Interventional procedure consultation document

Carotid artery stent placement for symptomatic extracranial carotid stenosis

Treating symptomatic narrowed or blocked carotid arteries using stents

The main arteries in the neck (the carotid arteries) can become narrowed or blocked by fatty deposits. Fragments of these fatty deposits can become detached from the walls of the carotid artery and become lodged in thinner arteries that supply blood to parts of the brain, causing a transient ischaemic attack (TIA, sometimes called a ‘mini stroke’) or a stroke.

In this procedure a metal mesh called a stent is used to widen the narrowed carotid artery. This procedure does not involve making a cut in the neck. Instead a fine wire is inserted into an artery in the leg and passed up into the carotid artery, and the stent is then moved into place along the wire. Some stenting also includes protective devices, to help to prevent any fragments loosened by the stent insertion from reaching smaller arteries and causing a stroke.

The National Institute for Health and Clinical Excellence (NICE) is examining carotid artery stent placement for symptomatic extracranial carotid stenosis and will publish guidance on its safety and efficacy to the NHS in England, Wales, Scotland and Northern Ireland. NICE’s Interventional Procedures Advisory Committee has considered the available evidence and the views of Specialist Advisers, who are consultants with knowledge of the procedure. The Advisory Committee has made provisional recommendations about carotid artery stent placement for symptomatic extracranial carotid stenosis.

This document summarises the procedure and sets out the provisional recommendations made by the Advisory Committee. It has been prepared for public consultation. The Advisory Committee particularly welcomes:

• comments on the provisional recommendations
• the identification of factual inaccuracies
• additional relevant evidence, with bibliographic references where possible.

Note that this document is not NICE’s formal guidance on this procedure. The recommendations are provisional and may change after consultation.

The process that NICE will follow after the consultation period ends is as follows.

• The Advisory Committee will meet again to consider the original evidence and its provisional recommendations in the light of the comments received during consultation.
• The Advisory Committee will then prepare draft guidance which will be the basis for NICE’s guidance on the use of the procedure in the NHS in England, Wales, Scotland and Northern Ireland.

For further details, see the Interventional Procedures Programme manual, which is available from the NICE website (www.nice.org.uk/ipprogrammemanual).

NICE is committed to promoting through its guidance race and disability equality and equality between men and women, and to eliminating all forms of discrimination. One of the ways we do this is by trying to involve as wide a range of people and interest groups as possible in the development of our guidance on interventional procedures. In particular, we aim to encourage people and organisations from groups in the population who might not normally comment on our guidance to do so. We also ask consultees to highlight any ways in which draft guidance fails to promote equality or tackle discrimination and give suggestions for how it might be improved. NICE reserves the right to summarise and edit comments received during consultations, or not to publish them at all, where in the reasonable opinion of NICE, the comments are voluminous, publication would be unlawful or publication would otherwise be inappropriate.

Closing date for comments: 21 January 2011

Target date for publication of guidance: April 2011

NICE is also consulting on the following procedure: Carotid artery stent placement for asymptomatic extracranial carotid stenosis

1   Provisional recommendations

1.1  Current evidence on the safety and efficacy of carotid artery stent placement for symptomatic extracranial carotid stenosis is adequate to support the use of this procedure provided that normal arrangements are in place for clinical governance and audit or research.

1.2  During the consent process, clinicians should ensure that patients understand the risk of stroke and other complications associated with this procedure. Clinicians should also ensure that patients understand their reasons for advising carotid artery stent placement rather than endarterectomy in their particular case.

1.3  Patient selection should be carried out by a multidisciplinary team, which should include an interventional radiologist or a neuroradiologist, a vascular surgeon and a physician with a specialist interest in stroke.

1.4  This procedure should only be carried out by clinicians with specific training and expertise in the technique who regularly perform complex endovascular interventions. The Royal College of Radiologists has produced training standards.

2   The procedure

2.1  Indications and current treatments

2.1.1  Stenosis of the extracranial carotid arteries due to atherosclerosis can cause symptoms in the form of transient ischaemic attacks (TIAs), visual loss or stroke. Patients with symptomatic carotid stenosis are at increased risk of stroke.

2.1.2  Good medical control of cardiovascular risk factors is essential.  Prompt treatment of the carotid stenosis is carried out in selected patients: carotid endarterectomy is the standard treatment.

2.2   Outline of the procedure

2.2.1  Carotid stenting is carried out with the patient under local anaesthesia via a percutaneous transfemoral approach. A guidewire is passed into the carotid artery, often followed by a small balloon catheter to pre-dilate the narrowed artery. A cerebral protection device is usually used to prevent any debris dislodged during stenting from passing into the cerebral circulation. A metal mesh (stent) is inserted to treat the stenosis, and with the aim of preventing both further embolism and restenosis.

2.2.2  Carotid stenting is a less invasive percutaneous procedure than endarterectomy but there has been concern about the risk of stroke caused by embolic material becoming dislodged during the procedure.

Sections 2.3 and 2.4 describe efficacy and safety outcomes from the published literature that the Committee considered as part of the evidence about this procedure. For more detailed information on the evidence, see the overview, available at www.nice.org.uk/guidance/IP/8/overview

2.3   Efficacy

The efficacy outcomes described below include stroke or death that occurred more than 30 days after the procedure (unless specified otherwise). These contrast with stroke or death occurring on or before 30 days, which were considered to be safety outcomes.

2.3.1  A meta-analysis of 3433 symptomatic patients reported no significant difference in mortality rate between patients treated by stenting (2% [32/1725]) and endarterectomy (1% [22/1708]); relative risk (RR) 1.44, 95% confidence interval (CI) 0.84 to 2.47 (p = 0.18) at 120-day follow-up. A randomised controlled trial (RCT) of 2522 patients reported no significant difference in mortality between patients treated by stenting (11%) and those treated by endarterectomy (13%); hazard ratio (HR) 1.12, 95% CI 0.83 to 1.51 (p = 0.45) at 2.5-year follow‑up (absolute figures not stated). The same study reported that among symptomatic patients there was no significant difference in the rate of stroke or death following stenting (8%) and endarterectomy (6%); HR 1.37, 95% CI 0.90 to 2.00 (p = 0.14) at 2.5-year follow-up (absolute figures not stated).  An RCT of 1214 symptomatic patients treated by stenting or endarterectomy reported that both groups had a 2% rate of ipsilateral stroke at 31-day to 2-year follow-up; HR 1.17, 95% CI 0.51 to 2.70 (p = not significant).

2.3.2  A UK national register of 953 symptomatic patients treated by stenting reported a 5-year rate of mortality, disabling stroke or mortality, and stroke of 19%, 21% and 7% respectively (data on 173, 167 and 156 patients respectively were available for analysis).

2.3.3  The Specialist Advisers listed a key efficacy outcome as long-term stroke prevention.

2.4   Safety

2.4.1  The meta-analysis of 3433 symptomatic patients reported no significant difference in mortality at 30-day follow-up between patients treated by stenting (1% [19/1679]) and those treated by endarterectomy (less than 1% [10/1645]); RR 1.86, 95% CI 0.87 to 4.00 (p = 0.10). In the UK national register of 953 symptomatic patients treated by stenting, mortality in the 30 days following the procedure was 2%.

2.4.2  The meta-analysis of 3433 symptomatic patients reported that the rate of stroke at 30-day follow-up was significantly higher following stenting (7% [125/1679]) than following endarterectomy (4% [70/1645]); RR 1.74, 95% CI 1.31 to 2.32 (p = 0.0001): this excess was attributable largely to patients older than 70 years. The UK national register of 953 symptomatic patients treated by stenting reported disabling stroke in 1% (8/829) of patients, non-disabling stroke in 3% (26/829) and TIA in 4% (32/829) at 30-day follow-up.

2.4.3  An RCT of 520 symptomatic patients reported that there was no significant difference in the rate of myocardial infarction at 30-day follow-up between patients treated by stent placement (less than 1% [1/261]) and those treated by endarterectomy (1% [2/259]); RR 0.5 (95% CI 0.04 to 5.4) (p = 0.62).

2.4.4  The Specialist Advisers listed known adverse events as access site complications, peripheral emboli, carotid artery rupture, femoral catheter access site damage and reactions to contrast material. They considered radiation-induced neoplasia to be a theoretical adverse event.

3   Further information

3.1  This guidance is a review of ‘Carotid artery stent placement for carotid stenosis’ NICE interventional procedures guidance 191 (2006).

3.2  For related NICE guidance see www.nice.org.uk

Bruce Campbell

Chairman, Interventional Procedures Advisory Committee

December 2010

_{Personal data will not be posted on the NICE website. In accordance with the Data Protection Act names will be anonymised, other than in circumstances where explicit permission has been given.}

 _{It is the responsibility of consultees to accurately cite academic work in order that they can be validated.}