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Is impaired cerebral vasomotor reactivity a predictive factor of stroke in asymptomatic patients?
A Y Gur1, I Bova, N M Bornstein
1Department of Neurology, Tel Aviv Sourasky Medical Center, Israel.
Insights
Impaired cerebral vasomotor reactivity in asymptomatic patients with severe carotid stenosis predicts future stroke risk. This finding may help identify high-risk individuals for preventive vascular surgery.
Area of Science:
- Neurology
- Vascular Surgery
- Diagnostic Imaging
Background:
- Severe internal carotid artery stenosis in asymptomatic patients poses a significant stroke risk.
- Cerebral vasomotor reactivity (CVR) offers insights into intracranial hemodynamics and stroke prediction.
- Assessing CVR is crucial for identifying high-risk individuals needing intervention.
Purpose of the Study:
- To evaluate CVR in asymptomatic patients with severe carotid stenosis.
- To determine the prognostic value of CVR in predicting cerebrovascular ischemic events.
Main Methods:
- Transcranial Doppler ultrasonography and the Diamox test were used to assess CVR.
- 44 asymptomatic patients with >70% internal carotid artery stenosis were studied.
- Prospective follow-up averaged 2 years.
Main Results:
- Impaired CVR was observed in 21 patients, while 23 had good CVR.
- The annual stroke rate was 2.3%, and ischemic events were 7.9%.
- Patients with impaired CVR experienced significantly more ischemic events (P = .009), including strokes and TIAs.
Conclusions:
- Impaired CVR is a significant predictor of ischemic cerebral events in this patient group.
- Preventive vascular surgery should be considered for asymptomatic patients with severe carotid stenosis and impaired CVR.
Background And Purpose:
Identification of the subgroup of asymptomatic patients with severe internal carotid artery stenosis and high risk of stroke has important clinical implications. Cerebral vasomotor reactivity provides information regarding intracranial hemodynamic features and might have a prognostic value in predicting cerebrovascular ischemic events, especially in patients with carotid stenosis. The aim of our study was to assess the cerebral vasomotor reactivity in asymptomatic patients with carotid stenosis and evaluate its role in stroke occurrence.
Methods:
Cerebral vasomotor reactivity was assessed using transcranial Doppler ultrasonology and the Diamox test (intravenous administration of 1.0 g acetazolamide) in 44 asymptomatic patients with severe (> 70%) internal carotid artery stenosis. Patients were followed up prospectively (mean, 2 years).
Results:
Cerebral vasomotor reactivity was estimated as good (> 40% increase of blood flow velocity in the middle cerebral artery ipsilateral to the carotid stenosis after undergoing the Diamox test) in 23 patients; it was impaired in the other 21. During the follow-up period, the overall annual rate for ipsilateral stokes was 2.3%; it was 7.9% for all ischemic cerebral events. No strokes or transient ischemic attacks occurred in the former group, but there were 7 cerebral ischemic events (2 strokes [1 fatal] and 5 transient ischemic attacks) in the latter group. There was a statistically significant correlation between cerebral ischemic events and impaired cerebral vasomotor reactivity (P = .009).
Conclusions:
The data of this preliminary study suggest an important role of impaired cerebral vasomotor reactivity in predicting ischemic cerebral events. Preventive vascular surgery might be considered in this high-risk subgroup of asymptomatic patients with severe carotid stenosis.