Interventional Procedure Consultation Document: Endovascular stent-graft placement in thoracic aortic aneurysms and dissections

The National Institute for Clinical Excellence is examining endovascular stent-graft placement in thoracic aortic aneurysms and dissections and will publish guidance on its safety and efficacy to the NHS in England, Wales and Scotland. The Institute's Interventional Procedures Advisory Committee has considered the available evidence and the views of Specialist Advisors, who are consultants with knowledge of the procedure. The Advisory Committee has made provisional recommendations about endovascular stent-graft placement in thoracic aortic aneurysms and dissections.

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 preliminary recommendations the identification of factual inaccuracies additional relevant evidence. Note that this document is not the Institute's formal guidance on this procedure. The recommendations are provisional and may change after consultation.

The process that the Institute 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 The Advisory Committee will then prepare draft guidance which will be the basis for the Institute's guidance on the use of the procedure in the NHS in England, Wales and Scotland. For further details, see the Interventional Procedures Programme manual, which is available from the Institute's website (www.nice.org.uk/ipprogrammemanual).

Closing date for comments: 22 March 2005

Target date for publication of guidance: June 2005

Note that this document is not the Institute's guidance on this procedure. The recommendations are provisional and may change after consultation.

1 Provisional recommendations

1.1 Current evidence on the safety and efficacy of endovascular stent-graft placement in thoracic aortic aneurysms and dissections indicates that it is a suitable alternative to surgery in properly selected patients, with the normal arrangements for consent, audit and clinical governance.

1.2 Clinicians should enter all patients having stent-graft placement in thoracic aortic aneurysms and dissections into the thoracic stent-graft registry supported by the Vascular Society of Great Britain and Ireland and the British Society of Interventional Radiology (www.bsir.org).

1.3 The procedure should be performed by a multidisciplinary team with access to facilities for cardiothoracic surgery and cardiopulmonary bypass.

2 The procedure

2.1 Indications

2.1.1 A thoracic aortic aneurysm is a condition in which weakening of the wall of the aorta leads to a localised dilatation of the vessel. In an aortic dissection, there is leakage of blood between the layers of the vessel wall. Aneurysms and dissections may rupture, causing massive internal bleeding. Rupture of the thoracic aorta has high mortality, even with treatment.

2.1.2 Conventional surgery for aneurysms of the thoracic aorta involves replacing the affected part of the aorta with a synthetic graft. Aortic dissections may be managed medically or surgically depending on the site involved and whether there are complicating features.

2.2 Outline of the procedure

2.2.1 Stent-graft placement involves placing a metallic stent covered with graft material inside the aorta. This is usually achieved by catheterising the femoral arteries. The stent-graft is positioned and deployed using X-ray guidance.

2.3 Efficacy

2.3.1 A systematic review of the published evidence on this procedure was commissioned by the Institute and completed in August 2004. A total of 29 studies were identified for inclusion: 27 case series and 2 comparative observational studies.

2.3.2 In one comparative study, the technical success rate was 100% (67/67 patients). The overall technical success rate was 93% over 18 studies (16 case series and 2 comparative studies).

2.3.3 The rate of conversion to open repair varied from 0% (0/26 patients) to 7% (1/14 patients). The proportion of patients who experienced an increase in aneurysm size varied from 0% (0/18) to 7% (2/29) of patients. In the study with the largest number of patients, the aneurysm increased in size (by ≥5 mm) in 5% (4/84) of patients. The proportion of patients who experienced a decrease in aneurysm size varied from 100% of patients (18/18) to 17% (5/29) of patients. For more details, refer to the sources of evidence (see Appendix).

2.4 Safety

2.4.1 The 30-day mortality rate varied from 0% (in several studies with a combined population of 94 patients) to 14% (2/14) of patients. The overall mortality ranged from 3% (1/37 patients) to 24% (11/46 patients) across 17 studies over a mean follow-up of 14 months.

2.4.2 The most commonly reported complication following stent-graft placement was endoleak (incomplete sealing of the aneurysm). Nineteen studies reported at least one patient with an endoleak, with a mean incidence of 13% over 12 months (the total number of patients in these studies was 752; follow-up ranged from 3 to 25 months). Five studies with a total of 83 patients reported that there were no cases of endoleak during a mean follow-up period of 12 months.

2.4.3 Injuries to the access artery were reported in nine case series, and included iliac artery dissection in 4% (1/26 patients), perforation of the iliac artery in 4% (1/27 patients) and dissection/rupture of the femoral artery in 6% (2/34 patients). One case series reported stent fracture in 13% (11/84) of patients, and six cases of stent migration were reported over 15 case series.

2.4.4 Other reported complications included wound complications in 25% (8/32) of patients, stroke in 19% (8/43), renal failure requiring dialysis in 11% (2/19), and paraplegia in 7% (3/43) of patients. For more details, refer to the sources of evidence (see Appendix).

2.5 Other comments

2.5.1 The Committee noted that there was a lack of long-term data on the durability of stent-grafts.

Bruce Campbell
Chairman, Interventional Procedures Advisory Committee
March 2005

Appendix: Sources of evidence

The following document, which summarises the evidence, was considered by the Interventional Procedures Advisory Committee when making its provisional recommendations.

A systematic review of the recent evidence for the efficacy and safety relating to the use of endovascular stent-graft (ESG) placement in the treatment of thoracic aortic aneurysms, August 2004.

Available from: www.nice.org.uk/ip001review