Mitral Valve Disease

Surgery

At some point, the risks from a leaking or narrowed heart valve (including blood clots, heart enlargement, stroke, and heart failure) become greater than the risks of surgery to fix the problem. Mayo cardiovascular experts assess these risks and advise patients if and when surgery is necessary.

Mayo Clinic surgeons have extensive experience and a strong record of excellence in heart valve repair and replacement. Mayo surgeons repair or replace more than 500 mitral valves each year. This volume makes Mayo one of the largest and most experienced medical centers for this surgery.

When is Surgery Needed

Most often, mitral valve leaking (regurgitation) is mild and severe regurgitation develops slowly. Because no symptoms develop for decades, the patient may not even know the condition is present. One of the most challenging aspects of treating mitral valve disease is determining when asymptomatic mitral valve regurgitation poses enough risk of congestive heart failure and irreversible heart damage to consider surgery rather than to continue treatment with medications.

The first objective guidelines for this surgery were established by a Mayo Clinic study of 456 patients who had mitral valve regurgitation that had not yet produced significant symptoms. The study found that patients with a regurgitant orifice (the orifice through which blood flows backwards) larger than 40 mm2 who were treated only with medication were more than five times more likely to die than those with the same severity of regurgitation who underwent valve repair surgery.

The most common reason for mitral valve surgery is regurgitation (leakage) due to mitral valve prolapse and other causes. Valves with regurgitation are usually repairable and rarely require replacement.

The other main reason for surgery is mitral valve stenosis (narrowing). Usually, narrowed valves require replacement.

Mayo Clinic offers minimally invasive heart surgery options for both surgeries.

Cardiovascular surgeons generally agree that, whenever possible, a heart valve should be repaired instead of replaced. Heart valve repair leaves patients with their own normally functioning tissue, which is resistant to infection and does not require taking blood-thinning medication.

In some cases, such as with valves damaged by rheumatic heart disease, the valve may be too damaged and must be replaced with a prosthetic (artificial) valve.

Surgery to Treat Mitral Regurgitation

Prolapsing mitral valve repair

Enlarge

At Mayo Clinic, 95 percent of patients with leaking caused by mitral valve prolapse undergo valve repair rather than replacement.

Surgery to fix leaking (regurgitation) due to mitral valve prolapse (bulge due to weakening) depends on the prolapse's location. The mitral valve is a bileaflets valve; it has two flaps or leaflets: posterior and anterior.

Annuloplasy band added for protection

Enlarge

If the prolapse occurs on the posterior leaflet, Mayo Clinic surgeons repair it by removing a section from the bulging area, sewing the cut edges back together, and sewing an annuloplasty band into the posterior section of the annulus (ring of fibrous tissue surrounding the leaflets) to reduce its circumference and ensure that the leaflets close properly. The durability of this repair at Mayo Clinic is very good; only about 0.5 percent of patients per year require a second surgery.

If the prolapse occurs on the anterior leaflet, Mayo Clinic's approach is to replace a torn or stretched-out supporting cord (chordae tendinae) with an artificial cord (neochordae) to better anchor the leaflet to the heart wall. Sometimes a section from the bulging area is also removed. As in repair to a posterior leaflet, an annuloplasty band is added for additional support.

If prolapse occurs on both leaflets (bileaflet), a combination of these techniques may be used.

Surgery to Treat Mitral Valve Stenosis

Surgery to eliminate mitral valve stenosis is sometimes accomplished by surgically separating or shaving back the valve leaflets (called commissurotomy). However, most patients with narrowed mitral valves require valve replacement.

Mitral Valve Replacement

Mitral valve replacement involves replacing the defective valve with a prosthetic (artificial) valve that is sewn to the annulus of the natural valve. Two kinds of replacement valves are available:

Mechanical valves

Mechanical valves made of synthetic materials are reliable and long-lasting. Because blood tends to stick to mechanical valves and create blood clots, patients with these valves need to take blood-thinning medicines (anticoagulants) for the rest of their lives.

Biological valves

Biological valves are made from animal tissue (called a xenograft) or taken from the human tissue of a donated heart (called an allograft or homograft). Sometimes, a patient's own tissue can be used for valve replacement (called an autograft/Ross procedure).

Patients with biological valves usually do not need to take blood-thinning medication. However, these valves are not as durable as mechanical valves and may need to be replaced. Biological valves are used most often in elderly patients.