NICE guidance - percutaneous pulmonary valve implantation for right ventricular outflow tract (RVOT) dysfunction

• Right Ventricular Outflow Tract (RVOT) dysfunction often occurs as part of complex congenital heart conditions, such as tetralogy of Fallot
  • 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
    
    
• reconstruction of the RVOT, done as part of surgery for congenital heart disease, is likely to need revision in the long term as a result of growth of the child and/or degeneration of any replacement valve. Normally, revision involves repeat surgery with replacement of the RVOT and/or any previously placed conduit
  
  
• PPVI (percutaneous pulmonary valve implantation) is an interim alternative to surgery for some patients. This approach is usually used for 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 replacement procedures during their lifetime
  • procedure:
    • aim of PPVI 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
    • procedure is done with the patient under general anaesthesia. PPVI 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 its relation to coronary arteries
      • a stent-mounted 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 dilated 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
    • most valves used in this procedure are derived from animal sources
      
      
  • NICE suggest that (1):
    • 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 (typically reoperative) with its associated risks. Therefore, this procedure may be used with normal arrangements for clinical governance, consent and audit

Reference:

• 1) NICE (January 2013). Percutaneous pulmonary valve implantation for right ventricular outflow tract dysfunction