International Multicenter Outcomes of Transcatheter Pulmonary Flow Restrictors in Congenital and Acquired Heart Disease

Composite non-hierarchical net clinical success, evaluated at the time of surgical PFR removal (either as a standalone procedure or during target surgery), and defined by meeting the following three criteria: 1) technical success (successful implantation and retention* of the MVP device in each branch PA), 2) clinical success (evidence of PBF restriction** at PFR removal), and 3) safety success (no major adverse device-related events (MADREs).

Technical success of PFR implantation (device successfully delivered, deployed, and retained in each branch PA) at hospital discharge after the index procedure.

Immediate flow restriction success of MVP-based PFRs, defined as technical success and evidence of pulmonary blood flow (BPF) restriction, at procedure conclusion (Evidence of

PBF restriction at procedure conclusion was defined as a minimal drop in oxygen saturation on arterial blood gas by 10% at the same level of FiO2 compared to preoperative levels, a systolic-diastolic Doppler-pattern across the PFRs with a minimum peak Doppler gradient of 40 mmHg (Vmax=3.2 m/s) on per-procedural ultrasound assessment, and, when performed, a reduction in the baseline QP/QS mismatch by 50%).

Safety success (freedom from MADREs*, vascular-, or procedure-related SAEs**) at the time of device removal. The severity of MADRE and SAE will be classified using a validated 1-to-5 scale, ranging from none to catastrophic.

*MADREs include device-related vascular erosion, vascular aneurysm/pseudoaneurysm, bronchial compression, device collapse, migration, embolization, thrombosis, fracture, infection, endocarditis, resulting in unplanned or anticipated device removal, or redo-intervention (surgical or catheter-based)

**SAEs encompassed device- vascular- or procedure-related adverse events resulting in death, life-threatening situations, hospitalization, disability, or major surgical intervention.

All-cause mortality rate at the time of device removal.

Freedom from unplanned PA reintervention (surgical or catheter-based) until surgical device removal

Freedom from unplanned PA intervention at 24 months following surgical device removal (such as angioplasty or stenting for residual stenosis or deformity at the former device site).