Transcatheter Mitral Valve Repair (TEER)

The mitral valve has two leaflets that meet like a pair of curtains when the heart contracts. They can fail to meet for two different reasons. In degenerative disease the leaflet tissue itself is faulty, stretched or torn, so part of it flails backwards. In functional disease the leaflets are normal but the heart chamber has enlarged and pulled them apart. Edge-to-edge repair addresses both by joining the leaflets at the point where they separate, creating a valve with two smaller openings instead of one large one, a shape first created by surgeons through an open operation. The clip is a small implanted device with two arms that grasp one leaflet each. One clip is often enough; two or three are used when the leak is wide. Nothing is removed and the valve is not replaced.

TEER is recommended for symptomatic severe mitral regurgitation when a heart team judges that open surgery carries unacceptable risk, for example because of advanced age, previous cardiac surgery, poor heart muscle function, lung disease or frailty. In degenerative disease it is used when the anatomy of the leak is suitable and surgery is not advisable. In functional disease, caused by an enlarged and weakened left ventricle, it is recommended for selected patients who remain breathless and are repeatedly admitted to hospital despite optimal heart failure medication and, where indicated, resynchronisation pacing. Suitability is decided from a detailed transoesophageal echocardiogram, which shows where the leak arises, how much leaflet tissue there is to grasp and whether the valve opening is wide enough to accept a clip without becoming narrowed.

The procedure is carried out in a hybrid catheter laboratory by an interventional cardiologist and an imaging cardiologist working together, under general anaesthesia. A transoesophageal echocardiography probe is placed to give a continuous three-dimensional view of the valve. A sheath is inserted into the femoral vein in the groin, and a needle is used to cross the thin wall between the two upper chambers of the heart, giving access to the left atrium directly above the mitral valve. The delivery system is steered so that the clip sits over the origin of the leak, aligned at right angles to the line where the leaflets meet. The arms are opened, the clip is pulled back to grasp both leaflets and, before it is released, the leak is measured again and the pressure in the left atrium is checked. If the result is not adequate the clip can be reopened and repositioned, or a second clip added. When the result is satisfactory the clip is detached and the catheters are removed, and the vein puncture is closed with a suture-based device. The procedure typically takes 1 to 3 hours.

Assessment is made by a heart team of interventional cardiologists, cardiac surgeons, imaging specialists and heart failure physicians. It includes transthoracic and transoesophageal echocardiography, an electrocardiogram, coronary angiography or computed tomography to check the coronary arteries, blood tests, and a formal estimate of surgical risk. Heart failure medication is optimised first, because in functional regurgitation the leak may improve on treatment alone. Dental review is arranged, as with any implanted cardiac device. Anticoagulation and antiplatelet plans are decided in advance, especially in patients with atrial fibrillation. For international patients the transoesophageal echocardiogram is the decisive investigation, and centres will normally repeat it themselves; sending previous images, the medication list and recent blood tests allows a preliminary opinion before travel.

Patients wake in a monitored area and are usually sitting and walking the following day, with only a small puncture site in the groin to care for. Bed rest for a few hours protects the vein puncture. An echocardiogram before discharge documents the residual leak and confirms the valve is not narrowed. Most people go home within 2 to 4 days. Ordinary activity resumes within 1 to 2 weeks, with heavy lifting avoided for a fortnight. Antiplatelet or anticoagulant medicine is prescribed according to the individual situation, and heart failure medicines are continued and titrated. Improvement in breathlessness is usually noticed over the first weeks as the lung pressures fall. For treatment abroad, plan about 7 to 10 days, which allows the pre-procedure imaging, the procedure itself, the discharge echocardiogram and an early follow-up review before flying.

TEER avoids the chest incision, the heart-lung machine and the long recovery of open surgery, but it is still a structural heart procedure with real risks. Recognised complications include bleeding or injury at the groin puncture, a persistent hole in the wall between the upper chambers, detachment of the clip from one leaflet, narrowing of the valve if the opening is reduced too much, injury to a leaflet, stroke, arrhythmia and, rarely, the need for urgent surgery. Serious complications are uncommon in experienced centres. The leak is not always abolished; the aim is to reduce it to mild or moderate, which is what improves symptoms. Trials in functional mitral regurgitation have shown fewer heart failure hospital admissions and improved survival in carefully selected patients, and in degenerative disease TEER reliably relieves symptoms in those who cannot have surgery. The clip is permanent, and surgical repair or replacement remains possible later if it becomes necessary.