Mitral Regurgitation Management
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Direct answer
Surgery, clip, or medication — the answer depends on whether the valve is diseased (primary MR) or the ventricle has pulled a normal valve out of shape (secondary MR), and the exam lives on that distinction. Severe primary (degenerative) MR — effective regurgitant orifice area of 0.4 cm² or more, regurgitant volume 60 mL or more, or a flail leaflet — is a surgical disease, with repair preferred over replacement wherever durable repair is achievable; operate when symptomatic, or asymptomatic with LVEF of 60 per cent or below, LV end-systolic dimension of 40 mm or more, new atrial fibrillation or pulmonary hypertension. Patients at prohibitive surgical risk go to transcatheter edge-to-edge repair. Secondary MR is a ventricle problem first: optimise guideline-directed therapy and CRT before anything else, then apply the COAPT criteria for TEER (LVEF 20-50 per cent, severe MR, symptoms despite maximally tolerated therapy), remembering that MITRA-FR showed no benefit in a broader population — severity of MR relative to ventricular size decides who profits.
What you must remember
- Severity numbers: EROA 0.4 cm² or more and regurgitant volume 60 mL or more define severe primary MR; a flail leaflet is severe by definition regardless of calculations.
- Asymptomatic surgical triggers: LVEF 60 per cent or below, LVESD 40 mm or more, new atrial fibrillation, or pulmonary artery systolic pressure above 50 mmHg — intervene before the ventricle decompensates.
- Repair over replacement: preserves the mitral apparatus and LV function, with lower operative mortality; posterior leaflet prolapse carries the highest repair durability.
- The EF paradox: an EF of 60 per cent in severe primary MR is already abnormal — the regurgitant low-impedance exit inflates EF; waiting for 50 per cent means waiting too long.
- Secondary MR ladder: guideline-directed therapy first (SGLT2 inhibitors included), CRT if indicated, reassess MR severity afterwards — MR often shrinks as therapy bites.
- COAPT versus MITRA-FR: COAPT-positive patients had severe disproportionate MR (EROA 30 mm² or more, or regurgitant volume 45 mL or more) with LVEF 20-50 per cent and symptoms despite therapy; MITRA-FR's broader, more dilated cohort showed no benefit.
- Surgical secondary MR: repair or chordal-sparing replacement when the patient is already undergoing CABG or another cardiac operation; isolated mitral surgery for secondary MR alone carries high risk and demands careful patient selection.
- Surveillance rhythm: severe asymptomatic primary MR with none of the triggers — echo every six months, watching for symptom onset.
Two patients with severe MR, two paths
First, a 54-year-old man with a flail posterior leaflet, EF 58 per cent, LVESD 42 mm, asymptomatic but referred for a new murmur. He meets an asymptomatic trigger (LVESD over 40, EF under 60) and, with high likelihood of durable repair at an experienced centre, early surgical repair is the recommendation — waiting for symptoms in a repairable valve forfeits the best window. Had he been frail with prohibitive surgical risk, edge-to-edge repair would enter the conversation.
Second, a 71-year-old with ischaemic cardiomyopathy, EF 30 per cent, on quadruple therapy including an SGLT2 inhibitor and not CRT-eligible, with severe functional MR (EROA 40 mm²) and repeated hospitalisations. He is a COAPT-profile patient: re-verify that therapy is maximally tolerated and MR still severe, then assess anatomy on transoesophageal echo for graspable leaflets and acceptable coaptation. TEER reduces his MR and readmissions; it will not replace a missing beta-blocker or an unfilled SGLT2 prescription.
How the exam frames it
The discriminating stems are three. "Why operate on an asymptomatic patient with EF 60?" — because EF 60 in severe MR is the tail of normal, and LVESD 40 mm and new AF are the early-warning lights. "Which secondary MR patient gets a clip?" — recite the COAPT criteria, and volunteer the MITRA-FR contrast with the proportionate/disproportionate MR explanation; quoting both trials with their populations is the difference between a pass answer and a good one. "Why repair rather than replace?" — the mitral apparatus anchors LV geometry and function; chordal-sparing replacement exists to borrow that principle. Indian examiners add a practical fourth: rheumatic mixed mitral disease masquerading as pure MR, where a destroyed subvalvular apparatus makes repair durability a different proposition.
Frequently asked questions
What quantitative criteria define severe primary mitral regurgitation?
Effective regurgitant orifice area of 0.4 cm² or more or regurgitant volume of 60 mL or more, with a flail leaflet qualifying as severe irrespective of calculations.
Which asymptomatic patients with severe primary MR need surgery?
Those with LVEF 60 per cent or below, LV end-systolic dimension 40 mm or more, new atrial fibrillation, or pulmonary hypertension above 50 mmHg systolic.
Why is mitral valve repair preferred to replacement?
Repair preserves the native valve and submitral apparatus, maintains ventricular geometry and function, and carries lower operative mortality with excellent durability for posterior leaflet disease.
Which secondary MR patients benefit from transcatheter edge-to-edge repair?
Those meeting COAPT criteria — LVEF 20-50 per cent, severe MR (EROA 30 mm² or more or regurgitant volume 45 mL or more), and persistent symptoms despite maximally tolerated guideline therapy.
What must precede intervention in secondary mitral regurgitation?
Optimisation of guideline-directed medical therapy and CRT where indicated, with reassessment of MR severity — the regurgitation frequently diminishes as ventricular therapy takes effect.