Melody vs. Mechanical Mitral Valve Replacement in Children Less Than Two Years of Age: A Single-Center Propensity Matched Analysis

M. K. Moroi, A. V. Vinogradsky, I. Feng, E. M. Cordoves, S. Levasseur, O. M. Barry, M. A. Crystal, E. A. Bacha, D. Kalfa, A. Goldstone
New York-Presbyterian/Columbia University Medical Center, New York, New York

Purpose: Pediatric mitral valve replacement (MVR) can be challenging due to small patient size and poor prosthesis durability, leading to significant morbidity and mortality. The balloon-expandable Melody valve has emerged as a promising alternative to mechanical prostheses. We compare outcomes of the Melody valve to mechanical MVR in young children.

Methods: We retrospectively reviewed 36 patients less than 2 years of age from a single center who underwent MVR with a Melody valve or mechanical prosthesis between 2005 and 2023. Propensity score matching was performed to account for baseline differences, yielding 2 groups of 12 patients each. The primary outcome was a composite of death, transplant, or surgical reintervention on the mitral valve prosthesis.

Results: Matched groups were similar across 24 baseline parameters. Median age and weight at MVR were 5.2 months [IQR: 3.5,10.2] and 6.5 kg [IQR: 4.9,7.6], respectively. Median follow-up time was 1.6 years [IQR: 0.4,6.4]. Melody patients had numerically shorter hospital stays (20.5 vs. 59.0 days, P=0.11) as well as lower mean mitral valve gradients at discharge (5.5 vs. 8.7 mmHg, P=0.046). In the mechanical group, 5 (41.7%) patients had a permanent pacemaker requirement at discharge, compared to 0 in the Melody group (P=0.04). Early surgical reinterventions were common in both groups (33.3% vs. 25%, P=1.00). There were 2 early mortalities, both due to cardiac arrest. The first was on postoperative day (POD) 12 following ECMO cannulation and emergent redo mechanical MVR on POD2 for left ventricular rupture due to Melody valve overdilation. The second arrest occurred on POD30 in a Melody patient. At 1 and 3 years, transplant-free survival (Melody: 82.5%±11.3%, 82.5%±11.3%; Mechanical: 77.8%±13.9%, 62.2±17.8%; P=0.92) and freedom from the composite endpoint (Melody: 73.3%±13.2%, 29.3%±16.9%; Mechanical: 72.2%±13.8%, 45.1±17.7%; P=0.32) were similar between groups. Three deaths were recorded in the mechanical valve group secondary to cardiac arrest (n=2) or multiorgan failure (n=1); however, these patients fell out of the cohort during matching.

Conclusion: In young patients with small mitral annuli, the Melody valve is associated with similar reintervention rates, decreased rates of permanent pacemaker insertion, and no permanent requirement for anticoagulation, making the Melody valve a better option for MVR in this population. Further studies with long-term follow up and larger samples sizes are warranted to corroborate our findings.

Identify the source of the funding for this research project: N/A