Children born with certain heart defects have impaired blood flow from the right ventricle to the pulmonary artery leading to the lungs, requiring implanted devices (known as right-ventricular outflow tract conduits) to maintain the flow. However, these conduits fail over time, and children typically face multiple open-heart operations during their lives to reopen the passage.
Now, a prospective multicenter study in the October 27 issue of the Journal of the American College of Cardiology, led by Children's Hospital Boston cardiologist Doff McElhinney, MD, finds good preliminary outcomes with a valve that can be delivered non-surgically -- threaded up a leg vein to the heart -- potentially avoiding the need for repeated open-heart operations.
The device, known as the Melody transcatheter pulmonary valve (Medtronic, Inc), received backing from an FDA advisory panel in July, suggesting FDA approval may come soon for certain patients. (See http://www.reuters.com/article/healthNews/idUSTRE56L71020090722). The device is currently approved in Europe and Canada; if approved by the FDA, it could be the first catheter-placed heart valve to be approved in the U.S.
"With a transcatheter valve, you don't have to open the chest and put the patient on heart-lung bypass machine, with all that that entails," says McElhinney. "Patients can come in, have a catheter procedure, stay overnight, then go home the next day."
The study, the first prospective, multicenter study of the device, involved 34 children and young adults at Children's Hospital Boston, Miami Children's Hospital and Morgan Stanley Children's Hospital (New York, NY) whose existing right-ventricular outflow conduits were malfunctioning, causing blood to flow backward from the pulmonary artery into the right ventricle (known as pulmonary regurgitation) or obstruction of blood from the right ventricle to the lungs. They had various forms of congenital heart disease, including tetralogy of Fallot, truncus arteriosus, aortic valve disease and transposition of the great arteries.
All patients underwent cardiac catheterization with the intention of implanting the artificial valve, and 30 of the 34 underwent actual implantation attempts, of which 29 were successful. Three patients (9 percent) had complications during implantation, but all survived.
At follow-up six months later, no patient had more than mild pulmonary regurgitation. Of 24 patients who had Class II or III heart failure (mild to moderate limitation of physical activity) before the procedure, 19 had improved by at least one functional class at six months, and no patient's function had declined.