November 16, 2018 by John Fernandez
Heart of the Matter: Advances in Aortic Valve Repair, Replacement (Video)
The importance of the aortic valve, one of four valves that regulate blood flow through the heart, cannot be overstated. The aortic valve separates the heart’s main pumping chamber (left ventricle) and the main artery that supplies oxygen-rich blood to your body.
A pioneer in procedures to replace the aortic valve via a minimally invasive procedure or repair it with valve-sparing surgery, Allan S. Stewart, M.D., chief of cardiac surgery at Miami Cardiac & Vascular Institute, draws analogies that helps the average patient better understand the aortic valve’s vital role.
“Like any movable part in an engine, the aortic valve wears out,” explains Dr. Stewart. “The way it wears out is not unlike what happens when you walk around barefoot — you get callouses on the bottom of your feet. That’s like the hardening of the valve leaflets and they get less and less movable. So they open less and less as time goes on. That makes the space for blood to pass very narrow. As a result, we may get tired with less activity or short of breath when we exert ourselves.”
That’s a key point that Dr. Stewart makes regarding the aortic valve and aging. Aortic stenosis, which means the aortic valve has narrowed over time and results in restricted blood flow to the aorta, is not just a part of aging, but a serious condition which can affect middle-aged or older adults.
(Watch Now. The Baptist Health News Team hears from Allan S. Stewart, M.D., chief of cardiac surgery at Miami Cardiac & Vascular Institute, as he explains advances in aortic valve repair and replacement. Video by Dylan Kyle.)
Heart Murmur and Other Symptoms
Aortic stenosis produces symptoms, such as abnormal heart sound (heart murmur) that can be heard through a stethoscope; shortness of breath, particularly when you have been very active or when you lie down; dizziness; fainting, chest pain or tightness, or irregular heartbeat. Aortic valve disease can cause very serious complications, including heart failure, stroke and blood cots.
Dr. Stewart has more than 13 years of experience in transcatheter aortic valve replacement (TAVR) procedures, and he has completed more than 1,000 since. Dr. Stewart came to Miami Cardiac & Vascular Institute in June from Mount Sinai Health System in New York, where he served as director of the Center for Aortic Disease, co-director of the Heart Valve Repair Center and medical director of International Medicine.
Diagnosing Aortic Valve Stenosis
The many advances in replacing or repairing the aortic valve cannot be realized unless an individual is first diagnosed with aortic valve disease, which often involves stenosis, or narrowing. Regular checkups are a must. Often, patients are diagnosed their primary care doctor who hears a “heart murmur” through a stethoscope.
To illustrate what a doctor would hear, Dr. Stewart makes the analogy of “putting your finger over a garden hose.”
“As it get’s tighter and tighter, less and less water comes out of the garden hose and it comes out at a higher velocity,” Dr. Stewart explains. “That velocity that is created with the hardening of the aortic valve is the murmur that a doctor hears when he or she listens to your chest, the ‘whooshing’ sound.”
Your doctor will determine that the valve is “getting tighter and tighter and that is what’s making you have that lack of energy,” he adds.
“Over the course of time, when the valve gets too narrow, it means not enough blood can get out of the heart and so it backs up into the rest of the system,” says Dr. Stewart. “It backs up into the lungs. That’s what is known as congestive heart failure. When you start to feel these symptoms, it’s generally not aging and it’s time to see your cardiologist.”
Replacing Diseased Aortic Valve
Interventional cardiologists and surgeons perform the TAVR procedure as a team. For the right candidate, TAVR replaces a diseased aortic valve with a new, biological valve. Physicians use a guide wire to move the new valve (collapsed and placed inside a catheter and wire mesh) through the leg artery and ultimately into the heart. They then expand a small balloon is used to open the diseased valve wider. Next, they position the new valve inside and check its function using echocardiography.
“As you can see, the valve is very springy,” Dr. Stewart explains, holding the small device that essentially replaces an aortic valve. “The valve is inside of this spring. And what we do is crimp this down and it actually becomes very, very small. And that’s mounted on a stent and that’s brought all the way across the old heart valve. Once it gets to where we need it, we spring it into place. It goes inside the old valve and pushes it to the side and this then becomes the new valve, which opens and closes without any impedance at all.”
Not all patients are candidates for TAVR. However, there is no need to ‘crack the chest’ open anymore. With a 3-inch incision, either between the ribs or just partially opening the breastbone, Dr. Stewart can safely replace the aortic valve in a much less traumatic way. This speeds recovery and returns the patient to normal activity levels much faster than traditional surgery.