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.

he 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.

Mitral regurgitation

The mitral valve divides the left atrium and left ventricle of the mammalian heart and controls the flow of blood. Blood is pumped from the atria to the ventricle and then from the ventricle to the aorta. This electrically co-ordinated cycle of contraction

A normally functioning mitral valve opens as the atrium fills with blood and closes when the atria contracts to push blood into the ventricle.

Mitral regurgitation is the most common form of valvular heart disease and is a result of the mitral valve failing to close properly when the left ventricle contracts. This causes blood to flow back into the left atrium. This reduces the efficiency of the heart as a pump and can lead to the development of heart failure.

Mitral regurgitation is usually treated by surgical valve repair or replacement under general anaesthetic.

Mitral regurgitation is typically treated by repair or replacement during open heart surgery. If the valve is suitable for repair, valve repair outcomes are better than valve replacement outcomes for patients.

MitraClip is a catheter based device capable of reducing mitral regurgitation without the requirement for open heart surgery and is intended for patients at high risk of valve repair or replacement by surgery.

The MitraClip device uses a stainless steel clip to bring the two leaflets of the mitral valve together and is a reproduction of the Alfieri surgical repair.

NICE IPG309

• Evidence on the safety and efficacy of percutaneous mitral valve leaflet repair for mitral regurgitation is currently inadequate in quality and quantity.

• Therefore, this procedure should only be used with special arrangements for clinical governance, consent and research for patients who are well enough for surgical mitral valve leaflet repair to treat their mitral regurgitation, or in the context of research for patients who are not well enough for surgical mitral valve leaflet repair to treat their mitral regurgitation.

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 421