Pulmonary Valve| The day before Thanksgiving, a young adult patient lay on an operating table in the Cardiac Catheterization Lab at University of Colorado Hospital. In a couple of hours, he would have reason to be especially grateful.
The patient, who is in his 20s, was the first at UCH to receive an artificial pulmonary valve via a minimally invasive procedure designed to treat a congenital narrowing of the vessel just below the valve. The condition, right ventricular outflow tract stenosis, increases pressure on the right ventricle, which pumps blood to the lungs. Left untreated, it can cause sudden death.
The Melody® valve, developed by Minneapolis-based Medtronic, is the first catheter-delivered pulmonary valve device approved by the Food and Drug Administration.
To place it, clinicians thread a catheter through the femoral vein in the leg to the heart. The catheter carries a valve sewn inside a stent, which supports and protects the valve when the natural action of the heart presses the valve against the sternum.
Clinicians destroy the old valve, position and deploy the new one and remove the catheter.
UCH and campus partner Children’s Hospital Colorado, which has implanted 19 Melody valves – more than half of them in adults – are the only hospitals in the state to perform the procedure, said Joseph Kay, MD, director of UCH’s Adult Congenital Heart Disease program. Kay assisted Thomas Fagan, MD, associate professor of Pediatric Cardiology at Children’s Hospital Colorado during the Nov. 23 procedure at UCH.
The Melody device implantation offers an important alternative to open-heart valve-replacement surgery, Kay said.
Where open-heart surgery entails lengthy hospitalization and recovery time, the Melody procedure generally gets patients out of the hospital in one day. They leave with only the mild limitation of avoiding heavy lifting for a week, Kay added.
“[The device] theoretically lowers the risk of death, but it almost certainly lowers morbidity,” Kay said. “Many patients with this condition have had third, fourth or fifth open-heart surgeries in their lives.”
That’s because tissue valves implanted in adults typically wear out within 15 or 20 years and have to be replaced, he explained. Children implanted with the valves often need them replaced in less time, he said.
Short of replacing the valve, procedures that prop open or destroy the malfunctioning pulmonary valve decrease pressure on the right ventricle, Kay said.
“The risk of death is gone, but patients don’t feel any better,” he noted. Without a valve to prevent blood from leaking back into the ventricle, he explained, the heart has to work harder to pump less blood. Over time, that can lead to right-side heart failure.
The FDA gave the Melody limited approval as a “humanitarian device” for treatment of right ventricular outflow tract problems. The agency gives such approval, Kay explained, when it knows there will be fewer than 5,000 implants per year.
To prove safety and efficacy of the device, hospitals are required to follow and track patient outcomes for the approved condition. They must also track and report outcomes if they use the device for something other than pulmonary valve replacement. For example, campus cardiologists have tried the Melody as a replacement for the tricuspid valve, which sits between the right ventricle and the right atrium (upper chamber) of the heart.
Kay said UCH currently performs about 30 open-heart pulmonary valve-replacement procedures in adults a year. If the Melody proves to be an effective alternative, he added, “we anticipate that that number will decrease.”