Aug 24 2007
A breakthrough new procedure may improve quality of life for children and adults with a common type of congenital heart defect that interferes with the body's ability to oxygenate blood through the lungs.
The minimally invasive procedure, which involves the implantation of the first-ever catheter-based pulmonary valve replacement, is currently performed by interventional cardiologists at Morgan Stanley Children's Hospital of NewYork-Presbyterian and Columbia University Medical Center -- the only New York City site and one of only three sites nationally that is offering the procedure as part of an ongoing clinical research trial.
Currently, babies with absent or defective pulmonary valves may require open-heart surgery to implant a valved-conduit (a two-inch tube with a valve inside) to open the connection between their right ventricle and pulmonary artery. But because the conduit's lifespan is limited by deterioration and patient growth, traditionally the invasive surgery must be repeated several times as the patient grows older.
The new transcatheter pulmonary valve (TPV) is designed to extend the lifespan of the conduit by improving the natural function of the patient's heart. The goal is to reduce the need for multiple open-heart surgeries.
Dr. William Hellenbrand leads the study at Morgan Stanley Children's Hospital of NewYork-Presbyterian, where he is chief of pediatric cardiology and director of the Pediatric Cardiac Catheterization Laboratory. He is also professor of clinical pediatrics at Columbia University College of Physicians and Surgeons.
"This unique and innovative procedure allows us to replace the patient's heart valve by threading the device through a vein in their leg and into their heart. Previous research has shown that these patients can expect a reduced need for potentially risky open-heart surgery -- and therefore improved quality of life," Dr. Hellenbrand explains.
The TPV device is currently only available in the research context to patients whose implanted valved-conduit has shown signs of narrowing and/or severe leakage. It is estimated that between 500 and 1,000 patients in the U.S. meet this criteria in a given year.
To date, 32 patients have been successfully implanted in the U.S., including 11 at Morgan Stanley Children's Hospital. In addition, nearly 300 patients have been successfully implanted with the device in Europe and Canada, where it has been approved for widespread use.
The initial feasibility study is sponsored by Medtronic, Inc. CardioVascular Business Unit of Minneapolis, Minn., makers of the Melody Transcatheter Pulmonary Valve (TPV) and Ensemble Transcatheter Delivery System used in the procedure. The study will look at the effectiveness of the procedure using echocardiography, chest radiography, fluoroscopy, cardiac MRI and other measures.
According to the American Heart Association (AHA), more than 25,000 U.S. babies are born each year with a congenital heart defect. Approximately 22 percent, or 4,800, of these babies born with congenital heart disease have defects disrupting the blood flow from the right ventricle to the pulmonary artery. For patients with this condition, their heart over-exerts itself trying to get oxygenated blood throughout the body. Additionally, they are at risk for arrhythmias and sudden death.
As part of a comprehensive interventional cardiology program, Morgan Stanley Children's Hospital offers a complete range of treatments for congenital heart conditions including atrial septal defects (ASD), ventricular septal defects (VSD), aortic stenosis (AS), patent ductus arteriosus (PDA), pulmonary atresia (PA) and more.