title: The carotid compression test for therapeutic occlusion of the internal carotid artery. Comparison of angiography with transcranial Doppler sonography.
abstract: BACKGROUND
  The anterior communicating artery is a key collateral pathway in patients with internal carotid artery (ICA) occlusions. Diagnostic balloon or manual occlusion of the ICA is a qualified test for the collateral function of the circle of Willis. The aim of our study was to test whether transcranial Doppler sonography (TCD) with manual carotid compression is able to predict the degree of cross-over flow and tolerance of ICA occlusion.
  
  
  METHODS
  A prospective study was performed on 88 patients suffering from neck tumors or inoperable ICA aneurysms with planned ligation or permanent balloon occlusion of the ICA. Preceding a balloon occlusion lasting 20 min we performed TCD with manual carotid compression test. Insufficient cross-over flow during transient carotid occlusion was defined angiographically as missing opacification of the middle cerebral artery (MCA) after selective injection of contrast media in the contralateral ICA, and sonographically as a decrease greater than 60% in flow velocity of the MCA ipsilateral to the carotid occlusion.
  
  
  RESULTS
  TCD and angiography could be compared in 70 of 88 patients. Angiography showed no or insufficient collateral flow in 26%. All patients (n = 10) with a decrease in MCA velocity greater than 60% on angiography showed missing or poor cross-over flow. A greater than 50% increase in the anterior cerebral artery (ACA) predicted moderate or good cross-over flow in 98%. Clinical observation revealed 11 transient neurological deficits. Eight of them showed insufficient cross-over flow angiographically and sonographically. In 2 of 11 only TCD revealed such low collateral supply. Neither technique predicted hemodynamic ischemia in only 1 of the 11.
  
  
  CONCLUSIONS
  TCD with carotid compression test is a valid method for predicting interhemispheric flow and clinically relevant hemodynamic compromise in cases of occlusion of the ICA.
authors.affiliation: Department of Neurology, University Clinics of Freiburg, Germany. hetzel@NZ11.ukl.uni-freiburg.de
authors.forename: A
authors.initials: A
authors.lastname: Hetzel
authors.forename: G
authors.initials: G
authors.lastname: von Reutern
authors.forename: M G
authors.initials: MG
authors.lastname: Wernz
authors.forename: D W
authors.initials: DW
authors.lastname: Droste
authors.forename: M
authors.initials: M
authors.lastname: Schumacher
mesh_terms: D000783:Aneurysm / Q000209:etiology / Q000628:therapy*; D001783:Blood Flow Velocity; D002343:Carotid Artery, Internal / Q000000981:diagnostic imaging / Q000503:physiopathology; D016893:Carotid Stenosis / Q000175:diagnosis* / Q000628:therapy*; D002404:Catheterization; D002533:Cerebral Angiography; D002560:Cerebrovascular Circulation; D002941:Circle of Willis / Q000000981:diagnostic imaging / Q000503:physiopathology; D006801:Humans; D011237:Predictive Value of Tests; D012680:Sensitivity and Specificity; D017585:Ultrasonography, Doppler, Transcranial