Off-pump minimal access mitral valve repair by artificial chordae insertion to treat mitral regurgitation

The mitral valve allows blood to flow from the left atrium to the left ventricle. Mitral regurgitation happens when the valve does not close properly, allowing blood to flow back into the atrium from the ventricle during systole (when the heart contracts). The heart must work harder, resulting in an enlarged left ventricle. If untreated, this can lead to problems including heart failure. Mitral regurgitation can be degenerative (primary or structural) or functional (secondary). Degenerative mitral regurgitation is caused by 'wear and tear' to the chordae and leaflets in the valve. In functional mitral regurgitation the chordae and leaflets are structurally normal but there is geometrical distortion of the subvalvular apparatus. This is caused by idiopathic cardiomyopathy or weakening of the cardiac walls because of coronary artery disease (ischaemic mitral regurgitation).

Degenerative mitral regurgitation is typically managed with open-heart surgery to repair or replace the mitral valve. This requires a sternotomy to access the heart and the use of cardiopulmonary bypass. Functional mitral regurgitation can be managed conservatively with medical treatments for heart failure, but this approach is not curative. Surgical procedures such as undersized annuloplasty may also be an option. People with mitral regurgitation of either cause are usually older (typically over 70 years) and frailer, with multiple comorbidities.

Open-heart surgery may pose excessive risks for some people, particularly those who are older, frailer, or who have multiple or complex comorbidities. For people for whom open-heart surgery is prohibitively high risk, minimal access surgical approaches have been developed, such as transcatheter artificial chordae insertion. These approaches can often be done through smaller incisions and without the need to stop the heart or use cardiopulmonary bypass. These options aim to reduce perioperative risk and improve recovery, although they may not be suitable for all anatomical presentations of mitral valve prolapse that cause mitral regurgitation.

NICE did a rapid review of the published literature on the efficacy and safety of this procedure. This comprised a comprehensive literature search and detailed review of the evidence from 12 sources, which was discussed by the committee. The evidence included 7 prospective case series, 2 retrospective registry studies, 2 retrospective cohort studies, and 1 retrospective case series. It is presented in the summary of key evidence section in the interventional procedures overview. Other relevant literature is in the appendix of the overview. The evidence informing this guidance was only in one device. This is the only device currently used for this procedure in the UK.

The professional experts and the committee considered the key efficacy outcomes to be:

• quality of life

• patient-reported outcomes

• survival

• mitral regurgitation grade reduction

• echocardiographic outcomes.

The professional experts and the committee considered the key safety outcomes to be:

• conversion to open-heart surgery

• mortality

• cardiovascular and cerebrovascular adverse events

• septicaemia

• bleeding

• pericardial and pleural effusion

• kidney injury

• heart rhythm conduction disturbances.

Patient commentary was sought but none was received.

The committee noted that if this procedure fails, it does not preclude the use of further interventions. This procedure can also be used in people who have already had open-heart surgery.

Published evidence focused on process outcomes and technical success, with signals of efficacy not as strong.

A clinical expert highlighted the need to focus on outcomes that are most important to people having the procedure.

A clinical expert emphasised the importance of mitral regurgitation reduction, and echocardiographic outcomes associated with this procedure.

The committee noted the importance of an experienced multidisciplinary team including a cardiac surgeon and a 2D and 3D transoesophageal echocardiography operator with experience of this procedure. It also noted the need for proctoring to assist surgeons who are new to the procedure.

A clinical expert noted that an isolated P2 prolapse is associated with the best outcomes for this procedure. For more complex anatomy, the experience of the surgeon must be taken into consideration.

The committee noted that centres should follow any proctoring and training requirements associated with the device used.

The committee noted that there is currently only one device used for this procedure in the UK, and that the company reviews transoesophageal echocardiograms for every person who will have the procedure and provides advice about the procedure's technical feasibility.

This procedure should only be done by cardiac surgeons because of the need for thoracotomy or sternotomy, the risk of bleeding and the potential for urgent conversion to open-heart surgery.

The prevalence of mitral regurgitation increases with age.

The prevalence of valvular disease is similar in men and women.

People with degenerative mitral valve disease may be considered disabled under the Equality Act 2010 if their condition has a substantial adverse impact on normal day to day activities for longer than 12 months.