High Coverage CARotid Stenting vs. Medical Management Alone to Prevent EmboliSm From symptomaTic Non-stenotic cARotid Disease (SyNC)

The purpose of the CARESTAR study is to analyse the clinical safety and efficacy of the CARESTO® heal Stent within standard clinical routine for the treatment of patients with symptomatic non-stenotic carotid disease (SyNC) <50% and with high-risk plaque features for stroke recurrence compared to the medical treatment group and with respect to the mid- and long-term clinical outcomes. By randomly assigning participants to the two treatment arms, the aim is to generate bias-free and reliable data that can provide information on the optimal treatment approach in this patient group. Despite advances in medical therapy and endovascular treatment, the optimal treatment strategy for low-grade vulnerable plaques remains unclear. There is therefore an urgent need to evaluate the efficacy and safety of minimally invasive procedures such as carotid stenting against medical treatment according to clinical routine in this specific patient group. With CARESTAR, a multicentre, prospective, randomised, parallel-grouped open label and blinded safety endpoint study this gap shall be closed. Given the considerations outlined above, symptomatic non-stenotic carotid disease (SyNC) <50% with neurological symptoms represents a desperate situation, where all available options for contribution to the improvement of the patient's state of health or to the prevention of secondary diseases should be considered.

Inclusion criteria

• Patients diagnosed with acute ischemic stroke or acute retinal artery ischemia within the last two weeks related to symptomatic non-stenotic carotid disease (SyNC) and high-risk carotid plaque features

• Ipsilateral acute ischemic stroke must be determined by acute ischemic infarct on DWI or CT OR
• by neurological symptoms indicating ipsilateral cortical deficits consistent with ischemia in the territory of the internal carotid artery and after exclusion of a significant microangiopathy
• Acute retinal artery ischemia must be determined by ophthalmologic examination
• Patients with no other identifiable cause of stroke, evaluated using standard echocardiographic examinations to exclude cardiogenic or aortogenic sources of embolism
• Symptomatic non-stenotic carotid disease defined as one or more plaques in the ipsilateral internal carotid artery causing 10-49% luminal narrowing AND
• Presence of high-risk plaque features which must be determined through visual inspection on CTA or MRI (Ultrasound findings alone are insufficient; features must be confirmed by CTA or MRI to meet the criteria):

• Identification of at least two of the following characteristics Plaque thickness ≥ 3mm Irregular plaque surface Ulceration <50% plaque calcification Lipid-rich necrotic core
• and/or identification of at least one of the following characteristics Intraplaque haemorrhage
• Presence of carotid web characterized as shelf-like/linear, smooth filling defects
• Plaque assessment including evaluation of the presence of high-risk features by routine imaging (CTA, MRI) confirmed by an independent CoreLab
• Signed Informed Consent Form
• Patient ≥ 18 years
• mRS ≤ 3 at time of randomisation
• Dual antiplatelet therapy (DAPT) according to standard of care before endovascular treatment

Exclusion criteria

• Patients with acute complete occlusion of the carotid artery in an emergency setting
• Incidence of acute infarcts in other vascular (i.e., not ipsilateral carotid) territories
• Patients in whom the stroke was likely caused by one of the following diseases:
• Small vessel disease

• Large vessel atherosclerotic disease ≥ 50%
• Cardioembolism
• Other known disease e.g. vasculitis
• Predominantly calcified Plaques (≥50% calcified plaque components on CT-Angio)
• Patients presenting with intraluminal carotid thrombus (e.g. characterized by 'donut sign' on CTA)
• Patients with highly tortuous vessels (>90°) which may prevent access or safe insertion of the stent
• Patients with post-CEA re-stenosis or post-CAS re-stenosis
• Patients with blood coagulation disorders
• Patients in whom access to the carotid lesion is impossible or associated with an increased risk of procedural complications
• Patients with lesions in the ostium of the common carotid artery
• Patients with known hypersensitivity to nickel-titanium
• Patients who are allergic to heparin
• Any known conditions that affect life expectancy to less than 12 months
• Any known conditions associated with an increased risk of endovascular treatment
• Patients not able to visit the outpatient clinic for annual follow-up