Mitral Valve Repair vs Replacement in Rheumatic Heart Disease: Indications and Long‑Term Survival
Introduction
Rheumatic heart disease (RHD) remains a leading cause of valvular pathology in India, with the mitral valve affected in approximately 70–80% of cases. Surgical intervention is often required when conservative medical therapy fails to control symptoms or prevent disease progression. The two principal surgical options are mitral valve repair (MVR) and mitral valve replacement (MVRp). This article delineates the indications for each procedure, outlines their respective risks and benefits, discusses perioperative pharmacotherapy, and compares long‑term survival data relevant to Indian patients.
Pathophysiology of Rheumatic Mitral Involvement
- Acute rheumatic fever leads to pancarditis and valvulitis.
- Chronic damage causes leaflet thickening, commissural fusion, chordal rupture, and subvalvular apparatus fibrosis.
- Resultant stenosis, regurgitation, or mixed lesions dictate surgical strategy.
Pre‑operative Assessment
- Echocardiography (Transthoracic & Transesophageal) – Evaluate valve morphology, severity of regurgitation/stenosis, left ventricular function, pulmonary pressures.
- CT Angiography – Assess aortic root, annulus size, and coronary anatomy when considering concomitant CABG.
- Laboratory Work‑up – CBC, coagulation profile, renal function, hepatitis B/C screening.
- Cardiac MRI – In selected cases to quantify ventricular volumes and fibrosis.
- Risk Scores – EuroSCORE II, STS score adapted for Indian populations.
Indications for Mitral Valve Repair (MVR)
- Isolated mitral regurgitation due to leaflet prolapse or flail with preserved subvalvular apparatus.
- Mixed lesions where regurgitation component predominates and stenosis is <60 mmHg.
- Patients <70 years with low operative risk and suitable annular anatomy (<20 mm).
- Presence of ventricular dysfunction (EF >35%) where preservation of native tissue is advantageous.
- Patients who wish to avoid long‑term anticoagulation (e.g., no mechanical valve).
Indications for Mitral Valve Replacement (MVRp)
- Severe mitral stenosis with calcification of leaflets or commissures precluding repair.
- Advanced rheumatic disease with extensive leaflet fibrosis, chordal rupture, and annular calcification.
- Mixed lesions with severe stenosis (gradient >40 mmHg) and significant regurgitation.
- Patients with active infection (endocarditis) or large vegetations where replacement is safer.
- Patients with contraindication to long‑term anticoagulation but requiring mechanical valve due to comorbidities.
Operative Techniques
MVR in RHD
- Chordal Transfer (Hegar Repair) – Transplanting intact chordae from the posterior to anterior leaflet.
- Annuloplasty Rings – Semi‑rigid or flexible rings sized 28–32 mm to reshape annulus.
- Leaflet Augmentation – Use of autologous pericardium or bovine pericardial patches.
- Subvalvular Apparatus Preservation – Maintaining papillary muscle attachments to preserve ventricular synchrony.
MVRp in RHD
- Mechanical Prosthesis (St. Jude, bileaflet) – Requires lifelong anticoagulation; suitable for younger patients with low bleeding risk.
- Bioprosthetic Valves (Carpentier‑Edwards, Medtronic) – No anticoagulation but limited durability (<10 years).
- Decalcinated Annulus & Root Replacement – In extensive calcification, annular debridement with bovine pericardial patch.
- Concomitant CABG – Often necessary in Indian patients with multi‑vessel coronary disease.
Perioperative Pharmacologic Management (India Specific)
- Anticoagulation – Mechanical valves: Enoxaparin bridging to warfarin (INR 2.5–3.5). Bioprosthetic valves: Low‑dose aspirin 75–100 mg daily.
- Aspirin & Clopidogrel – Dual antiplatelet therapy for 3 months post‑CABG, then aspirin alone.
- Statins (Atorvastatin 40–80 mg) – Reduce perioperative inflammation and improve graft patency.
- Beta‑Blockers (Metoprolol 50–100 mg) – Heart rate control; reduce arrhythmias.
- ACE Inhibitors (Enalapril 5–10 mg) – For LV dysfunction; titrate to max tolerated.
- Antibiotic Prophylaxis – Cefazolin 2 g IV pre‑op; extend to vancomycin if MRSA risk.
- Diuretics (Furosemide) – Manage fluid status; adjust post‑op based on urine output.
Risk Profile & Complications
- MVR – Lower operative mortality (0.5–1%) but higher risk of residual regurgitation if repair incomplete.
- MVRp – Higher operative mortality (1–2%) due to prosthesis‑related complications; risk of structural valve deterioration in bioprostheses.
- Both procedures share risks: bleeding, stroke, prosthetic valve endocarditis, and ventricular dysfunction.
Long‑Term Survival Outcomes (Indian Data)
- MVR – 10‑year survival ~88% in patients <65 years; recurrence of regurgitation <5% with annuloplasty.
- MVRp – 10‑year survival ~80% for mechanical valves; bioprosthetic valves show 70% at 10 years due to structural deterioration.
- Comparative studies (e.g., AIIMS Delhi cohort) demonstrate no significant difference in survival between repair and replacement when patients are appropriately selected.
- Quality of life scores (SF‑36) higher in repair group due to preservation of native tissue and avoidance of anticoagulation.
Conclusion
In rheumatic mitral disease, meticulous pre‑operative imaging and patient selection are paramount. Mitral valve repair offers superior preservation of ventricular function, lower bleeding risk, and avoidance of lifelong anticoagulation in suitable patients. Replacement remains the definitive option for extensive calcific disease or severe stenosis where repair is unfeasible. Indian clinicians should tailor pharmacologic therapy and surgical approach to individual risk profiles, leveraging regional expertise in valve surgery and perioperative care.