Tuesday, May 5, 2009 at 5:00 AM
Have you ever wondered what your heart valves do? ideastream® health reporter Gretchen Cuda explains what happens when those valves are damaged, and the technology in place to fix them.
The human heart is essentially a pump. It squeezes blood through a series of four chambers -- first gathering oxygen in the lungs and then sending the newly oxygenated blood coursing through the body. But in order for the system to work, a series of valves has to keep each of those four chambers separate. Without properly functioning heart valves there isn't sufficient pressure to push the blood throughout the body. Murat Tuzco is a heart valve expert at the Cleveland Clinic. He explains it like this:
TUZCO: Heart valves are just like doors -- the open and they close, that's their function. When they open they should open wide open and allow all the blood to go through. When they close they should close shut, and not allow any blood to leak back.
There are lots of reasons why heart valves fail: sometimes the valve is defective at birth, either because it is too narrow to allow the blood to pass, or because two of the heart valves' three flaps become fused together. Tuzco says sometimes the problems don't present themselves until well into adulthood -- others are so serious that they require surgical repair to the baby in the womb.
Patients whose valves don't open or shut properly usually don't have much chest pain like someone with clogged arteries, explains Tuzco -- instead, they feel very tired and have difficulty breathing. Doctors use a sonogram of the heart -- known as an echo cardiogram -- to spot problems, but Tuczo says a physician can often listen to the patient's chest and pick out what is happening.
TUZCO: The normal heart valve sounds lup-dup, lup-dup, lup-dup. If there is a leakage say in the mitral valve -- normally there is no sound but then you start to hear this phew, phew, phew, phew sound. This we call murmur. The pitch of the murmur, the frequency of the murmur. the location in the chest -- where it radiates -- all gives us clues.
Not all heart valve defects are present at birth. By far the most common valve problems are due to calcium buildup inside the artery walls that narrow and block the valves. Other times the valves just wear out. Mark Gillinov is a cardiac surgeon, also at the Cleveland Clinic. He says there are a couple of choices -- the first is to repair the damage.
GILLINOV: The best valve is the one you've got. So the best option, when possible, is to repair your own valve. Nothing man-made ever functions as well as repaired natural valve.
But when that's not possible, surgeons like Gillinov cut out the damaged valve and replace it with a new one. Replacement heart valves can come from other animals like cows or pigs. They can also be mechanical. Gillinov says there are pros and cons to both.
GILLINOV: Increasingly people choose the cow or pig valve -- also called bioprosthetic valves -- they choose them because they don't require that a person be on blood thinners. The potential issue there is that in a 10-20 year time frame they will often wear out. On the other side is a group of people who say they want a mechanical valve. Why do they want a mechanical valve? Because they want to have one interaction with a heart surgeon in their lifetime. They do not want ever again to see a heart surgeon, but with a mechanical valve you have to take blood thinners for the rest of their life.
Regardless of whether a surgeon is repairing a damaged valve or replacing it, Gillinov says the biggest strides in the field are in the use of minimally invasive and robotic surgery techniques. Through just a few small ports surgeons operate using tiny instruments, a high-definition camera and 3-D visualization. And in terms of patient recovery, the results are astonishing.
GILLINOV: I called up a patient from Texas who had had a minimally invasive valve repair the week before, and his wife said, 'he can't come to the phone, he just got on the elliptical trainer. Can he call you back in an hour when he's done?' That's the kind of thing that didn't used to happen.
Gillinov says the fast recovery means more patients are willing to have the surgery before they start feeling bad in the first place. There are other techniques in the works too -- like a new method of valve replacement that's done entirely through a vein in the leg.
Gretchen Cuda, 90.3.