Success rate of primary percutaneousballoon angioplasty in children withPulmonary Stenosis and Noonansyndrome

Background and aim: Noonan syndrome (NS) is associated with different types of heart defects of which a supravalvular pulmonary stenosis ((SV)PS) is the most frequent. Possible treatment options are percutaneous balloon pulmonary valvuloplasty (BVP) or surgical intervention. Anatomical location of the PS may help predict BVP failure. We aimed to identify factors predicting treatment outcome and reintervention rate of BVP in PS, in children with NS. Methods : Medical records of children with a diagnosis of NS and in follow-up at Antwerp- and Ghent University Hospitals from 2000 to 2022 were retrospectively reviewed. Results: 32 children were identified with a SVPS, either isolated or in combination with other heart defects. 69% of children with PS had SVPS. The prevalence of PS and SVPS was similar for all genes. An isolated SVPS was identified as a risk factor for intervention. An intervention was necessary in 17/32 patients (53%). All but 2 children with pulmonary valve stenosis had SVPS. Only 2 of 17 patients had primary surgical repair. The remaining 15 (13 with SVPS) underwent BVP, of which 10 (67%) needed a second intervention, but all of them ultimately needed surgical repair. The global success rate of BVP was (31,1%). Conclusion: SVPS is the most frequent heart defect in children with NS. The prevalence of SVPS was similar for all genes. Isolated SVPS is a risk factor for intervention. The success rate of BVP in patients with NS is low. BVP might still be useful in selected cases and might be considered to clarify the anatomical location of PS.