CLINICAL TRIAL PROTOCOL SPACE 2 Stent ... - SPACE-2 Studie

Clinical Trial Code: SPACE 2 Version: 10. October 2008 Final
1 INTRODUCTION
1.1 Scientific background
Treatment of individuals with asymptomatic carotid artery stenosis is handled
controversially. Surgery for asymptomatic and symptomatic carotid artery bifurcation
stenosis ranks among the most frequent surgical procedures worldwide. For Germany
about 25,000 procedures are performed every year. The superiority of carotid
endarterectomy (CEA) compared to medical treatment in symptomatic carotid disease
(in patients, who already had stroke or TIA on the side of the stenosis) is established,
provided that the surgical procedure can be done with a perioperative morbidity and
mortality of less than 6% [5]. The advantage of CEA for asymptomatic patients (those,
who did not have a previous cerebrovascular ipsilateral event) is less well established.
There is a mild superiority of this intervention compared with standard medical therapy,
provided that the operation can be done with the perioperative morbidity and mortality of
less than 3%. Even then, about 20 patients have to be treated to prevent one stroke
over a period of 5 years, which also causes doubts about the cost effectiveness of this
intervention [7].
Recently, for both symptomatic and asymptomatic carotid artery stenoses, an
alternative treatment, carotid stenting (stent-protected angioplasty, CAS) has been
developed. This treatment is used frequently in both, symptomatic and asymptomatic
patients. However, up to today, no prove of superiority or non-inferiority of carotid artery
stenting for symptomatic stenosis has been demonstrated [18, 20].
In the last decade, major advantages in medical primary prevention of cerebrovascular
and cardiovascular disease have been accomplished. Specifically, treatment of
hypertension with modern antihypertensive drugs such ACE inhibitors or ARBs, partially
in combination with diuretics and the use of statins have shown significant risk reduction
for both cerebrovascular and cardiovascular events [1, 13]. In addition, life style
modification, smoking cessation and individualized antiplatelet therapy may also have
an impact on the event rate in so far asymptomatic patients. The control groups in the
large trials for asymptomatic carotid artery disease (ACAS and ACST) originate from
more than a decade ago and, for the major part, have not received a medical primary
prevention strategy that would now be considered standard according to current
national and international guidelines [16]. Therefore, for asymptomatic carotid artery
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