The vast majority of procedures to repair or replace heart valves are done on the mitral and aortic valves on the left side of the heart. The mitral valve controls in?ow and the aortic valve controls out?ow for the hard-working left ventricle that pumps blood to the rest of the body. These two valves are more prone to disease, and they are also more crit- ical to the overall function of the heart.
The progress of valve disease in any one person can be unpredictable, so the course and timing of your treatment involves individualized decision making. If you are not having symptoms, or if your valve irregularity is not affecting your heart’s function negatively, your cardiologist may choose just to watch your condition carefully.
For badly damaged and narrowed valves, valvu- loplasty (opening a valve with a balloon-tipped catheter), or surgical repair or replacement may be necessary. A valvuloplasty is a less invasive procedure, because the repair is done using a catheter threaded into your heart through an artery. Other types of repair or valve replacement almost always involve open-heart surgery, meaning you are given a general anesthetic, the breastbone is divided, and a heart-lung machine takes over the function of your heart during the procedure.
Usually, your cardiologist and a thoracic (chest) surgeon will work together to determine what type of procedure is required, and when to do it. Even if you don’t have any symptoms, these procedures are some- times necessary to prevent damage to your heart.
Valvuloplasty
Valvuloplasty, which uses a balloon catheter to open a valve, is most often done to correct moderate to severe mitral valve stenosis. It can also be done on the tricuspid and pulmonary valves, and rarely, the aortic valve. The procedure is done in a catheterization laboratory rather than an operating room and is similar in many ways to balloon angioplasty done on coronary arteries .
You will be given a local anesthetic at the site where the catheter will be inserted, usually in the groin. The surgeon makes a small incision and threads a balloon-tipped catheter (a thin tube) into an artery or vein. To open a mitral valve, he or she guides the catheter up into the right atrium of the heart, piercing through the atrial septum (the wall that separates the right and left atria), and through the left atrium into the mitral valve. He or she in?ates the balloon, which opens up the stiffened or fused valve lea?ets, pushes aside and compresses any calcium deposits, and stretches the valve opening. Then the balloon is de?ated and the catheter is removed. The hole in the atrial septum will heal by itself.
There is some risk that the valve will close up again or leak some- what after the procedure. But after a successful valvuloplasty, you can probably enjoy a lifestyle as active as your lifestyle before the procedure, if not more so.
Other Types of Valve Repair
Other types of valve repair are open-heart surgical procedures. A sur- geon may ?x a valve in several ways:
• Commissurotomy is a procedure to open a narrowed (stenotic) valve by cutting between thickened or fused lea?ets along their natural edges (called commissures).
• Annuloplasty reshapes and strengthens a regurgitating (leaking) valve by inserting a ring device that supports the valve opening and enables it to close tightly. The valve is also surgically repaired.
• Cutting out part of a lea?et and then sewing the remaining tissue back together may enable the valve to close more tightly. Some- times holes or tears in a lea?et can be patched.
• Repairing supporting muscles (chordae tendoneae) that are torn or stretched may allow the lea?ets to close fully.
• Removing calcium buildup from leaflets may improve valve closure.
Repairing your own valve instead of replacing it may produce better, longer-lasting results and minimize complications such as blood clot- ting. But repair may not be possible if valves are badly damaged or are degenerated from calci?cation. If a person had rheumatic fever, the dis- ease can continue even after repair. Some mitral regurgitation caused by coronary artery disease is particularly dif?cult to treat successfully with- out replacing the valve.
Valve Replacement
If valve repair or valvuloplasty is not feasible or successful, a surgeon can remove your heart valve and replace it with either a mechanical or a biological substitute (prosthesis). A mechanical valve is made of metal and plastic; a biological valve (bioprosthesis) is made from animal or human tissue. Each type has some advantages and disadvantages that you and your doctor need to consider.
Mechanical valves offer the practical advantage of durability: even if they are placed in a young person, they are likely to last a lifetime. Many models are available; your surgeon may prefer one model over another because of the procedure required to place it, but from your point of view, there is little if any difference between these products. However, there is a tendency for blood to clot around any mechanical valve. A blood clot could clog the valve, or break off and travel elsewhere in the body (including the brain, which could cause stroke). As a result, anyone with a mechanical valve must take warfarin, an anticoagulant med- ication (see page 172), for life.
A biological valve, unlike a transplanted heart, is not living tissue and usually does not cause rejection problems. The natural tissue is sterilized and treated with preservatives. Several options are available: an animal tissue valve (xenograft or heterograft), usually the aortic valve of a pig; a human valve (allograft), retrieved from someone who has died; or more rarely, the person’s own valve (autograft)— for example, the pulmonary valve is moved from the right side of the heart to replace the aortic valve on the left—in what is known as the Ross procedure. (The pulmonary valve is then replaced with a prosthesis.) The main advantage of a biological valve is that it is much less likely to cause clotting than a mechanical valve. You may need to take anticoagulants for several weeks or months after the procedure, but not permanently. How- ever, the tissue is not as strong as a mechanical valve and more likely to calcify over time. An animal valve might need to be replaced in 10 to 15 years (or even sooner in a child or young adult). A human valve might last longer, but may not be readily available.
Generally, a mechanical valve is a practical choice for a person under 70 years of age who can safely take anticoagulants. A biological valve may be a good choice for an older person, particularly if he or she cannot tolerate anticoagulants, or for a woman who plans to become pregnant (because taking anticoagu- lants during pregnancy is not safe).
The risks of valve replacement surgery depend on your age, the overall condition of your heart, and other medical conditions. After suc- cessful surgery, you will probably be able to return to a normal level of exercise. Any arti?cial heart valve is subject to infective endocarditis, so you will need to take antibiotics before dental or surgical procedures .
What to Expect
If you and your doctor decide that repair or replacement of a heart valve is the best option for you, you will probably be able to schedule the operation at a time that is best for you (rather than having an emer- gency procedure). As for any surgical procedure, do not hesitate to dis- cuss any questions or concerns with your cardiologist and your surgeon. Make sure that they know about all medications you are taking, includ- ing over-the-counter drugs such as aspirin. If you smoke, your doctor will recommend that you quit at least 2 weeks (but preferably 6 weeks) before surgery, because smoking can lead to problems with blood clotting and breathing.
You will probably be admitted to the hos- pital the day before surgery or the morning of the procedure. Because general anesthesia is safest on an empty stomach, you will be told not to eat anything after midnight. (If you do, be sure to tell a doctor about it.) You will probably have a chest X-ray, blood tests, urine tests, and an electrocardiogram before the procedure, and you will be given a mild seda- tive to relax you before you go into the oper- ating room. Your chest will be washed, treated with antiseptic, and shaved if necessary.
You will be given a local anesthetic to numb your arm, and an intravenous line will be inserted to give you anesthesia. After you
are completely anesthetized, a tube will be placed down your trachea (windpipe) to connect you to a respirator, and another tube will be threaded through your nose and down your esophagus into your stom- ach to remove air and ?uids from your stomach. A catheter (thin tube) will be inserted in your urethra and up into your bladder to collect urine during the operation and recovery.
Your breastbone will be divided to expose your heart. A heart-lung machine will take over the function of your heart during surgery, so that your heart is immobile while the surgeon works. You will be given anticoagulant medications to prevent your blood from clotting.
Depending on the extent of surgery, the operation will take from 2 to 4 hours. When the valve repair or replacement is complete, your heart will be started again and the heart-lung machine will be disconnected. Most people spend 1 to 3 days in the intensive care unit and about a week in the hospital.
Your recovery from valve surgery may take several months, as your breastbone mends and your heart adjusts. Your doctor will advise you about physical activity, and he or she may recommend a cardiac rehabil- itation program. You may be able to go back to work in
1 to 4 months, depending on the physical demands of your job. You may need to take anticoagulant medications, either temporarily or permanently, if you have had a mechanical valve replacement.
Some people who have mechanical valves can occasionally hear a clicking sound in their chest—the sound of the new valve at work. This is a perfectly normal, and even reassuring, sign that the valve is working properly.
Valve repair or replacement is usually successful. Failure of a new valve is rare, but if you experience signs of valve failure (basically, the symptoms of valve problems, described earlier), tell your doctor imme- diately. You will also need to be on the alert for signs of infection, such as fever, weakness, chest pain, and shortness of breath. Endocarditis can affect arti?cial valves as well as natural ones.