O-1
In-Vitro Performance of Lifetech IBS Angel™ (Iron-based Bioresorbable Scaffold) Stents During Overdilation for Use in Pediatric Patients
Presenter
Kurt R Bjorkman, MD, University of Iowa Stead Family Children’s Hospital, Iowa City, IA
Kurt R Bjorkman, MD1, Jennifer R Maldonado, BS1, Stephanie A Saey, BS2 and Daniel Mclennan, M.B.B.S.3, (1)University of Iowa Stead Family Children’s Hospital, Iowa City, IA, (2)University of Iowa Carver College of Medicine, Iowa City, IA, (3)Milwaukee Hospital-Children's Wisconsin, Herma Heart Institute, Milwaukee, WI
Keywords: Congenital Heart Disease (CHD), Patent Ductus Arteriosus (PDA), Right Ventricular Outflow Tract (RVOT) and Structural Heart Disease (SHD)
Background
The use of stents in the young often requires follow-up procedures to keep pace with somatic growth in treatment of stenotic vessels, or additional surgical resection with palliative use in stenting the right ventricular outflow tract in tetralogy of Fallot or stenting the ductus arteriosus in ductal dependent lesions. Bioresorbable stents offer the potential for temporary palliation while avoiding some long term complications. Lifetech Iron-based Bioresorbable Scaffold (IBS) Angel™ stents have been demonstrated to have reliable strength and resorption in animal models. Here we tested these stents for performance during overdilation with assessment of foreshortening, napkin-ringing, and diameter at time of strut fracture.
Methods
Premounted Lifetech IBS Angel™ stents (3 stents of each size - 4mm by 8, 12, 15, and 38mm; 5mm by 8, 12 and 15mm) were inflated to 2
ATM above rated burst pressure and then post-dilated with 6mm, 7mm, 8mm, and 10mm balloons sequentially until stent fracture with continuous video recording. ImageJ software was used to measure foreshortening and stent diameter with each increase of 1atm until time of fracture. Dilation was continued until complete fracture of all struts with evaluation for napkin-ringing. All bench testing was completed with stents submerged in a water bath heated to a consistent 37°C to mimic in-vivo conditions. Stents were advanced through a 4Fr Prelude sheath prior to dilation and retrieved through sheath post-dilation for qualitative evaluation of fit.
Results
First strut fracture for all 4mm stents did not occur until they reached diameters greater than 6mm. First strut fracture for all 6mm stents (premounted on 5mm balloons) did not occur until post-dilated to a diameter of at least 8.9mm. Minimal napkin-ringing of struts was noted with overdilation. All premounted stents passed through 4Fr sheath easily and all balloons were retrieved with minimal resistance after dilation.
Conclusions
The 4mm and 6mm Lifetech IBS Angel™ stents demonstrated reliable post-dilation to diameters near 50% beyond parameters without fracture and were then found to have complete fracture of all struts without significant napkin-ringing allowing for further expansion if needed prior to bioresorption.