Clinical Trials for Heart Disease Patients: Catheter-Based Mitral Valve Repair
“Cardiovascular medicine is changing rapidly,” says Ryan Kaple, MD, an interventional cardiologist at Yale Medicine. He credits much of these changes to new availability of catheter-based procedures to repair and even replace valves, often without the need for open heart surgery.
A catheter is a long, flexible tube that a surgeon inserts into a blood vessel by making a small incision in the groin; the catheter is then snaked to the heart to deliver and implant a life-saving medical device. “We can fix arteries in the heart, we can close abnormal holes in the heart, and only really recently we can use catheters to repair and replace heart valves,” says Dr. Kaple.
TAVR, or Transcatheter Aortic Valve Replacement, has been available for years, but until very recently this approach has not been used for patients with mitral valve disease. Dr. Kaple explains that this is because there is a lot of variation, not only in the types of problems people with mitral valve defects may have but also because mitral valves themselves are unique in both size and shape. “A challenge has been to individualize treatment,” he notes.
The mitral valve has two flaps that must open and close to allow blood to flow in and out of the heart. But when patients experience mitral valve prolapse and mitral valve regurgitation, the two flaps of the valve don’t close all the way and blood flows backward into the heart, causing pooling. This gets worse over time and can lead to symptoms of heart failure.
As tends to be the case with new medical technologies, the use of catheter-based procedures has been limited to patients considered too high-risk for open heart surgery, although doctors believe many others would benefit from this approach as well. Now, at Yale, they can. “Clinical device trials are one of the unique things that we have at Yale,” Dr. Kaple explains. “This allows us to offer procedures to more patients.”
Yale is one of the few academic medical centers currently offering ongoing clinical device trials for treating mitral valve disease: the MitraClip for mitral valve repair, and Apollo for TMVR, or Transcatheter Mitral Valve Replacement. The MitraClip procedure delivers a small clip-like device into the mitral valve while the heart is still beating, and works by bringing the two flaps of the valve closer together so that they close properly. In the Apollo trial, surgeons use catheters to deliver an entirely new valve to the heart.
As catheter-based procedures are proven to be safe and effective, they become available to more and more patients. “At Yale, we are fortunate to be participating in these trials,” says Dr. Kaple. “The main effort of these trials and our program in general is to push the field of mitral valve repair and replacement forward.”