Caval valve implantation for tricuspid regurgitation

The tricuspid valve sits between the right atrium and right ventricle of the heart. Tricuspid regurgitation occurs because the tricuspid valve does not close properly during systole. It can result in blood refluxing back into the right atrium (leading to haemodynamically significant tricuspid regurgitation) and the 2 main caval veins (the superior vena cava and inferior vena cava). This makes the heart work harder and, if severe, can lead to heart failure. Tricuspid regurgitation can mainly be because of a problem with the valve anatomy itself. But it is more commonly secondary to an underlying cardiac problem that causes tricuspid annular dilatation or leaflet tethering. The valve leaflets and chords may be normal but, because of annulus dilatation, the valve leaflets fail to close properly and regurgitation of blood occurs.

People with mild tricuspid regurgitation do not usually have symptoms. If the regurgitation is severe, there may be fatigue and weakness, active pulsing in the neck veins, an enlarged liver, ascites, peripheral oedema and renal impairment. Pulmonary hypertension may develop.

Treatment may not be needed if there are no or mild symptoms. There are no specific medicines for treating tricuspid regurgitation itself, but symptoms of heart failure are managed with medicines such as diuretics and angiotensin-converting enzyme inhibitors. Medicines to reduce pulmonary artery pressure, pulmonary vascular resistance or both, may be used when there is severe functional tricuspid regurgitation and severe pulmonary hypertension.

People with severe symptoms may have surgery to repair or replace the tricuspid valve. Isolated tricuspid valve surgery is rarely done because it is associated with high morbidity and mortality. More commonly, it is done at the same time as surgery to the valves on the left side of the heart (mitral and aortic). Transcatheter tricuspid valve interventions (tricuspid valve repair and replacement) are an alternative for managing tricuspid regurgitation.

Caval valve implantation is indicated for haemodynamically significant tricuspid regurgitation and caval reflux in people who have advanced disease (with severe leaflet tethering and a large coaptation gap) and are at extreme risk from surgery. The aim is to reduce caval reflux and stop venous congestion, so improving symptoms of heart failure and quality of life for people who cannot have open heart surgery.

The procedure is done under local or general anaesthesia, and with fluoroscopy guidance. Transoesophageal echocardiography may be used to monitor the position and function of the deployed bioprostheses. Depending on the anatomical suitability, caval valve implantation can be single or bicaval. The bioprostheses can be dedicated self-expandable valves or balloon expandable prostheses used for transcatheter aortic valve replacement. They are implanted percutaneously through a delivery system using transfemoral access. The valves are implanted in the inferior vena cava, superior vena cava or both, at the level of the atriocaval junction. This is done without disturbing the native tricuspid valve in a cranial-caudal direction.