Evaluation of vasomotor reactivity by transcranial Doppler and acetazolamide test before and after extracranial-intracranial bypass in patients with internal carotid artery occlusion.

Karnik, Ronald; Valentin, Andreas; Ammerer, H. P.; Donath, Peter; Slaný, J

doi:10.1161/01.str.23.6.812

Cited by 49 publications

(30 citation statements)

References 36 publications

(13 reference statements)

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“…32 However, in the EC/IC bypass trials, selection of patients based on the CVR had not been performed in spite of the fact that this surgical approach has been associated with an improvement of cerebral hemodynamics. 33 In this study, we have demonstrated that intracerebral hemodynamic consequences of carotid occlusion can be very different. Exhausted or diminished CVR and an established BHI value, determined in our data to be Ͻ0.69, could constitute the basis for reconsidering the possibility of testing the efficacy of the classic or a new type 34 of surgical EC/IC bypass approach in a subgroup of patients considered to be at highest risk of developing stroke and with the most favorable odds of benefiting from surgical intervention.…”

Section: Discussionmentioning

confidence: 77%

Outcome of Carotid Artery Occlusion Is Predicted by Cerebrovascular Reactivity

Vernieri

Pasqualetti

Passarelli

et al. 1999

Stroke

239

167

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Background and Purpose-The purpose of this study was to investigate the possibility of obtaining prognostic indications in patients with internal carotid occlusion on the basis of intracranial hemodynamic status, presence of previous symptoms of cerebrovascular failure, and baseline characteristics. Methods-Cerebral hemodynamics were studied with transcranial Doppler ultrasonography. Cerebrovascular reactivity to apnea was calculated by means of the breath-holding index (BHI) in the middle cerebral arteries. Sixty-five patients with internal carotid artery occlusion were followed-up prospectively (median, 24 months), 23 patients were asymptomatic and 42 symptomatic (20 with transient ischemic attack and 22 with stroke). Results-During the follow-up period, 11 symptomatic patients and 1 asymptomatic patient had another ischemic event ipsilateral to carotid occlusion. Among factors considered, only lower BHI values in the middle cerebral arteries ipsilateral to carotid occlusion and older age were significantly associated with the risk of developing symptoms (Pϭ0.002 and Pϭ0.003, respectively; Cox regression multivariate analysis). Based on our data, a cut point of the BHI value for distinguishing between pathological and normal cerebrovascular reactivity was determined to be 0.69. All patients except one, who developed TIA or stroke during the follow-up period, had BHI values ipsilateral to carotid occlusion of Ͻ0.69. Conclusions-These data suggest that impaired cerebrovascular reactivity is predictive for cerebral ischemic events in patients with carotid occlusion. (Stroke. 1999;30:593-598.)

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Section: Discussionmentioning

confidence: 77%

Outcome of Carotid Artery Occlusion Is Predicted by Cerebrovascular Reactivity

Vernieri

Pasqualetti

Passarelli

et al. 1999

Stroke

239

167

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“…ACAS and SCAS. Karnik et al [23] found that extracran ial-intracranial bypass was beneficial for CVR. but did not specify whether their patients were symptomatic or asymptomatic.…”

Section: Discussionmentioning

confidence: 99%

Does Carotid Endarterectomy Modify Cerebral Vasomotor Reactivity?

Bornstein¹,

Gur²,

Shifrin³

et al. 1997

Cerebrovasc Dis

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The effects of carotid endarterectomy (CEA) on cerebral hemodynamics in certain groups of patients with severe carotid stenosis still remain unclear. Cerebral vasomotor reactivity (CVR) is an important indicator of intracranial blood supply and cerebral autoregulation. Symptomatic and asymptomatic patients with severe carotid stenosis and impaired CVR were evaluated before and after CEA. Transcranial Doppler ultrasonography (TCD) and the Diamox test (i.v. administration of 1.0 g acetazolamide) before and 3 months after CEA were performed in 42 patients (21 symptomatic, 21 asymptomatic) with severe (70–99%) carotid stenosis. CVR was assessed as the difference between peak blood flow velocities in the middle cerebral artery ipsilateral to the carotid stenosis before and after acetazolamide injection and as percent increase of blood flow velocity after acetazolamide (ANOVA). Three months after CEA there was statistically significant improvement of CVR in asymptomatic compared with symptomatic patients (p < 0.05, ANOVA). CEA improves CVR mostly in asymptomatic patients. TCD combined with the Diamox test appears to be a useful tool in assessing cerebral hemodynamics prior to carotid surgery, and might be an additional criterion for selecting asymptomatic patients for CEA.

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“…H0jer-Pedersen 3 reported that patients with unilateral occlusion of a major cerebral artery showed a smaller response to acetazolamide in the symptomatic hemisphere than in the asymptomatic hemisphere. Using TCD, Karnik et al 13 showed that the acetazolamideinduced increase of mean blood flow velocity in the MCA was smaller on the affected side than on the contralateral side in patients with unilateral internal carotid artery occlusion. In contrast, Vorstrup et al 20 reported that cerebral blood flow in the MCA territory and the mean flow velocity in the MCA increased to approximately the same degree on the occluded and nonoccluded sides after acetazolamide administration in patients with common carotid artery occlusion.…”

Section: Discussionmentioning

confidence: 99%

Evaluation of cerebral vasoreactivity by three-dimensional time-of-flight magnetic resonance angiography.

Mandai

Sueyoshi

Fukunaga

et al. 1994

Stroke

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Background and Purpose Cerebral vasoreactivity is an important indicator of the reserve capacity of the cerebral circulation. To make a quantitative analysis of cerebral vasoreactivity in individual major arterial territories, we evaluated the response to acetazolamide using three-dimensional timeof-flight magnetic resonance angiography.Methods We examined 10 healthy volunteers and 6 patients with unilateral stenosis of the middle cerebral artery by a 1.5 -T superconducting magnetic resonance imaging system. After a baseline vascular image was obtained, each subject received 17 mg/kg IV of acetazolamide; a second scan was performed 20 minutes later. Using a generally available personal computer and image analysis software, we measured the areas of the individual major arteries on collapsed axial vascular images and then calculated the vasoreactivity.Results The average vasoreactivity of individual major cerebral arterial territories in the healthy volunteers was as

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Evaluation of vasomotor reactivity by transcranial Doppler and acetazolamide test before and after extracranial-intracranial bypass in patients with internal carotid artery occlusion.

Cited by 49 publications

References 36 publications

Outcome of Carotid Artery Occlusion Is Predicted by Cerebrovascular Reactivity

Outcome of Carotid Artery Occlusion Is Predicted by Cerebrovascular Reactivity

Does Carotid Endarterectomy Modify Cerebral Vasomotor Reactivity?

Evaluation of cerebral vasoreactivity by three-dimensional time-of-flight magnetic resonance angiography.

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