Drug-eluting biodegradable poly-D/L-lactic acid vascular stents: an experimental pilot study.
OBJECTIVE
To evaluate in vivo a new drug-eluting biodegradable vascular stent with respect to biocompatibility, neointimal hyperplasia formation, and reliability.


METHODS
Self-expanding biodegradable poly-96L/4D-lactic acid (PLA) stents with 2 drugs (PLA + dexamethasone [DEX] and PLA + simvastatin [SIM]) and 2 different coatings (PLA + P(D,L)LA and PLA + polycaprolactone [PCL]) were compared with a self-expanding stainless steel Wallstent. The stents were implanted in both common iliac arteries of 8 pigs. Prior to sacrifice at 1 month, angiography was performed to determine patency. Specimens were harvested for quantitative histomorphometry; vascular injury and inflammation scores were assigned to the stented iliac segments.


RESULTS
All stented arteries were angiographically patent. The mean luminal diameter (3.05 mm) and area (30.36 mm2) of DEX-eluting PLA stents were decreased compared to other stents (PLA + P(D,L)LA: 3.66 mm and 43.92 mm2; PLA + SIM: 4.21 mm and 56.48 mm2; PLA + PCL: 4.19 mm and 54.64 mm2; Wallstent: 5.01 mm and 81.19 mm2). Wallstents and DEX-eluting PLA stents induced minimal intimal hyperplasia: PLA + DEX: 0.16 mm, PLA + P(D,L)LA: 0.35 mm, PLA + SIM: 0.33 mm, PLA + PCL: 0.29 mm, and Wallstent: 0.18 mm. The vascular injury scores demonstrated only mild vascular trauma for all stents. Only mild to moderate inflammatory reaction was noted around stent struts with a vascular inflammation score.


CONCLUSIONS
Biodegradable polymer stents appear to be biocompatible and reliable, causing minimal neointimal hyperplasia. Furthermore, the new biodegradable poly-D/L-lactic acid stent can be used as a local drug delivery vehicle. The DEX-eluting PLA stent reduces neointimal hyperplasia. The findings show a need for further investigation to prove the efficacy and safety of this new biodegradable drug-eluting stent.
Uurto
Ilkka
I
Department of Surgery, Satakunta Central Hospital, Pori, Finland. ilkka.uurto@uta.fi
Mikkonen
Joonas
J
Parkkinen
Jyrki
J
Keski-Nisula
Leo
L
Nevalainen
Timo
T
Kellomäki
Minna
M
Törmälä
Pertti
P
Salenius
Juha-Pekka
JP
D020341:Absorbable Implants; D000818:Animals; D001157:Arterial Occlusive Diseases / Q000188:drug therapy / Q000473:pathology / Q000601:surgery; D001807:Blood Vessel Prosthesis; D019917:Blood Vessel Prosthesis Implantation / Q000295:instrumentation*; D020099:Coated Materials, Biocompatible; D003907:Dexamethasone / Q000494:pharmacology; D004195:Disease Models, Animal; D005500:Follow-Up Studies; D005938:Glucocorticoids / Q000494:pharmacology; D019161:Hydroxymethylglutaryl-CoA Reductase Inhibitors / Q000494:pharmacology; D007083:Iliac Artery / Q000187:drug effects / Q000473:pathology / Q000601:surgery; D008297:Male; D010865:Pilot Projects; D011091:Polyesters; D011474:Prosthesis Design; D019821:Simvastatin / Q000494:pharmacology*; D015607:Stents; D013552:Swine
D020099:Coated Materials, Biocompatible; D005938:Glucocorticoids; D019161:Hydroxymethylglutaryl-CoA Reductase Inhibitors; D011091:Polyesters; C016240:polycaprolactone; C033616:poly(lactide); D003907:Dexamethasone; D019821:Simvastatin