Abstract 13447: Bilateral Branch Pulmonary Artery Melody® Valve Implantation Reduces Pulmonary Regurgitation in an Ovine Model of Postoperative Tetralogy of Fallot
Introduction: Transannular patch repair of tetralogy of Fallot (ToF) results in pulmonary insufficiency (PI) with dilation and distortion of the right ventricular outflow tract (RVOT) developing over time. Current transcatheter valve replacement technology is not applicable to such patients. Given this anatomical complexity, it seems unlikely that a single approach/device to transcatheter pulmonary valve replacement would work for all patients. We hypothesized that insertion of Melody® Valves (Medtronic Inc. Minneapolis MN) into the proximal right and left branch pulmonary arteries (PAs) would reduce pulmonary regurgitation fraction (PRF) in a model of PI and dilated RVOT.
Methods: Ten sheep underwent baseline cardiac catheterization, surgical pulmonary valvectomy and transannular patch placement. A subset (n=5) also underwent baseline cardiac MRI prior to surgery and additionally had Melody Valves (2 devices per animal) inserted into the proximal right and left PAs during the surgical procedure. Due to anatomical constraints, Melody Valves were placed distal to the right upper lobe (RUL) artery branch, leaving the RUL ‘unprotected’. Baseline MRIs (n=5) were used to determine control right ventricular ejection fraction (RV-EF). All animals underwent MRI and catheterization six weeks following surgery.
Results: Mean PRF was lower in the Melody Valve group, 15% ± 6% vs. 37% ± 3% (p <0.001). The unprotected RUL was responsible for 64% of the PRF measured in the Melody Valve group. RV-EF was lower in the non-Melody group when compared to control (58% ± 6% vs. 74% ± 6%; p = 0.02). The Melody Valve group's RV-EF was 69% ± 7% (vs. control, p=NS; vs. the non- Melody group, p = 0.04). Mean ventricular end-diastolic pressures (mmHg) were higher in the non-Melody vs. the Melody Valve animals: RVEDp = 15 ± 4 vs. 5.8 ± 2.5 (p = 0.007); LVEDp = 19 ± 2 vs. 12 ± 4.5 (p= 0.05). There were no differences in cardiac output.
Conclusions: Bilateral branch PA Melody Valve implantation significantly reduced PRF and altered RV and LV diastolic function favorably in a model of transannular patch repair for ToF. This novel intervention may offer potential benefit in treating patients with anatomically heterogeneous disease of the RVOT.
- © 2010 by American Heart Association, Inc.