The National Institute for Clinical Excellence is examining balloon angioplasty with or without stenting for pulmonary artery or right ventricular outflow tract obstruction 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 balloon angioplasty with or without stenting for pulmonary artery or right ventricular outflow tract obstruction.

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 recommendation
• 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• The Advisory Committee will then prepare draft guidance, which will be the basis for the Institute's guidance on the use of the procedure in the NHS in England, Wales and Scotland.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 Interim Guide to the Interventional Procedures Programme, which is available from the Institute's website (www.nice.org.uk/ip).

Closing date for comments: 23 March 2004

Target date for publication of guidance: June 2004

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

Current evidence on the safety and efficacy of balloon angioplasty with or without stenting for pulmonary artery or right ventricular outflow tract obstruction appears adequate to support the use of this procedure, provided that the normal arrangements are in place for consent, audit and clinical governance.

The procedure should only be performed by multidisciplinary teams in specialist centres.

Patients should be entered on to the UK Central Cardiac Audit Database (UKCCAD).

The right ventricular outflow tract includes the pulmonary valve and the tissue above and below it. Narrowing (stenosis) of this region may involve the area below the valve (subvalvar), the valve itself (valvar), or the area above the valve (supravalvar). Balloon angioplasty of valvar right ventricular outflow tract narrowing (pulmonary valve stenosis) is covered in a separate overview.

Congenital subvalvar and supravalvar right ventricular outflow tract stenosis usually occurs with other cardiac defects, such as ventricular septal defect or tetralogy of Fallot. Postoperative right ventricular outflow tract obstruction may occur after surgery done to create a conduit between the right ventricle and pulmonary artery in children with congenital anomalies. Narrowing may also occur beyond the right ventricular outflow tract, in one of the pulmonary arteries, or in their branches. Narrowing may also be congenital or occur following surgery for congenital defects.

Standard treatment of right ventricular outflow tract or pulmonary artery obstruction involves open chest surgery.

Balloon dilatation is a minimally invasive procedure that involves inserting a catheter into a large blood vessel, usually in the groin, and passing it up to the area of narrowing under X-ray control. A balloon is then inflated within the narrowing to dilate the obstruction. Stenting involves the insertion of a small tube into the narrow region following balloon angioplasty, to maintain patency.

No comparative studies were identified. Reports of technical success rates (defined as > 50% increase in pre-dilation diameter, > 50% decrease in pressure gradient or > 20% decrease in right ventricular to aortic peak pressure ratio) were 97% (77/79) for stent insertion and 60% (97/162) for balloon angioplasty in one study, and 53% (39/74) for balloon angioplasty in another study. For more details, refer to the sources of evidence (see Appendix).

The Specialist Advisors had no concerns regarding the efficacy of this procedure.

One of the studies reported a 3% (5/162) complication rate for patients undergoing balloon angioplasty. This included one femoral vein thrombosis, three pulmonary artery major dissections, and one transient pulmonary oedema. One study of stent implantation reported a complication rate of 1% (1/79 - a pleural perforation with haemopericardium). For more details, refer to the sources of evidence (see Appendix).

The Specialist Advisors listed potential complications as arrhythmia, haemorrhage, stent migration, embolisation, balloon rupture, blood vessel damage, and tricuspid valve damage.

data were available on the use of the technique for right ventricular outflow tract obstruction than for pulmonary artery or branch pulmonary artery obstruction.

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

• Interventional procedure overview of balloon angioplasty with or without stenting for pulmonary artery or right ventricular outflow tract obstruction, April 2003

Available from: www.nice.org.uk/ip087overview