Mitral Valve Disease

Mitral regurgitation (MR) is a leaking mitral valve — blood flows backward from the left ventricle into the left atrium during systole instead of all going forward into the aorta. Primary MR is caused by structural valve abnormality (MVP, chordal rupture). Secondary functional MR occurs when a dilated, failing ventricle distorts a structurally normal valve. Severe primary MR requires surgery (repair preferred). Severe secondary MR in heart failure may benefit from MitraClip (COAPT: −47% HF hospitalisation, −38% mortality) after optimising heart failure medications.

Mitral stenosis is narrowing of the mitral valve, obstructing blood flow from left atrium to left ventricle. In India, the dominant cause is rheumatic heart disease — valve damage following childhood streptococcal throat infection and rheumatic fever. Severe MS (MVA <1.0 cm²) causes breathlessness, atrial fibrillation, pulmonary hypertension, and haemoptysis. The preferred treatment for suitable anatomy is balloon mitral valvotomy (PBMV) — a catheter procedure that separates fused valve leaflets without open-chest surgery.

MitraClip is a catheter-based mitral valve repair procedure that clips the mitral leaflets together to reduce regurgitation — without open-chest surgery. It is approved for secondary MR in heart failure patients who remain symptomatic despite optimal medical therapy. COAPT (NEJM 2018) showed MitraClip reduced HF hospitalisation by 47% and mortality by 38% versus medical therapy in carefully selected patients.

Surgery is indicated for severe primary mitral regurgitation if you have any symptoms (breathlessness, fatigue, palpitations), or if your ejection fraction has dropped below 60%, or if the left ventricle has dilated beyond 40 mm in end-systolic diameter — even without symptoms. For mitral stenosis, intervention is needed when the valve area is severely narrowed (<1.0 cm²) or if you develop symptoms, atrial fibrillation, or pulmonary hypertension. Whenever possible, mitral valve repair is preferred over replacement as it preserves the native valve structure and avoids long-term anticoagulation. The exact timing and type of intervention are determined by echocardiographic measurements and your individual clinical profile.

Mild mitral regurgitation (MR) discovered incidentally on echocardiography often remains stable for years and may even improve with treatment of the underlying cause. In secondary (functional) MR caused by heart failure, optimising GDMT — particularly ARNi, beta-blockers, and SGLT2 inhibitors — can reduce the severity of MR by improving ventricular function and reducing mitral annular dilation. However, moderate-to-severe primary MR (caused by structural valve disease such as flail leaflet or chordal rupture) does not heal on its own and will typically progress over time. Surgery or transcatheter intervention is indicated when the regurgitation becomes severe or causes symptoms, LV dilation, or declining EF.

Mitral valve prolapse (MVP) is a condition where the mitral valve leaflets bulge (prolapse) back into the left atrium during the heart's contraction. It is relatively common, affecting 2–3% of the population. Most people with MVP have no symptoms and require no treatment other than periodic echocardiographic follow-up. However, some patients with MVP develop significant mitral regurgitation that may eventually require surgery. A small subset of patients with MVP — particularly those with 'arrythmogenic MVP' — may be at risk for ventricular arrhythmias. MVP is usually diagnosed on echocardiography, and follow-up is guided by the severity of associated MR and any symptoms.

The frequency of echocardiographic follow-up depends on the severity of the valve disease. For mild MR or MS with no symptoms, echocardiography every 2–3 years is sufficient. For moderate disease, annual or biannual echo is recommended. For severe MR without symptoms, echocardiography should be performed every 6–12 months to monitor LV function and dimensions — as surgery is indicated when EF drops below 60% or LVESD exceeds 40 mm. For severe MS, echo every 6–12 months monitors valve area and pulmonary pressures. After valve repair or replacement, a baseline post-procedure echo is performed and then annually or biennially depending on valve type and clinical status.

Pregnancy with mitral valve disease requires careful pre-conception counselling and multidisciplinary management by a cardiologist and obstetrician. Women with mild MR or MS and normal cardiac function usually tolerate pregnancy well with close monitoring. However, moderate-to-severe MS is poorly tolerated during pregnancy — the increased blood volume and heart rate of pregnancy can cause rapid decompensation with pulmonary oedema. Ideally, significant valve disease should be treated before pregnancy (with PBMV for MS or surgery for MR). Women with mechanical prosthetic valves face particular challenges due to the need for anticoagulation (warfarin is teratogenic; heparin requires careful management). All pregnant women with mitral valve disease should be managed in a specialist cardio-obstetric clinic.