Population-based study of delays in carotid imaging and surgery and the risk of recurrent stroke

Background: Benefit from carotid endarterectomy is greatest when performed within 2 weeks of a presenting TIA or stroke and decreases rapidly thereafter. Objective: To determine the delays to carotid imaging and endarterectomy in Oxfordshire, UK, and the consequences for the effectiveness of stroke prevention. Methods: All patients undergoing carotid imaging for ischemic retinal or cerebral TIA or stroke were identified in two populations: the population of Oxfordshire, UK (n = 680,772), from April 1, 2002, to March 31, 2003, and the Oxford Vascular Study (OXVASC) subpopulation (n = 92,000) from April 1, 2002, to March 31, 2004. The times from presenting event to referral, scanning, and endarterectomy (Oxfordshire population) and the risk of stroke prior to endarterectomy in patients with >= 50% symptomatic carotid stenosis (OXVASC population) were determined. Results: Among 853 patients who had carotid imaging in the Oxfordshire population, median (interquartile range) times from presenting event to referral, scanning, and endarterectomy were 9 (3 to 30), 33 (12 to 62), and 100 (59 to 137) days. Eighty-five patients were found to have 50 to 99% symptomatic stenosis, of whom 49 had endarterectomy. Only 3 (6%) had surgery within 2 weeks of their presenting event and only 21 (43%) within 12 weeks. The risk of stroke prior to endarterectomy in the OXVASC subpopulation with >= 50% stenosis was 21% (8 to 34%) at 2 weeks and 32% (17 to 47%) at 12 weeks, in half of which strokes were disabling or fatal. Conclusion: Delays to carotid imaging and endarterectomy after TIA or stroke in the United Kingdom are similar to those reported in several other countries and are associated with very high risks of otherwise preventable early recurrent stroke.