Three-Year Outcomes From the Harmony Native Outflow Tract Early Feasibility Study

Abstract

Background: The Harmony transcatheter pulmonary valve (TPV) was designed for treatment of postoperative pulmonary valve regurgitation in patients with repaired right ventricular outflow tracts.

Methods: The Native TPV EFS (Early Feasibility Study) is a prospective, multicenter, nonrandomized feasibility study. Three-year outcomes are reported.

Results: Of 20 implanted patients, 17 completed 3-year follow-up (maximum: 4.1 years). There were no deaths and 2 early explants. One patient did not complete the 3-year visit. In patients with available 3-year echocardiographic data, 1 had a mild paravalvular leak and the rest had none/trace; 1 patient had mild pulmonary valve regurgitation and the remainder had none/trace. The 3-year mean right ventricular outflow tract echocardiographic gradient was 15.7±5.5 mm Hg. Radiographically, no late frame fractures or erosions were identified. At 2 years, 2 patients presented with an increased echocardiographic outflow gradient (1 mixed lesion with moderate/severe pulmonary valve regurgitation). Computed tomography scans identified neointimal tissue ingrowth within the stent frame in both patients, and they were treated successfully with a transcatheter valve-in-valve procedure (Melody TPV). Additional follow-up computed tomography scans performed at 3.2±0.5 years after implant were obtained in 16 patients and revealed luminal tissue thickening at the inflow and outflow portion of the frame with no significant alteration of the valve housing.

Conclusions: Three-year results from the Native TPV EFS revealed stable Harmony TPV device position, good valve function in most, and the absence of moderate/severe paravalvular leak and significant late frame fractures. Two patients developed significant neointimal proliferation requiring valve-in-valve treatment, while all others had no clinically significant right ventricular outflow tract obstruction.

Clinical trial registration: URL: https://www.clinicaltrials.gov. Unique identifier: NCT01762124.

Keywords: Tetralogy of Fallot; congenital heart disease; echocardiography; pulmonary valve; stent; tomography.