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Medical Policy | ||
| Subject: Carotid, Vertebral and Intracranial Artery Angioplasty with or without Stent Placement | |||
| Policy #: SURG.00001 | Current Effective Date: | 02/05/2007 | |
| Status: Revised | Last Review Date: | 12/07/2006 | |
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Description/Scope
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 patients 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 policy addresses carotid, vertebral and intracranial artery angioplasty with or without stent placement.
Policy Statement
Medically Necessary:
Extracranial carotid artery angioplasty and stent placement (CAS) performed in conjunction with an FDA approved carotid stent system is considered medically necessary in patients who meet one or more of the following criteria AND can be safely treated or crossed by this approach AND who have no angiographically visible intramural thrombus:
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 patients with one or both of the following conditions:
Investigational/Not Medically Necessary:
Carotid artery angioplasty and stent placement (CAS) is considered investigational/not medically necessary when the above criteria are not met, including but not limited to, the following conditions:
Percutaneous Angioplasty (PTA) with or without associated stenting is considered investigational/not medically necessary when used in the treatment of atherosclerotic stenosis of:
Rationale
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 Am. J. 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.”
There are currently several 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), the NIH supported trial, CREST (Carotid Revascularization Endarterectomy versus Stenting Trial), and the SPACE trial (Stent Protected Angioplasty versus Carotid Endarterectomy).
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. 334 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 emboli-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 US Food and Drug Administration (FDA) granted Premarket Approval to Guidant Corporation’s two stent systems (the ACCULINKTM 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:
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 et al.) 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 ACCULINKTM and RX ACCULINKTM 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 recent 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.
Background/Overview
Description of Disease
Approximately 700,000 people in the US 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 US 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 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.
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%.
Definitions
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:
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:
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.
Coding
The following codes for treatments and procedures applicable to this policy 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:
CPT
CPT Category III
ICD-9 Procedure
ICD-9 Diagnosis
Services are Not Medically Necessary: For the procedure codes listed above, when adverse conditions as listed in the policy are present.
Services are Investigational/Not Medically Necessary: For the procedure codes listed above, when criteria are not met, for all other diagnoses not listed or when the code describes a procedure indicated in the Policy section as investigational/not medically necessary.
When services are also Investigational/Not Medically Necessary:
CPT
ICD-9 Procedure
ICD-9 Diagnosis
References
Peer Reviewed Publications:
Government Agency, Medical Society, and Other Authoritative Publications:
Web Sites for Additional Information
Index
ACCULINKTM 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. Policy History
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