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Intracranial arterial disease includes thromboembolic events, vascular stenoses, and aneurysms. Endovascular techniques have been investigated for treatment of intracranial arterial disease, as an alternative to intravenous tissue plasminogen activator (tPA) and supportive care for acute stenosis and as an alternative to risk factor modification for chronic stenosis. For cerebral aneurysms, stent-assisted coiling has been evaluated as an alternative to endovascular coiling in patients whose anatomy is not amenable to simple coiling.
Cerebrovascular diseases include a range of processes affecting the cerebral vascular system, including arterial thromboembolism, arterial stenosis, and arterial aneurysms, all of which can lead to restrictions in cerebral blood flow due to ischemia or hemorrhage. Endovascular techniques, including endovascular pharmacologic thrombolysis, endovascular mechanical embolectomy; using one of several types of devices, endovascular deployment of several types of stents, and angioplasty with or without stenting, have been investigated for treatment of cerebrovascular diseases.
While spontaneous thrombolysis does occur, treatment of ischemic stroke has focused on the use of intravenous tissue plasminogen activator (tPA) to promote dissolution of the clot and subsequent restoration of blood flow to the ischemic area of the brain. The use of intravenous tPA within 3 hours of stroke onset for selected patients is the standard of care for ischemic stroke treatment. Despite its benefits, widespread implementation of intravenous tPA is challenging. Reperfusion benefits decrease over time; infarcted brain tissue will not recover. In most states, fewer than 10% of ischemic stroke patients arrive in the hospital in time for intravenous tPA within the 3-hour window for its use. Because tPA is associated with an increased risk of intracranial bleeding, it is contraindicated in hemorrhagic stroke and in some ischemic stroke patients in which the risk of bleeding outweighs potential benefit, such as those with mild or resolving symptoms, hypocoagulable state, or advanced age.
There are several ways in which endovascular interventions may be used as a treatment for acute stroke. For patients who present with acute stroke within the time window for thrombolysis and meet other clinical criteria for intravenous tPA, endovascular interventions may be used in combination with thrombolysis. For patients who are not candidates for thrombolysis (eg, who present past the time window for thrombolysis), endovascular interventions can be considered as an alternative to standard conservative medical therapy.
Intravenous tPA has improved outcomes for many, but not all, ischemic stroke patients. Researchers have studied intra-arterial tPA, transcranial ultrasound energy, and mechanical clot destruction or clot removal as an alternative, or second line, to the established intravenous tPA therapy. Clots can be defined as located in large or small vessels. Large intracranial arteries include the internal carotid, Circle of Willis and the first 2 branches of the anterior (A1 and A2), middle (M1 and M2), and posterior (P1 and P2) cerebral arteries. These can be accessed with a catheter; further branches of the cerebral circulation are defined as small vessels and are too tortuous to be mechanically accessed with available technology.
Several types of endovascular treatments for ischemic strokes have been considered:
This policy focuses on the four devices with an indication for endovascular embolectomy for acute stroke.
Intracranial Atherosclerotic Disease
It is estimated that intracranial atherosclerosis 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). The “Warfarin-Aspirin Symptomatic Intracranial Disease (WASID) trial was a randomized trial that compared the incidence of stroke brain hemorrhage or death among patients randomized to receive either 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. In addition, if symptoms could be attributed to low flow ischemia, agents to increase mean arterial blood pressure and avoidance of orthostatic hypotension may be recommended. However, medical therapy is considered less than optimal. For example, in patients with persistent symptoms despite antithrombotic therapy, the subsequent rate of stroke or death is extremely high, estimated in one study at 45%, with recurrent events occurring within a month of the initial recurrence. Surgical approaches have met with limited success. The widely quoted Extracranial-Intracranial (EC/IC) Bypass study randomized 1,377 patients with symptomatic atherosclerosis of the internal carotid or middle cerebral arteries to medical care or EC/IC bypass. The outcomes in the two groups were similar, suggesting that the EC/IC bypass is ineffective in preventing cerebral ischemia. Due to inaccessibility, surgical options for the posterior circulation are even more limited.
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 vessels, and the increased use of stents, have created ongoing interest in exploring PTA as a minimally invasive treatment of this difficult-to-treat population. The majority of published studies of intracranial PTA has focused on the vertebrobasilar circulation. Two endovascular devices have FDA approval for treatment of symptomatic intracranial stenosis and are considered here.
Compared with acute ischemic stroke, cerebral aneurysms have a much lower incidence among the U.S. population, with prevalence between 0.5% and 6% of the population. However, they are associated with significant morbidity and mortality due to subarachnoid hemorrhage resulting from aneurysm rupture. Surgical clipping of intracranial aneurysms has been used since the 1960s, but the feasibility of clipping for aneurysms depends on the aneurysm location. Intracranial stents are also being used 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 need more repeat/follow-up procedures. In 2011, the Pipeline® Embolization Device, which falls into a new device category called “intracranial aneurysm flow diverters,” or flow-diverting stent, received FDA premarket approval for endovascular treatment of large or giant wide-necked intracranial aneurysms in the internal carotid artery. The Pipeline device is a braided, wire mesh device that is placed within the parent artery of an aneurysm to redirect blood flow away from the aneurysm with the goal of preventing aneurysm rupture and possibly decreasing aneurysm size.
Several devices for endovascular treatment of intracranial arterial disease have received clearance by FDA through either the 510(k) process or through the humanitarian device exemption (HDE) process. By indication, approved devices are as follows:
Currently 2 devices have received approval for atherosclerotic disease from the U.S. Food and Drug Administration (FDA) through the humanitarian device exemption (HDE) process. This form of FDA approval is available for devices used to treat conditions with an incidence of 4,000 or less per year; FDA only requires data showing “probable safety and effectiveness.” Devices with their labeled indications are as follows:
In 2011, FDA granted premarket approval to the Pipeline® Embolization Device (Covidien/ eV3 Neurovascular, Irvine, CA), an intracranial aneurysm flow diverter, for the endovascular treatment of adults (22 years of age or older) with large or giant wide-necked intracranial aneurysms in the internal carotid artery from the petrous to the superior hypophyseal segments (P100018). Approval was based on the Pipeline for Uncoilable for Failed Aneurysms Study, a single-arm, open-label feasibility study that included 108 patients aged 30 to 75 years with unruptured large and giant wide-necked aneurysms.
Two stents have received FDA approval though the Humanitarian Device Exemption (HDE) program for treatment of intracranial aneurysms:
Intracranial stent placement may be considered medically necessary as part of the endovascular treatment of intracranial aneurysms for patients when surgical treatment is not appropriate and standard endovascular techniques do not allow for complete isolation of the aneurysm, e.g., wide-neck aneurysm (4 mm or more) or sack-to-neck ratio less than 2:1.
Intracranial flow diverting stents with FDA approval for the treatment of intracranial aneurysms may be considered medically necessary as part of the endovascular treatment of intracranial aneurysms that meet anatomic criteria (see “Policy Guidelines”) and are not amenable to surgical treatment or standard endovascular therapy.
Intracranial stent placement is considered investigational in the treatment of intracranial aneurysms except as noted above.
Intracranial percutaneous transluminal angioplasty with or without stenting is considered investigational in the treatment of atherosclerotic cerebrovascular disease.
Endovascular interventions (mechanical embolectomy, angioplasty, stenting) are considered investigational in the treatment of acute stroke.
Federal Employee Program (FEP) may dictate that all FDA-approved devices, drugs or biologics may not be considered investigational and thus these devices may be assessed only on the basis of their medical necessity.
Flow-diverting stents are indicated for the treatment of large or giant wide-necked intracranial aneurysms, with a size of 10 mm or more and a neck diameter of 4 mm or more, in the internal carotid artery from the petrous to the superior hypophyseal segments.
This policy only addresses endovascular therapies used on intracranial vessels.
The coverage guidelines outlined in the Medical Policy Manual should not be used in lieu of the Member's specific benefit plan language.
Investigative service is defined as the use of any treatment procedure, facility, equipment, drug, device, or supply not yet recognized by certifying boards and/or approving or licensing agencies or published peer review criteria as standard, effective medical practice for the treatment of the condition being treated and as such therefore is not considered medically necessary.
7/2003: Approved by Medical Policy Advisory Committee (MPAC)
11/11/2005: Code Reference section updated, CPT codes 35475, 36100, 36215-36218 added, 37799 deleted; ICD9 procedure codes 00.40-00.43 added
3/10/2006: Coding updated. CPT4/HCPCS 2006 revisions added to policy
3/10/2006: Policy reviewed, no changes
5/24/2006: Coding update. 36100, 36215-36218 deleted
9/22/2006: Coding updated. ICD9 2006 revisions added to policy
5/10/2007: Policy reviewed, description section updated
8/19/2009: Policy reviewed, no changes
8/18/2010: Policy reviewed. Removed CPT code 35475 from the Non-Covered Codes Table based on the policy statement.
08/11/2011: Policy titled changed from "Percutaneous Transluminal Angioplasty of Intracranial Atherosclerotic Stenoses With or Without Stenting" to "Endovascular Procedures (Angioplasty and/or Stenting) for Intracranial Arterial Disease (Atherosclerosis and Aneurysms)" to reflect the wider scope of the policy. Policy description updated. Added a new policy statement to indicate that the use of stents may be considered medically necessary for treatment of selected patients with intracranial aneurysms. Use is generally reserved for cases where successful occlusion of the aneurysm cannot be obtained with standard endovascular techniques, e.g., wide-neck aneurysms. FEP verbiage added to the Policy Exceptions section. Added a Covered Codes table and moved the following codes from non-covered to covered: 61630, 61635, 00.40, 00.41, 00.42, 00.43, 00.44. Added the following codes to the Code Reference section: 00.45, 00.46, 00.47, 00.48, 00.62, 00.65, 430, 431, 437.3 and 747.81. Deleted 39.50 from the Code Reference section. Deleted the Non-Covered codes table.
06/06/2012: Policy reviewed; no changes.
08/09/2013: Policy reviewed; no changes.
04/22/2014: Policy reviewed; description updated regarding endovascular treatments and available devices with an indication for acute stroke. Added investigational policy statement that "Endovascular interventions (mechanical embolectomy, angioplasty, stenting) are considered investigational in the treatment of acute stroke."
10/30/2014: Added new policy statement that intracranial flow diverting stents with FDA approval for the treatment of intracranial aneurysms may be considered medically necessary as part of the endovascular treatment of intracranial aneurysms that meet anatomic criteria (see “Policy Guidelines”) and are not amenable to surgical treatment or standard endovascular therapy. Policy guidelines updated regarding flow-diverting stents.
Blue Cross Blue Shield Association policy # 2.01.54
This may not be a comprehensive list of procedure codes applicable to this policy.
The code(s) listed below are ONLY medically necessary if the procedure is performed according to the "Policy" section of this document.