Atrial fibrillation (AF), the irregular and rapid beating of the heart, can lead to the development of congestive heart failure.

Current treatment includes:

• controlling the rate and rhythm of the heart with medication
• a medically administered electric shock to the heart, known as cardioversion
• correcting electrical signal pathways in the heart by catheter ablation
• fitting a pacemaker to control the heart beat more regularly

AF patients have an increased risk of stroke; clots can form when the heart is not pumping effectively. The left atrial appendage (LAA), a long tubular hooked structure with a narrow junction where it joins the atrium of the heart, is an area of the heart where blood collects and begins to clot in patients with AF. Closing the LAA could prevent these clots from entering the circulatory system and causing complications such as stroke.

The risk of stroke in patients with atrial fibrillation is thought to be reduced by blocking the left atrial appendage.

The devices being evaluated in this registry are the Watchman device and the Amplatzer cardiac plug.

NICE IPG349

• Current evidence suggests that percutaneous occlusion of the left atrial appendage (LAA) is efficacious in reducing the risk of thromboembolic complications associated with non-valvular atrial fibrillation (AF). With regard to safety, there is a risk of life-threatening complications from the procedure, but the incidence of these is low. Therefore, this procedure may be used provided that normal arrangements are in place for clinical governance, consent and audit.

Patent foramen ovale

The structure of the embryonic heart is very different from the developed heart. In the fetal heart, oxygenated blood can enter the left atrium from the right atrium through the foramen ovale.

In the majority of people, the foramen ovale closes at birth when the lungs begin to function.

However, in approximately 15-25% of adults this channel does not close, leaving a patent (open) foramen ovale.

There is evidence suggesting individuals with PFO have a higher incidence of stroke than those who don’t. Substances, gas bubbles for example, are thought to cross from the right hand side of the heart to the left hand side of the heart through this opening, which then cause blockages in arterial circulation, thereby increasing the risk of stroke.

Percutaneous patent foramen closure (PFOC) is performed in hospitals under anaesthetic using x-ray guidance and usually takes less than one hour.

The closure device is delivered to the heart by a catheter delivery system. The usual access point is the femoral artery in the leg, the device is then guided to the right atrium over a wire. Once the device is in the right position, the device is deployed and the catheter is removed.

NICE IPG 109 :

• Current evidence suggests that there are no major safety concerns and that percutaneous closure of patent foramen ovale for the prevention of cerebral embolic stroke is efficacious in achieving closure of the foramen. However, its efficacy in preventing future strokes has not been clearly shown.

The clinical expert view is PFOC is likely to be beneficial in carefully selected individuals.

The UK TAVI program was established to capture and report outcomes on TAVI procedures performed in the UK.

The UK TAVI registry was created to define the characteristics and clinical outcomes of the patient population treated with TAVI, regardless of technology or access route, in every centre performing TAVI in the UK.

The project aims to capture detailed information on how TAVI is used to treat patients with severe aortic stenosis and significant comorbidities; improving the care of patients and benchmarking TAVI units to learn best practice.

The practice of collecting comprehensive clinical and outcome data by registry is a significant development in the introduction of new treatment technologies within the NHS. This process may help to shape commissioning by evaluation and encourage the safe introduction of new technologies into the NHS.

The registry is managed by NICOR with clinical direction and strategy provided by the British Cardiovascular Interventional Society (BCIS), the Society for Cardiothoracic Surgeons (SCTS), and the project steering group.

Aortic stenosis

The aortic valve opens when blood is pumped from the left ventricle into the aorta, narrowing of this valve (aortic stenosis) affects the efficiency of the heart as a pump.

Aortic valves are normally tricuspid, they have three valve leaflets, but are occasionally bicuspid (two valve leaflets). Aortic stenosis is most commonly caused by the calcification of the aortic valve or following acute rheumatic fever.

Aortic stenosis due to age-related calcification typically occurs in normal tricuspid valves in patients of 70-80 years old. Aortic stenosis in bicuspid valve due to age related calcification typically appears earlier, when the patient is in their 40s or 50s.

Aortic stenosis causes the heart to work harder to counter the decreased volume of blood being pumped. This increase in workload can lead to heart failure.

In patients who are well enough, stenotic valves are replaced surgically. However, there is a population of patients where the risks associated with surgical valve replacement are higher than the potential benefits.

TAVI (transcatheter aortic valve implantation) provides a less invasive alternative to cardiac surgery and avoids the requirement for cardiopulmonary bypass.

TAVI procedures insert the new prosthetic valve inside the existing valve. The new valve is delivered through a catheter inserted transfemorally (via an artery in the groin) or transapically (via an insertion between two ribs). This is possible as the replacement valve is collapsed before being delivered to the correct position in the aortic valve.

The existing stenotic valve is dilated using a balloon catheter, the new valve is positioned and expanded inside the aortic valve ring. The replacement valve is wedged into position against the existing aortic valve ring.

• NICE guidance Transcatheter aortic valve implantation for aortic stenosis IPG 586

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.