Mitral regurgitation (MR) affects 2% of the population and can be grouped into those with primary (degenerative) or secondary (functional) mitral regurgitation. The best way I describe this to patients is that there is either a problem with the door and hinges, or the frame of the door.
In degenerative MR the issue is with the door itself (i.e. myxomatous and valve prolapse) or the hinges (subvalvular apparatus e.g. ruptured chordae and flail) that prevents coaptation of the anterior and posterior leaflets. In functional MR the issue is with an enlarged door frame and caused by the patient’s underlying cardiomyopathy (e.g. ischaemia). The doors are often normal, but the leaflets are pulled apart due to left ventricular dilatation. In certain cases, there is mixed disease.
TMVr, or edge-to-edge repair, is based on the surgical technique of putting an Alfieri stitch to approximate the anterior and posterior leaflet creating a double orifice and reducing mitral regurgitation. It reduces symptoms of heart failure, hospitalisation and improves quality of life.
Patient selection and assessment
TMRv is approved in patients who are at unacceptably high risk for surgical mitral valve replacement and are on optimal medical therapy with 3+ to 4+ mitral regurgitation on echo, with ongoing NYHA class II-IV heart failure symptoms and ejection fraction above 20%.
Imaging with transthoracic (TTE) and transoesophageal echocardiography (TOE) to assess the cause of MR and procedural planning is key. Exclusion of coronary disease and haemodynamic assessment with right heart catheterisation allows clinicians to tailor optimal medical therapy and consider revascularisation.
Mitral regurgitation is dynamic and measures to achieve euvolaemia, reduce blood pressure, regulate heart rate, treat rhythm disturbance (e.g., AF) and improve cardiac synchrony (e.g., cardiac resynchronisation therapy) will improve MR and improve the clinical outcomes post TMVr.
Timing for intervention is when symptomatic patients on optimal medical therapy show signs of haemodynamic decompensation. For example, pulmonary hypertension at rest or on exercise without a significant precapillary component, dilatation of the left ventricle, reduction in ejection fraction, hospitalisation for heart failure or development of atrial fibrillation (often poorly tolerated).
Patient cases are reviewed by a multidisciplinary heart team consisting of a clinical nurse coordinator, structural and imaging cardiologists, anaesthetists, and cardiothoracic surgeon. We assess patients for frailty and quality of life, review their echoes for suitability for edge-to-edge repair and strategy for device implantation.
Procedure and management
The procedure is performed under general anaesthetic and takes under three hours. Access is via the right femoral vein followed by transeptal puncture into the left atrium under TOE guidance. A steerable guide is then advanced and positioned in the left atrium, the patient is fully heparinised and left atrial pressures are taken.
Following measurements of valve area, leaflet length and mechanism of mitral regurgitation the appropriate device size is selected. The device is positioned perpendicular to the line of coaptation to target the regurgitant jet and the leaflets are either simultaneous or independent grasped to achieve optimal leaflet coaptation.
The residual regurgitation is then assessed by TOE, valve area calculated to assess for mitral stenosis and device stability prior to the device being deployed. In valves that have large regurgitant orifices more than one clip is used to approximate the leaflets or provide stabilisation and an annuloplasty effect.
Post-implant left atrial pressure is measured to evaluate the haemodynamic effects and the guide sheath is removed. The septum is assessed by TOE for bidirectional shunt and closed using an ASD closure device if required. The femoral vein is closed using a stitch in a pre-close fashion or a Z stitch to provide external compression.
Post-procedurally the patients are monitored in a cardiac ward overnight and a TTE is performed prior to discharge to assess for residual MR, device stability and exclude any complications from the procedure. The majority of the patients are discharged the next day. Patients are put on aspirin and clopidogrel for six months only and do not need to be anticoagulated unless they have a prior indication (e.g. AF).
Key messages
- Mitral regurgitation is common and should be managed aggressively and referred for specialist follow-up
- TMVr reduces symptoms of heart failure, reduces hospitalisation and improves quality of life
- TMVr is a safe procedure, and most patients are discharged the following day without the need for lifelong anticoagulation unless there was a prior indication.
Author competing interests – No relevant disclosures