Medtronic's Melody Device Studied in the Native Right Ventricular Outflow Tract

August 13, 2018—A study was conducted to determine the safety and feasibility of transcatheter pulmonary valve replacement (TPVR) using the Melody valve (Medtronic) in native (nonconduit) right ventricular outflow tracts (nRVOT). The investigators also sought to identify factors associated with successful TPVR. The findings were published by Mary Hunt Martin, MD, et al in Journal of the American College of Cardiologist (JACC): Cardiovascular Interventions.

The background of the study is that the Melody valve is approved by the FDA for TPVR within right ventricle-to-pulmonary artery conduits and bioprosthetic pulmonary valves; however, most patients who need pulmonary valve replacement have nRVOT and TPVR has been adapted for this indication.

The multicenter retrospective study was composed of all patients presenting for nRVOT TPVR. Using preprocedural MRI, echocardiography, and catheterization data, the investigators evaluated procedural and early outcomes.

As summarized in JACC: Cardiovascular Interventions, of 229 patients (age 21 ± 15 years from 11 centers), 132 (58%) had successful TPVR. In the remaining 97 patients, 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 five (4%) serious complications, including prestent embolization requiring surgery in four patients, and arrhythmia in one.

The investigators found that higher precatheterization echocardiographic RVOT gradient was associated with TPVR success (P = .001) and larger center volume approached significance (P = .08). MRI anterior-posterior and lateral RVOT diameters were smaller in implanted versus nonimplanted patients (18.0 ± 3.6 vs 20.1 ± 3.5 mm; P = .005; 18.4 ± 4.3 vs 21.5 ± 3.8 mm; P = .002).

The study demonstrated that TPVR in nRVOT was feasible and safe. However, the findings also showed that approximately half of the patients presenting for catheterization did not undergo transcatheter pulmonary valve implantation, mainly because of prohibitively large nRVOT size. Improved understanding of MRI data and availability of larger devices may improve the success rate for nRVOT TPVR, advised the investigators in JACC: Cardiovascular Interventions.