Plain English Summary
Background and study aims
The aim of this study is to compare up-to-date medical (conservative) treatment (BMT) including lifestyle modification with carotid artery stenting (CAS) and carotid endarterectomy (CEA) in addition to those conservative treatments in the treatment of individuals with asymptomatic atherosclerotic carotid artery stenoses.
Who can participate?
Patients with asymptomatic stenosis of the extracranial carotid artery. Asymptomatic means without stroke or stroke-like symptoms attributable to the target stenosis within the previous 180 days.
What does the study involve?
Patients are allocated to one of the two substudies based on the decision of the including physician and the patient's preference: either CEA (SPACE2a substudy) or CAS (SPACE2b substudy). Patients in the SPACE2a study will be randomly allocated to receive either CEA + BMT or BMT alone, while those in the SPACE2b study will be randomly allocated to receive either CAS + BMT or BMT alone. BMT is defined as the best medical treatment of hypertension, blood glucose and hyperlipidemia according to current guidelines.
What are the possible benefits and risks of participating?
The benefit from every treatment is the proposed reduction of future cerebrovascular and cardiovascular events. Each treatment arm carries specific risks. Risks from the conservative treatment are mainly due to possible side effects of the medication. The most important risk of both CAS and CEA is the risk of periprocedural stroke.
Where is the study run from?
University hospitals of Heidelberg, Kiel and Munich (technical university).
When is the study starting and how long is it expected to run for?
Recruitment of subjects started in October 2009. The overall duration of the trial is expected to be about 9 years.
Who is funding the study?
German Research Council (Deutsche Forschungsgemeinschaft [DFG]), Germany.
Who is the main contact?
Prof. Werner Hacke
Prof Werner Hacke
Department of Neurology
University of Heidelberg
Im Neuenheimer Feld 400
+49 (0)6221 568211
Stent-protected angioplasty in asymptomatic carotid artery stenosis vs endarterectomy: a randomised, controlled, open, multi-centre study
Current hypothesis as of 19/12/2013:
Two separate superiority trials of interventions versus best medical treatment (BMT) are designed. The decision for one type of intervention is made (carotid endarterectomy [CEA] = SPACE2a or carotid artery stenting [CAS] = SPACE2b) prior to randomization. In both studies (SPACE2a and SPACE2b) the interventional treatment groups (CEA and CAS) will be compared with best medical treatment (BMT) separately. In addition, data from the CEA and CAS groups will be compared in an explorative manner.
Protocol can be found at: http://www.space-2.de/de/service/03/
1. Superiority of stent-protected angioplasty or carotid endarterectomy (CEA) as compared to best medical treatment with respect to the composite primary endpoint
2. Stent-protected angioplasty is not inferior to carotid endarterectomy with respect to the composite primary endpoint
1. Ethics Committee of the University of Heidelberg, 20/10/2008, ref: S-311/2008
2. Ethics Committee of the University of Heidelberg gave approval on change of study design (amendment 25.09.2012) on 04/04/2013
Randomised controlled open multi-centre study with two two-arm clinical trials
Primary study design
Secondary study design
Randomised controlled trial
Patient information sheet
Can be found at: http://www.space-2.de/downloads/SPACE-2%20Patienteninformation.pdf (German only)
Asymptomatic moderate to severe stenosis of the extracranial carotid artery
Current interventions as of 19/12/2013:
Patients are allocated to one of the two substudies based on the decision of the including physician and the patient's preference: either CEA (SPACE2a substudy) or CAS (SPACE2b substudy). Patients in the SPACE2a study will be randomly allocated to receive either CEA + BMT or BMT alone, while those in the SPACE2b study will be randomly allocated to receive either CAS + BMT or BMT alone. BMT is defined as optimal medical treatment of hypertension, blood glucose and hyperlipidemia according to current guidelines.
1. BMT alone
2. Stent-protected angioplasty and BMT
3. Carotid endarterectomy and BMT
Primary outcome measure
Cumulative rate of events consisting of:
1. Any stroke within 30 days of treatment
2. Death from any cause within 30 days
3. Ipsilateral ischaemic stroke within five years
Secondary outcome measures
1. All single components of the primary endpoint clusters
2. Any stroke, vascular death or myocardial infarction within 30 days (five years)
3. Any ischaemic stroke within 30 days (five years)
4. Disabling stroke within 30 days (five years)
5. Technical failure of intervention
6. Rate of re-stenosis (NASCET more than or equal to 50%)
7. Rate of myocardial infarction (30 days)
Overall trial start date
Overall trial end date
Reason abandoned (if study stopped)
Participant inclusion criteria
Sonographic identification of a more than or equal to 50% stenosis (North American Symptomatic Carotid Endarterectomy Trial [NASCET] criteria) of the extracranial carotid artery in a patient (both genders, age limit 85 years) without symptoms attributable to the target stenosis within the previous 180 days.
Target number of participants
2 x 1636
Total final enrolment
Participant exclusion criteria
Non-atherosclerotic origin of carotid stenosis.
Recruitment start date
Recruitment end date
Countries of recruitment
Austria, Germany, Switzerland
Trial participating centre
University of Heidelberg
German Research Association, DFG
Funding Body Type
private sector organisation
Funding Body Subtype
Trusts, charities, foundations (both public and private)
Results and Publications
Publication and dissemination plan
Not provided at time of registration
Intention to publish date
Participant level data
Not provided at time of registration
Basic results (scientific)
Reiff T, Stingele R, Eckstein HH, Fraedrich G, Jansen O, Mudra H, Mansmann U, Hacke W, Ringleb P, , Stent-protected angioplasty in asymptomatic carotid artery stenosis vs. endarterectomy: SPACE2 - a three-arm randomised-controlled clinical trial., Int J Stroke, 2009, 4, 4, 294-299, doi: 10.1111/j.1747-4949.2009.00290.x.
Eckstein HH, Reiff T, Ringleb P, Jansen O, Mansmann U, Hacke W; SPACE 2 Investigators, SPACE-2: A Missed Opportunity to Compare Carotid Endarterectomy, Carotid Stenting, and Best Medical Treatment in Patients with Asymptomatic Carotid Stenoses., Eur J Vasc Endovasc Surg, 2016, doi: 10.1016/j.ejvs.2016.02.005.