AVNeo (Aortic valve neocuspidization, Ozaki Procedure)
AVNeo is a surgical procedure that is used to treat people with aortic valve disease, an umbrella term for diseases and conditions in which the aortic valve doesn’t work properly, resulting in impaired blood flow between the heart and the aorta, which can lead to disturbed blood flow throughout the whole body.
Every time your heart beats, blood flows into and out of your heart, delivering oxygen-rich blood to organs and tissues throughout the body. Inside the heart, blood flow is carefully controlled by four valves which regulate the passage of blood from one chamber of the heart to another and from the heart to the rest of the body.
One of these valves, known as the aortic valve, lies at the junction between the heart’s left ventricle—the left chamber of the heart—and the aorta, the largest artery in the body. This valve plays a crucial role in regulating passage of blood from the heart to the rest of the body.
To do its job, the aortic valve relies on three leaflets, or cusps. These leaflets open to allow blood to flow out of the heart into the aorta and then close to prevent blood from flowing backwards into the heart. When something goes wrong with the aortic valve, it can result in serious heart problems, such as heart failure. Fortunately, there are treatments for aortic valve disease, including aortic valve replacement and a procedure known as aortic valve neocuspidization, or AVNeo.
What is AVNeo?
AVNeo is a surgical procedure used to treat aortic valve disease. It’s sometimes called the Ozaki procedure after Shigeyuki Ozaki, the Japanese surgeon who developed and first described the technique in 2011.
In AVNeo, a surgeon removes the patient’s diseased aortic valve. Replacement leaflets are then made using tissue taken from the patient’s own pericardium, the tissue membrane that surrounds the heart, and sewn into the aortic valve, effectively reconstructing a new valve. The reconstructed valve is reimplanted at the junction of the heart’s left ventricle and the aorta, where it regulates blood flow. One advantage of the procedure is that it uses the patient’s own tissue, so no foreign material has to be implanted.
What conditions can be treated with AVNeo?
AVNeo is used to treat people with aortic valve disease, of which there are two main types:
- Aortic stenosis occurs when the opening of the aortic valve becomes narrowed, forcing the heart to work harder to pump blood. Because the valve is narrowed, less blood than usual makes it into the aorta and the rest of the body.
- Aortic regurgitation occurs when the valve’s leaflets cannot close properly. Some of the blood that the heart pumps through the aortic valve and into the aorta regurgitates, or leaks, back into the heart. The heart must work harder to ensure that an adequate supply of blood reaches the aorta and gets delivered to the rest of the body.
Several conditions can cause aortic stenosis or regurgitation, including:
- Congenital aortic valve disease. A small percentage of babies are born with heart defects, such as in the aortic valve. The most common of these is a bicuspid aortic valve (BAV), in which the valve is made up of two leaflets, rather than three. Rarely, babies may be born with only one leaflet or they may have four leaflets.
- Infective endocarditis, a condition in which bacteria or another pathogen infects the lining of the heart and/or heart valves, impairing the function of the aortic valve.
- Aging. Over time, wear and tear of the valve, calcium deposits, and stiffening of the leaflets can lead to aortic stenosis or regurgitation.
- Diseases such as rheumatoid arthritis, systemic lupus erythematosus, and rheumatic fever, among others, can cause problems with the structure and function of the aortic valve.
In general, AVNeo can be used to treat all of the above aortic valve disorders in all ages, as well as aortic valve problems caused by other conditions. The procedure is well-suited for people under 60 years of age who don’t want to have their damaged aortic valve replaced with an artificial, mechanical valve via an aortic valve replacement procedure. People who have aortic valve disease that cannot be effectively treated with aortic valve repair are also good candidates.
What happens during an AVNeo procedure?
AVNeo is performed using general anesthesia, meaning the patient will be asleep and won’t feel pain during the procedure.
The surgeon begins by making an incision down the center of the chest and through the breastbone.
During the procedure, the heart is stopped, and the patient is connected to a heart-lung bypass machine, which temporarily takes over the work of the heart and lungs, keeping the blood oxygenated and flowing throughout the body.
Once the chest is opened, a piece of the pericardium, the sac that surrounds the heart, is removed and bathed in a chemical called glutaraldehyde, then rinsed in sterile saline solution. Treating the pericardium with glutaraldehyde makes it more durable.
Next, the surgeon removes the diseased aortic valve. At this point, new, replacement leaflets must be made out of the section of pericardium removed earlier in the procedure. To do so, the glutaraldehyde-treated pericardium is placed on a flat surface. A template—essentially a stencil—is then placed over the tissue. The surgeon uses a marker to trace the shape and size of the new leaflets, then cuts them out of the pericardium. Once the new leaflets have been prepared, they are sewn onto the native aortic valve ring, reconstructing the new aortic valve from the patient’s own tissue
The patient will be gradually weaned off the heart-bypass machine. When the patient’s heart is beating again, the surgeon makes sure the reconstructed aortic valve is working properly using an imaging test called transesophageal echocardiography. This test uses sound waves to create images of the heart as it beats. After the valve is deemed to be in good working order, the surgeon closes the breastbone and then stitches up the initial incision.
What is recovery from an AVNeo procedure like?
Following surgery, patients may need to stay in the intensive care unit (ICU) for a day or two, followed by a few more days in the hospital, where they will be closely monitored until they are ready to go home.
Patients need to take low-dose aspirin for up to 6 months following surgery. No other treatment for blood thinning, such as Coumadin, is needed. Periodical follow-up appointments to check how well the reconstructed aortic valve is functioning are also necessary.
What are the risks of the procedure?
AVNeo is considered a safe procedure, but like all surgeries, comes with certain risks. These include complications from the surgery itself, including increased risk of bleeding, infection, and blood clots.
What are the advantages of the AVNeo procedure?
Traditionally, the leading treatment for aortic valve disease is aortic valve replacement surgery. In this procedure, a surgeon removes the patient’s aortic valve and replaces it with a prosthetic one. The replacement valve may be a “biological” prosthesis taken from a donor or an animal, or it may be a “mechanical” valve comprised of man-made materials such as metal. While prosthetic valves have extended and saved countless lives of people with aortic valve disease, they do have some drawbacks. Biological valves, for instance, can deteriorate over time, especially in young patients, and may need to be replaced. Mechanical valves, by contrast, are more durable, but their use requires that people take blood thinners (to prevent blood clots) for the rest of their lives, increasing their risk of bleeding and other side effects.
AVNeo is a promising alternative treatment for aortic valve disease. The procedure improves blood flow to the aorta, which can reduce symptoms associated with aortic valve disease and improves quality of life. What’s more, most people who undergo the procedure don’t need to take blood thinners and studies have found that the reconstructed valve used in the AVNeo procedure is durable and works well to regulate blood flow over the short and medium term. Long-term studies of the durability and effectiveness of AVNeo are ongoing.
What makes Yale Medicine unique in its approach to the AVNeo procedure?
"Yale has one of the world’s most experienced teams performing the AVNeo procedure,” says Yale Medicine cardiac surgeon Markus Krane, MD. “Yale offers the whole spectrum of techniques to treat aortic valve disease and works together with the patient to choose the best option for each patient’s condition and needs.”