Mitral Valve Repair
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Direct answer
Repair rather than replacement is the preferred operation for degenerative mitral regurgitation whenever the valve is pliable and non-calcified, because it preserves the subvalvar apparatus, avoids lifelong anticoagulation and delivers better survival and freedom from endocarditis. The archetype — posterior P2 prolapse corrected by quadrangular resection with annular plication and a ring annuloplasty — succeeds in well over 90% of degenerative valves in experienced hands. Indian practice adds a decisive caveat: rheumatic disease, with thickened leaflets, fused commissures and shortened chordae, makes durable repair far harder, so mechanical replacement remains common in the young rheumatic patient.
What you must remember
- Carpentier classification: type I normal leaflet motion (perforation, annular dilatation), type II excessive motion (prolapse, flail, chordal rupture), type III restricted motion (IIIa structural — rheumatic; IIIb functional — ischaemic).
- Surgery for severe primary regurgitation: once symptomatic; when asymptomatic with ejection fraction 30–60%, end-systolic diameter 40 mm or more, new atrial fibrillation, or pulmonary artery systolic pressure above 50 mmHg at rest.
- Posterior prolapse: quadrangular resection with annular plication, sliding plasty for excess leaflet height, plus a complete semi-rigid ring.
- Anterior prolapse: chordal transfer from the posterior leaflet or polytetrafluoroethylene neochords (Gore-Tex loops) — with a lower repair expectation than posterior disease.
- Functional or ischaemic regurgitation: undersized ring annuloplasty, with chordal-sparing replacement debated when leaflets are tethered.
- Repair is favoured for pliable, non-calcified leaflets with localised pathology; replacement for extensive rheumatic subvalvar disease, heavy calcification, or destruction by endocarditis.
- Preserve the subvalvar apparatus at any replacement: chordal preservation prevents posterior wall rupture and ventricular dysfunction after mitral valve replacement — a viva staple.
- Durability: roughly 90–95% freedom from reoperation at ten years for degenerative repair in reference centres; rheumatic repair durability is substantially lower.
A repair walked through, from echo to ring
A 48-year-old man presents with exertional dyspnoea, an apical pansystolic murmur radiating to the axilla, and a flail P2 with severe regurgitation, ejection fraction 58%, end-systolic diameter 44 mm. Transoesophageal echo confirms a single prolapsing segment, pliable anterior leaflet and no calcification — assessability is high. Go through the operation as the surgeon does: bicaval and left atrial exposure; the flail P2 resected as a quadrangle, the annular defect plicated, a sliding plasty advancing the remaining posterior leaflet to avoid systolic anterior motion; a complete semi-rigid ring, sized to the anterior leaflet, remodelling the dilated annulus. Saline testing shows a competent coaptation line; post-bypass transoesophageal echo confirms no more than trivial regurgitation. Had it shown more than mild residual leak, the honest answers are a second pump run and, if the tissue defeats repair, chordal-sparing replacement — a decision made on the table, not resisted out of pride. That willingness to convert is itself an exam point.
The Indian twist: rheumatic valves
The stem that separates candidates places a 24-year-old with rheumatic mitral disease on the table: thickened leaflets, fused commissures, shortened chordae, mixed stenosis and regurgitation. Applying degenerative repair rules here fails — commissurotomy with annuloplasty in unfavourable rheumatic anatomy carries recurrence rates that rival its early successes, and the patient returns within a decade. Yet a mechanical valve in a young woman who may become pregnant trades progression for the problems of warfarin. Indian programmes therefore individualise: repair for pliable, minimally calcified valves with predominant regurgitation; mechanical replacement with chordal preservation when subvalvar disease is extensive. Saying "repairability depends on the rheumatic phenotype, not on the diagnosis" is the sentence that earns the mark.
Frequently asked questions
What are the Carpentier classes of leaflet motion?
Type I is normal motion with a perforated leaflet or dilated annulus, type II excessive motion from prolapse or chordal rupture, type III restricted motion — IIIa structural such as rheumatic disease, IIIb functional from ischaemic tethering.
When should asymptomatic severe mitral regurgitation be operated on?
At an ejection fraction of 60% or less, end-systolic diameter 40 mm or more, new atrial fibrillation, or pulmonary artery systolic pressure above 50 mmHg — provided repair is likely and surgical risk acceptable.
What is done for a flail P2 segment?
Quadrangular resection of the segment with annular plication, often a sliding plasty, completed by a semi-rigid ring annuloplasty. This is the commonest and most durable repair in degenerative disease.
Why must the subvalvar apparatus be preserved during replacement?
Chordal and papillary muscle continuity maintains left ventricular geometry and function; sacrificing it causes low-output syndrome and risks posterior ventricular rupture. Chordal-sparing replacement is the standard defence.
Which mitral valves go for replacement rather than repair?
Those with extensive rheumatic subvalvar disease and calcification, destructive endocarditis, or severe annular calcification that defeats plasty. Mechanical prostheses dominate in young rheumatic patients in India.
How is repair quality confirmed intraoperatively?
Saline distension of the ventricle shows the coaptation line, and post-bypass transoesophageal echocardiography grades residual regurgitation. More than mild residual leads to a second pump run or chordal-sparing replacement.