Distribution of vascular lesions in ischaemic stroke: a magnetic resonance angiographic study

Carotid endarterectomy is now an accepted modality for reducing the threat of recurrence of ischaemic strokes in patients with severe carotid artery stenosis. However, the incidence of carotid artery stenosis, and hence the applicability of carotid endarterectomy in the Indian population is not known. We conducted a prospective study to detect and quantify extracranial and intracranial arterial lesions using magnetic resonance angiography in consecutive patients with ischaemic strokes.

All patients with recent onset of ischaemic stroke (< 4 months) had a magnetic resonance angiography done to evaluate the neck vessels as well as the circle of Willis and its branches. The degree of stenosis of the internal carotid or common carotid artery was measured according to the criteria described by the North American Symptomatic Carotid Endarterectomy Trial (NASCET) collaborators. The site and extent of the extracranial and intracranial arterial lesions were correlated with the clinical features and the pattern of infarcts on magnetic resonance imaging or computerized tomographic scan of the brain.

The magnetic resonance angiography was abnormal in 56 out of 100 patients included in the study. Severe stenosis (> 70%) of the extracranial carotid arteries was seen in 26 patients. Lesions suitable for carotid endarterectomy were present in only 11 patients (42.3% of those with severe stenosis).

Our results are in contrast to those reported from western countries where the likelihood of a surgically correctable lesion being present is 60%-70%. We found operable lesions in only 11%. Intracranial atherosclerotic disease causing strokes is probably more common in India. Therefore, although carotid endarterectomy is the only accepted surgical procedure for secondary prophylaxis of stroke, there is a need to find an alternative surgical intervention for the predominantly intracranial pathology found in the Indian population.