Innovative Application of Pressure Gradient Measurement in Internal Carotid Stenosis in Patients Undergoing CAS

About 20% of stroke causes are atherosclerotic strokes caused by carotid artery stenosis.

In 2005, 92% of carotid artery interventions in the USA were performed in asymptomatic patients. It should be noted that screening in the general population for carotid artery disease is unwarranted, due to uncertain eligibility criteria for interventional treatment of asymptomatic patients. On the other hand, 10-15% of all patients with a first-ever stroke will experience an ischemic stroke as a result of previously untreated, asymptomatic, significant carotid artery stenosis.

Carotid artery angioplasty with stent placement (CAS) has become the second method of revascularization. ed, however, there is a great deal of ambiguity in the application of these criteria, which stems from the ratio of the risk to the possible benefit to the patient of performing the procedure, as well as the cost-effectiveness for health care systems.

OBJECTIVES The overall goal is (following the model of measuring fractional flow reserve - FFR) to try to establish a new parameter that could prove helpful in qualifying patients for percutaneous internal carotid artery angioplasty with stent implantation (CAS). Determining whether measuring the pressure gradient across the stenosis will determine which patients will benefit from the CAS procedure. In the absence of convincing evidence on the effects of CAS, especially for so-called asymptomatic patients, it is advisable to establish a parameter that would complement the eligibility criteria that, on the one hand, could prevent strokes in the population of patients with silent internal carotid artery stenosis and, on the other hand, avoid performing the procedure in the absence of benefit.

PRIMARY ENDPOINTS:

1. Assessment of cerebral perfusion by magnetic resonanse before and after CAS
2. Assessment of cognitive symptoms using before and after CAS
3. Assessment of neurological symptoms before and after CAS
4. Assessment of otolaryngological symptoms before and after CAS

SECONDARY ENDPOINTS:

Creation of a non-invasive computed tomography protocol with pressure gradient assessment in patients with carotid artery stenosis.

A final version of the algorithm based on a new diagnostic measurement (concentration gradient) ready to be used in the diagnosis of CAS-eligible patients with an implemented function for automatic classification of measurement results that will indicate the group of patients who will benefit from the CAS procedure.

After qualification for the study (by a neurologist and vascular surgeon), patients meeting properly the inclusion and exclusion criteria will be referred for imaging studies with Doppler ultrasound, angio-CT scan of the arteries of the neck and head and cerebral perfusion in magnetic resonanse (assessment of the cerebral perfusion alterations using DSC (dynamic susceptibility contrast).

In addition, blood will be drawn and stored for subsequent testing. Afterwards, patients qualified for internal carotid artery angioplasty procedures will receive standard saturation treatment with two antiplatelet drugs (acetylsalicylic acid, clopidogrel) before the procedure, strictly according to the guidelines. The procedures are carried out with approved medical equipment (carotid stent, angioplasty balloon, peripheral neuroprotection). The selection of the appropriate equipment used for the procedure depends on the clinical situation, the experience of the operator and the anatomical conditions of the carotid arteries.

Measurements (invasive pressure in carotid artery) taken during the procedure before angioplasty (after insertion of the neuroprotection into the internal carotid artery) and after stent implantation:

COURSE OF THE STUDY

Baseline examination:

* Doppler ultrasound of the extracranial cephalic arteries
* initial qualification for CAS /neurologist, vascular surgeon/
* informed consent to participate in the study
* cardiological consultation (modification of risk factors)
* angio-CT of the neck and head
* assessment of the cerebral perfusion alterations using DSC (dynamic susceptibility contrast) MR perfusion
* additional neurological (with questionnaires), psychological (with questionnaires) and otolaryngological examination
* surgery (CAS) - Department of Vascular Surgery, Department of Cardiology

Measurements (invasive pressure) taken during the procedure before angioplasty (after insertion of the neuroprotection into the internal carotid artery) and after stent implantation:

* placement of a micro catheter to measure invasive pressure
* taking a measurement in the internal carotid artery above the stenosis (in the normal section of this artery)
* performing a measurement before the stenosis (in the normal segment of the common carotid artery at the level of the exit of the external carotid artery)
* reading the pressure gradient after obtaining a stable value (a minimum of 5 cardiac cycles)

  * The study of intravascular pressure measurements will be performed using a special micro catheter of about 1mm in size (i.e., more than 2 times smaller than the delivery system for distal protection, which is the standard procedure, so the risk of complications is minimal). In the study protocol, the insertion of the catheter and measurement of pressures will be followed by the placement of a neuroprotection device in the distal carotid artery (standard of practice) to avoid possible complications.

Evaluation during treatment:

* angio-CT of the neck and head, 3 month after CAS
* assessment of the cerebral perfusion alterations using DSC (dynamic susceptibility contrast) MR perfusion, 3 month after CAS
* Doppler ultrasound of the extracranial cephalic arteries, 3 and 12 month after CAS
* Neurological (with questionnaires), psychological (with questionnaires) and otolaryngological examination betwenn 10-16 week after CAS
* Cardiological evaluation at 3, 6, 12 month after CAS (modification of risk factors)

Eligibility Criteria:
Inclusion Criteria:

* Stenosis of the internal carotid artery in symptomatic patients: \> 50%, (confirmed by non-invasive imaging studies: USG, angio-CT), qualified for angioplasty with stent implantation
* Stenosis of the internal carotid artery in asymptomatic patients: \>60%, (confirmed by non-invasive imaging studies: USG, angio-CT), qualified for angioplasty with stent implantation
* Age of patients: \> 18 years of age
* Provided informed consent to participate in the study.

Exclusion Criteria:

* Inability to obtain informed consent to participate in the study.
* Difficult anatomy of the aortic arch and the descending cephalic arteries (increased atherosclerotic lesions, acute angle of departure of the common carotid arteries, kinking of the internal carotid arteries).