Mitral valve surgery is performed by cardiovascular surgeons to treat congenital mitral valve disease, mitral valve stenosis, and mitral valve regurgitation. Disease mitral valves are repaired or replaced. The decision for repair vs. replacement is based on:
- Diagnostic test results (echocardiogram and cardiac catheterization)
- Heart structure and anatomy
- The patient’s age
- The presence of other medical conditions
Indications for Mitral Valve Surgery
Early surgical intervention (for valve repair in particular) may prevent irreversible heart damage. The decision about timing for elective (non-emergency) valve surgery is made between a patient and his or her doctor and is based on comparing the risk of surgery with the benefits available from surgery. Indications for having surgery sooner than later include:
- Severe mitral valve regurgitation in the presence of congestive heart failure symptoms.
- Severe mitral valve regurgitation as diagnosed by echocardiography.
- Enlargement of the left atrium, especially in association with an arrhythmia.
Traditional vs. Minimally Invasive Surgical Approaches
Patients who need surgery on the mitral valve alone or who need multi-valve surgery may be candidates for the minimally invasive approach, but the surgeon makes the determination based on each individual case. The patient’s individual anatomy, diagnosis, and overall heart function are contributing factors. This approach may also include the use of a surgical robot.
Advantages of Mitral Valve Repair
Mitral valve repair is the best option for patients with mitral valve regurgitation and for many with mitral valve stenosis because of the following advantages:
- Better survival and outcome statistics
- Better preservation of heart function and anatomy
- Lower risk of complications, such as stroke or endocarditis (infection)
- No need for anticoagulation therapy
- Improved lifestyle
Mitral valve repair is technically more difficult than mitral valve replacement. Operative success depends on the valve condition, the experience, training, and skill level of the surgeon, and the collaboration between the echocardiographer and the surgeon
Surgical Techniques for Mitral Valve Repair
- Problems with the posterior mitral leaflet are generally corrected with a small triangular or quadrangular resection of the abnormal portion of the valve.
- Problems with the anterior mitral leaflet are managed by transferring or creating new chordae tendinae.
- Mitral valve stenosis can be repaired with a mitral commisurotomy.
- All repairs include an annuloplasty, which is a complete or partial ring placed around the opening of the valve to restore and retain its correct size and shape.
- Mitral valve repair techniques are technically challenging and require a skilled and experienced surgical team to achieve the best result.
Complicated Repair Situations
Patients with mitral valve disease often have complicating conditions, including:
- A mitral valve that has been damaged by endocarditis.
- A mitral valve that has been damaged by calcium deposits.
- A previous mitral valve repair that has failed.
- Atrial fibrillation, an abnormal heart rhythm that may require a concurrent ablation or Maze procedure.
- Coronary artery bypass surgery, aortic valve surgery, or other heart surgery that has caused a new problem with the mitral valve.
Results of Mitral Valve Repair
A cardiovascular surgeon can predict but cannot guarantee the likelihood of a successful mitral valve repair. The long-term outcome of a successful repair is most likely to be good, especially for degenerative valve disease. Statistics show up to a 95% chance that a repaired valve will need no further intervention in the next 10 to 20 years (fewer for a more complex repair). However, rheumatic fever can continue to damage a repaired valve, and mitral regurgitation associated with coronary artery disease creates unpredictable repair results.
Mitral Valve Replacement
If valve repair is not an option, the valve may need to be replaced. Mitral valve replacement is an open heart procedure performed by a cardiothoracic surgeon to treat mitral valve stenosis and mitral valve regurgitation (or a combination of the two called myxomatous valve disease). The native (original) valve is removed, and a new valve is sewn in its place. The new valve can be a biological, homograft, or mechanical valve.
Biological valves are made from pig tissue (porcine), cow tissue (bovine), or pericardium from other species. The natural tissue is supported by an artificial framework, which gives it structure and allows it to be surgically implanted. Biological tissue valves are also called bioprosthetic valves. They last from 15 to 20 years after implantation, are readily accepted by the body, and usually do not cause blood clotting problems.
A homograft valve has been donated from another human who has died. After removal from a donated human heart, it is treated with antibiotics, placed in preservative, and frozen under sterile conditions. Homograft valves are sometimes, but not commonly, used to repair a mitral valve.
Mechanical valves are usually bileaflet valves that are made with non-reactive, well tolerated materials like pyrolite (qualities similar to a diamond) carbon leaflets surrounded with a polyester knit fabric—covered ring. Surgeons choose the type of valve to implant based on how it is sewn into place, but few differences exist between them. The advantage of mechanical valves is their excellent durability—they do not wear out over time. A huge disadvantage is that blood clots on mechanical valves. Because of this risk, patients with a mechanical heart valve must take anticoagulant medications or “blood thinners” and be routinely tested for its level in their blood for the rest of their lives. Blood clots also pose a serious risk for causing stroke.
Past history of heart surgery, patient age, general health, and other conditions that require surgical treatment affect individual risk. Each patient who undergoes elective heart valve surgery should discuss risk factors and potential outcomes with his or her surgeon prior to undergoing the operation.
Life after Mitral Valve Surgery
Patients who undergo successful mitral valve surgery can expect to return to their preoperative condition or better. After wounds have healed, few if any restrictions are placed on the patient’s activity.
Cleveland Clinic www.clevelandclinic.org/heartcenter/pub/guide/disease/valve/mvrepair.htm
Society of Thoracic Surgeons www.sts.org/sections/patientinformation/valvesurgery/mitralvalverepair/
Hoag Heart Institute www.hoaghospital.org/heartinstitute/ValveCenter-ValveRepair.aspx