2 The condition, current treatments and procedure
2.1 The mitral valve allows blood to flow from the left atrium to the left ventricle. Mitral valve regurgitation (MR) happens when the valve doesn't close properly, allowing blood to flow back into the atrium from the ventricle during systole. The heart has to work harder, resulting in an enlarged left ventricle. If not treated, this can lead to problems including heart failure.
2.2 MR can be degenerative (primary or structural) or functional (secondary). Degenerative MR is caused by 'wear and tear' to the chords and leaflets in the valve. In functional MR the chords and leaflets are structurally normal but there is geometrical distortion of the subvalvular apparatus caused by idiopathic cardiomyopathy, or weakening of the cardiac walls caused by coronary artery disease (ischaemic MR).
2.3 Degenerative MR is treated by surgery to repair or replace the mitral valve. Functional MR can be conservatively managed using drugs for treating heart failure but this is not curative, and surgical options such as undersized annuloplasty may be an option. However, people with MR of either cause are usually older (typically over 70 years) and frail, with multiple comorbidities. This increases the perioperative risks of morbidity and mortality for open heart surgery. For these patients, percutaneous mitral valve leaflet repair (PMVR) may be an appropriate management option.
2.4 PMVR is a treatment option for MR if the mitral valve meets the anatomical eligibility criteria for coaption length, coaption depth, flail gap and flail width. The procedure is done using general anaesthesia and transoesophageal echocardiography guidance, with the optional use of fluoroscopy. Access is provided through the femoral vein and an atrial trans-septal puncture is done to reach the mitral valve.
2.5 The device is lowered through the mitral valve into the left ventricle. The arms of the device grip the leaflets, bringing them closer together, and the device is released from the delivery system. Adequate reduction of MR is assessed using echocardiography. Sometimes, more than 1 device is needed. After the procedure, patients usually have anti-platelet therapy for 6 months.