Abstract W P353: Benign Natural History of Occlusion in Asymptomatic Carotid Stenosis

Introduction: One commonly stated reason for stenting of asymptomatic carotid stenosis is to prevent carotid occlusion. However, the Circle of Willis provides substantial protection against occlusion, so this objective may be misguided. In the NASCET trial, patients with near occlusion of the internal carotid had a lower risk of stroke than did patients with lesser degrees of stenosis. We studied the effects of progression to occlusion among patients with asymptomatic stenosis of the internal carotid artery (ICA). Methods: We studied the outcome of all consecutive patients in our clinic database with asymptomatic carotid stenosis of ≥60% at baseline between 1991 and 2010, who were followed for at least two years with carotid ultrasound and clinical evaluation. Results: 370 patients were included; mean age ± SD 68.8 ± 10.3; 210 (56.8%) were men. Systolic blood pressure was 149.8 ± 22.2, low-density lipoprotein 2.3 ± 1.1 mmol/L, smoking pack-years 24.5 ± 23.3. Only one individual (0.03%) with near occlusion of the ICA developed a new ipsilateral internal carotid artery (ICA) occlusion within a year. This patient experienced episodes of ipsilateral amaurosis fugax before the occlusion (which occurred after he was referred for endarterectomy), but remained asymptomatic after the ICA was totally occluded. Conclusion: Occlusion of asymptomatic carotid stenosis is a rare and usually benign occurrence. In patients with asymptomatic carotid stenosis. The risk of stroke from carotid occlusion is well below the risk of stroke from stenting. Preventing ICA occlusion is not a valid reason to perform carotid stenting in patients with asymptomatic carotid stenosis.