Implantation of the Melody Transcatheter Pulmonary Valve in Patients With a Dysfunctional Right Ventricular Outflow Tract Conduit: Early Results From the U.S. Clinical Trial

Abstract

This study was designed to evaluate the safety, procedural success, and short-term effectiveness of the Melody transcatheter pulmonary valve (Medtronic, Inc., Minneapolis, Minnesota) in patients with dysfunctional right ventricular outflow tract conduits. Conduit dysfunction has recently been treated with transcatheter pulmonary valve placement. There have been no prospective, multicenter trials evaluating this technology. Standardized entry criteria, implantation, and follow-up protocols were used. Nonimplanting core laboratories were used to evaluate results. Between January 2007 and September 2007, 34 patients underwent catheterization for intended Melody valve implantation at 3 centers. Mean age was 19.4 +/- 7.7 years. Initial conduit Doppler mean gradient was 28.8 +/- 10.1 mm Hg, and 94% of patients had moderate or severe pulmonary regurgitation (PR). Implantation was successful in 29 of 30 attempts and not attempted in 4 patients. Procedural complications included conduit rupture requiring urgent surgery and device removal (n = 1), wide-complex tachycardia (n = 1), and distal pulmonary artery guidewire perforation (n = 1). Peak systolic conduit gradient fell acutely from 37.2 +/- 16.3 mm Hg to 17.3 +/- 7.3 mm Hg, and no patient had more than mild PR. There were no deaths or further device explants. At 6-month follow-up, conduit Doppler mean gradient was 22.4 +/- 8.1 mm Hg, and PR fraction by magnetic resonance imaging was significantly improved (3.3 +/- 3.6% vs. 27.6 +/- 13.3%, p < 0.0001). Stent fracture occurred in 8 of 29 implants; 3 of these were treated with a second Melody valve for recurrent stenosis later in follow-up. Implantation of the Melody valve for right ventricular outflow tract conduit dysfunction can be performed by experienced operators at multiple centers, appears safe, and has encouraging acute and short-term outcomes.