Surgical treatment of diseased heart valves

Some people with diseased or damaged heart valves can lead normal lives as long as they get careful medical supervision. Medical treatment with drugs may prevent the need for further intervention. Others with more severe heart valve damage need surgery. In some cases, operating to repair a patient own valve may relieve the stenosis or leakage. In other cases, the valve is so badly damaged that it must be replaced. The best solution depends on the patient's clinical condition as well as the patient's needs.

Heart Valve repair:

Most heart surgeons believe that if a heart valve can be repaired with the likelihood of relatively good long-term results, repair should be attempted rather than valve replacement. Although many excellent artificial heart valves are currently available, the perfect heart valve substitute has yet to be developed. If any one of the four valves is stenotic or narrowed, physicians may be able to open the closed valve with a scalpel by carefully opening the fused leaflets, or commissures. This is called commissurotomy or valvotomy. It is most commonly done in patients who require heart surgery for congenital pulmonary stenosis and those requiring mitral valve surgery for mitral valve stenosis related to rheumatic fever. The short-term and long-term results in both cases are quite good.

For mitral valve incompetence and tricuspid valve incompetence, there are numerous repair techniques that can be used depending on the circumstances. Two common surgical repair procedures are:

1. Ring Annuloplasty: which is a procedure in which the annulus, or ring like part of the valve, is tightened by placing a ring of metal, cloth or tissue around the valve (for example, the Cosgrove and Carpentier-Edwards Ring).
2. Surgical reconstruction of the leaflets, chordae, and/or papillary muscles of the valve. This can be done by cutting away extra cusp tissue and sewing the edges together, or by shortening the cords that act like hinges.

Heart Valve Replacement:

Sometimes heart valves are seriously deformed, degenerated, or destroyed. When that is the case, repairing the valve isn’t reasonable. The old damaged native valve is removed and replaced with a new non-native prosthetic valve, which can be mechanical or made of tissue.

Mechanical valves are made of hard and durable metals, carbon ceramics, and plastic fabrics. These materials have been used for many years in mechanical heart valves. A fabric ring made from polyester is used to attach the mechnical valve to tissues in the patient's heart. The cuff in a larger mitral valve sizes contains a polytetrafluroethylene (PTFE) surgical felt. New mechanical heart valve has 2 leaflets that tilt to open and close. The leaflets are hinged to the valve housing. . They tend to be low profile so they take up less space and have better flow characteristics. These types of valves have been put on pulse duplicators with which accelerated wear can be tested. Tests of one hundred simulated years of use show very little actual wear on the valve. These tests indicate that, in most cases, satisfactory function can be expected for many years.

The advantage of mechanical valves is that they are durable due to the strong materials used in their construction. These materials however, are not natural to the body so they may need medications (Anticoagulants) to prevent blood clots from forming on the mechanical valve.

Anticoagulant is also referred to as a “blood thinner,” which prevents blood clots from forming on the valve itself. The most common anticoagulant is coumadin, otherwise known as warfarin. Coumadin works by prolonging the time it takes for your blood to clot. The drug must be carefully monitored by taking a blood test (INR). Your physician (cardiologist or primary care physician) will prescribe a dose to keep the INR within certain parameters. In order to control the level in your body, it is important to take Coumadin at the same time each day and to avoid alcohol consumption, which affects the action of Coumadin. It is recommended that you ask your physician before you take any over-the-counter medications, including aspirin, cold remedies, antibiotics, vitamins, and sleeping pills.

If the anticoagulation is too great ( high level of INR test), the patient is more prone to develop bleeding problems, which can include bleeding into the stomach, intestines, brain, or kidneys. A person with bleeding ulcers would be prone to bleed more. If you were cut, you would have a problem with abnormal bleeding. The Coumadin treatment can be reversed in an emergency situation if necessary.

Another problem related to mechanical heart valves is blood clots that occur even if the anticoagulation level is appropriate. These clots can form on or near the artificial valve and travel to various parts of the body, causing strokes and other

Problems ( if you have a mechanical mitral valve and you developed a clot on this valve, you will mostly complain of shortness of breath and you will need to go to the emergency room to do an echocardiogram to confirm the diagnosis. You might need another surgery for replacement of this clotted mechanical valve). Fortunately, the incidence of this is small.

A tissue valve has the advantage of being similar to the natural heart valve. That's why these valves are well tolerated in the body) without special medication. The disadvantage of a tissue valve is that it is usually less durable than natural valves or mechanical valves.  They wear out more rapidly especially in children and young adults. Currently, the most commonly used tissue valves come from a pig. The pig valve can be used to replace any of the four human heart valves. Another type of tissue valve is made from the pericardium of a cow or horse.  Another type of tissue valve is the aortic homograft valve, which is used to replace the aortic valve and sometimes the pulmonary valve. These valves come from a human donor and are removed right after death. The incidence of blood clot problems with these tissue valves is generally quite low. Most patients with tissue valves do not need to be anticoagulated.

Some patients who undergo aortic valve replacement have a procedure called the Ross Procedure. During this operation, patients have their own pulmonary valve removed and used to replace the aortic valve. The pulmonary valve is then replaced with a homograft.

Both mechanical and tissue heart valves are more prone to become infected than your own normal heart valves.

A surgeon will use his or her experience and knowledge to recommend the valve best suited for a patient's condition. Factors include the patient's age, the extent of valve disease, the Size of the valve being replaced, the patient's ability and willingness to take anticoagulation medications (blood thinners), and the need for the patient to take anticoagulation medications because of other cardiac conditions (Atrial fibrillation)

Heart valve surgery can be performed by three surgical approaches:

Sternotomy: an incision is made down the middle of your chest separating your breastbone and muscle. The breastbone is closed with stainless steel wires at the conclusion of surgery.

Thoracotomy: an incision is made in your rib cage similar to lung surgery.