Surgery Section - Extracranial Carotid Angioplasty/Stenting

IMPORTANT REMINDER

Regence Medical Policies are developed to provide guidance for members and providers regarding coverage in accordance with contract terms. Benefit determinations are based in all cases on the applicable contract language. To the extent there may be any conflict between the Medical Policy and contract language, the contract language takes precedence.

PLEASE NOTE: Contracts exclude from coverage, among other things, services or procedures that are considered investigational or cosmetic. Providers may bill members for services or procedures that are considered investigational or cosmetic. Providers are encouraged to inform members before rendering such services that the members are likely to be financially responsible for the cost of these services.

DESCRIPTION

Carotid angioplasty and stenting (CAS) is the insertion of a stent (wire-mesh tube) into a narrowed carotid artery. A catheter (a long hollow tube) is inserted into the groin artery and guided through the arteries to the narrowing in the carotid artery. A balloon at the end of the catheter is inflated to push open the narrowed area, and a metal stent is inserted to keep this area from narrowing again. The procedure is performed with the patient fully awake and without sedation. At present, most practitioners also use a distally placed embolic protection (DEP) device that is designed to reduce the risk of stroke caused by thromboembolic material dislodged during CAS. Carotid angioplasty is rarely performed without stent placement.

The U.S. Food and Drug Administration (FDA) has approved several carotid artery stents and DEP devices from various manufacturers. The FDA has mandated postmarketing studies for these devices. Each FDA-approved carotid stent system is indicated for combined use with a DEP device.
  
Note: This policy does not address percutaneous angioplasty and stenting of intracranial or venous vessels, which are addressed in separate policies (see Cross References below).

POLICY/CRITERIA

Carotid angioplasty, with or without associated stenting and distal embolic protection, is considered investigational.

POSITION STATEMENT

The evidence is insufficient to permit conclusions about the benefits of carotid angioplasty, with or without associated stenting and distal embolic protection, as a treatment for stenosis of the carotid artery.

• There is no reliable evidence from well-designed, well executed, prospective, randomized controlled trials demonstrating that carotid artery angioplasty/stenting (CAS) is equally or more effective than open carotid endarterectomy (CEA), the current standard of care for carotid artery stenosis.
• Available evidence does not demonstrate that CAS, compared to CEA, is performed with acceptable periprocedural stroke/death rates, or that it provides a net health benefit to patients at high medical risk.
• There is limited evidence on the durability of CAS, as measured by the need for repeat interventions over subsequent years.
• There is limited evidence on the long-term effectiveness of CAS in preventing stroke, neurological complications, or death.
• While there is limited evidence to suggest that CAS may be beneficial in the group of patients at high surgical risk due to complications of anatomy and comorbid conditions, present evidence has not clearly differentiated outcomes for this subgroup according to symptomatic status.

Effectiveness

Technology Assessments and Meta-analyses

Cochrane Reviews

The 2007 and 2009 Cochrane Reviews assessed the risks and benefits of endovascular treatment (CAS) compared to open carotid endarterectomy (CEA). The reviews included 12 and 10 randomized controlled trials respectively. (3, 4)

The review found the data from these studies to be conflicting and difficult to interpret.  Several flaws undermine the validity of the study findings:

• The overall estimates of effect were imprecise and difficult to interpret due to substantial heterogeneity among the trials such as different patient populations, outcome measures, endovascular procedures, and durations of follow-up. In addition, stopped and completed trials were analyzed together.
• Some studies were stopped early due to recruitment, safety, or futility issues. The early termination may have lead to an overestimate of the risk or the benefit of the treatment.
• No intention-to-treat (ITT) or partial ITT analyses were carried out, which may have biased the estimates of treatment effect.
• Use of antiplatelet medications before, during, and after the treatment may have confounded the study findings.
• Long-term efficacy was difficult to assess because outcome measures and length of follow-up differed greatly among the studies

The review concluded that “the data are insufficient to support a change from routine clinical practice in the types of patient for which carotid endarterectomy is the current standard treatment.”

Follow-up of the Trials Included in the Cochrane Reviews

Subsequent to the publication of the Cochrane reviews, two long-term follow-up reports of the CAVATAS trial were published (5, 6) Both reports summarize the long-term effects  of CAS compared to CEA on restenosis and/or the risk of stroke and other major adverse events. Although both reports found CEA to lead to more favorable outcomes, the findings are unreliable due to at least one of the following flaws: 

• No intention-to-treat (ITT) was carried out, which may have biased the estimates of treatment effect.
• Heterogenous patient populations (e.g. patients with and without stent placement) may have lead to biased estimations of treatment effects.
• The study was underpowered (not able to detect reliably clinically important differences between the treatment groups).

BlueCross BlueShield Association (BCBSA) Technology Evaluation Center (TEC) Assessment

The 2007 BCBSA TEC assessment concurs with the findings in the Cochrane reviews. (2)

Other Meta-analyses

In addition to the Cochrane reviews and TEC Assessments, several other meta-analyses of the studies that compare carotid angioplasty/stenting (CAS) with endarterectomy (CEA) have been published. (7-9) Although these analyses consistently found evidence that favors CEA over CES, they are limited by pooling results from heterogenous studies (different patient samples, endovascular procedures, durations of follow-up and/or completion status of the trials).

Non-randomized Trials, Case Series and Registries

Non-randomized trials, case series and registries on carotid angioplasty and stenting (CAS) found that that cumulative periprocedural death, stroke, and myocardial infarction (MI) rates for CAS exceed accepted standards ( ≤ 3% for asymptomatic and ≤6% for symptomatic patients). (10-17) While these studies contribute to the body of knowledge by providing direction for future research, evidence from these studies is unreliable due to inherent design flaws, such as non-random allocation of treatment and lack of appropriate comparison groups. In addition, registry data may be unreliable due to incomplete reporting. Finally, the technology under investigation may change over time, further limiting the ability to carry out reliable comparisons based on the registry data.

Clinical Practice Guidelines

The 2008 update of the evidence-based guideline on stroke prevention from the American Heart Association/American Stroke Association Council on Stroke (18) includes recommendations on interventional approaches for patients with extracranial carotid artery atherosclerosis. The guideline affirms that CEA is the preferred treatment for patients with recent (i.e., in the past 6 months) transient ischemic attack or non-disabling ischemic stroke and severe ipsilateral carotid stenosis (between 70% and 90% of the lumen diameter), when performed by a surgeon with less than 6% perioperative morbidity and mortality. The guideline also recommends considering CEA for similar patients with moderate carotid stenosis (50% to 69% of the vessel lumen), depending on patient-specific factors such as age, gender, comorbidities, and severity of initial symptoms. Finally, the guideline recommends that carotid artery angioplasty/stenting (CAS) may be considered as a reasonable alternative to CEA for patients with symptomatic severe stenosis (>70%), in whom the stenosis is difficult to access surgically, or with medical conditions that greatly increase the risk for surgery, or when other specific circumstances exist (e.g., radiation-induced stenosis or restenosis after prior CEA), provided it is performed by operators with established periprocedural morbidity and mortality rates of 4% to 6%. The guideline classifies the evidence in support of CAS as “conflicting evidence and/or a divergence of opinion about the usefulness/efficacy of a procedure/treatment” derived from a single randomized trial or nonrandomized studies.  

SAFETY

Long-term safety and complication rates for carotid angioplasty/stenting (CAS) are unknown compared to other therapies; however, several adverse reactions are reported in the published literature including, but not limited to death, stroke, myocardial infarction, intracerebral bleed, restenosis, neurological events, and hyper-perfusion post procedure.

References

1. BlueCross BlueShield Association Medical Policy Reference Manual, Policy No. 7.01.68
2. 2007 BlueCross and BlueShield Association Technology Evaluation Center (TEC) Assessment:  Angioplasty and Stenting of the Cervical Carotid Artery with Embolic Protection of the Cerebral Circulation. T-1cervical carotid artery with distal embolic protection of the cerebral circulation. T-15
3. Ederle J, Featherstone RL, Brown MM. Percutaneous transluminal angioplasty and stenting for carotid artery stenosis. Cochrane Database Syst Rev 2007; (4):CD000515
4. Ederle J, Featherstone RL, Brown MM. Randomized controlled trials comparing endarterectomy and endovascular treatment for carotid artery stenosis: a Cochrane Review. Stroke 2009;40:1373-80
5. Bonati LH, Ederle J, McCabe DJ at al. Long-term risk of carotid restenosis in patients randomly assigned to endovascular treatment or endarterectomy in the Carotid and Vertebral Artery Transluminal Angioplasty Study (CAVATAS): long-term follow-up of a randomized trial. Lancet Neurol. 2009 Oct;8(10):908-917. Epub 2009 Aug 28
6. Ederle J, Bonati LH, Dobson J at al. Endovascular treatment with angioplasty or stenting versus endarterectomy in patients with carotid artery stenosis in the Carotid And Vertebral Artery Transluminal Angioplasty Study (CAVATAS): long-term follow-up of a randomized trial. Lancet Neurol. 2009 Oct;8(10):898-907. Epub 2009 Aug 28.
7. 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):470-9
8. 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):350-5
9. Brahmanandam S, Ding EL, Conte MS et al. Clinical results of carotid artery stenting compared with carotid endarterectomy. J Vasc Surg 2008; 47(2):343-9
10. White CJ, Iyer SS, Hopkins LN et al. Carotid stenting with distal protection in high surgical risk patients: the BEACH trial 30 day results. Catheter Cardiovasc Interv 2006;67(4):503-12
11. Safian RD, Bresnahan JF, Jaff MR et al. Protected carotid stenting in high-risk patients with severe carotid artery stenosis. J Am Coll Cardiol 2006;47(12):2384-9
12. Gray WA, Hopkins LN, Yadav S et al. Protected carotid stenting in high-surgical-risk patients: the ARCHeR results. J Vasc Surg 2006;44(2):258-68
13. 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 2006;69(3):341-8
14. CaRESS Steering Committee. Carotid Revascularization Using Endarterectomy or Stenting Systems (CaRESS) phase I clinical trial: 1-year results. J Vasc Surg 2005;42(2):213-9
15. 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):316-23
16. 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):812-21
17. 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):427-34
18. Adams RJ, Albers G, Alberts MJ, Benavente O, Furie K, Goldstein LB, Gorelick P, Halperin J, Harbaugh R, Johnston SC, Katzan I, Kelly-Hayes M, Kenton EJ, Marks M, Sacco RL, Schwamm LH, American Heart Association, American Stroke Association. Guidelines for prevention of stroke in patients with ischemic stroke or transient ischemic attack. Update to the AHA/ASA recommendations for the prevention of stroke in patients with stroke and transient ischemic attack. Stroke 2008 May;39(5):1647-52

Cross References

Percutaneous Venous Transluminal Angioplasty and Stenting, Regence Medical Policy Manual, Surgery, Policy No. 109

Percutaneous Transluminal Angioplasty of Intracranial Atherosclerotic Stenoses With or Without Stenting, Regence Medical Policy Manual, Surgery, No. 141

Surgery Section Table of Contents