Pulmonary Homograft Constructs as a Bailout Strategy for Mitral Valve Replacement in Infants

Objective To describe the use of customized pulmonary homograft–based mitral valve replacement mounted on two different external scaffold platforms as a bailout strategy in infants in whom mitral valve repair was not feasible and conventional prostheses were size-inappropriate or unavailable. Mitral valve replacement in infants is challenging because conventional prostheses are poorly size-matched and mechanical valves require lifelong anticoagulation. Methods Two infants underwent customized pulmonary homograft–based mitral valve replacement using different scaffolds. Patient 1 was a 3.2-kg infant with mitral arcade, severe mitral regurgitation, and moderate mitral stenosis; a 17-mm pulmonary homograft reinforced with stainless steel wire was mounted within a 20-mm ePTFE tube graft and implanted supra-annularly. Patient 2 was a 5.5-kg term infant with double outlet right ventricle, ventricular septal defect, and congenital mitral stenosis who developed recurrent severe stenosis after repair; at 4 months, a pulmonary homograft was mounted inside a covered ePTFE stent and expanded to 16 mm. Results In Patient 1, progressive dysfunction from distal conduit distortion, leaflet malcoaptation, and perivalvar dehiscence required Melody valve revision at 2 months of age. At 3 months after Melody valve implantation, the patient had no reintervention, mitral stenosis or regurgitation, or left ventricular outflow tract (LVOT) obstruction. In Patient 2, immediate postoperative transesophageal echocardiography demonstrated a mean gradient of 3 mm Hg, trivial central regurgitation, no perivalvar leak, and no LVOT obstruction. At 1 month, the construct had a mean gradient of 4–6 mm Hg, mild regurgitation, preserved biventricular function, and no LVOT obstruction. Conclusions Pulmonary homograft leaflets can be adapted to different external scaffold platforms for infant mitral replacement as a bailout strategy when repair is not feasible and standard prostheses are size-inappropriate. These early cases suggest that application may depend on scaffold geometry, annular sealing, and avoidance of adverse subvalvar or LVOT interaction. Long-term follow-up is needed to determine durability.