Features April 2013 Issue

Understand the Risks, Realities Of Having a Bioprosthetic Valve

A new study shows a cholesterol marker could accelerate valve degeneration, but there are other dangers to keep in mind.

Receiving a new heart valve can be a lifesaving treatment, but it’s important to understand the limitations and realities of life with a prosthetic valve. A recent study in the Journal of the American College of Cardiology, for example, found that having elevated plasma ratios of two established cholesterol markers can significantly increase the risk of valve degradation in a patient with a bioprosthetic aortic valve. The two markers were apolipoprotein B and A1 (apoB and apoA1).

ApoB is a major component of LDL (“bad”) cholesterol, while apoA1 is a component of HDL (“good”) cholesterol. “Statins definitely improve the healthy ratio, but it hasn’t been thoroughly studied to see if they improve the longevity of prosthetic valves,” says Cleveland Clinic cardiologist Stephen Ellis, MD, adding that a 2003 study suggests that statin therapy may help prolong the life of prosthetic heart valves.

What to Expect
If you have a bioprosthetic heart valve, meaning it’s made with animal tissue (often from a pig), you have probably been told that its “shelf life” is limited, unlike a mechanical valve, which theoretically should last a lifetime. Dr. Ellis says that the typical bioprosthetic heart valve will last eight to 15 years, but that the time frame is variable and can be influenced by factors such as chronic kidney disease and other health factors. “Although not completely understood, there is an overlap of risk factors for valve disease, particularly aortic stenosis, and coronary artery disease (CAD),” he says.

That means risk factors such as hypertension, high cholesterol and smoking can contribute to CAD and raise your risk of valve disease, too. And a bioprosthetic valve is still vulnerable to those same risk factors.

So following your doctor’s advice about diet, exercise and medication adherence is just as important with a new valve as it is with your original heart valves.

Prosthetic Valve Risks
Two main risks associated with valve replacement are infections and blood clot formation.

Dr. Ellis explains that the risk of valve infection is about one to two percent in the first year, and then much less afterwards. Prophylactic antibiotics, used to prevent an infection rather than treat an existing one, are given to anyone who receives a new heart valve.

The risk of blood clots is about one to three percent per year, Dr. Ellis says, but that the risk and medication treatment regimen will vary, depending on the valve that is replaced. For instance, the blood clot risk associated with an aortic valve replacement is low, while the risks associated with a mitral valve replacement are much higher. In both cases, patients should take warfarin (Coumadin) for a period of months, though again that will depend on the procedure and the overall health of the patient.

A study published in the Journal of the American Medical Association in late 2012 suggests that warfarin use in patients receiving bioprosthetic aortic valves should last at least six months, though you may have other reasons for continuing on antiplatelet therapy.

Aspirin therapy is usually recommended for all valve patients to help reduce future clot risks.

Monitoring Your New Valve
If you can avoid infection after your valve replacement surgery and you can follow your anticoagulant therapy, you should have few problems with your new valve for several years. However, problems with calcification or tissue damage are still a possibility. Dr. Ellis recommends having your new valve checked about every two years or more frequently if your doctor advises.

Once signs of degradation begin, you will need to have it monitored more often. Dr. Ellis adds that it’s especially important to tell your doctor about any symptoms you have, such as shortness of breath, lightheadedness or chest pain, as these can signal heart valve trouble.