Interventional procedure consultation document

Percutaneous pulmonary valve implantation for right ventricular outflow tract dysfunction

Treating right ventricular outflow tract dysfunction with an artificial valve implanted using a catheter

Right ventricular outflow tract (RVOT) dysfunction is the term given to abnormalities of the pulmonary valve (one of the valves in the heart) and the right ventricular outflow tract. It causes blood to flow abnormally between the heart and the lungs and is often congenital (present from birth). If left untreated, right ventricular outflow tract dysfunction can reduce life expectancy. Faulty heart valves are usually replaced during open heart surgery, but with time the replacements can degenerate and fail. Using a catheter to implant an artificial valve is an alternative to further open heart surgery – it is a less invasive procedure, because it does not involve opening up the chest. In this procedure, the replacement valve is implanted through a catheter (a narrow tube), which is inserted through the skin and into a large vein in the groin and then into the pulmonary artery. The replacement valve is implanted within a wire mesh tube called a stent.

The National Institute for Health and Clinical Excellence (NICE) is examining percutaneous pulmonary valve implantation for right ventricular outflow tract dysfunction 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 percutaneous pulmonary valve implantation for right ventricular outflow tract dysfunction.

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).

Through its guidance NICE is committed to promoting race and disability equality, 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 interventional procedures guidance. In particular, we aim to encourage people and organisations from groups who might not normally comment on our guidance to do so.

In order to help us promote equality through our guidance, we should be grateful if you would consider the following question:

Are there any issues that require special attention in light of NICE’s duties to have due regard to the need to eliminate unlawful discrimination and promote equality and foster good relations between people with a characteristic protected by the equalities legislation and others?

Please note that 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: 18 September 2012

Target date for publication of guidance: February 2013

1   Provisional recommendations

1.1   The evidence on percutaneous pulmonary valve implantation (PPVI) for right ventricular outflow tract (RVOT) dysfunction shows good short-term efficacy. There is little evidence on long-term efficacy but it is well documented that these valves may need to be replaced in the longer term. With regard to safety there are well-recognised complications, particularly stent fractures in the longer term, which may or may not have clinical effects. Patients having this procedure are often very unwell and might otherwise need open heart surgery (frequently reoperative) with its associated risks. Therefore, this procedure may be used with normal arrangements for clinical governance, consent and audit.

1.2   The procedure should be performed only in specialist units and with arrangements in place for cardiac surgical support in the event of complications.

1.3   Patient selection should be carried out by a multidisciplinary team including a paediatric cardiologist, an interventional cardiologist, a radiologist and a cardiothoracic surgeon with a special interest in congenital heart disease.

1.4   This is a technically challenging procedure that should be performed only by clinicians with training and experience in interventional paediatric cardiology.

1.5   Clinicians should enter details about all patients undergoing percutaneous pulmonary valve implantation for RVOT dysfunction onto the UK Central Cardiac Audit Database (UK CCAD). In addition, further information on long-term outcomes would be useful.

2   The procedure

2.1   Indications and current treatments

2.1.1   RVOT dysfunction often occurs as part of complex congenital heart conditions, such as tetralogy of Fallot. It may take the form of pulmonary valve stenosis, pulmonary valve incompetence (regurgitation) or both. Depending on the severity of the condition and associated structural abnormalities of the heart, RVOT dysfunction causes varying degrees of right ventricular hypertrophy and right heart failure. If left untreated, it can be a life-limiting condition.

2.1.2.   Reconstruction of the RVOT, done as part of surgery for congenital heart disease, is likely to require revision in the long term as a result of growth of the child and/or degeneration of any replacement valve. Normally, revision requires repeat surgery with replacement of conduit and/or pulmonary valve which is a major cardiac surgery requiring pulmonary bypass.

2.1.3   Percutaneous pulmonary valve implantation is an interim alternative to surgery for some patients. This approach is usually done in patients who have had a previous RVOT conduit or valve replacement. Many of the patients with this condition are adolescents or young adults, who may need multiple valve procedures during their lifetime.

2.2    Outline of the procedure

2.2.1   The aim of percutaneous pulmonary valve implantation is to provide a less invasive intervention than open heart surgery to improve pulmonary valve function and circulation to the lungs while reducing pressure in the right ventricle. The treatment strategy may be to delay the need for further surgical revision.

2.2.2   The procedure is done with the patient under general anaesthesia. Percutaneous pulmonary valve implantation is done by inserting a catheter system through a large vein (typically the femoral vein). Angiography is used to identify the anatomy of the RVOT and coronary arteries. A stent-mounted biological valve is introduced over a guidewire and is positioned in the RVOT, under fluoroscopic guidance. A balloon is then inflated to deploy the valve. Sometimes a plain stent is inserted first to dilate the RVOT and provide a regular surface onto which the stent-mounted valve can be fixed. This may decrease the risk of stent fracture, and thereby increase the longevity of the valve. The procedure can be repeated if necessary.

2.2.3   Valves used in the procedure may be derived from animal sources.

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/392/overview

2.3   Efficacy

2.3.1   A non-randomised comparative study of 108 patients, 54 treated by PPVI alone and 54 treated by pre-stenting followed by PPVI, reported a significant decrease in mean right ventricular systolic pressure from 57 to 42 mmHg for patients treated by PPVI only (n=52) (p<0.0001) and from 65 to 41 mmHg for pre-stenting followed by PPVI (n=54) (p<0.0001) at 1-year follow-up (p=0.02 between groups).

2.3.2   In a case series of 155 patients, there was a significant reduction in mean right ventricular systolic pressure from 63 to 45 mmHg and RVOT gradient from 37 to 17 mmHg ‘after the procedure’ (no further details) (p<0.001).

2.3.3   In a case series of 102 patients, pulmonary regurgitation (assessed by magnetic resonance imaging [MRI]) significantly decreased from a median of 16% to 1% ‘after the procedure’ (p<0.001).

2.3.4   In a case series of 36 patients, the percentage of patients with a New York Heart Association (NYHA) functional status of I (no limitation of physical activity) increased from 15% (5/33) at baseline to 82% (27/33) at 6-month follow-up and patients with NYHA functional status IV (inability to carry out any physical activity without physical discomfort) decreased from 6% at baseline to 0% at 6-month follow-up (absolute figures not reported).

2.3.5   In a case series of 28 patients, cardiopulmonary exercise testing showed that the oxygen uptake (peak VO₂) improved from 24 ml/kg/minute before treatment with PPVI (n=24) to 28 ml/kg/minute at median 6-month follow-up (n=19, p<0.0001).

2.3.6   In the case series of 155 patients, 93%, 86%, 84% and 70% of patients did not need to have further surgery and 95%, 87%, 73%, and 73% did not need any further transcatheter reintervention at 10, 30, 50, and 70 months respectively (absolute figures not reported).

2.3.7   The Specialist Advisers listed the following additional key efficacy outcomes: reduced pulmonary incompetence, avoiding a sternotomy incision and cardiopulmonary bypass, and shorter recovery time, with less risk of post-operative infection and bleeding.

2.4   Safety

2.4.1   Death was reported in 4% (2/54) of patients treated by PPVI and in 4% (2/54) of patients treated by pre-stenting followed by PPVI in the non-randomised comparative study of 108 patients (1 death was within 30 days). In patients treated by PPVI alone, 1 patient died after a chest infection 2 months after the procedure and 1 patient with pulmonary hypertension died after ‘presumed’ arrhythmia 24 months after the procedure. In patients treated by pre-stenting followed by PPVI, 1 patient died because of pulmonary oedema 1 day after the procedure and 1 patient died because of ‘presumed’ arrhythmia 8 months after the procedure. Death (within 30 days) was reported in less than 1% of patients (1/136) in a case series of 136 patients. The patient had coronary artery dissection and intracranial haemorrhage.

2.4.2   Bacterial endocarditis was reported in 1 patient in the case series of 102 patients. The valve was surgically removed and replaced by a homograft valve 6 months after the procedure. One patient developed endocarditis in a case series of 20 patients and the valve was explanted at 6 months.

2.4.3   Stent fractures were reported in 29% (15/52) of patients treated by PPVI alone and in 17% (9/52) of patients treated by pre-stenting followed by PPVI at 1-year follow-up in the non-randomised comparative study of 108 patients. Stent fractures occurred in 21% (absolute figures not reported) of patients in the case series of 155 patients. Nine patients had required reintervention (further details not reported) by median 28-month follow-up.

2.4.4   Valve migration was reported in 9% (3/34) of patients in the case series of 36 patients. Two patients were treated by surgical pulmonary valve replacement. Valve migration during the procedure was reported in 1 patient who was treated by a further implantation during the same procedure (no further details reported).

2.4.5   Conduit rupture/tear (no further details) was reported in 2 patients in the case series of 136 patients at 6-month follow-up. One patient was treated by replacement conduit and the other by covered stent placement.

2.4.6   The valve had to be removed in 4% (2/54) of patients treated by PPVI alone in the non-randomised comparative study of 108 patients. This was because of RVOT pseudoaneurysm in 1 patient (at 16 months) and endocarditis in 1 patient (at 19 months).

2.4.7   Complete atrioventricular block occurred in 1 patient during the procedure in the case series of 102 patients; the patient’s heart rate reverted to sinus rhythm after 21 days.

2.4.8   The Specialist Advisers listed the following additional theoretical adverse events: pulmonary artery dissection and rupture, perforation of the heart, embolisation of the device, bleeding from cannulation site, and vascular perforation.

2.5   Other comments

2.5.1   The Committee noted that the ages of the patients in the published studies varied. The number of previous procedures patients had undergone was also often unclear: this may influence the outcomes of PPVI.

2.5.2   The Committee noted apparent duplication of patients in published studies.

2.5.3   The Committee recognised that stent fracture is a risk in the longer term and this underpinned the recommendation for continued data collection about long-term outcomes. It noted that devices continue to evolve and that developments in their design may influence long-term performance.

3    Further information

3.1    This guidance is a review of ‘Percutaneous pulmonary valve implantation for right ventricular outflow tract dysfunction’ NICE interventional procedures guidance 237 (2007).

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

Bruce Campbell

Chairman, Interventional Procedures Advisory Committee

August 2012

_{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.}