This document addresses extracranial (cervical) carotid, vertebral and intracranial artery stent placement with or without angioplasty. 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 can be performed percutaneously (that is, passage of a balloon catheter into the lesion via a femoral or brachial artery, followed by dilatation of the blocked segment and stent placement) or through a small incision in the neck (that is, transcarotid artery revascularization [TCAR]). TCAR employs a flow reversal system to provide continuous embolic protection throughout the CAS procedure for extracranial carotid artery stenosis. 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.

Clinical Indications

Medically Necessary:

Extracranial Stent Placement with or without Angioplasty:

Extracranial carotid artery stent placement with or without angioplasty is considered medically necessary for individuals who meet EITHER A or B of the following criteria and can be safely treated by this approach and who have no angiographically visible intraluminal thrombus:

1. 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 which put the individual at a high risk or unsuitable for surgery:
   1. Congestive heart failure (NYHA Class III/IV) or left ventricular ejection fraction less than 30%; or
   2. Open heart surgery needed within the next 6 weeks; or
   3. Recent myocardial infarction (greater than 24 hours and less than 4 weeks); or
   4. Severe chronic obstructive pulmonary disease; or
   5. Unstable angina (CCS class III/IV); or
   6. Inability to move the neck to a suitable position for surgery; or
   7. Tracheostomy.
      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 carotid bulb and bifurcation of the common carotid; or
   3. Pseudoaneurysm; or
   4. Radiation-induced stenosis following previous radiation therapy to the neck or radical neck dissection; or
   5. Restenosis after carotid endarterectomy (CEA); or
   6. Severe tandem lesions that may require endovascular therapy; or
   7. Stenosis secondary to arterial dissection; or
   8. Stenosis secondary to fibromuscular dysplasia; or
   9. Stenosis secondary to Takayasu arteritis; or
   10. Stenosis that is surgically difficult to access (for example, high bifurcation requiring mandibular dislocation); or
   11. Stenosis associated with contralateral carotid artery occlusion; or
   12. Inability to move the neck to a suitable position for surgery; or
   13. Tracheostomy.

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

Intracranial Stent with or without Angioplasty:

Percutaneous intracranial artery stent placement with or without angioplasty is considered medically necessary as part of the treatment of individuals with an intracranial aneurysm when ALL of the following criteria are met:

1. Surgical treatment is not appropriate or attempted surgery was unsuccessful; and
2. Standard endovascular techniques (coiling) are inadequate to achieve complete isolation of the aneurysm because of anatomic considerations which include, but are not limited to:
   1. wide-neck aneurysm (4 mm or more); or
   2. sack-to-neck ratio less than 2:1.

Not Medically Necessary:

Carotid artery angioplasty and stent placement (CAS) is considered 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; or
2. Severe symptomatic carotid stenosis in individuals not meeting the criteria above; or
3. Symptomatic stenosis less than 50% of the relevant carotid artery; or
4. Asymptomatic stenosis less than 80% of the relevant carotid artery; or
5. Carotid stenosis with angiographically visible intraluminal thrombus; or
6. A stenosis that cannot be safely reached or crossed by endovascular approach.

Percutaneous stent placement with or without associated percutaneous angioplasty is considered not medically necessary when used in the treatment of stenosis of:

1. Vertebral arteries; or
2. Intracranial arteries.

Percutaneous stent placement with or without associated percutaneous angioplasty is considered not medically necessary when used in the treatment of aneurysm of:

1. Vertebral arteries; or
2. Intracranial arteries, except when the criteria above are met.

Percutaneous angioplasty of the intracranial arteries when performed without associated stent placement is considered not medically necessary.