Which Asymptomatic Carotid Stenoses should be Treated?

Recent randomized trials have furthered our understanding of the natural history of asymptomatic carotid stenosis. In one large multi-national study, patients experienced a reduction in stroke risk over 10 years (reduction for men 17.1% to 10.8% and for women 14.7% to 6.5%). However, the benefit of surgery was markedly narrowed in all patients when the end point was defined as any stroke or perioperative death; the risk of such undesirable outcomes at 10 years in non-operated patients was 17.9% while the risk in operated patients was 13.4%.

There is increasing evidence that plaques prone to embolization have a different character then those apt to remain clinically silent. As such, our attention should be focused on defining the likelihood of later embolization of asymptomatic lesions based on the composition of bifurcation plaques and other morphologic criteria. Methods could include ultrasound, MRI, embolic detection and other noninvasive techniques. In most cases, patients over 75 years of age with lesions of less than 70% should receive medical management. Intervention should be reserved for younger patients with complex plaques as documented by CT angiograms. Decision making can be further improved with embolic detection protocols and ancillary tests such as MRI to detect clinically silent infarcts and morphologic features of unstable plaques.

For lesions >70%, we follow the Society of Vascular Surgery guidelines for management of asymptomatic patients and only recommend intervention provided 1) the patient has at least a 3 year life expectancy and 2) the perioperative stroke/death rate for treatment is equal to or < 3%.