Patients with in-stent restenosis in carotid artery indicated to carotid intervention will be randomized into repeated carotid percutaneous transluminal angioplasty with or without stenting or carotid endarterectomy with stent removal. The objective of the randomized study is to compare the safety and effectiveness of CEA and CAS in patients with in-stent restenosis of the ICA.

Patients: Patients with in-stent restenosis in carotid artery indicated to carotid intervention will be randomized into repeated carotid percutaneous transluminal angioplasty with or without stenting or carotid endarterectomy with stent removal.

Repeated carotid percutaneous transluminal angioplasty with or without stenting: Endovascular interventions are going to be performed in local anesthesia from femoral access. Unfractioned heparin (100 IU/kg bodyweight) will be administered in all patients. The procedures will start with diagnostic angiography. Upon verification of severity and morphology of the in-stent stenosis 90 cm long 6F sheath will be introduced into the CCA. The procedures will be performed using distal filter protection. In severe stenoses predilation with 3 or 4 mm diameter balloon will be carried out. In-stent restenoses will be treated preferentially with 5 mm diameter drug eluting balloon. Atropin, up to the dose of 1.0 milligram, can be administered intravenously to prevent serious bradycardia during dilation. Stent will be placed within previous stent in cases of suboptimal PTA result and the decision will be left to the discretion of the interventional specialist. Whenever possible, double-layer technology stent will be used to ensure supreme wall coverage. Distal filter will be removed followed by the completion angiogram including intracranial arteries. Dual antiplatelet therapy (clopidogrel 75 mg/day and acetylsalicylic acid 100 mg/day) will be administered for at least 6 weeks post-procedure. All patients will undergo pre-procedural laboratory testing regarding clopidogrel resistance. In poor responders clopidogrel is going to be replaced by prasugrel or ticagrelor.

Carotid endarterectomy with stent removal: Surgery will be performed in a general or a local anesthesia (decision will be left to the discretion of the operating team) using a cut in front angle of the sternomastoid muscle. Common carotid artery (CCA) and later internal carotid artery (ICA) and external carotid artery (ECA) will be cut free. Common carotid artery, ICA and ECA will be temporarily closed. Using a longitudinal cut of CCA and ICA, stent with an atherosclerotic plaque will be visualized. The stent and a plaque will be withdrawn under the microscopic control and later a suture of arteriotomy will be performed using a monofil non-absorbent fibre 6/0. Just before the end of surgery, hemostatic process will be controlled and drainage will be done. Surgery will be completed by suture of subcutis and cutis. Unfractioned heparin (100 IU/kg bodyweight) could be administered in all patients just before the arteriotomy. In the case of the insufficient collateral flow into middle cerebral artery after clipping of the CCA and ICA, a temporal shunt could be used. Antiplatelet therapy (Aggrenox, clopidogrel 75 mg/day or acetylsalicylic acid 100 mg/day) will be used continuously in all patients.

Clinical examinations: Standard physical and neurologic examinations will be performed before intervention, 24 hours and 30 days after intervention. Evaluation of the neurologic deficit will be performed using the National Institutes of Health Stroke Scale (NIHSS) and modified Rankin scale before, 24 hours and 30 days after intervention.

Randomization: Consecutive patients will be assigned to the carotid endarterctomy with stent removal or repeated carotid percutaneous transluminal angioplasty with or without stenting by a computer-generated 1:1 randomization.

Statistical analysis: All statistical tests will be performed at the Center for Health Research, Faculty of Medicine, University of Ostrava. The normality of distribution of all proceeded data will be checked using the Shapiro-Wilk test. Data with a normal distribution will be reported as the mean ± standard deviation. Parameters not fitting a normal distribution will be presented as the mean, median and interquartile range. Categorical variables in the two arms will be compared by Fisher's exact test. Continuous variables will be compared by the Student's t-test for normally distributed values, or the Mann-Whitney U test. Spearman correlation coefficient and intraclass correlation coefficient will be calculated for the evaluation of interobserver and intraobserver agreements of brain infarction volume measurement. Multiple logistic regression analyses will be used to determine the possible predictors of stroke, TIA, retinal infarction, amaurosis fugax, myocardial infarction or vascular death. All tests will be carried out at an alpha level of significance of 0.05.

Inclusion Criteria:

• In-stent restenosis in carotid artery 70 - 99 %
• Indication to carotid intervention
• Age 18-80 years
• Functionally independent with a modified Rankin score value of 0 - 2 points
• Signed Informed consent

Exclusion Criteria:

• Contraindication to general anesthesia
• Contraindication to angiography (iodine allergy, etc.)
• Technically impossible to perform angioplasty with or without stenting
• Participation in other clinical study within 60 days
• Technically impossible to perform carotid endarterectomy

Data will be available at Mendeley