Off-label use of Lifetech KONAR-MF™ ventricular septal defect occluder for large patent ductus arteriosus closure in <6 ​kg infants.

Background: Device PDA closure is increasingly used in smaller patients. Major safety concerns remain when applied to <6 ​kg infants with large PDA and challenging anatomy. We aimed to report our experience with the new Konar-MF™ ventricular septal defect (VSD) occluder for transcatheter closure of large patent ductus arteriosus (PDA) in infants <6 ​kg. Methods: Infants <6 ​kg in whom PDA occlusion was attempted using the Konar-MF™ VSD occluder were analyzed to review procedural characteristics and outcomes. Prospective follow-up was achieved until August 2021. Results: A total of 9 implantations were performed in 7 infants [age: 5.3 ​± ​3.4 (1.7-10.1) months, weight: 4.1 ​± ​0.8 (2.9-5.8) kg]. All PDAs were large and short [minimal ductal diameter: 5.6 ​± ​1.0 (4.5-7.0) mm, ductal length: 4.3 ​± ​0.6 (3.5-5) mm]. Successful device implantation was achieved in all cases without major complication. Early device embolization occurred in 1 case with safe percutaneous device removal. Late percutaneous device retrieval was achieved 5 weeks after implantation because of symptomatic residual shunt. In both cases a second Konar-MF™ VSD occluder was implanted with excellent outcome. Over a median follow-up of 12 (6-25) months, 1 patient died from a device-unrelated cause; all remaining patients are asymptomatic, with complete occlusion and no delayed device-related complication. Conclusions: Transcatheter closure of large PDA using the Konar-MF™ VSD occluder appears to be feasible, effective and safe in <6 ​kg infants. This approach might be an alternative to surgical ligation in carefully selected infants, although that remains to be confirmed by extensive experience and long-term outcomes data.