Background and Clinical Need Pulmonary artery stenosis (PAS) and aortic coarctation (CoA) are among the most common congenital cardiovascular conditions requiring catheter-based intervention in infants and children. Current standard of care involves balloon dilation and implantation of permanent metallic stents. While effective in the short term, permanent stents present a significant limitation in pediatric patients: they cannot accommodate somatic growth, necessitating repeated balloon dilations and re-interventions throughout childhood. Furthermore, permanent metallic implants preclude normal vessel remodeling, restrict MRI imaging quality, and complicate future surgical access.
The unmet clinical need is substantial. A bioresorbable stent that provides acute vessel support, maintains patency through the critical healing phase, and then completely resorbs - leaving no permanent implant - would represent a paradigm shift in the management of pediatric congenital cardiovascular stenoses.
Device Description The CardiaZn stent is a bioresorbable endovascular stent fabricated from a zinc-silver (ZnAg) alloy. Zinc is an essential trace element with well-characterized metabolic pathways, and its corrosion byproducts are biocompatible and cleared through normal physiological mechanisms. The addition of silver enhances mechanical properties including radial strength and corrosion kinetics. The device is balloon-expandable and delivered via standard cardiac catheterization technique.
The ZnAg alloy platform distinguishes CardiaZn from polymer-based bioresorbable scaffolds, which have demonstrated limitations in radial strength and degradation kinetics, and from magnesium-based platforms, which resorb too rapidly for the intended application window. The zinc-silver system is designed to provide sufficient radial support through the vessel healing phase, with a resorption timeline aligned to the biological requirements of pediatric vascular remodeling.
The device is drug-free, relying entirely on the mechanical and biological properties of the ZnAg alloy to achieve its clinical objectives. This drug-free positioning is supported by pediatric case data from magnesium-based platforms demonstrating that bioresorbable metal scaffolds can achieve clinically meaningful outcomes without pharmacological augmentation.
Study Rationale Preclinical evaluation of the CardiaZn stent has included comprehensive in vitro testing, biocompatibility assessment per ISO 10993 standards, and a GLP animal study. Results have demonstrated adequate radial strength, biocompatible corrosion byproduct profile, and vessel patency consistent with the intended clinical application. These data support proceeding to first-in-human evaluation under an FDA Investigational Device Exemption.
Prior FDA engagement through the TAP Pre-Submission program (Q-Submission U230126-A010) established alignment on study design, endpoint selection, and statistical approach prior to IDE submission.
Study Design PEDIASORB is a prospective, multicenter, single-arm, open-label, pivotal clinical study. A total of 45 eligible subjects will be enrolled at up to 11 investigational sites. The study population includes subjects aged under 9 years presenting with hemodynamically significant discrete aortic coarctation or pulmonary artery stenosis.
To ensure balanced representation of both indications, neither the pulmonary artery stenosis nor the aortic coarctation population may contribute more than 70% of total enrollment, ensuring a minimum of 14 subjects per treatment location. At least 50% of enrollments will occur at United States investigational sites.
Patients will be screened for pre-operative eligibility within 60 days prior to the index procedure. Following confirmation of intraoperative eligibility criteria via angiography, eligible subjects will undergo implantation of the CardiaZn stent via standard cardiac catheterization technique.
Follow-Up All subjects will be followed for 5 years post-procedure. Follow-up visits are scheduled at hospital discharge and at months 1, 3, 6, and 12, and annually through year 5. Each follow-up visit includes physical examination, laboratory testing, health status assessment, imaging evaluation, and review of concomitant medications and procedures. CT angiography will be performed in all subjects at 6 months post-procedure.
Adverse events will be collected from initial informed consent through study exit.
Primary Endpoints
The co-primary endpoints are:
Device success at the index procedure, defined as successful delivery and deployment of the CardiaZn stent with achievement of adequate vessel patency as assessed by angiography Freedom from pre-defined procedure- and device-related serious adverse events of interest through 6 months post-procedure
Secondary Endpoints Secondary endpoints include assessment of vessel patency, peak-to-peak pressure gradient, vessel diameter, and freedom from re-intervention through 5 years of follow-up. Long-term safety will be assessed through collection of all adverse events, serious adverse events, and device-related complications through study exit.
Statistical Considerations The study is designed as a single-arm pivotal trial with performance goal comparisons against pre-specified objective performance criteria derived from published literature and historical data for the current standard of care. The sample size of 45 subjects provides adequate statistical power to test the co-primary endpoints at the pre-specified significance level. A formal statistical analysis plan has been developed and is included as an attachment to the IDE submission.
Data Safety Monitoring An independent Data Safety Monitoring Board (DSMB) will provide ongoing oversight of subject safety throughout the trial. A Clinical Events Committee (CEC) will provide independent adjudication of all adverse events and endpoints. Interim analyses will be conducted per the DSMB charter.
Regulatory Background The CardiaZn stent is an investigational device. This study is being conducted under FDA IDE number U230126. Prior FDA engagement was conducted through the TAP Pre-Submission program. The study is sponsored by PediaStent and conducted in accordance with applicable FDA regulations, Good Clinical Practice guidelines, and the principles of the Declaration of Helsinki.
