Natural history of > or =60% asymptomatic carotid stenosis in patients with contralateral carotid occlusion.

Abstract

Although the Asymptomatic Carotid Atherosclerosis Study (ACAS) reported that carotid endarterectomy (CEA) is beneficial for patients with asymptomatic > or =60% carotid stenosis (ACS), several other studies have reported mixed results. Our prospective study analyzed the natural history of > or =60% ACS in patients with contralateral carotid occlusion (CCO). During a 10-year period, patients with 60-<70% ACS with CCO were entered into a protocol of clinical examination and duplex surveillance every 6 months. All patients underwent maximum medical therapy. Late CEAs were considered if lesions became symptomatic or progressed to > or =70% stenosis. A Kaplan-Meier lifetable analysis was performed to estimate the freedom from both ipsilateral strokes and all strokes. Eighty-two patients were enrolled with a mean follow-up of 59.5 months (range, 7-141 months). Late strokes were noted in 27 of 82 patients (33%); 19 (23%) were ipsilateral and 8 (10%) were contralateral (side of CCO). Late transient ischemic attacks (TIAs) were noted in 22 of 82 (27%, 7 ipsilateral and 15 contralateral). The combined neurologic event (TIA/stroke) rate was 60% (49 of 82, 32% ipsilateral and 28% contralateral). Kaplan-Meier lifetable analysis showed that the rates of freedom from ipsilateral strokes, all strokes, and progression to > or =70% stenosis at 1, 2, 3, 4, and 5 years were 94%, 90%, 85%, 80%, 73%; 94%, 89%, 84%, 77%, 67%; and 99%, 96%, 92%, 86%, and 82%, respectively. The ipsilateral stroke-free survival rates at l, 2, 3, 4, and 5 years were 94%, 88%, 78%, 70%, and 63%. Twenty-one late CEAs were performed with no perioperative stroke/deaths (5 for ipsilateral TIAs, 9 for ipsilateral strokes, and 7 for > or =70% ACS). Overall, 20 (24%, 11 with symptoms and 9 asymptomatic) progressed to > or =70% stenosis. Patients with 60-<70% ACS and CCO with maximal medical therapy carry a higher incidence of ipsilateral strokes and all strokes than what was reported by the ACAS study; therefore, prophylactic CEA may be justified in these patients.