Right Heart Remodeling After Pulmonary Valve Replacement in Patients With Pulmonary Atresia With Intact Ventricular Septum and Critical Pulmonary Stenosis

Background: Patients with pulmonary atresia or critical pulmonary stenosis with intact ventricular septum (PA/IVS) and biventricular circulation may require pulmonary valve replacement (PVR). Right ventricular (RV) remodeling after PVR is well-described in tetralogy of Fallot (TOF); we sought to investigate RV changes in PA/IVS using cardiac magnetic resonance imaging (CMR). Methods: A retrospective cohort of PA/IVS patients who underwent PVR at Boston Children's Hospital from 1995-2021 with CMR before and after PVR was matched 1:3 with TOF patients by age at PVR. Median regression modeling was performed with post-PVR indexed RV end-diastolic volume (RVEDVi) as the primary outcome. Results: 20 PA/IVS patients (cases) were matched with 60 TOF (controls), with median age at PVR 14 years. Pre-PVR RVEDVi was similar between groups; cases had higher RV ejection fraction (EF; 51.4 vs 48.6%, p=0.03). Pre-PVR RV free wall and LV longitudinal strain (LS) were similar, although LV mid-cavity circumferential strain (CS) was decreased in cases (-15.6 vs -17.1, p=0.001). At median 2 years after PVR, RVEDVi was similarly reduced; cases continued to have higher RV EF (52.3% vs 46.9%, p=0.007) with less reduction in RV mass (Δ4.5 vs 9.6 g/m2, p=0.004). Post PVR, RV and LV LS remained unchanged and LV CS was similar, though lower in cases. Conclusion: Compared with TOF patients, PA/IVS patients demonstrate similar RV remodeling after PVR, with lesser reduction in RV mass and comparatively higher RVEF. While no differences were detected in peak systolic RV or LV strain values, further investigation of diastolic parameters is needed. ### Competing Interest Statement The authors have declared no competing interest. ### Funding Statement No external funding was received in relation to this work. ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: The study was approved by the Institutional Review Board at BCH, and individual patient consent was waived I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable. Yes The data that support the findings of this study are available from the corresponding author upon request.