Safety and Feasibility of Melody Transcatheter Pulmonary Valve Replacement in the Native Right Ventricular Outflow Tract: A Multicenter Pediatric Heart Network Scholar Study.

OBJECTIVES:This study sought to determine the safety and feasibility of transcatheter pulmonary valve replacement (TPVR) using the Melody valve in native (nonconduit) right ventricular outflow tracts (nRVOT), and to identify factors associated with successful TPVR. BACKGROUND:The Melody valve is Food and Drug Administration-approved for TPVR within right ventricle-to-pulmonary artery conduits and bioprosthetic pulmonary valves. However, most patients needing pulmonary valve replacement have nRVOT and TPVR has been adapted for this indication. METHODS:In this multicenter retrospective study of all patients presenting for nRVOT TPVR, we collected pre-procedural magnetic resonance imaging, echocardiography, and catheterization data, and evaluated procedural and early outcomes. RESULTS:Of 229 patients (age 21 ± 15 years from 11 centers), 132 (58%) had successful TPVR. In the remaining 97, TPVR was not performed, most often because of prohibitively large nRVOT (n = 67) or compression of the aortic root or coronary arteries (n = 18). There were no deaths and 5 (4%) serious complications, including pre-stent embolization requiring surgery in 4 patients, and arrhythmia in 1. Higher pre-catheterization echocardiographic RVOT gradient was associated with TPVR success (p = 0.001) and larger center volume approached significance (p = 0.08). Magnetic resonance imaging anterior-posterior and lateral RVOT diameters were smaller in implanted versus nonimplanted patients (18.0 ± 3.6 mm vs. 20.1 ± 3.5 mm; p = 0.005; 18.4 ± 4.3 mm vs. 21.5 ± 3.8 mm; p = 0.002). CONCLUSIONS:TPVR in the nRVOT was feasible and safe. However, nearly half the patients presenting for catheterization did not undergo TPV implantation, mainly because of prohibitively large nRVOT size. Improved understanding of magnetic resonance imaging data and availability of larger devices may improve the success rate for nRVOT TPVR.