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.: Aortic Valve Stenosis

Photo of a artificial valve being surgically implanted into one of Dr. Ott's patientsValvular heart problems involve primarily narrowing (stenosis) or leakage (insufficiency or regurgitation) of the aortic valve (primary outlet valve of the heart) or mitral valve (primary valve between the upper and lower chambers of the heart). All blood pumped by the heart passes through these valves. Problems can be caused by rheumatic fever or simply by degenerative changes occurring over many years of opening and closing every second of the day. Certain systemic illness and disease can contribute to the development of valve problems including auto immune disease such as arthritis, infections and kidney failure.

A congenital defect in which the aortic valve has only two leaflets instead of three is one of the most common causes of aortic valve narrowing.

Aortic valve disease of a degree that requires surgical intervention usually requires replacement of the valve although repair is possible depending on the specific anatomic situation and the experience of the surgeon. The most important decision facing a patient who requires aortic valve replacement is the type of valve to use. The decision can only be made after a thorough, open and honest discussion with a surgeon experienced with all types of valve devices.

Photo of a synthetic mechanical valve

Valves used for replacement are of two basic types: tissue and mechanical. Mechanical valves are constructed entirely of man made materials usually pyrolite carbon, a diamond hard material attached to a Dacron sewing ring to attach it to the patient's tissue. Current mechanical valves are usually of a tilting disk one way flow design and have the advantage that they do not wear out. Mechanical valves do, however, require lifelong treatment with Coumadin, a blood thinner that can cause increased susceptibility to bleeding particularly in older patients.

 

Illustration of a real-tissue valve being replaced during a surgical procedure

Tissue valves include several types all of which have the advantage of not requiring Coumadin but only long term

treatment with a platelet inhibitor blood thinner such as enteric coated baby aspirin which has few side effects. All

tissue valves have the disadvantage that they may wear out with time and require further valve surgery. However, with current advances in valve preparation and preservation techniques, one can expect an 85-90% chance that a tissue valve will remain functional after 15-20 years. These valves are most appropriate for patients over 50-60 years of age and are constructed from either bovine (cow) pericardium or porcine (pig) heart tissue. In younger more physically active patients, homograft valves (cryopreserved (deep frozen) human cadaver valves) may be appropriate because of their favorable hemodynamic characteristics but they require a more extensive operation and may wear out with time.

Another valve option suitable primarily for younger patients and children is the so called Ross switch procedure which consists of transferring the patient’s pulmonary valve to replace the diseased aortic valve. The pulmonary valve must then be replaced with a cryopreserved human cadaver valve. This procedure offers an excellent hemodynamic result, but is a much more extensive procedure technically, has a higher operative mortality and leaves the patient with two tissue valves that will eventually wear out rather than just one. Nonetheless, it is appropriate to use in specialized cases.

Dr. Ott has the advantage of having extensive experience in valve surgery of all types and will thoroughly discuss the risks and benefits of each in an honest and unbiased fashion based on the individual patient’s data, needs and wishes.

 

David A. Ott, M.D.
Post Office Box 20345
Houston, Texas 77225
Phone - (832) 355-4917
Fax - (832) 355-3770
Service - (832) 355-4900
© 2005 Dr. David A. Ott, M.D.
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daott@heart.thi.tmc.edu