Abstract 16010: A Novel Biodegradable Stent Design Applicable for Pediatric Use in Congenital Heart Disease : Bench Testing and Initial Results in a Rabbit Model
INTRODUCTION: Biodegradable stents designed for use in infants would offer tremendous advantages by avoiding a permanent implant in a growing child. The bench testing and initial results of a coil based design manufactured with Poly-L-Lactic Acid (PLLA) are presented.
METHODS/RESULTS: PLLA fibers (520 kD) were extruded at 1800C and drawn to 0.1mm diameter at 600C. Comparisons were made with stents fabricated with a single helical (SH) and dual helical (DH) design and also with fibers annealed at 620 C. The collapse pressure and expansion were best with annealed stents. The collapse pressure was 0.18 - 1 ATM for 8 - 2.5 mm diameter DH stents respectively. SH and DH stents were successfully deployed in right external iliac arteries to 2.5-3.5 mm in 12 adult 3.5 kg New Zealand white rabbits via a 5Fr sheath in the right carotid artery. The first 6 were euthanized with good apposition on angiography and intravascular ultrasound (IVUS) when inflated to >100% vessel size. Two rabbits were survived for 1 week and 4 rabbits for 1 month. Stents were inflated to 103-125% of the vessel size and the treated right and control left external iliac vessels were harvested. At 1 week there was no acute luminal thrombosis and at 1 month no late thrombosis, minimal neo-intimal proliferation and the internal elastic membrane was intact (see figure 1). Minimal luminal loss was noted at 1week and 1 month on follow up IVUS. Micro thrombus formation at the stent strut-vessel wall junction was noted at 1 week with remodeling by fibroblast infiltration and neo-intimal proliferation at 1 month. The proximal and distal ends of the SH design collapsed which did not occur with the DH design. No other complications were noted.
CONCLUSIONS: The annealed DH stent design yields a stress reduced surface leading to minimal impact on the internal elastic membrane and inflammatory response. This study demonstrates the feasibility and acute safety of this design with the potential to reach diameters of 8 mm.
- © 2011 by American Heart Association, Inc.