What are the indications for a carotid duplex scan?

Carotid duplex scanning offers a quick and non-invasive method for detecting extracranial carotid arterial disease. However, the increasing awareness of the association of carotid disease and cerebrovascular symptoms, together with the recognition that carotid endarterectomy offers the possibility of prevention of a major stroke [1], means that requests for investigation are constantly increasing. The Dundee Vascular Laboratory undertakes the majority of carotid duplex scans in the Tayside region and we have found an increasing burden is being placed on a limited resource that is required for other vascular investigations. In 1994 we carried out 1389 carotid examinations of which 929 (66.9%) showed either no abnormality or no more than a 50% stenosis in one vessel. More importantly, of the 1052 new requests 832 (79.1%) fell into the same category. In order to ascertain if the number of new requests could be reduced a retrospective analysis of the referral indications for a carotid duplex scan in the last 5 years has been undertaken.