Crimping-induced structural gradients explain the lasting strength of poly L-lactide bioresorbable vascular scaffolds during hydrolysis
[1];
[2];
- California Institute of Technology (CalTech), Pasadena, CA (United States)
- California Institute of Technology (CalTech), Pasadena, CA (United States); ENEA Centro Ricerche Portici (Italy)
- Abbott Vascular, Santa Clara, CA (United States)
- Abbott Vascular, Santa Clara, CA (United States); Gilead Sciences, Inc., Foster City, CA (United States)
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 stents—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 most—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.
- Research Organization:
- Argonne National Lab. (ANL), Argonne, IL (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC), Basic Energy Sciences (BES). Scientific User Facilities Division; National Inst. of Health
- Grant/Contract Number:
- AC02-06CH11357; F31HL137308
- OSTI ID:
- 1482248
- Journal Information:
- Proceedings of the National Academy of Sciences of the United States of America, Vol. 115, Issue 41; ISSN 0027-8424
- Publisher:
- National Academy of SciencesCopyright Statement
- Country of Publication:
- United States
- Language:
- ENGLISH
Web of Science
Similar Records
Evaluation of a Bioabsorbable Self-Expandable Vein Stent-Base Made of Poly(l-lactide) In Vitro and In Vivo
Acute Stent-Induced Endothelial Denudation: Biomechanical Predictors of Vascular Injury