Most heart valve problems involve either the aortic valve or mitral valve. Most often, diseased valves either allow blood to leak backwards into a heart chamber or a blood vessel, or they become narrow and restrict blood flow. In some cases, valves can be repaired; in other cases, they need to be replaced. Traditionally, if the patient is healthy enough, a diseased heart valve has been repaired or replaced using open-heart surgery.
Innovations Under Study
Today, medical researchers and device manufacturers are working to develop catheter-based approaches to repair diseased valves. If successful, catheter-based valve repair could reduce the need for patients to undergo highly invasive open-heart surgery. The first patients to benefit from innovations in catheter approaches will be those who are eligible for clinical trials designed to evaluate the safety and effectiveness of devices that are, at this point, experimental.
Also under exploration are new surgical techniques for heart valve repair that are less invasive than open-heart surgery. These procedures use smaller incisions than traditional open-chest surgeries. They do, however, require that the patient be placed on a heart-lung bypass machine to filter and oxygenate blood during the operation.
Mitral Valve Repair Via Catheter
Researchers are exploring two catheter-based approaches to repair the mitral valve, which regulates blood flow between the left atrium (upper chamber) and the left ventricle (lower chamber):
- Delivering a mechanical clip via catheter, threaded through the veins into the heart and to the mitral valve: The clip, acting like a clothespin, grasps the flaps (or leaflets) of the mitral valve when the heart contracts. The clip closes and secures the edges of the valve flaps together at their centers. The result is a bow-tie shaped opening that permits blood flow from the left atrium to the left ventricle during relaxation of the heart, and enables the valve flaps to close more effectively during contraction so that blood leaking backward into the left atrium is reduced. Learn more about the study: "Percutaneous Mitral Repair With the MitraClip® Device for Functional Mitral Regurgitation: Acute Success, One-Year Durability and Reverse LV Remodeling in the Initial EVEREST Cohort."
- Delivering a device via catheter to change the size and shape of the mitral annulus, the ring of tissue that encircles the valve, in order to help the mitral flaps close properly. One study is testing the safety and effectiveness of planting a spring-type device in the coronary sinus as a way to alter the shape and size of the annulus and encourage the valve’s flaps to close properly.
These approaches have not yet received approval from the U.S. Food and Drug Administration.
Aortic Valve Repair Via Catheter
Balloon valvuloplasty (much like angioplasty for opening blocked vessels in the heart) is being used as an alternative to open-heart surgery to widen narrowed aortic valves, particularly in patients whose hearts have been damaged by rheumatic heart disease. The balloon, delivered by catheter to the aortic valve, is inflated inside the valve to push it wider so more blood can flow through. While valvuloplasty is less risky than open heart surgery, valves opened using this approach almost always re-narrow within six months to two years. Techniques to make valvuloplasty more effective continue to be developed.
Another new development in the treatment of the aortic valve is called transcatheter aortic valve implantation (TAVI).
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Watch this animation to learn more about a new, less invasive procedure for replacing the aortic valve called transcatheter aortic valve implantation or TAVI. (Animation provided courtesy of Medtronic.)
On Nov. 2, 2011, the Food and Drug Administration (FDA) approved a new treatment for patients with severe aortic valve stenosis. Surgery continues to be the most successful way to treat this disease. However, some patients with aortic stenosis who are older or who have other medical problems face a greater than 50 percent chance of dying from open-heart surgery. Now, with the FDA’s approval of the Edwards SAPIEN transcatheter heart valve, many of these patients can have transcatheter aortic valve implantation (TAVI), a procedure to replace the old valve. This new procedure replaces the diseased aortic valve through a tube that is placed in the patient’s leg, or through an incision in the chest that is much smaller than traditional surgery.
The FDA’s decision to approve SAPIEN is based on the results of findings from the PARTNER clinical trial. Patients in the clinical trial who received TAVI were significantly less likely to die within the first year of the procedure. They experienced more improvement in their symptoms than the group who received other treatments, including balloon valvuloplasty, a procedure that stretches open the valve but does not replace it. Unfortunately, SAPIEN recipients also had more strokes and other vascular complications, such as bleeding. So it is important to discuss the risks and benefits of all possible treatments with your doctor. Download these important questions to ask your doctor if you are considering this procedure for yourself or for someone you love.