When a heart valve becomes diseased, blood flow is either restricted due to a too-small opening, or blood is allowed to flow backward into the heart. Traditionally, replacing any valve has required open-heart surgery.
Innovations Under Study
New technologies are making it possible to replace the aortic and pulmonary valves via a catheter (thin, flexible tube) guided through the arteries to the heart. (The aortic valve controls blood flow from the heart into the aorta, the main artery to the body; the pulmonary valve controls blood flow between the heart and the arteries that carry blood between the heart and lungs.)
Aortic and Pulmonary Valve Replacement
Two catheter-delivered devices for replacing aortic and pulmonary valves have been approved in Europe, and several hundred patients worldwide have been treated using the catheter-based approach. In the United States, a feasibility trial has been completed for replacing the aortic valve with catheter-based approaches, and a randomized clinical trial has just begun for patients considered at high risk for conventional aortic valve replacement. The procedure under study for aortic valve replacement may also be used to replace the pulmonary valve.
Mitral Valve Replacement
Devices that would enable physicians to replace a diseased mitral valve without open-heart surgery are in the earliest stages of development. Much progress is needed in their development before they will be available for use.