Medical Policy: 07.01.32
Original Effective Date: July 2006
Reviewed: June 2020
Revised: June 2020
This policy contains information which is clinical in nature. The policy is not medical advice. The information in this policy is used by Wellmark to make determinations whether medical treatment is covered under the terms of a Wellmark member's health benefit plan. Physicians and other health care providers are responsible for medical advice and treatment. If you have specific health care needs, you should consult an appropriate health care professional. If you would like to request an accessible version of this document, please contact customer service at 800-524-9242.
Benefit determinations are based on the applicable contract language in effect at the time the services were rendered. Exclusions, limitations or exceptions may apply. Benefits may vary based on contract, and individual member benefits must be verified. Wellmark determines medical necessity only if the benefit exists and no contract exclusions are applicable. This medical policy may not apply to FEP. Benefits are determined by the Federal Employee Program.
This Medical Policy document describes the status of medical technology at the time the document was developed. Since that time, new technology may have emerged or new medical literature may have been published. This Medical Policy will be reviewed regularly and be updated as scientific and medical literature becomes available.
It is estimated that intracranial atherosclerotic lesions (stenosis) causes about 8% of all ischemic strokes. Intracranial stenosis may contribute to stroke in two ways: either due to embolism or low flow ischemia in the absence of collateral circulation. Recurrent annual stroke rates are estimated at 4%-12% per year with atherosclerosis of the intracranial anterior circulation, and 2.5%-15% per year with lesions of the posterior (vertebrobasilar) circulation. Medical treatment typically includes either anticoagulant therapy (i.e.,warfarin) or antiplatelet therapy (i.e.,aspirin).
Percutaneous transluminal angioplasty (PTA) has been approached cautiously for use in the intracranial circulation, due to technical difficulties in catheter and stent design and the risk of embolism, which may result in devastating complications if occurring in the posterior fossa or brain stem. However, improvement in the ability to track catheterization, allowing catheterization of tortuous veins, and the increased use of stents have lead to further research on PTA as minimally invasive treatment of this difficult-to-treat population. The majority of published research studies of intracranial PTA have focused on the vertebrobasilar circulation.
In a trial sponsored by the Medical University of South Carolina, Stenting vs. Aggressive Medical Management for Preventing Recurrent Stroke in Intracranial Stenosis (SAMMPRIS), investigators planned to determine whether intracranial stenting with intensive medical therapy is superior to the medical therapy alone for preventing second stroke in high-risk patients with symptomatic stenosis of a major intracranial artery. Recent research has suggested a benefit in prevention of recurring stroke by aggressively treating risk factors such as hypertension, elevated LDL, and diabetes. It has been hypothesized that combining intracranial stenting with aggressive medical management will significantly decrease the incidence of a second stroke. In April 2011, the SAMMPRIS trial was halted due to the high risk of stroke and death in the stenting group according to the U.S. National Institutes of Health.
Intracranial stents are also being utilized in the treatment of cerebral aneurysms. Stent-assisted coiling began as an approach to treat fusiform or wide-neck aneurysms in which other surgical or endovascular treatment strategies may not be feasible. As experience grew, stenting was also used in smaller berry aneurysms as an approach to decrease the rate of retreatment needed in patients who receive coiling. A randomized trial has demonstrated that treatment of ruptured intracranial aneurysms with coiling leads to improved short-term outcome compared with surgical clipping; however, patients who receive coiling have a need for more repeat/follow-up procedures.
Aneurysmal subarachnoid hemorrhage (SAH) is a common form of stroke. Frequently, a significant number of patients with this condition develop angiographical or clinical vasospasm with devastating consequences. The pathogenesis of cerebral vasospasm following SAH remains unclear despite extensive research. Due to the lack of a clear etiology, medical treatment is still largely limited to hypertensive-hypervolemic-hemodilution (triple-H) therapy, and calcium channel blockers (e.g., nimodipine). Cerebral vasospasm that has become refractory to maximal medical therapy can be treated with intra-arterial infusion of vasodilators (e.g. papaverine). Moreover, recent advent in the field of interventional neurology and the development of minimally invasive techniques has resulted in expansion of potential therapeutic approaches for cerebral vasospasm secondary to aneurysmal subarachnoid hemorrhage (SAH). Balloon angioplasty is being investigated as a treatment option in patients with vasospasm following aneurysmal SAH; however its effectiveness for this indication has yet to be established.
The following PICOT was used to determine literature available for use in stenosis.
Patients with severe stenosis (70 to 99% of the diameter of a major intracranial artery).
Devices for treatment of intracranial stenosis have received the FDA approval through the humanitarian device exemption process. The Neurolink System was approved based on the Stenting of Symptomatic Atherosclerosis Lesions in the Vertebral or Intracranial Arteries (SSYLVIA) trial, a prospective, nonrandomized, multicenter, international study of 61 patients.48, The Wingspan Stent System was evaluated in a prospective study of 45 patients enrolled at 12 international centers.49, The SSYLVIA study reported an all-stroke rate of 13.1% over a mean follow-up of 216 days; the Wingspan study reported an all-stroke rate of 9.5% over a mean follow-up of 174 days.
The FDA summary of safety and effectiveness for the Wingspan device offered the following conclusions and the FDA appears to have based its approval of Wingspan in part on the favorable comparison with the Neurolink device: “…the probable benefit to health from using the Wingspan Stent System with Gateway PTA Balloon Catheter for treating transcranial stenosis outweighs the risk of illness or injury when used in accordance with the Instructions for Use and when taking into account the probable risks and benefits of currently available alternative forms of treatment.”
Medical treatment typically includes either anticoagulant therapy (ie, warfarin) or antiplatelet therapy (eg, aspirin). The Warfarin-Aspirin Symptomatic Intracranial Disease trial assessed the incidence of stroke brain hemorrhage or death among patients randomized to aspirin or warfarin, The trial found that over a mean 1.8 years of follow-up, warfarin provided no benefit over aspirin and was associated with a significantly higher rate of complications. Also, if symptoms could be attributed to low-flow ischemia, agents to increase mean arterial blood pressure and avoid orthostatic hypotension may be recommended. However, medical therapy has been considered less than optimal. For example, in patients with persistent symptoms despite antithrombotic therapy, the subsequent rate of stroke or death has been extremely high, estimated in 1 study at 45%, with recurrent events within 1 month of the initial event. Surgical approaches have met with limited success. The widely cited extracranial-intracranial bypass study randomized 1377 patients with symptomatic atherosclerosis of the internal carotid or middle cerebral arteries to medical care or extracranial-intracranial bypass., Outcomes in both groups were similar, suggesting that the extracranial-intracranial bypass is ineffective in preventing cerebral ischemia. Due to inaccessibility, surgical options for the posterior circulation are even more limited. Percutaneous transluminal angioplasty has been approached cautiously for use in intracranial circulation, due to technical difficulties in the catheter and stent design and the risk of embolism, which may result in devastating complications if occurring in the posterior fossa or brain stem. However, improvement in the ability to track catheterization, allowing catheterization of tortuous vessels, and the increased use of stents have created ongoing interest in percutaneous transluminal angioplasty as a minimally invasive treatment of this difficult-to treat population. Most published studies of intracranial percutaneous transluminal angioplasty have focused on vertebrobasilar circulation.
The outcomes of interest are stroke, death, function and quality of life. Treatment-related adverse effects, including vessel perforation, hemorrhage, or thrombus formation in a new site, are important safety outcomes. Evidence for both short-term (30 day) and long-term (out to 2-years) outcomes are needed.
In 2013, the American Heart Association Stroke Council, Council on Cardiovascular Nursing, Council on Peripheral Vascular Disease, and Council on Clinical Cardiology issued Guidelines for the Early Management of Patients with Acute Ischemic Stroke which contain two new recommendations that concur with the other specialty medical society guidance regarding extracranial and intracranial artery angioplasty and stenting as a treatment of acute ischemic stroke as follows:
The American Heart Association and the American Stroke Association published joint guidelines on the early management of patients with acute ischemic stroke (AHA, 2018). These guidelines included several recommendations relevant to the use of endovascular therapies for acute stroke.
Vascular Surgery recommendations from Choosing Wisely Canada state: Don’t perform carotid endarterectomies or stenting in most asymptomatic high risk patients with limited life expectancy. The purpose of carotid artery surgery and stenting is to prevent stroke and, when combined with appropriate medical therapy, is a successful strategy in selected, mainly symptomatic, patients. Medical therapy alone is an effective alternative in many asymptomatic patients and safer in those who are elderly or at high risk for surgery and stenting and don’t have the life expectancy to benefit from such a prophylactic procedure.
The Neurolink® system, marketed by the Guidant Corporation, is indicated for the treatment of patients with recurrent intracranial stroke attributable to atherosclerotic disease refractory to medical therapy in intracranial vessels ranging from 2.5 to 4.5 mm in diameter with a stenosis greater than or equal to 50% and that are accessible to the stent system.
The Wingspan™ Stent System with Gateway™ PTA Balloon Catheter, marketed by Boston Scientific, received HDE approval from the FDA in 2005 to treat refractory intracranial atherosclerotic disease resulting in 50 percent or greater narrowing in the intracranial arteries. Following analysis of data from the SAMMPRIS study, the original HDE clinical study and other clinical studies performed after the stent’s HDE approval, the FDA revised the use and labeling for the Wingspan™ stent in August 2012. The new labeling approves the use of Wingspan™ stent for a very select group of patients who are between 22 and 80 years of age and meet all of the following criteria: Have had two or more strokes despite aggressive medical management;
The Wingspan™ Stent System should not be used for the treatment of TIAs or treatment of stroke with onset of symptoms within seven days or less of treatment.
In 2002, the Neuroform Microdelivery Stent System received HDE approval from the FDA for use with embolic coils for treatment of wide-neck intracranial aneurysms that cannot be treated by surgical clipping. Similarly, in 2007, the Enterprise Vascular Reconstruction Device and Delivery System received HDE approval from the FDA for use with embolic coils for treatment of wide-neck, intracranial, saccular or fusiform aneurysms.
For additional information on Humanitarian Use Device Exemption see Policy 10.01.14
Intracranial stent placement as part of the endovascular treatment of an intracranial aneurysm may be considered as medically necessary:
Intracranial stent placement is considered investigational in the treatment of intracranial aneurysms except as noted above.
Intracranial percutaneous angioplasty, with or without stenting, for the treatment of atherosclerotic cerebrovascular disease is considered investigational.
Intracranial percutaneous angioplasty, with or without stenting, for the treatment of cerebral vasospasm following aneurysmal subarachnoid hemorrhage is considered investigational due to the lack of evidence demonstrating its impact on improved health outcomes.
Percutaneous transluminal angioplasty (PTA) of the intracranial cerebrovascular artery with the Neurolink® Stent & Delivery Catheter and Neurolink® Balloon Dilatation Catheter System is considered not medically necessary and, therefore, not covered for individuals with any of the following absolute contraindications:
PTA of the intracranial cerebrovascular artery with the Wingspan™ Stent System with Gateway™ PTA Balloon Catheter is considered not medically necessary and, therefore, not covered for individuals with any of the following absolute contraindications:
There is preliminary evidence that balloon angioplasty, with or without stenting, may be effective in treating symptomatic patients with intra-cranial stenosis, available data are mainly from retrospective case series. Randomized controlled studies are needed to ascertain the effectiveness of this technology compared to best medical care in preventing stroke in patients with intra-cranial stenosis that is symptomatic or asymptomatic. The clinical benefit of balloon angioplasty, with or without stenting has not been firmly established. There is insufficient evidence at this time to permit conclusions on net health outcome. Therefore, intracranial percutaneous angioplasty, with or without stenting for the treatment of atherosclerotic stenosis is considered investigational.
There is some preliminary evidence from retrospective case series studies that balloon angioplasty may be beneficial in treating cerebral vasospasm following aneurysmal subarachnoid hemorrhage (SAH), its effectiveness in the prevention and treatment of this condition needs to be verified by prospective, randomized, controlled trials. There is insufficient evidence at this time to permit conclusions on net health outcome. Therefore, intracranial percutaneous angioplasty, with or without stenting for the treatment of cerebral vasospasm following aneurysmal subarachnoid hemorrhage (SAH) is considered investigational.
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