NONINVASIVE ASSESSMENT OF CO-2-INDUCED CEREBRAL VASOMOTOR RESPONSE IN NORMAL INDIVIDUALS AND PATIENTS WITH INTERNAL CAROTID-ARTERY OCCLUSIONS
NONINVASIVE ASSESSMENT OF CO-2-INDUCED CEREBRAL VASOMOTOR RESPONSE IN NORMAL INDIVIDUALS AND PATIENTS WITH INTERNAL CAROTID-ARTERY OCCLUSIONS
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DOI:
10.1161/01.str.19.8.963
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发表时间:
1988-08-01
期刊:
影响因子:
8.3
通讯作者:
OTIS, SM
中科院分区:
文献类型:
--
作者:
RINGELSTEIN, EB;SIEVERS, C;OTIS, SM
To evaluate the CO2-induced vasomotor reactivity of the cerebral vasculature, relative changes of blood flow velocity within the middle cerebral artery were measured by transcranial Doppler ultrasonography during normocapnia and various degrees of hypercapnia and hypocapnia. We studied 40 normal individuals and 40 patients with unilateral and 15 patients with bilateral internal carotid artery occlusions. When blood flow velocity changes as percent of normocapnic values were plotted against end-tidal CO2 volume percent, a biasymptotic curve (a tangent-hyperbolic function) gave the best fit of the scattergram. The distance between the upper and lower asymptotes was defined as cerebral vasomotor reactivity. In the normal individuals, mean .+-. SD vasomotor reactivity was 85.63 .+-. 15.96%. In patients with internal carotid artery occlusions, vasomotor reactivity was significantly lower than normal on both the occluded (mean 45.2%, median 50.4%; p < 0.001) and the nonoccluded (mean .+-. SD 67.7 .+-. 13.3%, p < 0.01) sides in the unilateral group and on both sides (mean .+-. SD 36.6 .+-. 15.9% and 44.9 .+-. 24.6%, p < 0.001) in the bilateral group. The difference between vasomotor reactivity for symptomatic and asymptomatic unilateral occlusions was also highly significant (mean 37.6% and 62.9%, p < 0.006). Vasomotor reactivity was also significantly lower in patients with low-flow infarctions on computed tomography than in patients with normal scans (mean .+-. SD 36.7 .+-. 25% and 60.2 .+-. 16.9%, p < 0.0008). A striking association of low-flow infarctions, ischemic ophthalmopathy, and hypostatic transient ischemic attacks was found with vasomotor reactivities of < 34% or even paradoxical reactions. Transcranial Doppler ultrasonographic evaluation of cerebral vasomotor reactivity is a new, feasible, noninvasive, and reproducible technique that allows selection and quantification of patients with true cerebrovascular insufficiency.