The MICHI NEUROPROTECTION SYSTEM: Evaluation of Performance in Carotid Artery Stent Procedures (The LOTUS Study)

Cerebral embolization during carotid artery stenting (CAS) can often precipitate severe adverse neurological effects. Most major clinical studies of CAS have used distal filters for cerebral protection and have compared the neurologic complication rates with those of carotid endarterectomy (CEA). Many currently available embolic protection devices, however, have limited efficacy in capturing microembolic debris liberated during stenting, pre-dilatation and post-dilatation. Furthermore, distal protection systems are limited by the need to cross the lesion prior to deployment. Some studies have shown a relatively high incidence of cerebral infarction even when distal protection devices are employed.

Cerebral protection with carotid flow reversal is a method that was developed by Parodi, et al. (2005), as an alternative to the use of distal protection devices. While novel in its approach, this method too has its limitations. Criado, et al. (2004), developed a derivative technique that employs carotid flow reversal prior to traversing the stenosis that can be accomplished by directly accessing carotid anatomy without the use of the transfemoral approach. Major benefits to this method include the ability to perform the procedure on patients with severe carotid tortuosity and difficult aortic arch anatomy.

Inclusion criteria

• Subject must be > 21 years of age.
• Subject has the ability to understand and cooperate with study procedures and agrees to return for all required follow-up visits, tests, and exams.
• International Normalized Ratio (INR) must be ≤ 1.5 at the time of the procedure (subjects taking warfarin may be included if their dose is tapered prior to the procedure to meet the inclusion criterion. Dose may be returned to a therapeutic level after the procedure).
• The subject must sign a written informed consent prior to the procedure, using a form that is approved by the local medical Ethics Committee (EC).
• The life expectancy of the subject is at least one year.
• The subject has a lesion located in the internal carotid artery (ICA); the carotid bifurcation may be involved.
• The subject must have a minimum distance of 5 cm between the clavicle and bifurcation, as assessed by duplex Doppler ultrasound, computed axial tomographic (CT) angiography or magnetic resonance (MR) angiography.

Exclusion criteria

• The subject is participating in another investigational study that would interfere with the conduct or result of this study.
• The subject has dementia or a neurological illness that may confound the neurological evaluation.
• Presence of any one of the following anatomic risk factors:

• Previous radiation treatment to the neck or radical neck dissection
• Tracheostomy or tracheal stoma
• Laryngectomy
• Contralateral laryngeal nerve palsy
• Severe tandem lesions
• Inability to extend the head due to cervical arthritis or other cervical disorders
• Total occlusion of the target vessel.
• There is an existing, previously placed stent in the target artery.
• The subject has a known life-threatening allergy to the contrast media that cannot be treated.
• Subject has history of intolerance or allergic reaction to any of the study medications including aspirin, clopidogrel bisulfate (Plavix®) or ticlopidine (Ticlid®), prasugrel heparin or bivalirudin (Angiomax™). Subjects must be able to tolerate a combination of aspirin and clopidogrel/ticlopidine or prasugrel.
• The subject has a gastrointestinal bleed that would interfere with antiplatelet therapy.
• The subject has known cardiac sources of emboli.
• Subject has Hemoglobin (Hgb) less than 8 gm/dL (unless on dialysis), platelet count < 50,000/mm3, or known heparin associated thrombocytopenia.
• Subject has documented atrial fibrillation in the prior 90 days.
• The subject has a history of bleeding diathesis or coagulopathy including thrombocytopenia or an inability to receive heparin in amounts sufficient to maintain an activated clotting time (ACT) at > 250, or if the subject will refuse blood transfusions.
• The subject has atherosclerotic disease involving the ipsilateral common carotid artery (CCA) that precludes safe placement of the sheath.
• The subject has abnormal angiographic findings other than that of the target lesion that indicate the subject is at risk for a stroke, such as: ipsilateral arterial stenosis greater in severity than the target lesion, cerebral aneurysm, or arteriovenous malformation of the cerebral vasculature.
• There is evidence of a carotid artery dissection prior to the initiation of the procedure.
• There is an angiographically visible thrombus.
• There is any condition that precludes proper angiographic assessment or makes percutaneous arterial access unsafe, e.g. morbid obesity, sustained systolic blood pressure > 180 mm Hg, tortuosity, occlusive disease, vessel anatomy or aortic arch anatomy.
• Occlusion (TIMI 0 flow), or string sign of the ipsilateral common or internal carotid artery.
• There is evidence of bilateral carotid stenosis that would require intervention within 30 days of procedure.
• There is evidence of a major stroke (NIHSS ≥10) within the previous 30 days of the procedure or the patient is considered, by the investigator, to be at high risk for hemorrhagic stroke.
• There is a planned treatment of a non-target lesion within 30 days post procedure.
• There is a history of intracranial hemorrhage within the previous 3 months, including hemorrhagic transformation of an ischemic stroke.
• There is history of an ipsilateral stroke with fluctuating neurologic symptoms within one year prior to the procedure.
• Female subjects who are pregnant (negative pregnancy test is required in women of childbearing potential).
• Subjects, who the Investigator determines, to be at risk of Deep Vein Thrombosis (DVT)