Abstract 3083: Implantation of the Medtronic Melody Transcatheter Pulmonary Valve in Patients with Dysfunctional Right Ventricular Outflow Tract (RVOT) Conduits: Procedural and 6-Month Results from the U.S. Feasibility Trial

Abstract

RVOT conduit dysfunction can now be treated with transcatheter pulmonary valve placement (TPV). We report procedural and 6-mo outcomes of the prospective multicenter U.S. feasibility trial for TPV using the Melody valved stent. Outcomes included safety, procedural success and short-term effectiveness. Entry criteria included: weight ≥30 kg, RVOT conduit ≥16mm when implanted, and ≥moderate RVOT obstruction (RVOTO; mean gradient ≥40mmHg if NYHA class I, ≥35mmHg if higher) and/or regurgitation (PR; severe if class I, moderate if higher) by echo. Exercise testing, MRI, and chest CT were performed before catheterization (cath). The cath and TPV protocol was standardized, including high pressure balloon angioplasty when needed and balloon sizing of the conduit prior to TPV. In this 5-center study, 58 pts (median age 18 yrs) were enrolled and underwent cath from 1/07–5/08. The mean RVOT gradient on echo was 28±11mmHg and PR was severe or moderate in all but 5 pts. 5 pts were excluded at cath due to risk of coronary compression (2) or other predefined anatomic/hemodynamic factors (3). A Melody was implanted in the RVOT conduit in the other 53 pts. The peak RVOT gradient at cath was reduced from 36±16 to 15±7mmHg (p<0.001) and all pts had no/trivial PR. There were no deaths. In 1 pt, TPV was complicated by conduit rupture, which was managed surgically. Non-surgical complications included atrial tachycardia (1) and PA perforation by a guidewire (1). In 30 pts with 6-mo follow-up data, PR was none (29) or trivial (1) by echo, and mean RVOT gradient was 20±8mmHg, unchanged from discharge (19±8mmHg, p=0.9 by paired analysis). On 6-mo MRI (n=26), median PR fraction was 0%, down from 29% pre-TPV (p<0.001). 1 pt had a second Melody placed 3 mo after TPV for stent fracture and recurrent RVOTO. 8 other pts had stent fractures. There were no other adverse events through 6-mo follow-up, but 2 pts had a second Melody placed for stent fracture with RVOTO ~1 yr post-TPV. In this prospective multicenter study, TPV was safe and technically successful overall, with encouraging acute and 6-mo outcomes. Stent fracture with recurrent RVOTO, observed in ~10% of pts, may be overcome by pre-TPV RVOT angioplasty with or without stent implantation.