A novel design biodegradable stent for use in congenital heart disease: mid-term results in rabbit descending aorta.

OBJECTIVES: This study evaluates the feasibility of delivery and deployment of low and medium molecular weight (LMW and MMW, respectively) double-opposing helical (DH) poly-l-lactic acid biodegradable stent (BDS) in rabbit descending aorta (DAO). Secondary objectives were to assess patency and inflammation of stented vessels at 9 months and to investigate safety following intentional embolization of stent fragments in DAO. BACKGROUND: A BDS that will relieve aortic obstruction and disappears as the child grows older allowing for preservation of aortic wall elasticity and natural growth of aorta will be ideal to treat Coarctation (CoA). BDS have never been evaluated in the DAO. METHODS: Seven New Zealand white rabbits underwent implantation of DH-LMW (n = 7), DH-MMW (n = 3), and metal stents (n = 7) in DAO. BDS fragments were intentionally embolized into DAO in two rabbits. RESULTS: All stents were deployed via a 6-French sheath. Five BDS covered the origin of major DAO side branches. Angiography and intravascular ultrasound showed good stent apposition to the wall of DAO with minimal luminal loss at 9 months follow-up. All stents had minimal neointimal hyperplasia on histopathology. Adverse events included 1 death, 1 aortic aneurysm, and lower extremity ulceration due to self-mutilation in an embolization rabbit. CONCLUSIONS: Pilot study confirms the feasibility of delivery and deployment of up to 6-millimeter diameter DH BDS in rabbit DAO. Stent integrity with DH design was maintained at 9 months with minimal vessel inflammation. Potential morbidity due to embolized BD fragments cannot be ruled out and needs further evaluation.

A novel biodegradable stent applicable for use in congenital heart disease: bench testing and feasibility results in a rabbit model.

OBJECTIVES: A novel double opposed helical (DH) biodegradable stent was designed and fabricated for CHD applications. The primary objective was to evaluate the feasibility of DH stent delivery and deployment in rabbit external iliac arteries (EIA). Secondary objectives were to assess stent patency, thrombosis and inflammation at 1-week and 1-month follow-up. BACKGROUND: Biodegradable stents have largely been designed for adult cardiovascular indications, to avoid long term complications of permanent implants. A growing child with congenital heart disease (CHD) would especially derive substantial benefit from this technology. METHODS: DH stents were manufactured to 3, 4, 5, and 6-mm diameter with poly-l-lactic acid (PLLA) fibers. Bench test analysis was performed. Six DH stents were implanted in rabbit EIA. Vessel patency was assessed at 1-week and 1-month follow-up with repeat angiography, intravascular ultrasound (IVUS). Histopathological evaluation was performed. RESULTS: The elastic recoil and collapse pressure of DH stents were comparable to conventional metal stents. All DH stents were successfully delivered and implanted with good apposition to the vessel wall and no collapse of the proximal, mid or distal ends. All stented vessels remained patent. No acute or early stent thrombosis was noted. Histopathology showed minimal inflammatory response and mild neointimal proliferation at 1 month follow-up. CONCLUSIONS: In vitro results of DH PLLA biodegradable stents are comparable to conventional metal stents. The pilot animal study confirms the delivery and deployment of the DH stents to the desired location. The DH design can be used to fabricate larger diameter stents needed for CHD.

Bacterial sensitivity assessment of multifunctional polymeric coatings for airway stents.

Current interventional technology for pediatric airway obstruction consists of cardiovascular stents and silicon tubes. These devices are composed of permanent materials that have limitations in biocompatibility and mechanical properties that make them controversial for used in pediatrics. Bioresorbable stents offer a temporary intervention that dissolves in the body over time and can serve as a platform for local drug delivery. Here we investigate a novel approach to use an antibiotic, ciprofloxacin, as a polymerization initiator to synthesize poly(ciprofloxacin fumaric acid) (PCFA) and then a second polymer using gadodiamide as an initiator to synthesize poly(gadodiamide ciprofloxacin fumaric acid) (PGCFA). Polymer structure, degradation, thermal properties, and rheological behavior were analyzed. Ciprofloxacin released was determined and polymer degradation extracts were used in bacterial sensitivity assessments with four common airway pathogens. PCFA and PGCFA polymers and drug release properties were compared to our previously published polymer poly(fumaric acid) (PFA). These novel polymers enable new possibilities as coatings for bioresorbable biomedical applications that require antibiotic resistance and imaging capabilities. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 2153-2161, 2017.