The NICOR Transcatheter Mitral & Tricuspid Valve registry collects data on all transcatheter interventions on the mitral and tricuspid valve carried out in NHS hospitals and some private sector hospitals in England.
Cardiac surgery procedures on these valves are included in a separate National Adult Cardiac Surgery Audit overseen by NICOR.
Mitral and Tricuspid Valve disease
The mitral and tricuspid valves are the left and right atrioventricular valves of the heart. The atrioventricular valves connect the top atrial chambers with their corresponding bottom ventricular chambers. Valve function problems can be due to stenosis (restricted opening) or regurgitation (leaking) of the valve.
Heart valve disease is a disease of advancing age in high income, industrialised countries and particularly prevalent in adults over the age of 75. Mitral and Tricuspid Regurgitation can both be broadly divided into primary (structural abnormality of the valve) and secondary (abnormality in size and function of the heart chamber) aetiologies. Mitral stenosis due to degenerative disease is seen more commonly now in this country compared to rhematic mitral stenosis due to the change in epidemiology.
What are Transcatheter Mitral & Tricuspid Valve interventions?
This is an evolving group of interventional treatments relating mainly to mitral regurgitation and tricuspid regurgitation. Catheter-based approaches have emerged as treatment options as a high proportion of patients either do not receive treatment beyond medical therapy due to their high surgical risk or do not have any other option beyond medical therapy. This unmet need is expected to increase with the changes in life expectancy and the growing ageing population.
These interventions contrast with transcatheter aortic valve implantation (TAVI) however due to their differing aetiologies and the complex anatomy of these valves. There are several different procedural techniques at various stages of investigation or clinical practice. There is a major emphasis on imaging to assess for anatomical suitability and to guide the procedure itself. Techniques can involve repair of the valve using a device that targets a particular structural component of the valve or implantation of a device which effectively acts to replace the existing one.
What procedures are captured in this registry?
The registry has been designed to capture all mitral and tricuspid procedures and keep pace with the rapid advances in technology.
The most established intervention at present is Mitral Transcatheter Edge to Edge Repair (variably described as percutaneous mitral valve leaflet repair or similar) for the treatment of mitral regurgitation. Other technologies and procedures will be delivered by some hospitals, but this will be at a smaller, more variable level across the country and often as part of research studies.
The registry therefore also includes tricuspid transcatheter edge to edge repair, ‘TAVI-in-Mitral’ and further novel procedures such as transcatheter mitral or tricuspid valve replacement whereby a prosthesis is implanted in the mitral and tricuspid positions respectively.
The registry also enables national data capture of niche procedures that have been performed for longer periods at generally low volume such as balloon mitral valvuloplasty (balloon stretching of the mitral valve) for rheumatic mitral stenosis, and percutaneous paravalvular mitral and tricuspid leak repair (device closure of leaks around previously implanted cardiac surgical prosthetic valves).
The mitral transcatheter edge to edge repair procedure which is presently the most established procedure in clinical practice is described in more detail below.
Mitral Transcatheter Edge to Edge Repair
Mitral Transcatheter Edge to Edge Repair (TEER) has recently become widely available across England and can be used to treat patients with both primary and secondary mitral regurgitation who are too high risk for open heart surgery or where surgery is not indicated.
There are presently two commercially available mitral TEER devices called MitraClip (Abbott) and PASCAL (Edwards Lifesciences). The procedure is minimally invasive and performed in the cardiac catheterisation laboratory under general anaesthesia with trans-oesophageal echocardiography (ultrasound imaging by placing a specialised probe in the oesophagus) and X-ray guidance. Vascular access is via the skin and into the femoral vein (vessel in the groin) which leads to the right atrium. A technique to access the left atrium called a trans-septal puncture is performed which allows placement of a large bore guide catheter. The device is delivered through this guide catheter using a delivery catheter. The device is manoeuvred to bring together the segments of the two valve leaflets responsible for the leak. More than one device can be implanted to achieve an effective reduction in the mitral regurgitation. Following completion, the catheter system is removed, and the hole created in the top of the groin is sealed. Patients are woken up from anaesthesia straight after the procedure and recovery is quick due to the minimally invasive nature.
What is the purpose of this registry?
The aim of this registry is to collect clinical and outcome data on transcatheter procedures used to treat mitral and tricuspid valve disease. This is a significant development and will enable identification of key metrics for benchmarking, improving care of patients undergoing these procedures and for the safe introduction of new transcatheter mitral and tricuspid valve technologies in this country.