Assessment of the Melody valve in the mitral position in young children by echocardiography.

OBJECTIVES: Mitral valve replacement (MVR) in young children is limited by the lack of small prostheses. Our institution began performing MVR with modified, surgically placed, stented jugular vein grafts (Melody valve) in 2010. We sought to describe key echocardiographic features for pre- and postoperative assessment of this novel form of MVR.
METHODS: The pre- and postoperative echocardiograms of 24 patients who underwent Melody MVR were reviewed. In addition to standard measurements, preoperative potential measurements of the mitral annulus were performed whereby dimensions were estimated for Melody sizing. A ratio of the narrowest subaortic region in systole to the actual mitral valve dimension (SubA:MV) was assessed for risk of postoperative left ventricular outflow tract obstruction (LVOTO).
RESULTS: Melody MVR was performed at a median of 8.5 months (5.6 kg) for stenosis (5), regurgitation (3), and mixed disease (16). Preoperatively, actual mitral z scores measured hypoplastic (median -3.1 for the lateral [lat] dimension; -2.1 for the anteroposterior [AP] dimension). The potential measurements often had normal z scores with fair correlation with intraoperative Melody dilation (ρ = 0.51 and 0.50 for lat and AP dimensions, respectively, both P = .01). A preoperative SubA:MV <0.5 was associated with postoperative LVOTO, which occurred in 4 patients. Postoperatively, mitral gradients substantially improved, with low values relative to the effective orifice area of the Melody valve. No patients had significant regurgitation or perivalvar leak.
CONCLUSIONS: Preoperative echocardiographic measurements may help guide intraoperative sizing for Melody MVR and identify patients at risk for postoperative LVOTO. Acute postoperative hemodynamic results were favorable; however, ongoing assessment is warranted.