Percutaneous extracranial carotid artery angioplasty with stenting (CAS) or without stenting has been investigated as a minimally invasive alternative to the current standard of care, that being carotid endarterectomy (CEA).  CAS involves the passage of a balloon catheter into the lesion via a femoral or brachial artery, followed by dilatation of the blocked segment and stent placement.  Similarly, angioplasty and stenting has been investigated as an alternative treatment for individuals with symptomatic intracranial artery and extracranial vertebrobasilar artery stenosis, since these conditions portend a poor prognosis even with medical therapy, and surgical intervention is associated with considerable morbidity.  This document addresses percutaneous carotid, vertebral and intracranial artery angioplasty with or without stent placement.

Medically Necessary:

Extracranial carotid artery angioplasty and stent placement (CAS) performed in conjunction with an FDA approved carotid stent system is considered medically necessary for individuals who meet one or more of the following criteria AND can be safely treated by this approach AND who have no angiographically visible intramural thrombus:

1. Symptomatic stenosis equal to or greater than 50%, or asymptomatic stenosis equal to or > 80% in an individual at a high risk for surgery due to one or more of the following conditions:
   1. Age > 80 years; or
   2. Congestive heart failure (NYHA Class III/IV) and/or left ventricular ejection fraction < 30%; or
   3. Open heart surgery needed within the next 6 weeks; or
   4. Recent myocardial infarction (> 24 hours and < 4 weeks); or
   5. Severe chronic obstructive pulmonary disease; or
   6. Unstable angina (CCS class III/IV).
      OR
2. Symptomatic stenosis equal to or greater than 50% or asymptomatic stenosis equal to or greater than 80% and one or more of the following conditions:
   1. Contralateral laryngeal nerve palsy; or
   2. Existence of lesions distal or proximal to the usual location; or
   3. Radiation-induced stenosis following previous radiation therapy to the neck or radical neck dissection; or
   4. Restenosis after carotid endarterectomy (CEA); or
   5. Severe tandem lesions that may require endovascular therapy; or
   6. Stenosis secondary to arterial dissection; or
   7. Stenosis secondary to fibromuscular dysplasia; or
   8. Stenosis secondary to Takayasu arteritis; or
   9. Stenosis that is surgically difficult to access (e.g., high bifurcation requiring mandibular dislocation); or
   10. Stenosis associated with contralateral carotid artery occlusion; or
   11. Pseudoaneurysm.
       OR
3. Inability to move the neck to a suitable position for surgery.
   OR
4. Tracheostomy. 

Note: If, in exceptional circumstances, extracranial carotid artery angioplasty is performed without stent placement, the above medically necessary criteria must still be met.

Not Medically Necessary:

Carotid artery angioplasty and stent placement (CAS) is considered not medically necessary in individuals with one or both of the following conditions:

1. Carotid stenosis with angiographically visible intraluminal thrombus; OR
2. A stenosis that cannot be safely reached or crossed by endovascular approach. 

Investigational and Not Medically Necessary:

Carotid artery angioplasty and stent placement (CAS) is considered investigational and not medically necessary when the above criteria are not met, including but not limited to, the following conditions:

1. Complete occlusion (100% stenosis) of the relevant carotid artery;
2. Severe symptomatic carotid stenosis in individuals not meeting the criteria above;
3. Symptomatic stenosis < 50% of the relevant carotid artery;
4. Asymptomatic stenosis < 80% of the relevant carotid artery.

Percutaneous Angioplasty (PTA) with or without associated stenting is considered investigational and not medically necessary when used in the treatment of atherosclerotic stenosis of:

• Extracranial vertebral arteries;
• Intracranial arteries.

Currently, carotid endarterectomy would be considered the established "gold standard" procedure for patients with symptomatic and significant carotid artery stenosis. However, this is an invasive procedure associated with well-defined, (albeit acceptable) complications including the possibility of nerve injuries. A percutaneous endovascular approach to carotid artery lesions has been attractive, particularly since this technique has been applied successfully in other areas of the vascular tree including the coronary and lower limb circulation. However, unlike coronary or iliac angioplasty, occlusion of the carotid artery may not be amenable to emergency surgical correction. Serious embolic complications including stroke and death remain an issue.

The majority of published data represent prospective uncontrolled studies with a number of variables including patient selection criteria, type of stent used, and use or non-use of an embolic protection device. Initial studies reported higher complication rates for stroke and/or death than carotid endarterectomy (10% - 12% for CAS versus 5.8% for CEA). More recent studies, however, including two randomized studies, suggest similar major complication rates for the two procedures, together with similar restenosis rates. However, the two randomized studies were performed at a single institution by a particularly experienced operator and consisted of relatively small sample sizes. Also, in other studies, issues related to patient selection, inconsistent use of stents and protection devices and short follow-up indicate the need for further larger scale, longer term randomized, controlled studies comparing CAS with CEA to determine the relative efficacy and complication rates of these procedures. The multi-center Carotid and Vertebral Artery Transluminal Angioplasty Study (CAVATAS) randomized 504 mostly symptomatic patients with 70% carotid artery stenosis to receive endovascular treatment or CEA. There was no difference in the rates of death or stroke at 30 days, and three year follow-up showed no difference in the rate of stroke. This trial has been criticized, however, because the rate of stroke or death was higher than that reported in other randomized trials of CEA. Also, residual and restenosis was more frequent with the endovascular approach than CEA (14% versus 4% respectively). However, it should be noted that only 22% of patients in this trial received stents. Two earlier randomized trials of carotid stenting were stopped early because of inferior outcomes, which were thought related to earlier stent designs and inexperience with the technique.

Brown MM, the principal investigator of CAVATAS and CAVATAS-2 (an ongoing international study), in an editorial in the American Journal of Medicine (2004) wrote, "There is, therefore, a need for further randomized trials of carotid stenting with protection devices compared with carotid endarterectomy to establish convincingly the value of carotid stenting." Brown further stated: "Although the early results of carotid stenting with protection devices appear encouraging, there are no long term data to rival that available from the carotid surgical trials. Hence, caution argues that stenting should continue to be seen as an experimental procedure and carried out only in the context of randomized clinical trials."

Currently, there are multi-center, randomized, controlled studies in progress in Europe and the United States. These include the International CAVATAS-2 study (Carotid and Vertebral Artery Transluminal Angioplasty Study) and the NIH supported trial, CREST (Carotid Revascularization Endarterectomy versus Stenting Trial). Results of two other trials, the SPACE trial (Stent Supported Percutaneous Angioplasty of the Carotid Artery versus Endarterectomy) and the EVA-3S trial (Endarterectomy versus Angioplasty in Patients with Symptomatic Severe Carotid Stenosis) are now available. The SPACE trial was a randomized non-inferiority trial that provided outcomes data at 30 days which failed to prove the non-inferiority of carotid artery stenting (CAS), compared to conventional carotid endarterectomy. However, the authors state that the results do not justify widespread use in the short term of CAS, and outcomes at 6-24 months are awaited (Ringleb, 2006). Published results of the EVA-3S trial reported finding that, for symptomatic patients with carotid stenosis of 60% or more, the rates of death and stroke at 30 days and 6 months following surgery were lower for endarterectomy, compared with carotid stenting (Mas, 2006).

Four year follow-up results of the EVA-3S trial were recently compiled which found that the safety of stenting needs to be improved for patients with symptomatic carotid stenosis. This multicenter, randomized trial compared the safety of carotid angioplasty and stenting (CAS) with carotid endarterectomy (CEA). Patients were eligible for the EVA-3S study if they were 18 years or older, had a transient ischemic attack (TIA) or a nondisabling stroke (or retinal infarct) within 120 days before enrollment, and had an atherosclerotic stenosis of 60% to 99% of the symptomatic carotid artery. The study enrolled 527 patients who were randomly assigned to undergo CEA (n=262) or CAS (n=265). The primary endpoint was the rate of any periprocedural stroke or death within 30 days postprocedure; the EVA-3S trial was terminated early because of a higher 30-day risk of stroke or death in the CAS group. The main secondary endpoint was a composite of any periprocedural stroke or death and any nonprocedural ipsilateral stroke during four years of follow-up.

After four years of follow-up, the cumulative probability of periprocedural stroke or death and nonprocedural ipsilateral stroke was higher with CAS than with CEA (11.1% versus 6.2%; hazard ratio [HR], 1•97; 95% confidence interval [CI], 1•06 to 3•67; P=0•03). The HR for any stroke or periprocedural death was 1.77 (CI, 1.03 to 3.02; P=0.04). Additional findings determined by the researchers to be statistically insignificant included: HR for any stroke or death was 1.39 (CI, 0.96 to 2.00; P=0.08); HR for any periprocedural disabling stroke or death or any nonprocedural fatal or disabling ipsilateral stroke was 2.00 (CI, 0.75 to 5.33; P=0.17); HR for any fatal or disabling stroke or periprocedural death was 1.68 (CI, 0.74 to 3.84; P=0.22); and HR for any disabling stroke or death was 1.20 (CI, 0.78 to 1.85; P=0.41). The authors concluded that for patients with symptomatic carotid stenosis, CAS is not as safe an alternative as CEA, although CAS is as effective as CEA for prevention of middle-term ipsilateral stroke (Mas, 2008).

Yadav and colleagues reported on results of the SAPPHIRE trial (Stenting and Angioplasty with Protection in Patients at High Risk for Endarterectomy) in October 2004. Three hundred thirty four patients classified as "high risk," based on the presence of neurological symptoms and a greater than 50% stenosis of the common or internal carotid artery or who were asymptomatic with greater than 80% stenosis, were randomized to CEA or CAS. Of the 167 patients randomly assigned to stenting, 159 received the assigned treatment. Of the 167 patients assigned to surgery, 151 received the assigned treatment. All patients also had one or more medical or surgical comorbid conditions that placed them at high risk for carotid endarterectomy. Exclusion criteria for the trial included history of bleeding disorder along with other criteria. The technique employed Cordis Corporation's PRECISE™ Nitinol Stent System with the ANGIOGUARD™ Embolic Capture Guide-wire System. At one year, superior results were reported for the CAS group as measured by a composite end point of major adverse events including all-cause death, stroke, and myocardial infarction (12% for CAS vs. 20% for CEA). The authors concluded that among patients with severe carotid-artery stenosis and coexisting conditions, carotid stenting with the use of an embolic-protection device is not inferior to carotid endarterectomy.

Meanwhile, most authors currently writing in the literature are of the opinion that carotid endarterectomy, a proven effective long term surgical approach, remains the gold standard of interventional care and do not advocate the widespread practice of carotid angioplasty with stenting as an alternative at this time, particularly in patients not at high risk for CEA.

In August 2004, the U.S. Food and Drug Administration (FDA) granted Premarket Approval to Guidant Corporation's two stent systems (the ACCULINK™ Carotid Stent System and the RX ACCULINK™ Carotid Stent System), which are used in conjunction with two carotid embolic protection systems (the ACCUNET™ and the RX ACCUNET™ Embolic Protection Systems, Guidant Corp.) for the treatment of patients at high risk for adverse events from carotid endarterectomy who require carotid revascularization and meet the following criteria:

1. Patients with neurological symptoms and equal to or > 50% stenosis of the common or internal carotid artery by ultrasound or angiogram OR patients without neurological symptoms and equal to or > 80% stenosis of the common or internal carotid artery by ultrasound or angiogram; AND
   
2. Patients must have a reference vessel diameter within the range of 4.0mm and 9.0mm at the target lesion.

As part of this approval, Guidant agreed to conduct long term follow-up of patients in the studies it submitted to the FDA and conduct another post approval study including 1,000 newly enrolled patients. The data submitted to the FDA, on which its approval was based, were from 3 prospective, non-randomized, multicenter, single arm trials known as ARCHeR 1, 2 and 3 (ACCULINK for Revascularization of Carotids in High Risk Patients) enrolling a total of 581 patients who were considered either high risk for CEA or not surgical candidates for current surgical options (CEA) and who were symptomatic with a 50% or greater carotid artery stenosis, or asymptomatic with an 80% or greater stenosis. The ARCHeR results were published in 2006 (Gray, 2006). The primary composite endpoint of 30 day combined incidence of death, stroke and myocardial infarction plus one year incidence of ipsilateral stroke was 9.6%. This was compared to 14.4% for historical surgical controls involving similar high surgical risk patient populations. Target lesion revascularization at one and two years was 2.2% and 2.9% respectively. These studies suggest that CAS may be safe and effective in a subset of patients who are not candidates for CEA.

On Sept. 6, 2005, the FDA approved the Xact® Carotid Stent System (Abbott Vascular Devices, Redwood City, CA) for use in conjunction with the Abbott Emboshield® Protection System for very similar indications to the ACCULINK™ and RX ACCULINK™ devices.

Additional carotid stent and embolic protection systems with FDA approval include the Protégé® GPS™ and Protégé® RX Carotid Stent Systems used with the SpiderRX™ Embolic Protection Device (ev3 Inc., Plymouth, MN), which received FDA approval in January 2007. This CAS system was evaluated via the Carotid Revascularization with ev3 Inc. Arterial Technology Evolution (CREATE) Trial. The NexStent® Carotid Stent and Monorail® Delivery System (Endotex Interventional Systems, Inc., Cupertino, CA) received FDA approval in October 2006. It is also compatible with the FilterWire EZ™ Embolic Protection System. FDA approval for the FilterWire EZ Embolic Protection System, as well as for the two associated CAS systems, was based on a prospective, nonrandomized multicenter clinical trial (Carotid Artery revascularization using the Boston Scientific EPI FilterWire EX and the EndoTex NExStent [CABERNET]). These devices received FDA approval for similar indications to the prior approved devices.

Overall, CAS appears to be a reasonable option for patients who are poor surgical candidates for reasons of either anatomy or comorbidities, and who otherwise meet the criteria for revascularization. However, CEA remains the gold standard procedure for patients who are not at high risk for this procedure. A report from the Therapeutics and Technology Assessment Subcommittee of the American Academy of Neurology (Chaturvedi, 2005) commented that there are several important areas for further investigation pertaining to CAS, including the role of cerebral hemodynamics in risk stratification for patients with carotid stenosis, such as the examination of indices of vaso-reactivity and cerebral perfusion, which has not been emphasized in recent multicenter trials, to date.

Although there are few studies dealing with the effect of carotid artery angioplasty with or without stenting on symptomatic carotid stenosis due to fibromuscular dysplasia, there are few treatment options for this population. In addition, the rarity of the condition also makes it unlikely that studies with moderate to large sample sizes will be conducted in the near future. Consequently, carotid artery angioplasty with or without stenting remains an important treatment option for these patients and has been successfully carried out in the community.

There is a paucity of evidence concerning the net benefit of angioplasty and stenting for extracranial vertebral arteries and intracranial arteries. The SSYLVIA trial (Stenting of Symptomatic Atherosclerotic Lesions in the Vertebral or Intracranial Arteries) was a multicenter, non-randomized prospective feasibility study using the NEUROLINK intracranial stent system (Guidant Corporation). It included 61 symptomatic patients who had suffered a transient ischemic attack (TIA) or stroke attributable to a single arterial stenosis of at least 50%. Following stent placement, the stroke rate within 30 days was 6.6%, and 30-day to 12 month stroke rate was 7.3%. At 6 months, the restenosis rate (>50% stenosis) was 32.4% for intracranial stents and 42.9% for extracranial vertebral stents. The investigators acknowledged, "Currently there is no proven benefit of this procedure relative to medical therapy."

On August 3, 2005 the Center for Devices and Radiological Health (CDRH) of the FDA approved the Wingspan Stent System™ with Gateway™ PTA Balloon Catheter (Boston Scientific Corp., San Leandro, CA) through its Humanitarian Device Exemption (HDE) application process. This device is approved for the following indication: for improving cerebral artery lumen diameter in patients with intracranial atherosclerotic disease which has been refractory to medical therapy in intracranial vessels with greater than or equal to 50% stenosis that are accessible to the system. This first such device to receive FDA approval for the treatment of stenosed intracranial arteries is being made available, according to the manufacturer, on an initial limited basis to a small number of the most experienced neurovascular centers equipped to treat these very delicate and tortuous brain vessels. The Wingspan HDE clinical study was a prospective, single arm, multi-center safety study involving 45 adults with recurrent stroke attributable to an intracranial artery stenosis of at least 50% and refractory to medical therapy. Following angioplasty and stent placement, the all-cause stroke rates at 30 days and 6 months were 4.4% and 9.5% respectively (ipsilateral stroke rates 4.4% and 7.1%). At 6 months, the restenosis rate (at least 50% stenosis) was 7.5% (data taken from the Wingspan study submitted by Boston Scientific).

Symptomatic intracranial artery stenosis, even when managed medically, carries a poor prognosis (at least a 9-12% annual risk of major stroke or death according to Higashida, 2006). However, most authors in recent reviews of intracranial artery angioplasty and stenting are of the opinion that further randomized clinical trials are needed, comparing this procedure to best medical management, in order to establish whether long term clinical outcomes are, in fact, improved as a result of angioplasty and stenting (Hartmann, 2005; Higashida, 2006; Komotar, 2005; Hanel, 2005).

Currently the available data and evidence are insufficient to establish the benefit to health outcomes of angioplasty and stenting for intracranial artery stenosis relative to best medical management.

Description of Disease

Approximately 700,000 people in the U.S. will have a stroke this year, and close to 30% will be under the age of 65. Stroke is the third leading cause of death in the U.S. and stenosis of one or both of the carotid arteries is a leading risk factor for stroke. Treatment of carotid artery stenosis includes risk factor modification, i.e., smoking cessation, weight reduction, lower cholesterol levels, exercise, reduction of elevated blood pressure, glycemic control, medication (e.g., antiplatelet therapy), and in some cases surgical intervention (carotid artery endarterectomy, percutaneous transluminal angioplasty with stenting). The NASCET (North American Symptomatic Carotid Endarterectomy Trial), a major trial that confirmed the efficacy of CEA, defined "severe" stenosis to be 70% - 99%. At this level of stenosis, patients are typically referred for CEA if there are no safety issues (e.g., due to comorbidities or characteristics of the lesions).

Fibromuscular dysplasia is a nonatherosclerotic, noninflammatory disease of the blood vessels that most commonly affects the internal carotid and renal arteries. The condition is rare and the cause is unknown, although cigarette smoking and a history of hypertension may increase the risk. The severity of symptoms varies widely and may result in arterial stenosis, aneurysms, and dissection (separation of the layers of the vessel wall) that result in significant morbidity. Therapy may include drug therapy (to treat hypertension that results from renal artery involvement), surgical revascularization, and angioplasty.

Vertebral artery and intracranial artery stenosis have a poor prognosis and generally lead to neurological deterioration or death. Medical management is the treatment option most used. Surgical risks and complications are significant.

Description of Technology

Traditionally, surgical treatment has been with open carotid artery endarterectomy. The carotid artery is exposed through an incision and the atherosclerotic plaque causing the narrowing is removed surgically. Recently, carotid artery angioplasty and stenting emerged as an alternative to open surgery. While carotid angioplasty has been performed alone, currently this procedure typically includes the placement of a stent, in order to prevent restenosis. However, in certain conditions of fibromuscular dysplasia and in situations where stent placement is technically not feasible, angioplasty alone may be performed.

Stent implantation is a supplement to angioplasty, in which a balloon introduced via a catheter is inserted through a blockage and expanded to enlarge the vessel, allowing restoration of blood flow. This procedure involves the permanent placement of a mechanical device within blocked arteries or veins in order to compress the obstructive material and to support the vessel wall, preventing both constriction and further blockage. Insertion of an embolic protection device may accompany stent placement. This device consists of a small wire mesh or basket that is used to capture any embolic debris that may dislodge from the lesion in order to prevent the debris from reaching the brain or other intracranial areas. Such devices are purported to further decrease the neurologic event risk from carotid angioplasty and stenting.

In 2007, a consensus document on carotid stenting was released by the American College of Cardiology Foundation/Society for Cardiovascular Angiography and Interventions/Society for Vascular Medicine and Biology/Society of Interventional Radiology/American Society of Interventional & Therapeutic Neuroradiology (ACCF/SCAI/SVMB/SIR/ASITN). This document states that, "CAS is viewed as a reasonable alternative to CEA, particularly in patients at high risk for CEA, and use of EPDs (embolic protection devices) seems to be important in reducing risk of stroke…At the present time, the evidence is insufficient to support CAS in asymptomatic high-risk patients who have < 80% stenosis or in patients who are not at high-risk for surgery" (Bates, 2007).

In 2003, a collaborative panel of the Joint Standards of Practice Committee of the American Society of Interventional and Therapeutic Neuroradiology, the American Society of Neuroradiology, and the Society of Interventional Radiology developed quality improvement guidelines for the performance of cervical carotid angioplasty and stent placement. The document includes standards for qualifications and responsibilities of personnel, specifications of the procedure, equipment quality and control, documentation, thresholds, success and complication rates, quality control and improvement, safety, infection control, and patient education concerns. Furthermore, the document outlines suggested inclusion criteria and relative and absolute contraindications for CAS (Barr, 2003).

In 2002, the FDA granted a Humanitarian Device Exemption for the NEUROLINK® System for use in a small subset of patients who suffer from recurrent stroke attributable to atherosclerotic disease. Human Device Exemptions (HDEs) differ from the standard FDA approval process and are designed to allow the use of qualified devices without requiring the rigorous safety and efficacy testing required for standard device approvals. A humanitarian device is one that is intended to benefit patients in the treatment and diagnosis of rare diseases or conditions that affect or are manifested in fewer than 4,000 individuals in the United States per year. The goal of the HDE process is to allow the use of specific devices for indications where other alternatives are unavailable. A healthcare provider is responsible for obtaining Institutional Review Board approval before a humanitarian device with an exemption may be administered to or implanted in a patient. CDRH determined that, based on the data submitted in the HDE, the NEUROLINK® System will not expose patients to an unreasonable or significant risk of illness or injury. The probable benefit to health from using the device outweighs the risks of illness or injury [for the treatment of patients with recurrent stroke attributable to atherosclerotic disease refractory to medical therapy in intracranial vessels ranging from 2.5 to 4.5 mm in diameter with ≥ 50% stenosis that are accessible to the stent system]. The FDA issued an approval order on August 9, 2002.

Proposed Benefits

CAS is purported to decrease stenosis in carotid arteries with varying degrees of blockage. Theoretically, with blood flowing more freely through the artery, symptoms such as transient ischemic attacks are diminished or relieved completely and the risk of stroke, which may include death, is also greatly diminished. Although CEA provides the same advantages, CAS is a less invasive procedure and is promoted as an alternative to CEA particularly in patients where an invasive procedure would lead to a high risk of complications. Studies show that the technical success of CAS ranges from about 96% to 100% and residual stenosis after CAS ranges from 2% to 15%.

Possible Risks

Risks include restenosis after implantation of the stent (generally uncommon). Non-neurologic complications (e.g., slow heart rate, transient loss of consciousness) may occur during the procedure. Neurologic complications are generally due to embolic debris that dislodged from the site of the lesion either during or after the procedure and may lead to stroke and/or death. In recent studies, the overall postoperative neurologic complication rates have ranged from about 0% to 10%.

Angina pectoris: chest pain that is typically severe and crushing; the patient experiences a feeling of pressure and suffocation just behind the breastbone (the sternum) caused by an inadequate supply of oxygen to the heart muscle

Canadian Cardiovascular Society (CCS): further defines anginal classes as follows:

Class I:     Ordinary physical activity does not cause angina
Class II:   Slight limitation of ordinary activity
Class III:  Marked limitation of ordinary physical activity
Class IV:  Inability to carry on physical activity without discomfort

Contralateral: on the opposite side of the body

Carotid arteries: arteries originating from the aorta that pass through the neck flowing up to the brain; the carotid arteries and their subsequent branches supply approximately 80% of the brains' blood supply

Ejection fraction: a measure of the pumping efficiency of the heart

Endarterectomy: a surgical procedure where the fatty build up in the wall of an artery is directly removed; this procedure is most typically done in the carotid artery when there is a severe or symptomatic narrowing of the vessel lumen

Heart failure: failure of the heart to adequately pump blood to the rest of the body; fatigue, shortness of breath, and fluid overload causing peripheral edema are common signs and symptoms. The New York Heart Association (NYHA) has classified heart failure into four categories:

Class I:  Symptoms cause no limitation of physical activity. Ordinary physical activity does not lead to undue fatigue, palpitations, or dyspnea
Class II:   Symptoms cause slight limitation of physical activity. Patient is comfortable at rest, but ordinary physical activity results in fatigue, palpitations, or dyspnea
Class III:  Symptoms cause marked limitation of physical activity. Patient is comfortable at rest, but even slight physical activity causes fatigue, palpitations, or dyspnea
Class IV: Symptoms of cardiac insufficiency are present at rest, and discomfort is increased with any physical activity

Intracranial arteries: arteries located within the skull; the intracranial arteries are comprised of branches of the carotid and vertebral arteries that supply blood to the brain, (i.e., anterior, middle and posterior cerebral, vertebrobasilar or basilar)

Stenosis: a narrowing in a blood vessel such as an artery; this narrowing is usually caused by fatty deposits (atherosclerosis) in the vessel wall

Vertebral arteries: arteries located at the back of the neck that originate from the subclavian arteries; the vertebral arteries and their subsequent branches supply approximately 20% of the brains' blood supply

The following codes for treatments and procedures applicable to this document are included below for informational purposes.  Inclusion or exclusion of a procedure, diagnosis or device code(s) does not constitute or imply member coverage or provider reimbursement policy. Please refer to the member's contract benefits in effect at the time of service to determine coverage or non-coverage of these services as it applies to an individual member.

When services may be Medically Necessary when criteria are met: 

When services are Not Medically Necessary:
For the procedure codes listed above, when adverse conditions as listed in the Position Statement section are present.

When services are Investigational and Not Medically Necessary:
For the procedure codes listed above when criteria are not met, or when the code describes a procedure indicated in the Position Statement section as investigational and not medically necessary.

When services are also Investigational and Not Medically Necessary:

Peer Reviewed Publications:

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2. Albuquerque FC, Fiorella D, Han P, et al. A reappraisal of angioplasty and stenting for the treatment of vertebral origin stenosis. Neurosurgery. 2003; 53:607-616.
3. Barnett HJM, Taylor DW, Eliasziw M, et al. Benefit of carotid endarterectomy in patients with symptomatic moderate or severe stenosis. N Engl J Med. 1998; 339:1415-1425.
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7. Brott TG, et al. Carotid Revascularization for Prevention of Stroke: Carotid Endarterectomy and Carotid Artery Stenting. Mayo Clinic Proc. September, 2004; 79(9):1197-1208.
8. Brown MM. Editorial. Carotid artery stenting – evolution of a technique to rival carotid endarterectomy. American Journal of Medicine. 2004; 116(4):273-275.
9. Bush RL, Lin PH, Bianco CC, et al. Carotid artery stenting in a community setting: experience outside of a clinical trial. Annals of Vascular Surgery. 2003;17:629-634.
10. Caplan LR, et al.  Angioplasty and stenting to treat occlusive vascular disease.  Reviews in Neurological Diseases.  2006; 3(1).
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12. Chaturvedi S, Fessler R. Angioplasty and stenting for stroke prevention: good questions that need answers.  Neurology. 2002; 59(5):664-668.
13. Cloud GC, Crawley F, Clifton A, et al. Vertebral artery origin angioplasty and primary stenting: safety and restenosis rates in a prospective series. J Neurol Neurosurg Psychiatry. 2003; 74(5):586-590.
14. Cloud GC, Markus HS. Vertebral artery stenosis. Current Treatment Options. Cardiovascular Medicine. 2004 April; 6(2):121-127.
15. Cremonesi A, Manetti R, Setacci F, et al. Protested carotid stenting: clinical advantages and complications of embolic protection devices in 442 consecutive patients. Stroke. 2003; 34:1936-1943.
16. Curry TK, Messina LM. Fibromuscular dysplasia; when is intervention warranted?  Seminars in Vasc Surg. 2003; 16(3):190-99.
17. Derdeyn CP, Chimowitz MI. Angioplasty and stenting for atherosclerotic intracranial stenosis: Rationale for a randomized clinical trial. Neuroimag Clin N Am. 2007; 17:355–363.
18. Dietz A, Berkefeld J, Theron JG, et al. Endovascular treatment of symptomatic carotid stenosis using stent placement: long-term follow-up of patients with a balanced surgical risk/benefit ratio. Stroke. 2001; 32(8):1855-1859.
19. Doerfler A, Becker W, Wanke I, et al. Endovascular treatment of cerebrovascular disease. Curr Opin Neurol. 2004; 17(4):481-487.
20. Eckstein HH, Ringleb P, Allenberg JR, et al. Results of the Stent-Protected Angioplasty versus Carotid Endarterectomy (SPACE) study to treat symptomatic stenoses at 2 years: a multinational, prospective, randomised trial. Lancet Neurol. 2008 Sep 5.
21. Fiorella D, Levy EI, Turk AS, et al. US multicenter experience with the wingspan stent system for the treatment of intracranial atheromatous disease: Periprocedural results. Stroke. 2007; 38(3):881-887.
22. Fox DJ, Moran CJ, Cross DT, et al. Long-term outcomes after angioplasty for symptomatic extracranial carotid stenosis in poor surgical candidates. Stroke. 2002; 33(12):2877-2880.
23. Gable DR, et al. Intermediate follow up of carotid artery stent placement. American Journal of Surgery. 2003; 185(3):183-187.
24. Gasparis AP, Ricotta L, Cuadra SA, et al. High-risk carotid endarterectomy: Fact or fiction. J Vasc Surg. 2003; 37(1):40-46.
25. Gray WA et al.  Protected carotid stenting in high-surgical risk patients: The ARCHeR results J Vasc Surg 2006; 44: 258-69.
26. Gray WA, Yadav JS, Verta P et al. The CAPTURE registry: results of carotid stenting with embolic protection in the post approval setting. Catheter Cardiovasc Interv. 2007; 69(3):341-348.
27. Gress DR, Smith WS, Dowd CF, et al. Angioplasty for intracranial symptomatic vertebrobasilar ischemia. Neurosurgery. 2002; 51(1):23-29.
28. Gupta R, Schumacher HC, Mangla S, et al. Urgent endovascular revascularization for symptomatic intracranial atherosclerotic stenosis. Neurology. 2003; 61(12):1729-1735.
29. Gurm HS, Yadav JS, Fayad P et al. Long-term results of carotid stenting versus endarterectomy in high-risk patients. N Engl J Med. 2008; 358(15):1572-1579.
30. Hanel RA, et al.  Intracranial atherosclerotic disease:  common, dangerous and treatable.  Cl Neurosurg. 2005; 52:68-75.
31. Hartmann M, Jansen O.  Angioplasty and stenting of intracranial stenosis.  Curr Opin Neurol. 2005; 18:39-45.
32. Higashida RT, et al. Standards of Practice. Reporting Standards for Carotid Artery Angioplasty and Stent Placement. J Vasc Interv Radiol. 2004; 15(5):421-422.
33. Higashida RT, Meyers PM.  Intracranial angioplasty and stenting for cerebral atherosclerosis: new treatments are needed!  Neuroradiology. 2006; 48:367-372.
34. Hobson RW. Carotid Artery Stenting. Surg Clin N Am. 2004a; 84:1281–1294.
35. Hobson RW. Rationale and status of randomized controlled clinical trials in carotid artery stenting. Seminars in Vascular Surgery. 2003a; 16:311-316.
36. Hobson RW. Update on the carotid revascularization endarterectomy versus stent trial (CREST) protocol. J Am Coll Surg. 2002; 194(1):S-9 - S-14.
37. Hobson RW, Lal BK, Chaktoura E, et al. Carotid artery stenting: analysis of data for 105 patients at high risk. J Vasc Surg. 2003b; 37:1234-1239.
38. Hobson RW 2^nd, Howard VJ, Roubin GS, et al.  CREST Investigators.  Carotid artery stenting is associated with increased complications in octogenarians:  30-day stroke and death rates in the CREST lead-in phase.  J Vasc Surg. 2004b; 40(6):1106-1111.
39. Hobson RW, Brott TG, Roubin GS, et al. Closure of the lead-in phase of CREST (Carotid Revascularization Endarterectomy vs Stenting trial): 30-day and one year analysis. Stroke. 2008; (2):557. 
40. Iyer SS, White CJ, Hopkins LN et al. Carotid artery revascularization in high-surgical-risk patients using the Carotid WALLSTENT and FilterWire EX/EZ: 1-year outcomes in the BEACH Pivotal Group. J Am Coll Cardiol. 2008; 51(4):427-434.
41. Jordan WD, Alcocer F, Wirthlin DJ, et al. High-risk carotid endarterectomy: Challenges for carotid stent protocols. J Vasc Surg. 2002;35(1):16-22.
42. Kastrup A, Groschel K, Krapf H, et al. Early outcome of carotid angioplasty and stenting with and without cerebral protection devices: a systemic review of the literature. Stroke. 2003; 34(3):813-819.
43. Katzen BT, Criado FJ, Ramee SR et al. Carotid artery stenting with emboli protection surveillance study: thirty-day results of the CASES-PMS study. Catheter Cardiovasc Interv. 2007; 70(2):316-323.
44. Komotar RJ, et al.  Current endovascular treatment options for intracranial carotid artery atherosclerosis.  Neurosurg Focus. 2005; 18(1):E5.
45. Lal BK, Hobson RW 2^nd. Treatment of carotid artery disease:  stenting or surgery.  Curr Neurol Neurosci Rep.  2007; 7(1):49-53.
46. Luebke T, Aleksic M, Brunkwall J. Meta-analysis of randomized trials comparing carotid endarterectomy and endovascular treatment. Eur J Vasc Endovasc Surg. 2007; 34(4):470-479.
47. Levy EI, Horowitz MB, Koebbe CJ, et al. Transluminal stent-assisted angioplasty of the intracranial vertebrobasilar system for medically refractory, posterior circulation ischemia: early results. Neurosurgery. 2001; 48(6):1215-1223.
48. Lifante I, Hirsh JA, Selim M, et al. Safety of latest-generation self-expanding stents in patients with NASCETineligible severe symptomatic extracranial internal carotid artery stenosis. Arch Neurol. 2004; 61:39-43.
49. Marks MP, Marcellus ML, Do HM, et al. Intracranial angioplasty without stenting for symptomatic atherosclerotic stenosis: Long-term follow-up. AJNR Am J Neuroradiol. 2005; 26(3):525-530.
50. Mas JL, Chatellier G, Beyssen B, et al.  EVA-3S Investigators.  Endarterectomy versus stenting in patients with symptomatic severe carotid stenosis.  N Engl J Med. 2006; 355(16):1660-1671.
51. Mas JL, Trinquart L, Levs D, et al. Endarterectomy Versus Angioplasty in Patients with Symptomatic Severe Carotid Stenosis (EVA-3S) trial: results up to 4 years from a randomised, multicentre trial. Lancet Neurol. 2008 Sep 5.
52. McCabe DJ, Pereira AC, Clifton A, et al. Restenosis after carotid angioplasty, stenting or endarterectomy in the Carotid and Vertebral Artery Transluminal Angioplasty Study (CAVATAS).  Stroke. 2005; 36(2):281-286.
53. Mukherjee D, Yadav JS. Percutaneous treatment for carotid stenosis. Cardiol Clin. 2002; 20(4):589-597.
54. Naylor AR, Bolla A, Abbott RJ, et al. Randomized study of carotid angioplasty and stenting versus carotid endarterectomy: a stopped trial. J Vasc Surg. 1998; 28(2):326-334.
55. Paniagua D, Howell M, Strickman N, et al. Outcomes following extracranial carotid artery stenting in high-risk Patients. J Invasive Cardiol. 2001; 13(5):375-381.
56. Perler BA. Carotid endarterectomy: the "gold standard" in the endovascular era. Journal of the American College of Surgeons. 2002; 194(1 suppl):S2-8.
57. Qureshi AI, Knape C, Maroney M, et al. Multicenter clinical trial of the NexStent coiled sheet stent in the treatment of extracranial carotid artery stenosis: immediate results and late clinical outcomes. J Neurosurg. 2003; 99:264-270.
58. Reimers B, et al. Routine use of cerebral protection during carotid artery stenting: results of a multi-center registry of 753 patients. American Journal of Medicine. 2004; 116(4):217-222.
59. Ringleb PA, Allenberg J, Bruckmann H, et al.  The SPACE Collaborative Group:  30 day results from the SPACE trial of stent-protected angioplasty versus carotid endarterectomy in symptomatic patients:  a randomized non-inferiority trial.  Lancet.  2006; 368(9543):1239-1247, 1215-1216.
60. Ringleb PA, Chatellier G, Hacke W et al. Safety of endovascular treatment of carotid artery stenosis compared with surgical treatment: a meta-analysis. J Vasc Surg. 2008; 47(2):350-355.
61. Rockman CB, Su W, Lamparello, PJ, et al. A reassessment of carotid endarterectomy in the face of contralateral carotid occlusion: Surgical results in symptomatic and asymptomatic patients. J Vasc Surg. 2002; 36(4):668-673.
62. Roubin GS, New G, Iyer SS, et al. Immediate and late clinical outcomes of carotid artery stenting in patients with symptomatic and asymptomatic carotid artery stenosis. Circ. 2001; 103(4):532-537.
63. Shawl FA. Carotid artery stenting: acute and long-term results. Curr Opin Cardiol. 2002; 17(6):671-676.
64. Slovut DP, Olin JW. Fibromuscular dysplasia. N Engl J Med. 2004; 350:1862-1871.
65. Spes CH, Schwende A, Beier F et al. Short- and long-term outcome after carotid artery stenting with neuroprotection: single-center experience within a prospective registry. Clin Res Cardiol. 2007; 96(11):812-821.
66. Steinbauer MG, Pfister K, Greindl M, et al. Alert for increased long-term follow-up after carotid artery stenting: results of a prospective, randomized, single-center trial of carotid artery stenting vs. carotid endarterectomy. J Vasc Surg. 2008; 48(1):93-98. Epub 2008 May 16.
67. Yadav JS, et al. Protected Carotid-Artery Stenting versus Endarterectomy in High-Risk Patients.  N Engl J Med 2004; 351(15):1493-1501.
68. Yu W, Smith WS, Singh V, et al. Long-term outcome of endovascular stenting for symptomatic basilar artery stenosis. Neurology. 2005; 64(6):1055-1057.
69. Zaidat O, et al. Long-term outcome of endovascular stenting for symptomatic basilar artery stenosis.  Neruology. 2005; 65(8).

Government Agency, Medical Society, and Other Authoritative Publications:

1. Abbott Vascular. Carotid Stenting vs. Surgery of Severe Carotid Artery Disease and Stroke Prevention in Asymptomatic Patients (ACT I). National Library of Medicine (NLM) Identifier: NCT00106938. Last updated September 15, 2009.  Available at: http://clinicaltrials.gov/ct2/show/NCT00106938.  Accessed on October 1, 2009.
2. Barr JD, Connors JJ III, Sacks D, et al. Joint Standards of Practice Committee of the American Society of Interventional and Therapeutic Neuroradiology, the American Society of Neuroradiology, and the Society of Interventional Radiology. Quality improvement guidelines for the performance of cervical carotid angioplasty and stent placement. J Vasc Interv Radiol. 2003; 14:S321-S335.
3. Bates ER, Babb JD, Casey DE Jr, et al. American College of Cardiology Foundation Task Force; American Society of Interventional & Therapeutic Neuroradiology; Society for Cardiovascular Angiography and Interventions; Society for Vascular Medicine and Biology; Society for Interventional Radiology (ACCF/SCAI/SVMB/SIR/ASITN). 2007 Clinical Expert Consensus Document on carotid stenting. Vasc Med. 2007; 12(1):35-83.
4. Bettman MA, Katzen BT, Whisnat J, et al. Carotid stenting and angioplasty: a statement for healthcare professionals from the Councils on Cardiovascular Radiology, Stroke, Cardio-Thoracic and Vascular Surgery, Epidemiology and Prevention, and Clinical Cardiology, American Heart Association. Circulation. 1998: 97(1): 121-123.
5. BlueCross BlueShield Association.  Angioplasty and stenting of the cervical carotid artery with distal embolic protection of the cerebral circulation. TEC Assessment, 2004; 19(15).
6. BlueCross BlueShield Association.  Angioplasty and stenting of the cervical carotid artery with embolic protection of the cerebral circulation.  TEC Assessment, 2007; 24(1).
7. CaRESS Steering Committee. Carotid revascularization using endarterectomy or stenting systems (CaRESS) phase I clinical trial: one year results.  J Vasc Surg. 2005; 42(2): 213-219.
8. Centers for Medicare & Medicaid Services (CMS). Decision memo for percutaneous transluminal angioplasty (PTA) of the carotid artery concurrent with stenting (CAG-00085R3). Medicare Coverage Database. Rockville, MD: CMS; April 30, 2007.  Available at: http://www.cms.hhs.gov/mcd/viewdecisionmemo.asp?id=194.  Accessed on October 1, 2009.
9. Centers for Medicare and Medicaid Services.  National Coverage Determination for Percutaneous Transluminal Angioplasty, NCD #20.7.  Effective date March 17, 2005.  Updated April 30, 2007.  Available at: http://www.cms.hhs.gov/mcd/viewdecisionmemo.asp?from2=viewdecisionmemo.asp&id=157&. Accessed on October 1, 2009.
10. Centers for Medicare and Medicaid Services. National Coverage Determination for Vertebral Artery Surgery. NCD #20.1. Effective date not posted. Available at: http://www.cms.hhs.gov/mcd/viewncd.asp?ncd_id=20.1&ncd_version=1&basket=ncd%3A20%2E1%3A1%3AVertebral+Artery+Surgery.  Accessed on  October 1, 2009.
11. Centers for Medicare and Medicaid Services.  National Coverage Determination and Decision Memo for Intracranial Stenting and Angioplasty (CAG-00085R2).  Effective date November 6, 2006. Available at: https://www.cms.hhs.gov/mcd/viewdraftdecisionmemo.asp?from2=viewdraftdecisionmemo.asp&id=214&. Accessed on October 1, 2009.
12. Centers for Medicare and Medicaid Services (CMS). Medicare Coverage Database. Proposed Decision Memo for Percutaneous Transluminal Angioplasty (PTA) of the Carotid Artery Concurrent with Stenting (CAG-00085R7). September 10, 2009. Available at: https://www.cms.hhs.gov/mcd/viewdraftdecisionmemo.asp?id=230.  Accessed on October 1, 2009.
13. Chaturvedi S, Bruno A, Feasby T, et al. Carotid endarterectomy – an evidence based review. Report of the Therapeutics and Technology Assessment Subcommittee of the American Academy of Neurology. Neurology. 2005; 65:794-801.  Available at: http://www.neurology.org/cgi/content/full/65/6/794.  Accessed on October 1, 2009.
14. Connors JJ 3rd, Sacks D, Furlan AJ, et al. NeuroVascular Coalition Writing Group; American Academy of Neurology; American Association of Neurological Surgeons; American Society of Interventional and Therapeutic Radiology; American Society of Neuroradiology; Congress of Neurological Surgeons; AANS/CNS Cerebrovascular Section; Society of Interventional Radiology. Training, competency, and credentialing standards for diagnostic cervicocerebral angiography, carotid stenting, and cerebrovascular intervention: a joint statement from the American Academy of Neurology, American Association of Neurological Surgeons, American Society of Interventional and Therapeutic Radiology, American Society of Neuroradiology, Congress of Neurological Surgeons, AANS/CNS Cerebrovascular Section, and Society of Interventional Radiology. Radiology. 2005; 234(1):26-34.
15. Coward LJ, Featherstone RL, Brown MM. Percutaneous transluminal angioplasty and stenting for vertebral artery stenosis.  Cochrane Database Syst Rev. 2005; (2):CD000516.
16. Cruz-Flores S, Diamond AL. Angioplasty for intracranial artery stenosis. Cochrane Database Syst Rev. 2006;(3):CD004133.
17. Ederle J, Featherstone RL, Brown MM. Percutaneous transluminal angioplasty and stenting for carotid artery stenosis. Cochrane Database Syst Rev. 2007; (4):CD000515.
18. Hayes, Inc. Hayes Medical Technology Directory. Carotid artery stenting for the treatment of carotid artery stenosis. Lansdale, PA: Hayes, Inc; September 29, 2009.
19. Higashida RT, Meyers PM, Connors JJ, et al. Intracranial angioplasty and stenting for cerebral atherosclerosis: a position statement of the American Society of Interventional and Therapeutic Neuroradiology, Society of Interventional Radiology and the American Society of Neuroradiology.  Am J Neuroradiol. 2005; 26(9):2323-2327.
20. Hijazi ZM, Bove AA, Bacharach JM. RE: NCA for Percutaneous Angioplasty (PTA) of the Carotid Artery Concurrent with Stenting (CAG-0085R7). April 17, 2009. American College of Cardiology (ACC). Available at: http://www.acc.org/advocacy/pdfs/CmtLtr%20NCD%20PTA%20CAS.pdf.  Accessed on October 1, 2009.
21. Hobson RW, 2nd, Mackey WC, Ascher E, et al. Society for Vascular Surgery. Management of atherosclerotic carotid artery disease: clinical practice guidelines of the Society for Vascular Surgery. J Vasc Surg. 2008; 48(2):480-486.  Available at:  http://www.vascularweb.org/professionals/Practice_Issues/PDF_Doc_JPEG/Carotid-CPG-090508%20JVS.pdf.  Accessed on October 1, 2009.
22. Institute for Clinical Systems Improvement Technology Assessment Report:  Carotid, Vertebral and Intracranial Artery Angioplasty and Stenting.  June 2006.  Available at:  http://www.icsi.org/guidelines_and_more/technology_assessment_reports/technology_assessment_reports_-_active/carotid__vertebral_and_intracranial_artery_angioplasty_and_stenting.html. Accessed on October 1, 2009.
23. Liapis CD, Bell PR, Mikhailidis D, et al.; ESVS Guidelines Collaborators. ESVS guidelines. Invasive treatment for carotid stenosis: indications, techniques. Eur J Vasc Endovasc Surg. 2009; 37(4 Suppl):1-19.
24. Mazighi M, et al. Prospective study of asymptomatic atherothrombotic intracranial stenoses: The GESICA Study.  Neurology. 2006; 66(8).
25. National Institute for Health and Clinical Excellence (NICE). Endovascular stent insertion for intracranial atherosclerotic disease. Interventional Procedure Guidance 233. London, UK: NICE; October 2007. 
26. National Institute for Clinical Excellence (NICE). Carotid artery stent placement for carotid stenosis: Interventional Procedure Consultation Document. London, UK: NICE; August 2004. Available at: http://www.nice.org.uk/guidance/index.jsp?action=article&r=true&o=31227.  Accessed on October 1, 2009.
27. Sacco RL, Adams R, Albers G, et al.  AHA/ASA Guidelines.  Guidelines for Prevention of Stroke in Patients With Ischemic Stroke or Transient Ischemic Attack  A statement for healthcare professionals from the American Heart Association/American Stroke Association Council on Stroke: Co-sponsored by the Council on Cardiovascular Radiology and Intervention: The American Academy of Neurology affirms the value of this guideline  Stroke. 2006; 37(2):577-617.
28. Stenting of symptomatic atherosclerotic lesions in the vertebral or intracranial arteries (SSYLVIA).  The SSYLVIA Study Investigators.  Stroke. 2004; 35:1388.
29. Stenting and angioplasty with protection in patients at high risk for endarterectomy: 3-year results (SAPPHIRE: 3 year results). ACC Cardiosource Review Journal. 2008; 17.
30. Tice JA. California Technology Assessment Forum:  Carotid Artery Stenting.  June 17, 2009.  Available at: http://www.ctaf.org/content/assessment/detail/1026.  Accessed on October 1, 2009.
31. U.S. Food and Drug Administration (FDA). Center for Devices and Radiological Health (CDRH).  New Device Approval: NEUROLINK^® System Approval Letter and Labeling; August 9, 2002.  Available at: http://www.accessdata.fda.gov/cdrh_docs/pdf/H010004a.pdf.  Accessed on October 1, 2009.
32. U.S. Food and Drug Administration (FDA). Center for Devices and Radiological Health (CDRH). New Device Approval Letter August 30, 2004. ACCULINK^™ Carotid Stent system; RX ACCULINK^™ Carotid Stent System.  Available at: http://www.accessdata.fda.gov/cdrh_docs/pdf4/p040012a.pdf. Accessed on October 1, 2009.
33. U.S. Food and Drug Administration (FDA). Center for Devices and Radiological Health (CDRH). New Device Approval Letter Sept. 6, 2005.: Xact^® Carotid Stent System.  Available at: http://www.accessdata.fda.gov/cdrh_docs/pdf4/p040038a.pdf.  Accessed on October 1, 2009.
34. U.S. Food and Drug Administration (FDA). Center for Devices and Radiological Health (CDRH). New Device Approval Summary of Safety and Effectiveness. January 24, 2007. Protege^® GPS^TM Carotid Stent System Protege^® RX Carotid Stent System. Available at:   http://www.fda.gov/MedicalDevices/ProductsandMedicalProcedures/DeviceApprovalsandClearances/Recently-ApprovedDevices/ucm077040.htm.  Accessed on October 21, 2009.
35. U.S. Food and Drug Administration (FDA). Center for Devices and Radiological Health (CDRH). New Device Approval Letter Aug. 3, 2005. Wingspan^™ Stent System with Gateway^™ PTA Balloon Catheter.  Available at: http://www.accessdata.fda.gov/cdrh_docs/pdf5/h050001a.pdf.  Accessed on October 1, 2009.
36. U.S. Food and Drug Administration (FDA). Humanitarian Device Exemption (HDE). The Wingspan^™ HDE Study.  Evaluation of the Wingspan Stent System in Intracranial Atherosclerotic Disease (ICAD). (Submitted to the FDA for regulatory approval under the Humanitarian Device Exemption [HDE] approval process. January 27, 2005. Boston Scientific Corporation, San Leandro, CA..) Information available at: http://www.medicalnewstoday.com/medicalnews.php?newsid=28903&nfid=rssfeeds.  Accessed on October 1, 2009.
37. Zaidat OO, Klucznik R, Alexander MJ, et al. National Institutes of Health (NIH). Multi-center Wingspan Intracranial Stent Registry Study Group. The NIH registry on use of the Wingspan stent for symptomatic 70-99% intracranial arterial stenosis. Neurology. 2008; 70(17):1518-1524.
38. Zwienenberg-Lee M, Hartman J, Rudisill N, et al. Balloon prophylaxis for aneurysmal vasospasm (BPAV) Study Group. Effect of prophylactic transluminal balloon angioplasty on cerebral vasospasm and outcome in patients with Fisher grade III subarachnoid hemorrhage: Results of a phase II multicenter, randomized, clinical trial. Stroke. 2008; 39(6):1759-1765.

1. American Heart Association. Available at: http://www.amhrt.org/presenter.jhtml?identifier=1200000. Accessed on October 1, 2009. 
2. American Stroke Association.  Available at:  http://www.strokeassociation.org/presenter.jhtml?identifier=1200037. Accessed on October 1, 2009. 

ACCULINK™ Carotid Stent System
Angioguard™ Emboli Capture Guidewire
CAS
CEA
Cordis PRECISE™ Nitinol Stent System
NEUROLINK® System
Protege® GPS™
Protege® RX Carotid Stent System

The use of specific product names is illustrative only.  It is not intended to be a recommendation of one product over another, and is not intended to represent a complete listing of all products available.