Anatomy of the Mitral Valve

The heart is a biological pump with four chambers and four valves directing the flow of blood. The right side of the heart collects the blood from the body and pumps it into the lungs.

The left side of the heart collects the blood from the lungs and, in turn, pumps it into the body. Between the two chambers on the right side lies the tricuspid valve. The other valve -- the pulmonary valve -- is on the right side is between the bottom chamber and the main feeding artery to the lungs.

On the left side lies the mitral valve between the top chamber and the bottom chamber. The aortic valve lies between the bottom chamber on the left side and the main feeding vessel of the body -- the aorta. The pulmonary valve and the aortic valve have three leaflets and are relatively simple valves. Their function resembles that of valves of an engine, except these valves allow blood to flow in one direction only.

The mitral valve is a complex apparatus whose function is intimately related to the left ventricle -- the bottom chamber on the left side. This valve has four basic components; the annulus, or ring of the valve; two leaflets; the chords that attach to the free edge of the leaflets at one point, and to the papillary muscles at the other end. All are attached to the base of the left ventricle. All these components work in harmony to maintain an effective and efficient function of the left ventricle.

Disorders of the Mitral Valve: Any disruption of the mitral valve components could lead to a leaking of the valve. This is commonly known as mitral regurgitation.

A narrowing of the valve -- mitral stenosis -- could also occur--and is much more common in third-world countries. Typically it is linked to the disease -- rheumatic fever. This condition is rare in the United States.

A much more common condition is mitral valve prolapse, which causes poor operation of the mitral valve leaflets, and may result in leakage or a backward flow of blood into the left atrium from the left ventricle.

However, not all patients with mitral valve prolapse have symptoms or leakage and do not require treatment. They need to be followed carefully to detect progression of this disorder.

As mitral regurgitation progresses, fluid builds up in the lungs and increases the workload of the left ventricle. The body compensates for this by retaining more fluid, and by increasing muscle mass of the left ventricle. At some point, the compensation fails. Patients become progressively more symptomatic, and this can result in congestive heart failure and dilation of the left ventricle.

Symptoms of Mitral Valve Disorders: Not all patients with mitral valve prolapse need surgery, unless there is a significant regurgitation of blood, resulting in symptoms, such as:

  • Shortness of breath with exertion or exercise and/or when lying down flat in bed;
  • Swelling of ankles and feet;
  • Awakening in the middle of the night with shortness of breath;
  • Fatigue, feeling tired with a lack of energy.

The fluid the body retains to compensate for the leaky valve tends to gravitate toward the feet during the day, causing ankle swelling, and manifests itself as tightness of shoes in the evening. In a prone position at night, the fluid that has gravitated to the feet moves back into the bloodstream, causing increased lung congestion. This requires patients to wake up and sit up, preferably near an open window, in order to obtain relief.

Treatment of Mitral Valve Disorders:

Once it's determined that a diseased heart valve needs treatment, the available choices are valve repair or valve replacement:

McLaren offers traditional and robotic assisted mitral valve repair surgery.

  • Valve repair - which preserves the patient's valve and leaflets. Sometimes repairs require a minimal surgery procedure and other times repairs need a more extensive surgery. Repair is most often possible for mitral valve regurgitation and tricuspid valve regurgitation.
    • Transcatheter Mitral Valve repair. This procedure uses an implant that goes onto the center of the mitral valve. This is a minimally invasive procedure called transcatheter mitral valve repair. This reduces the mitral regurgitation and allows the valve to continue to open and close, allowing blood to flow. The procedure takes 1-2 hours with an average of a one-night stay at the hospital.
  • Valve replacement - which may include transcatheter aortic valve implantation or replacement (TAVR or TAVI), or other minimally invasive procedure. In many cases, the best long-term solution may require a more involved surgery such as the Ross procedure or the insertion of a new tissue or manufactured valve. Treatment with medications, including diuretics, may be recommended.

After mitral valve repair, all patients are kept on a medication to thin the blood for two to three months to allow for healing to occur within the heart. These blood thinners are usually stopped unless the patient has an irregular heartbeat. Patients who have had a mitral valve replacement are required to continue taking Coumadin for life.