Crimping-induced structural gradients explain the lasting strength of poly L-lactide bioresorbable vascular scaffolds during hydrolysis

TitleCrimping-induced structural gradients explain the lasting strength of poly L-lactide bioresorbable vascular scaffolds during hydrolysis
Publication TypeArticolo su Rivista peer-reviewed
Year of Publication2018
AuthorsRamachandran, K., Di Luccio Tiziana, Ailianou A., Kossuth M.B., Oberhauser J.P., and Kornfield J.A.
JournalProceedings of the National Academy of Sciences of the United States of America
Volume115
Pagination10239-10244
ISSN00278424
Abstract

Biodegradable polymers open the way to treatment of heart disease using transient implants (bioresorbable vascular scaffolds, BVSs) that overcome the most serious complication associated with permanent metal stentsi late stent thrombosis. Here, we address the long-standing paradox that the clinically approved BVS maintains its radial strength even after 9 mo of hydrolysis, which induces a ∼40% decrease in the poly L-lactide molecular weight (Mn). X-ray microdiffraction evidence of nonuniform hydrolysis in the scaffold reveals that regions subjected to tensile stress during crimping develop a microstructure that provides strength and resists hydrolysis. These beneficial morphological changes occur where they are needed mosti where stress is localized when a radial load is placed on the scaffold. We hypothesize that the observed decrease in Mn reflects the majority of the material, which is undeformed during crimping. Thus, the global measures of degradation may be decoupled from the localized, degradation-resistant regions that confer the ability to support the artery for the first several months after implantation. © 2018 National Academy of Sciences. All rights reserved.

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URLhttps://www.scopus.com/inward/record.uri?eid=2-s2.0-85054764373&doi=10.1073%2fpnas.1807347115&partnerID=40&md5=8924e6a2ad4f589d3b83d62c06437551
DOI10.1073/pnas.1807347115