Interventional Procedure Consultation Document - Stent-graft placement in abdominal aortic aneurysm

NATIONAL INSTITUTE FOR HEALTH AND CLINICAL EXCELLENCE

Interventional Procedure Consultation Document

Stent-graft placement in abdominal aortic aneurysm

The National Institute for Health and Clinical Excellence is examining stent-graft placement in abdominal aortic aneurysm 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 stent-graft placement in abdominal aortic aneurysm.
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  • The Advisory Committee will then prepare draft guidance which will be the basis for the Institute's guidance on the use of the procedure in the NHS in England, Wales and Scotland.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: 20 December 2005
Target date for publication of guidance: March 2006


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 efficacy and short-term safety of stent-graft placement in abdominal aortic aneurysms appears adequate to support the use of this procedure provided that the normal arrangements are in place for consent, audit and clinical governance.

1.2 Clinicians should ensure that patients fully understand the long-term uncertainties and the potential complications associated with this procedure. In particular, patients should understand: the risks of endovascular leaks; the possibility of secondary intervention; and the need for lifelong follow-up. Patients should be provided with clear written information. In addition, use of the Institute's Information for the public is recommended (available from www.nice.org.uk/IPGXXXpublicinfo [details to be available at publication]).
1.3 Patient selection is important, particularly for patients who would normally be considered unfit for surgery.
1.4

Publication of long-term data would be useful. It is recommended that all patients who have the procedure are entered onto one of the existing registries.



2 The procedure
2.1 Indications
2.1.1 Stent-graft placement is used to treat aneurysms of the abdominal aorta. Weakening of the wall of the aorta can lead to widening of the vessel, or aneurysm. Aneurysms may rupture causing internal bleeding, which if untreated, is usually fatal.
2.1.2

The standard treatment for abdominal aortic aneurysm is open surgical repair. The aneurysm is opened and a graft is then sewn in above and below the weakened area to allow normal blood flow.

2.2 Outline of the procedure
2.2.1

Stent-graft placement is a minimally invasive alternative to open repair. The graft is mounted on a stent, which is inserted into the aorta via a catheter in the femoral artery. The stent-graft is opened under X-ray guidance and positioned across the aneurysm.

2.3 Efficacy
2.3.1

A systematic review of the published evidence on this procedure was commissioned by the Institute and completed in June 2005. A total of 77 studies were identified for inclusion. This comprised: four randomised controlled trials (RCTs) including the EndoVascular Aneurysm Repair (EVAR) 1 trial comparing stent-graft placement and open surgical repair, and the EVAR 2 trial comparing stent-graft placement in patients considered unfit for surgical repair with standard medical care; 17 non-randomised controlled trials; 22 comparative observational studies; 28 case series and six registry publications.

2.3.2 Data from the EVAR 1 trial at a median follow-up of 35 months reported an aneurysm rupture rate of 0.9% (5/543) following endovascular repair, compared with 0.2% (1/539) following open repair. Early aneurysm rupture rates of 0.2% (1/534) and 0.3% (13/3859) were reported in one non-randomised controlled trial and seven case series, respectively.
2.3.3 In the EVAR 1 trial, 16% (85/529) of patients required secondary intervention following stent-graft placement, compared with 7% (36/519) of patients following open repair. From the non-randomised controlled studies, secondary intervention rates were 20% following stent-graft placement and 6% following open repair.
2.3.4

The EVAR 2 trial reported that at 4 years, 26% of the group who had had stent-graft placement had required at least one intervention compared with 4% of the group who had received standard medical care. However, if crossovers are considered a secondary intervention, then the secondary intervention rate in the group who received standard medical care became comparable (approximately 30%). For more details, refer to the sources of evidence (see Appendix).

 

2.4 Safety
2.4.1

From a meta-analysis of data from three RCTs, stent-graft placement was associated with a 30-day mortality rate of 2% (12/759 patients) compared with 5% (33/709 patients) for open repair. In patients considered unfit for surgery, the 30-day mortality following stent-graft placement was 9% (13/150 patients).

2.4.2 During more prolonged follow-up to 4 years, the EVAR 1 trial reported no significant difference between the all-cause mortality rate in the group who had had stent-graft placement and the group who had had open repair.
2.4.3 The most common adverse event following stent-graft placement was endoleak originating from retrograde collateral flow into the aneurysm sac via aortic branches (type II). This occurred in 19% of patients at 1 year. However, this now rarely requires secondary intervention. The incidence of pulmonary complications and haemorrhagic events was significantly lower in the stent-graft placement group than in the open repair group.
2.4.4 Technical complications included stent migration, which happened in 1% of patients within the first year, and stent wire fracture, which happened in 3% of patients within the first year. For more details, refer to the sources of evidence (see Appendix).
2.5 Other comments
2.5.1 It was noted that these procedures are rapidly evolving.
2.5.2 The follow-up phase of the EVAR trials continues, and long-term results are expected to be published in 2010.

Christopher Bunch
Vice-Chairman, Interventional Procedures Advisory Committee
December 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 update of the recent evidence for the safety and efficacy of elective endovascular repair in the management of infrarenal abdominal aortic aneurysms, June 2005

Available from: www.nice.org.uk/ip026review

This page was last updated: 07 February 2011