Short- and medium-term outcomes after transcatheter pulmonary valve placement in the expanded multicenter US melody valve trial

Abstract

Background: Transcatheter pulmonary valve placement is an emerging therapy for pulmonary regurgitation and right ventricular outflow tract obstruction in selected patients. The Melody valve was recently approved in the United States for placement in dysfunctional right ventricular outflow tract conduits.

Methods and results: From January 2007 to August 2009, 136 patients (median age, 19 years) underwent catheterization for intended Melody valve implantation at 5 centers. Implantation was attempted in 124 patients; in the other 12, transcatheter pulmonary valve placement was not attempted because of the risk of coronary artery compression (n=6) or other clinical or protocol contraindications. There was 1 death from intracranial hemorrhage after coronary artery dissection, and 1 valve was explanted after conduit rupture. The median peak right ventricular outflow tract gradient was 37 mm Hg before implantation and 12 mm Hg immediately after implantation. Before implantation, pulmonary regurgitation was moderate or severe in 92 patients (81% with data); no patient had more than mild pulmonary regurgitation early after implantation or during follow-up (>or=1 year in 65 patients). Freedom from diagnosis of stent fracture was 77.8+/-4.3% at 14 months. Freedom from Melody valve dysfunction or reintervention was 93.5+/-2.4% at 1 year. A higher right ventricular outflow tract gradient at discharge (P=0.003) and younger age (P=0.01) were associated with shorter freedom from dysfunction.

Conclusions: In this updated report from the multicenter US Melody valve trial, we demonstrated an ongoing high rate of procedural success and encouraging short-term valve function. All reinterventions in this series were for right ventricular outflow tract obstruction, highlighting the importance of patient selection, adequate relief of obstruction, and measures to prevent and manage stent fracture. Clinical Trial Registration- URL: http://www.clinicaltrials.gov. Unique identifier: NCT00740870.

Figure 1

Angiograms demonstrating (A) preimplantation conduit obstruction and PR and (B) relief of obstruction and a competent valve after TPV. This patient with tetralogy of Fallot and pulmonary atresia had a primary indication of PR assigned on the basis of preimplantation echocardiography, which showed severe PR and a mean echocardiographic RVOT gradient of 18 mm Hg, although the directly measured RVOT gradient was 60 mm Hg at the time of catheterization. At the 2-year follow-up, there was no stent fracture, no PR, and a mean Doppler RVOT gradient of 11 mm Hg. C, Preimplantation mean Doppler RVOT gradient and echocardiographic PR grade are depicted in each patient according to the site-determined primary implantation indication: RVOT obstruction (solid red circles), PR (solid blue triangles), or mixed PR and obstruction (open purple circles). Patients of all NYHA classes are depicted; thus, some patients with moderate PR and a gradient >40 mm Hg are in the mixed indication category (NYHA class II or higher), and others are in the RVOT obstruction category (NYHA class I).

Figure 2

In this patient with tetralogy of Fallot and pulmonary atresia, the conduit passed over a large anterior RV coronary branch that arose from the proximal left coronary artery. Selective coronary angiograms with simultaneous inflation of an angioplasty balloon (B) in the conduit demonstrate occlusion of this RV branch. Angiography from a right anterior oblique projection shows (A) early occlusion of the anomalous coronary (arrow), with persistent distal contrast, and (B) subsequent resumption of flow as the balloon was deflated (arrow). C and D, Subsequent angiography in a lateral projection demonstrates complete occlusion of the coronary branch with balloon inflation to higher pressure. In C, the arrow indicates the proximal stump of the occluded vessel, which then fills (multiple arrows) as the balloon is deflated in D.

Figure 3

Bar graph depicting the distribution of echocardiographic PR grades before TPV, at discharge, and at 6-month, 1-year, and 2-year follow-up evaluations among patients who underwent Melody implant. For technical reasons, the degree of PR could not be adequately graded from the preimplantation echocardiogram in 6 patients, the discharge echocardiogram in 3, and the 6-month echocardiogram in 1.

Figure 4

Flow diagram depicting the number of patients in each NYHA functional class and changes in status from before implantation to the 6-month, 1-year, and 2-year follow-up evaluations.

Figure 5

Kaplan–Meier curves depicting (A) survival free from RVOT reintervention, (B) freedom from placement of a second Melody valve, (C) freedom from diagnosis of stent fracture, and (D) freedom from Melody valve dysfunction, with separate curves for patients with a primary implantation indication of PR and those with an indication of RVOT obstruction or mixed disease (O/M). Error bars indicate SE. The shaded regions in the graph showing freedom from diagnosis of stent fracture indicate the follow-up windows for the 3-, 6-, 12-, and 24-month evaluations.