Evaluation of the cerebral vasodilatory capacity by the acetazolamide test before EC-IC bypass surgery in patients with occlusion of the internal carotid artery
Cerebral blood flow (CBF) was measured by xenon-133 inhalation tomography in 18 patients with cerebrovascular disease before and 4 months after extracranial-intracranial bypass surgery. Only patients who showed a reduced CBF in areas that were intact on the CT scan and relevant to the clinical and angiographical findings were operated. The majority of the patients had suffered a minor stroke with or without subsequent transient ischemic attacks. They were studied at least 6 weeks following the stroke. All patients had an occlusion of the relevant internal carotid artery. To identify preoperatively the patients with a compromised collateral circulation and hence reduced CBF due to reduced perfusion pressure, a cerebral vasodilatory stress test was performed using acetazolamide (Diamox). In normal subjects, Diamox has been shown to increase tomographic CBF without change of the flow distribution. In the present series 9 patients showed a significant redistribution of flow in favor of the non-occluded side (positive Diamox test). Two of these 9 patients showed even a paradoxical decrease in focal CBF preoperatively, i.e., a steal effect. These 2 patients were the only patients who improved in focal CBF after shunting. The remaining 9 patients all showed uniform flow responses (negative Diamox test), and none of these increased in focal CBF postoperatively. The finding of an unchanged flow map postoperatively confirmed that the low flow areas were not due to restricted flow via collateral pathways. However, an increase in the regional vasodilatory capacity was observed postoperatively in the majority of patients.
- Research Organization:
- Univ. Hospital, Copenhagen, Denmark
- OSTI ID:
- 6702491
- Journal Information:
- Stroke; (United States), Vol. 6
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
CEREBRAL ARTERIES
TOMOGRAPHY
VASODILATION
BLOOD FLOW
CAROTID ARTERIES
INHALATION
PATIENTS
VASCULAR DISEASES
VASODILATORS
XENON 133
ARTERIES
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BLOOD VESSELS
BODY
CARDIOVASCULAR AGENTS
CARDIOVASCULAR SYSTEM
DAYS LIVING RADIOISOTOPES
DIAGNOSTIC TECHNIQUES
DISEASES
DRUGS
EVEN-ODD NUCLEI
INTAKE
INTERMEDIATE MASS NUCLEI
INTERNAL CONVERSION RADIOISOTOPES
ISOMERIC TRANSITION ISOTOPES
ISOTOPES
NUCLEI
ORGANS
RADIOISOTOPES
XENON ISOTOPES
550601* - Medicine- Unsealed Radionuclides in Diagnostics