The mitral valve is one of four valves that regulates blood flow through the heart. The mitral valve is located between the left upper and left lower chamber of the heart (left atrium and left ventricle, respectively).
Mitral valve regurgitation (or “insufficiency,” as it is sometimes called) may be the result of a condition called mitral valve prolapse, in which the valve leaflets and the fibers, or cords, that support them become floppy and elongated. Mitral valve prolapse does not always lead to regurgitation. In fact, many people who have mitral valve prolapse never develop severe leaking of the mitral valve.
Patients with mitral regurgitation rarely have symptoms until the valve is leaking severely. These symptoms include difficulty breathing, trouble exercising and fatigue. Physicians often recommend treatment for severe mitral regurgitation before symptoms develop.
Severe mitral regurgitation over time can lead to an increase in the size of the heart (left atrium and ventricle), a decrease in the amount of blood flow to the body and an increase in the work of the heart. Failure of the left ventricle may result.
Treatments for Mitral Regurgitation
Depending on the severity of your heart valve disease, your cardiologist may recommend:
- Surgical treatment
- Non-surgical, less invasive treatment
No medications have been proven to help the flaps of the mitral valve close properly. However, your doctor may recommend medications to help reduce the symptoms of mitral regurgitation.
If you are diagnosed with mild (grade 1) or moderate (grade 2) mitral regurgitation, your doctor may decide the best care approach is to monitor your condition and prescribe drugs to help treat its symptoms. These medications may include:
Even if you are on medications, you may notice an increase in fatigue or shortness of breath. If this occurs, you should let your doctor know immediately.
- Diuretics: Drugs that help reduce fluid accumulation in your body by increasing fluid loss through urination.
- Medications to decrease high blood pressure, which can complicate mitral regurgitation. Your doctor may recommend you take one or more of these anti-hypertensive medications to help manage your blood pressure:
- Beta blockers, which act to reduce heart rate and the heart’s output of blood
- Vasodilators,which act to dilate (widen) blood vessels. Examples include ACE inhibitors and calcium channel blockers.
- Antibiotics: Drugs that kill bacteria may help prevent or treat endocarditis (en-do-CAR-di-tis), an infection of the heart valves. Leaking heart valves are at higher risk of being infected during routine teeth cleaning or surgery.
If you are diagnosed with moderate to severe (grade 3) or severe (grade 4) mitral regurgitation, your doctor may recommend a surgical treatment.
One measure used to determine whether a surgical approach should be taken is called the “ejection fraction.” The ejection fraction measures the fraction of blood that your heart’s left lower chamber is able to pump to the body during a heartbeat.
Surgery is recommended to treat the mitral valve if the ejection fraction drops below 65 percent, or if the left ventricle is enlarged (larger than 45 millimeters). Your doctor may recommend surgical treatment of the valve if a chance in your left ventricle is detected by ultrasound, even if you do not have symptoms.
Depending on your condition, your doctor may recommend either of these two surgical approaches:
Valve repair, when possible, is preferred over valve replacement. Heart function is usually better if your valve can be repaired. And complications are typically fewer than with valve replacement.
- Mitral valve repair or
- Mitral valve replacement
What to expect
Before surgery, you will receive a general anesthetic, which is a medicine that will put you into a deep sleep during the procedure. During the surgery, your doctor will make an incision (cut) along the length of your breast bone (the flat bone in the center of your chest) to expose your heart.
You will be connected to a heart-lung bypass machine, which will take over your breathing and blood circulation during the surgery. The surgeon will stop your heart, make a cut in it to expose the valve, then repair or replace the valve.
Mitral Valve Repair
Various techniques may be used alone or in combination to repair the mitral valve:
Newer surgical techniques use endoscopy to perform these procedures. Endoscopy requires smaller incisions and involves robotic surgical techniques.
- Leaflet resection, in which the surgeon “re-models” the leaflets by removing some portion of the leaflet tissue and reconnecting the leaflets with sutures;
- Annuloplasty, in which-the surgeon implants a ring (a collar-like structure) around the opening of the mitral valve to make it smaller.
- Edge-to-Edge, a procedure in which the surgeon fastens portions of the valve leaflets together.
- Chordal transposition, in which the surgeon re-positions and re-attaches the fibers (Chordae tendineae) that connect the muscles in the left ventricle to the mitral valve leaflets.
Mitral Valve Replacement
If your valve cannot be repaired and it must be replaced, your surgeon will implant an artificial, or prosthetic (PROS-the-tic), valve. An artificial valve can be either mechanical (made of metallic components) or tissue.
- Mechanical valves
Mechanical valves are devices made of metallic materials, such as titanium. They offer life-long durability and rarely need to be replaced. The main risk with mechanical valves is blood clot formation (thromboembolism – THROM-bo-EM-BO-lism). In order to prevent blood clots after receiving a mechanical valve, you will need to take blood thinners for the rest of your life.
A secondary risk is associated with taking the blood-thinning medications. Blood-thinning medications increase the risk of bleeding. If the blood-thinning drugs make the blood too “thin,” you can experience excessive bleeding even with minor cuts. If the blood is too “thick,” clots can form on the valve that can later break off and lodge in the blood vessels to the heart or brain, increasing the risk of heart attack or stroke.
Careful monitoring to ensure the correct levels of anti-coagulation medications is critical. It may require a monthly visit to the doctor’s office. New home monitoring units may make it possible to regulate your blood-thinning medications without going to the doctor’s office.
- Tissue valves
Tissue valves are made of valve tissue taken from a cow (bovine), pig (porcine) or human cadaver (homograft). Because tissue valves do not encourage blood clot formation, patients who receive them do not need to take blood-thinning medicines for very long.
However, tissue valves have not historically been as long-lasting as mechanical valves. A tissue valve (also called a bioprosthetic) can wear out over a period of 10 to 15 or more years. If it deteriorates significantly, the valve must be replaced. Replacement, of course, requires repeat surgery. Because of durability concerns, tissue valves are implanted primarily in older patients. However, they have improved steadily and are being used more and more frequently.
Risks of Heart Valve Surgery
- Death. The overall mortality risk (risk of death) for heart valve surgery is less than 5 percent (5 out of every 100 patients).
- Irregular heart beat or arrhythmia. Arrhythmias can make you tired or short of breath and put you at risk of blood clots. You may need to take anti-coagulant (blood thinning) medications to lower the risk of blood clots, which may form in the heart due to irregular heart beat.
- Infection. After valve surgery, you may be prone to endocarditis (en-do-CAR-di-tis), an infection or inflammation of the heart valves. It occurs when bacteria enter the bloodstream and infect damaged valve leaflets. People who have abnormal or damaged heart valves or who have received an artificial heart valve are more vulnerable to the infection.
- Risks associated with being put to sleep with general anesthesia.
- Risks, such as bleeding, associated with surgery.
After Valve Surgery
Your recovery in the hospital may last from four to 10 days, depending on your condition. You may spend the first days after surgery in an intensive care unit (ICU) where your heart will be closely monitored.
While in the ICU, you may have a number of tubes in your body to help recovery, including a tube to help you breathe, a tube to drain fluids from the stomach while you are not eating, tubes to drain fluid from your chest, a small tube to empty your bladder and a tube in your arm to measure blood pressure. These will be removed when you are moved out of the ICU to another care unit.
You will receive therapy to prevent complications such as pneumonia, collapsed lung or infection. A nurse or therapist may lead you in deep breathing exercises and coughing and encourage you to move your legs to lower the chance of blood clot formation. Your therapy may also include gentle patting on the back to loosen fluids in the lungs.
Physical therapy will also be part of the recovery process. In the hospital, you will be encouraged to walk around and you will be shown how to move your arms without hurting your breastbone. You will also learn how to do daily activities in ways that will not interfere with the healing process.
Non-Surgical, Less Invasive Treatments
New, experimental approaches that do not require open heart surgery are being developed to repair the mitral valve and stop mitral regurgitation.
These approaches use a catheter, a small flexible tube threaded through the arteries from the upper thigh to the heart. Several approaches are under development, but have not been approved in the United States by the Food and Drug Administration.
- In one approach, a mechanical clip (not unlike a tiny clothespin), is guided to the mitral valve through the catheter. The clip catches the edges of the valve’s leaflets to pull them together and improve their ability to stop blood from leaking back into the upper left chamber. Doctors have collected three years of results with the clip in a non-random study. A study is underway to compare the clip’s effectiveness with that of surgical repair.
- In another approach, doctors are exploring ways to thread a spring-type device through the arteries that can change the shape and size of the annulus, the ring of tissue that encircles the opening of the mitral valve. A change in size and shape of the annulus is intended to help the valve leaflets close properly.