SAN FRANCISCO, Nov. 9 (Xinhua) — A recent study found mechanical heart valves may be safer in certain cases than biological valves, and should be used more in heart-valve replacements, especially for younger patients.
According to the study conducted by researchers at the Stanford University School of Medicine, for patients undergoing mitral valve replacement, a mechanical valve is actually beneficial until the age of 70.
On the other hand, patients who undergo aortic valve replacement can hardly benefit from implanting mechanical valves after they turn 55.
Mechanical valves can last a lifetime, but they come with increased risks of blood clotting and bleeding. Patients with mechanical valves have to take the blood-thinning medication warfarin for a lifetime.
Biological valves, which are most often made from pig or cow tissue, do not increase the risk of bleeding or clotting, but they wear out within about 10 to 15 years, making a second surgery likely.
The news release of the study, published Wednesday, quoted estimates of the American Heart Association as saying that 5 million Americans suffer from heart-valve disease, which forces the heart to work harder to pump blood and can lead to heart failure and sudden death.
The disease can be present at birth or result from infections, heart attacks or other heart conditions.
When a patient is diagnosed as having a valve that is unable to pump blood to the body smoothly, an open-heart surgery to replace the valve with a new one is generally recommended.
Each year, more than 50,000 people in the United States undergo either aortic- or mitral-valve replacement surgery, according to the study.
The Stanford researchers compared the long-term risks and benefits of mechanical valves and those made of animal tissue by examining rates of mortality, stroke, bleeding and reoperation in patients who had heart-valve surgery at 142 hospitals in the U.S. state of California between 1996 and 2013.
In their views, a mechanical…