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Course of cerebrovascular reactivity in patients with carotid artery occlusions
Insights
Cerebrovascular reactivity in patients with carotid artery occlusions often improves spontaneously over time. This natural recovery can influence treatment decisions, potentially delaying interventions like antihypertensive therapy.
Area of Science:
- Neurology
- Vascular Surgery
- Neuroimaging
Background:
- Internal carotid artery occlusions increase stroke risk, particularly with impaired cerebrovascular reactivity.
- The potential for spontaneous recovery of cerebral hemodynamics via collateral development in these patients remains unclear.
Purpose of the Study:
- To investigate the natural course of cerebrovascular reactivity in patients with internal carotid artery occlusions.
- To determine if cerebral hemodynamics can be restored over time in this patient population.
Main Methods:
- Assessed cerebrovascular reactivity using transcranial Doppler CO2 testing in 452 patients with carotid occlusions over 5 years.
- Reinvestigated 98 patients at least once between 2 to 58 months (mean 26 months) to track changes in reactivity.
Main Results:
- Patients with recent stroke/TIA or severe contralateral carotid stenosis showed higher initial impairment of CO2 reactivity.
- Spontaneous improvement in cerebrovascular reactivity was observed in 64% of patients without significant contralateral stenosis, primarily within the first few months.
- Improved hemodynamics were noted after contralateral stenosis endarterectomy; however, stroke occurred in 5 non-surgical patients, including those with persistently impaired reactivity.
Conclusions:
- Impaired cerebrovascular reactivity in most carotid occlusion patients improves spontaneously over time.
- Therapeutic decisions, such as avoiding antihypertensive treatment initially, may be influenced by observed reactivity changes.
- In cases of persistently depleted hemodynamics, surgical interventions like bypass or contralateral endarterectomy may be beneficial.
Background And Purpose:
Patients with internal carotid artery occlusions and highly impaired cerebrovascular reactivity have been identified as having an increased risk of stroke. It is still unclear, however, whether cerebral hemodynamics may be restored in the course of time by the development of collaterals.
Methods:
During a 5-year period we assessed cerebrovascular reactivity in 452 carotid occlusions by transcranial Doppler CO2 testing. Ninety-eight patients could be reinvestigated at least once after 2 to 58 months (mean follow-up time, 26 months).
Results:
On admission, patients with recent transient ischemic attack or stroke (< or = 3 months) as well as patients with contralateral carotid stenoses of 80% diameter reduction or greater and occlusions revealed a significantly higher incidence of impaired CO2 reactivity (P < .0001 and P < .01, respectively). During follow-up, 64% of the patients with no or minor contralateral carotid stenoses, but only 22% of the patients with bilateral carotid occlusions, showed a spontaneous improvement in cerebrovascular reactivity (P < .001), mainly during the first few months. In six of eight patients cerebral hemodynamics on the occluded side improved after endarterectomy of a contralateral high-grade carotid stenosis. Five of the patients who did not undergo surgery developed a stroke during follow-up, with three of them occurring in patients with permanently exhausted cerebrovascular reactivity.
Conclusions:
In the majority of patients with carotid occlusions an initially impaired cerebrovascular reactivity improves spontaneously with time. This could influence therapeutic decisions: During the first few months antihypertensive treatment may be avoided in such cases until a reestablished reactivity can be demonstrated. If cerebral hemodynamics remain depleted, extracranial-intracranial bypass surgery or endarterectomy of an asymptomatic contralateral high-grade carotid stenosis could be helpful.