Does a cardiothoracic surgeon replace the mitral valve?

Does a Cardiothoracic Surgeon Replace the Mitral Valve?

Yes, cardiothoracic surgeons perform mitral valve replacement, but repair is strongly preferred over replacement in virtually all cases of primary mitral regurgitation when a durable repair is technically feasible. 1, 2

When Replacement Is Performed

Cardiothoracic surgeons replace the mitral valve in specific clinical scenarios where repair is not feasible or has failed:

Mandatory Replacement Scenarios

• Failed repair attempt – If an attempted repair does not achieve adequate results (residual moderate or greater MR), replacement becomes mandatory during the same operation because a poor repair carries higher risk than a well-performed replacement. 1, 2, 3

• Extensive calcification – Severe mitral annular or leaflet calcification that precludes reliable suture placement or valve reconstruction requires replacement. 1, 4

• Rheumatic disease with severe restriction – Advanced rheumatic lesions with heavily scarred, immobile leaflets are often not amenable to durable repair. 1, 5

• Structural valve deterioration – Bioprosthetic valve failure or mechanical valve thrombosis necessitates replacement. 1, 5

• Severe leaflet tethering in secondary MR – When tenting height exceeds 10 mm or an inferobasal aneurysm is present, chord-sparing replacement may be preferred over repair. 1

Relative Indications for Replacement

• Complex anterior or bileaflet disease – When more than 50% of the anterior leaflet is involved with myxomatous degeneration and a durable repair cannot be reliably achieved, replacement is preferable to an inadequate repair. 1, 2

• Prior cardiac surgery or radiation – Patients with previous sternotomy or chest radiation face substantially increased risk with reoperation; replacement may be chosen to avoid potential need for future repair revision. 1

• Infective endocarditis with extensive destruction – When valve tissue is too damaged to reconstruct, replacement is required. 1, 5

Why Repair Is Strongly Preferred

The evidence overwhelmingly favors repair over replacement when technically feasible:

• Operative mortality is approximately 50% lower with repair compared to replacement, based on Society of Thoracic Surgeons database analyses. 1, 2

• Left ventricular function is better preserved following repair because the native mitral apparatus maintains efficient ventricular geometry and contractility. 1, 2

• Prosthetic valve complications are avoided – Repair eliminates risks of thromboembolism, anticoagulation-related hemorrhage (mechanical valves), and structural valve deterioration (bioprosthetic valves). 1, 2

• Long-term survival is superior – For isolated posterior leaflet disease, repair achieves survival equivalent to age-matched general population, with 95% freedom from reoperation and >80% freedom from recurrent moderate-to-severe MR at 15–20 years. 1, 2

Critical Surgical Principle

For isolated posterior leaflet disease, replacement should NOT be performed unless a repair has been attempted and failed; this is a Class III (Harm) recommendation. 1, 2 Up to half of the posterior leaflet may be excised, plicated, or resuspended, and surgeons performing mitral procedures should achieve ≥90% success rate for posterior leaflet repair. 1, 2

Surgical Access and Technique

When replacement is necessary, cardiothoracic surgeons use:

• Standard median sternotomy with cardiopulmonary bypass and cardioplegic arrest. 2

• Minimally invasive approaches via right minithoracotomy, port-access, thoracoscopic, or robotic assistance yield comparable outcomes to full sternotomy when performed by highly experienced surgeons. 1, 2

• Chordal-sparing technique is essential – Preservation of the subvalvular apparatus maintains left ventricular geometry and prevents postoperative ventricular dysfunction; this applies to both mechanical and bioprosthetic implants. 2

Valve Selection for Replacement

• Mechanical prostheses provide superior durability but require lifelong warfarin anticoagulation; preferred for younger patients who can reliably manage anticoagulation. 2

• Bioprosthetic valves avoid long-term anticoagulation but undergo structural deterioration after 10–15 years; generally favored for patients older than 65–70 years or those with contraindications to anticoagulation. 2

Operative Mortality and Outcomes

• Replacement mortality ranges from 2% to 6% in experienced centers, roughly double the 1%–3% mortality observed with repair. 2

• Risk increases markedly in elderly patients with severe symptoms and pulmonary hypertension, those with prior cardiac surgery, or when combined with other cardiac operations. 2

• Complete heart block requiring permanent pacemaker occurs in 1%–2% of replacements. 2

Volume and Expertise Considerations

Patients requiring mitral valve surgery should be referred to centers performing >140 mitral operations per year, where repair rates reach ~77% (versus ~48% at low-volume centers) and operative mortality is approximately 50% lower. 1, 2 Complex repairs should be performed by surgeons with specific expertise in mitral valve reconstruction. 1

Common Pitfall

The most critical error is performing replacement when a durable repair is achievable. 2 When in doubt about repair durability, replacement is preferable to a poor repair, but the threshold for choosing replacement should be high given the substantial mortality and morbidity advantages of successful repair. 1, 2