Results of the Stent-Protected Angioplasty versus Carotid Endarterectomy (SPACE) study to treat symptomatic stenoses at 2 years: a multinational, prospective, randomised trial

SummaryBackgroundThe SPACE trial is a multinational, prospective, randomised study to test the hypothesis that carotid artery stenting is not inferior to carotid endarterectomy for treating patients with severe symptomatic carotid artery stenosis. We did not prove non-inferiority of carotid artery stenting compared with carotid endarterectomy for the 30-day complication rate, and we now report the results at 2 years.MethodsBetween March, 2001, and February, 2006, patients with symptomatic, severe (≥70%) carotid artery stenosis were recruited to this non-inferiority trial and randomly assigned with a block randomisation design to have carotid artery angioplasty with stenting or carotid artery endarterectomy. 2-year endpoints include several clinical endpoints and the incidence of recurrent carotid stenosis of at least 70%. Clinical and vascular follow-up was done by a certified neurologist. Analyes were by intention to treat and per protocol. This trial is registered with ISRCTN, number 57874028.12.Findings1 214 patients were randomly assigned (613 were randomly assigned to carotid angioplasty with stenting and 601 were randomly assigned to carotid endarterectomy). In both the intention-to-treat and per-protocol analyses the Kaplan-Meier estimates of ipsilateral ischaemic strokes up to 2 years after the procedure and any periprocedural stroke or death do not differ between the carotid artery stenting and the carotid endarterectomy groups (intention to treat 9·5% vs 8·8%; hazard ratio (HR) 1·10, 95%CI 0·75 to 1·61; log-rank p=0·62; per protocol 9·4% vs 7·8%; HR 1·23, 95%CI 0·82 to 1·83; log-rank p=0·31). In both the intention-to-treat and per-protocol populations, recurrent stenosis of 70% or more is significantly more frequent in the carotid artery stenting group compared with the carotid endarterectomy group, with a life-table estimate of 10·7% versus 4·6% (p=0·0009) and 11·1% versus 4·6% (p=0·0007), respectively. Only two incidences of recurrent stenoses after carotid artery stenting led to neurological symptoms.InterpretationAfter 2 years' follow-up, the rate of recurrent ipsilateral ischaemic strokes reported in the SPACE trial is similar for both treatment groups. The incidence of recurrent carotid stenosis at 2 years, as defined by ultrasound, is significantly higher after carotid artery stenting. However, it cannot be excluded that the degree of in-stent stenosis is slightly overestimated by conventional ultrasound criteria.FundingFederal Ministry of Education and Research; German Research Foundation; The German Society of Neurology; The German Society of Neuroradiology; The German Radiological Society; Boston Scientific; Guidant; Sanofi-Aventis.