title: A biodegradable slotted tube stent based on poly(L-lactide) and poly(4-hydroxybutyrate) for rapid balloon-expansion.
abstract: Safe vascular stent application requires rapid expansion of the stent to minimize the risk of procedural ischemia. While high expansion speeds can be achieved with metallic stents, they are not necessarily feasible with biodegradable polymeric stents due to the viscoelastic material behavior. This study reports on a novel biodegradable polymer blend material based on poly(L-lactide) (PLLA) and poly(4-hydroxybutyrate) (P4HB), and describes the mechanical properties and in vitro degradation behavior of a balloon-expandable slotted tube stent concept. The stent prototypes with nominal dimensions of 6.0 x 25 mm were manufactured by laser machining of solution cast PLLA/P4HB tubes (I.D. = 2.8 mm, d = 300 microm). The stents were expanded within 1 min by balloon inflation to 8 bar, after 5 min preconditioning in 37 degrees C water. Recoil and collapse pressure were 4.2% and 1.1 bar, respectively. During in vitro degradation collapse pressure initially increased to a maximum at 4 w and then decreased thereafter. After 48 w, molecular weight was decreased by 82%. In summary, the PLLA/P4HB slotted tube stents allowed for rapid balloon-expansion and exhibited adequate mechanical scaffolding properties suitable for a broad range of vascular and non-vascular applications.
authors.affiliation: Institute for Biomedical Engineering, University of Rostock, Ernst-Heydemann-Str. 6, D-18057, Rostock, Germany. niels.grabow@medizin.uni-rostock.de
authors.forename: Niels
authors.initials: N
authors.lastname: Grabow
authors.forename: Carsten M
authors.initials: CM
authors.lastname: Bünger
authors.forename: Christine
authors.initials: C
authors.lastname: Schultze
authors.forename: Kathleen
authors.initials: K
authors.lastname: Schmohl
authors.forename: David P
authors.initials: DP
authors.lastname: Martin
authors.forename: Simon F
authors.initials: SF
authors.lastname: Williams
authors.forename: Katrin
authors.initials: K
authors.lastname: Sternberg
authors.forename: Klaus-Peter
authors.initials: KP
authors.lastname: Schmitz
mesh_terms: D020341:Absorbable Implants; D001672:Biocompatible Materials / Q000737:chemistry*; D001807:Blood Vessel Prosthesis; D002404:Catheterization / Q000295:instrumentation* / Q000379:methods; D004867:Equipment Design; D019544:Equipment Failure Analysis; D010865:Pilot Projects; D011091:Polyesters / Q000737:chemistry*; D015607:Stents
chemical_list: D001672:Biocompatible Materials; D011091:Polyesters; C107955:poly(4-hydroxybutanoate); C033616:poly(lactide)