patients in Groups 2 and 3 (p<0.05 for both groups). TCD assessment of cerebral collateralization helps predict hemodynamic consequences of cross clamping during carotid endarterectomy. (Stroke 1988;19:1328-1334) C erebrovascular collateral blood supply plays an essential role in cerebral perfusion. In patients undergoing carotid endarterectomy the correlation of preoperative assessment of collateral potential with cerebral perfusion during extracranial carotid artery cross clamping enhances our understanding of intracerebral hemodynamics.Transcranial Doppler ultrasonography (TCD) can directly insonate the intracranial arteries to evaluate collateral perfusion around the circle of Willis. '-3 In addition, TCD provides continuous noninvasive monitoring of middle cerebral artery (MCA) blood velocity (MCAV) and immediately detects changes in cerebral perfusion during carotid artery manipulation and cross clamping.4 -6 The purposes of our study were to correlate prospectively the

Assessment of ≥50% and <50% Intracranial Stenoses by Transcranial Color-Coded Duplex Sonography

“…TCCS may misdiagnose intracranial stenoses in conditions with increased cerebral blood flow, such as cross-flow through the circle of Willis, leptomeningeal anastomoses supplied by the ACA in the presence of high-grade stenosis or occlusion of the MCA, and arteriovenous malformation. 8,11,23,37,38 No ACA stenosis was diagnosed when ultrasonic findings indicated the presence of collateral flow through the anterior communicating artery or high-grade stenosis or occlusion of the ipsilateral MCA. Patients with angiographic signs of arteriovenous malformations were excluded.…”

Comparison of transcranial and cervical continuous-wave Doppler in the evaluation of intracranial collateral circulation.

“…6 Middle cerebral artery velocity and posterior cerebral artery velocities were obtained bilaterally in patients with a suitable window. The spectral analysis of each intracranial signal was performed with online 64 fast Fourier transformation.…”

Collateral Circulation

“…Operative management may also be influenced, as inadequacy of collateral pathways on angiography and TCD correlates with intraoperative electroencephalographic changes. [35][36][37] …”