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Aortic valve stenosis
Stenotic aortic valvesneed to be repaired or replaced before irreversible damage to the heart occurs. The timing of repair or replacement is critical because once the symptoms of heart failure develop--chest pain, fainting, shortness of breath--survival is limited to two or three years if the condition is left untreated.
Typically the aortic valve is replaced after the symptoms develop, which may occur in infancy or adulthood. In rare instances, aortic valve replacement is recommended in patients who have not yet developed symptoms but have very tight valves. In any case, the aortic valve can be surgically repaired or replaced in almost all patients, from children to otherwise healthy people in their 80s.
Infants who develop symptoms of aortic stenosis need treatment early on in life and often follow a two-stage treatment plan starting with balloon valvuloplasty. Balloon valvuloplasty is a heart catheterization procedure where a small tube equipped with an inflatable device is inserted inside the heart where it is dilated to mechanically widen the valve. This procedure is usually performed to delay surgical replacement of the valve until the infant has time to reach childhood, when a normal-sized valve can be used for replacement. When necessary, surgeons can replace valves in infants, but it's preferable to wait until the infant reaches childhood.
When stenosis occurs in the older child or adult, it frequently is associated with a bicuspid aortic valve. For these patients, replacement may not be necessary until the stenosis worsens or leakage develops. Medications may be used to delay replacement and help alleviate some of the symptoms of stenosis. Digitalis may be prescribed to augment the contraction of the ventricle. Diuretics, vasodilators, or antiarrhythmics may be prescribed to reduce the workload on the heart, and/or regulate the heart rhythm. In this situation, the condition of the valve and function of the heart are carefully monitored with regular checkups to ensure that the valve is replaced at the appropriate time before the left ventricle is irreversibly damaged.
Valve replacement requires heart surgery. The surgeon removes the faulty valve and replaces it with an artificial one--either a mechanical prosthetic valve or a bioprosthetic valve. Approximately 95 percent of all valve replacements are performed on mitral or aortic valves. Occasionally, the surgeon will need to use a complex procedure when repairing or replacing the valve to enlarge the aorta and/or part of the left ventricle leading to the aortic valve to accommodate an adequate-sized valve. The key to selecting the right prosthetic valve involves weighing the advantages and disadvantages of certain valves with the risk of anticoagulation therapy.
Mechanical prosthetic valves, made of synthetic materials, are more durable than tissue valves but require a blood-thinning drug, like warfarin, to be taken for the rest of an individual's life. People who take these drugs must have their blood tested regularly to ensure that their blood has not gotten too "thick" or "thin." This constant monitoring can be especially challenging in children. In addition, blood thinners are not recommended for people who play contact sports and pose risks for a developing fetus. Women who wish to have a pregnancy or young adults who wish to participate in contact sports should discuss in detail the choice of valves with the congenital cardiologist and surgeon.
Bioprosthetic valves do not require blood thinners; however, they are not are not as durable as mechanical valves and may require replacement within 10 years. In general, patients younger than 70 receive mechanical valves; those over 65 receive bioprostheses. For some younger people, a bioprosthetic valve may be used with the understanding that an additional surgery will be necessary in the future to replace it with a mechanical valve.
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