No evidence that severity of stroke in internal carotid occlusion is related to collateral arteries

¹ University of Edinburgh, United Kingdom
² Western General Hospital, United Kingdom

^* To whom correspondence should be addressed. E-mail: jmw{at}skull.dcn.ed.ac.uk.

Accepted 6 February 2006

	Abstract

Background and Purpose: The neurological effects of internal carotid artery (ICA) occlusion vary between patients. We investigated whether the severity of symptoms in a large group of patients with ipsilateral or/and contralateral ICA occlusion at presentation with ocular or cerebral ischaemic symptoms could be explained by patency of other extra or intracranial arteries to act as collateral pathways.

Methods: We prospectively identified all patients (n=2881) with stroke, cerebral transient ischaemic attack (TIA), retinal artery occlusion (RAO) and amaurosis fugax (AFx) presenting to our hospital over five years, obtained detailed history and examination, and examined the intra and extracranial arteries with carotid and colour-power transcranial Doppler ultrasound.

Results: After exclusion of the 148 patients with intracranial haemorrhage on brain imaging and the 336 patients with cerebral symptoms and no brain imaging, there were 2397 remaining patients (1713 ischaemic strokes, 401 cerebral TIAs, 193 AFx and 90 RAO). Of 2228 (93%) with carotid Doppler imaging, 195 (9%) had ICA occlusion. Amongst those patients with cortical events, disease in potential collateral arteries (contralateral ICA, external carotid, ipsilateral or contralateral vertebral or intracranial arteries) was equally distributed amongst patients with severe and mild ischaemic presenting symptoms.

Summary: We found no evidence that the clinical presentation associated with an ICA occlusion was related to patency of other extra- or intracranial arteries to act as collateral pathways. Further work is required to investigate what determines the clinical effects of ICA occlusion.

Keywords: Carotid occlusion, carotid Doppler, collateral circulation, ischaemic stroke, transient ischaemic attacks