Impaired transcranial Doppler ultrasound cerebrovascular reactivity before carotid intervention is not predictive of a subsequent ischaemic event

Abstract

Aim: After carotid endarterectomy (CEA) or carotid angioplasty and stenting (CAS) for patients with severe carotid stenosis, an ischaemic event may still happen in up to 9% of patients over a 2year period. We aimed to investigate whether baseline cerebrovascular reactivity could predict a subsequent ischaemic event after intervention. Methods: A total of 51 patients with severe carotid stenosis (more than 70% stenosis from ultrasonography) and data on cerebrovascular reactivity were reviewed. Thirty-six patients had either CEA or CAS performed and were recruited for analysis. Transcranial Doppler ultrasonography was used to examine the reactivity of the middle cerebral artery to 5% carbon dioxide in oxygen. Normal cerebrovascular reactivity was defined by >1% increase per unit change in end-tidal CO2 in ipsilateral middle cerebral artery velocity in response to 5% carbon dioxide in oxygen. The mean follow-up period was 66months. Results: Twenty-six patients had symptomatic carotid stenosis and 10 patients had asymptomatic carotid stenosis. There were four subsequent ischaemic events during follow up. None of the nine patients with impaired baseline ipsilateral cerebrovascular reactivity had a subsequent ischaemic event. Conclusion: From our patient cohort, impaired baseline ipsilateral cerebrovascular reactivity before carotid intervention was not predictive of a subsequent ischaemic event. © 2008 The Authors; Journal compilation © 2008 College of Surgeons of Hong Kong.