Scanning electron microscopic assessment of the biodegradable coating on expanded biolimus-eluting stents.
OBJECTIVE
Biodegradable coatings on drug-eluting stents (DES) may help to avoid adverse long-term effects of DES such as late/very late stent thrombosis which is partly attributed to durable polymers. As the post-expansion morphology of biodegradable coatings is greatly unknown, we investigated the polylactic acid coating on biolimus-eluting BioMatrix stents.


RESULTS
Scanning electron microscopy (SEM) was used to carefully examine five 3.5mm stents following expansion at 6-14atm (maximum 7% overstretch). SEM examination demonstrated only mild cracks of the coating after stent expansion at 6 atm. An increase in expansion pressure, associated with mild stent overstretch, resulted in more severe cracks. Lifting of the coating together with few sites of partial detachment of fragments was noticed after stent expansion in water at 14atm; these irregularities further increased after aggressive oversized partial postdilatation with a 5.0mm non-compliant balloon with additional secondary cracks.


CONCLUSIONS
SEM assessment suggests a relatively low elasticity of the biodegradable coating on BioMatrix stents. At nominal pressure, stents showed predominantly mild cracks of the coating, while cracks increased after slight overstretch. Aggressive overexpansion of the stent, such as sometimes required in left main bifurcation stenting, worsened cracks and led to some detachment of fragments of the coating in vitro.
Basalus
Mounir W Z
MW
Department of Cardiology, Thoraxcentrum Twente, Enschede, The Netherlands.
van Houwelingen
K Gert
KG
Ankone
Marc
M
de Man
Frits H A F
FH
von Birgelen
Clemens
C
D020341:Absorbable Implants / Q000706:statistics & numerical data*; D015374:Biosensing Techniques / Q000295:instrumentation / Q000379:methods; D054855:Drug-Eluting Stents / Q000706:statistics & numerical data*; D004867:Equipment Design; D006801:Humans; D007166:Immunosuppressive Agents / Q000008:administration & dosage / Q000627:therapeutic use; D008855:Microscopy, Electron, Scanning / Q000379:methods; D015203:Reproducibility of Results; D020123:Sirolimus / Q000008:administration & dosage / Q000031:analogs & derivatives / Q000627:therapeutic use; D014867:Water
D007166:Immunosuppressive Agents; D014867:Water; C518022:umirolimus; D020123:Sirolimus