The National Institute for Health and Clinical Excellence is examining high-intensity focused ultrasound as an associated procedure with other cardiac surgery 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 high-intensity focused ultrasound as an associated procedure with other cardiac surgery.
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• The Advisory Committee will then prepare draft guidance which will be the basis for the Institute's guidance on the use of the procedure in the NHS in England, Wales and Scotland.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: 31 January 2006
Target date for publication of guidance: April 2006

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 high-intensity focused ultrasound for atrial fibrillation as an associated procedure with other cardiac surgery is insufficient for this procedure to be used without special arrangements for consent and for audit or research.

Clinicians wishing to undertake high-intensity focused ultrasound for atrial fibrillation as an associated procedure with other cardiac surgery should take the following actions.

• Inform the clinical governance leads in their Trusts.
  
• Ensure that patients understand the uncertainty about the procedure's safety and efficacy and provide them with clear written information. In addition, use of the Institute's Information for the public is recommended (available from www.nice.org.uk/IPGXXXpublicinfo).
  
• Audit and review clinical outcomes of all patients having high-intensity focused ultrasound for atrial fibrillation as an associated procedure with other cardiac surgery.
  

Publication of safety and efficacy outcomes will be useful. The Institute may review the procedure upon publication of further evidence.

Conservative treatments include medication, electrical cardioversion to control the heart rhythm, and anticoagulants to prevent the formation of blood clots. Surgery for atrial fibrillation is usually performed at the same time as open heart surgery for another indication, such as mitral valve disease. The conventional surgical approach, known as the Cox maze procedure, involves making multiple, strategically placed incisions in both atria to isolate and stop the abnormal electrical impulses. Alternative methods of creating lesions in the atria by ablation have been developed, using energy sources such as radiofrequency, microwave, cryotherapy and ultrasound.

High-intensity focused ultrasound (HIFU) for atrial fibrillation is typically carried out in patients undergoing concomitant open heart surgery (often mitral valve replacement or repair). An ultrasound device is placed outside the left atrium of the beating heart, and delivers focused ultrasound energy across the wall of the heart. Absorption of the ultrasound energy creates a rise in temperature, which destroys the cardiac tissue within the focal area and disrupts the transmission of the abnormal electrical impulses.

Efficacy is based on the results of one case series in 103 patients, in which 85% (80/94) of patients were free from atrial fibrillation at 6 months follow-up. This was achieved in 80% of patients who had permanent atrial fibrillation and in 100% of patients who had intermittent (paroxysmal and persistent) atrial fibrillation. For more details, refer to the sources of evidence (see Appendix).

The Specialist Advisors stated that the key efficacy outcomes should include normalisation of sinus rhythm, persistence or recurrence of atrial fibrillation, ratio of procedure time to bypass time, atrial transport function, and quality of life.

Evidence of safety was based on the same case series in 103 patients. Early (up to 30 days after the operation) and late (more than 30 days after the operation) complications were reported in the case series, but none were considered to be related to the device or the procedure. Early complications included bleeding that required surgical exploration in 6% (6/103) of patients; complete heart block in 4% (4/103) and sinus dysfunction in 1% (1/103), which both required implantation of permanent pacemakers; stroke in 3% (3/103); and serious deep wound infection in 1% (1/103). Late complications included sinus node dysfunction requiring implantation of a permanent pacemaker in 3% (3/103) of patients, ventilation pneumopathy in 1% (1/103), delayed cardiac tamponade in 1% (1/103), and transient ischaemic attack in 1% (1/103).

The Institute is also developing Interventional Procedures guidance on percutaneous radiofrequency catheter ablation for atrial fibrillation (www.nice.org.uk/ip_300) and a clinical guideline on atrial fibrillation (www.nice.org.uk/guidelines.inprogress.atrialfibrillation).

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

• Interventional procedure overview of high-intensity focused ultrasound for atrial fibrillation as an associated procedure with other cardiac surgery, October 2005
  

Available from: www.nice.org.uk/ip312overview