(From the September 2015 Issue of PediatricsOnline)
Introduced to the United States in 2007, the Medtronic Melody® Transcatheter Pulmonary Valve has already been found to result in reduction of right ventricular outflow tract (RVOT) obstruction, elimination of pulmonary regurgitation and clinical improvement after implantation. The Melody valve is the only FDA-approved minimally-invasive valve replacement option for congenital heart disease patients in this country.
Its relatively recent introduction, though, means that longer-term data about Melody valve function have been lacking. A recent article in the journal Circulation is the first to show that the improvements seen soon after Melody procedures were maintained in the large majority of patients enrolled in an Investigational Device Exemption trial. The median follow-up time was 4.5 years, with some follow-ups occurring as long as seven years after implantation.
Additionally, five-year freedom from reintervention was 76 percent, and five-year freedom from explantation was 92 percent.
“Those numbers actually overestimate the current risk of reintervention and explantation,” says John Cheatham, MD, lead author of the article and director of Cardiac Catheterization and Interventional Therapy at Nationwide Children’s Hospital. “There have been several changes in implantation practice over time, including the wider adoption of prestenting. There was more compete relief of RVOT obstruction and longer freedom from reintervention in patients who were enrolled later in the study.”
Dr. Cheatham is also a professor of Pediatrics and Internal Medicine at The Ohio State University College of Medicine and co-director of The Heart Center at Nationwide Children’s. He was involved in the design and testing of the stent for the Melody valve as well as the valve’s delivery balloon.
There were 148 patients in the study cohort who were discharged with the Melody valve in place. Patients ranged from 7 to 53 years of age, with a median age of 19. A total of 32 patients underwent RVOT reintervention – 27 for obstruction (with stent fracture in 22), three for endocarditis (two with stenosis and one with pulmonary regurgitation) and two with right ventricular dysfunction. Four people died: one of multisystem failure resulting from sepsis/endocarditis and three from causes with no apparent relationship to the Melody valve. Survival at five years was estimated to be 98 percent.
In a speculative analysis, the authors found that the incidence of Melody stent fracture and associated RVOT obstruction would have been reduced substantially with the current practice of presenting and focus on limiting RVOT gradients. Infection and endocarditis were also notable adverse outcomes, and need further investigation, according to Dr. Cheatham.
In the 113 patients who were alive and did not have a reintervention, the follow-up gradient was unchanged from early after their initial Melody valve procedures and only one patient had more than mild pulmonary regurgitation.
“We saw long-term hemodynamic benefits and clinical improvements with transcatheter pulmonary valve replacement with the Melody valve,” Dr. Cheatham says. “A continued focus on preventing adverse outcomes will be important going forward.”
Cheatham JP, Hellenbrand WE, Zahn EM, Jones TK, Berman DP, Vincent JA, McElhinney DB. Clinical and hemodynamic outcomes up to 7 years after transcatheter pulmonary valve replacement in the U.S. Melody valve investigational device exemption trial. Circulation. 2015 Jun 2;131(22):1960-70.