title: Vascular response and mechanical integrity of the new biodegradable polymer coated sirolimus-eluting PROLIM stent implanted in porcine coronary arteries.
abstract: BACKGROUND
  Although durable polymer coated drug-eluting stents (DES) are standard care in percutaneous coronary interventions, new stent platforms employing biodegradable polymer based drug delivery are increasingly being used in clinical practice.
  
  
  OBJECTIVE
  To evaluate the short- (28 days) and medium-term (90 days) vascular effects of the new biodegradable polymer coated sirolimus-eluting stent - the PROLIM stent.
  
  
  METHODS
  The objectives of the study were evaluated using standard angiographic and histological methods. In addition, the mechanical integrity of tested stents was assessed using Faxitron imaging. A total of 12 PROLIM stents, 11 biodegradable polymer only coated stents (BPCS), and 12 bare metal stents (BMS) were implanted in the coronary arteries of 16 female non-atheroslerotic domestic swine using an overstretch of 1.1:1.0.
  
  
  RESULTS
  At 28 days, neointimal proliferation was significantly lower in the PROLIM and BMS stents compared to the BPCS stents (p ≤ 0.05). Interestingly, despite thin neointima found at this time in the PROLIM group, there was a further significant decrease in neointimal formation between 28 and 90 days (p = 0.04). Although a statistically bigger neointima was found in BPCS stents at 28 days compared to the PROLIM and BMS stents, there was a 50% decrease in the neointimal area at 90 days follow-up (p = 0.02) which reached the level seen in other groups. The endothelialisation was completed in all tested stents after 28 days. There was a significant increase of fibrin depositions in the PROLIM treated arteries at 28 days which were resorbed nearly completely at 90 days follow-up. At 28 days, the inflammatory response was found to be numerically higher in the BPCS stents (p = NS) compared to other tested groups. On the contrary, at 90 days follow-up when the degradation process of the polymer had been completed, the inflammatory reaction decreased substantially to the level seen in the PROLIM and BMS stents. Faxitron analysis of the stented arteries revealed no major abnormalities except for isolated strut fractures observed in the mid portions of two BMS stents and one BPCS stent.
  
  
  CONCLUSIONS
  The PROLIM - a biodegradable polymer coated sirolimus-eluting stent - demonstrates very good short-term and medium-term angiographic and histological results. The lack of 'catch-up phenomenon', fast endothelialisation process, and minimal inflammatory reaction may contribute to favourable clinical outcomes using PROLIM stents.
authors: Center for Cardiovascular Research and Development, American Heart of Poland SA, Katowice, Poland. kpmilewski@gmail.com
authors: Krzysztof
authors: K
authors: Milewski
authors: Bogdan
authors: B
authors: Gorycki
authors: Piotr P
authors: PP
authors: Buszman
authors: Michał
authors: M
authors: Jelonek
authors: Diane
authors: D
authors: Beaudry
authors: Jean Martin
authors: JM
authors: Lapointe
authors: Louis Georges
authors: LG
authors: Guy
authors: Motaz
authors: M
authors: Abusamra
authors: Jacek
authors: J
authors: Pająk
authors: Wojciech
authors: W
authors: Kinasz
authors: Wojciech
authors: W
authors: Wojakowski
authors: Guy
authors: G
authors: Leclerc
authors: Robert J
authors: RJ
authors: Gil
authors: Paweł E
authors: PE
authors: Buszman
mesh_terms: D020341:Absorbable Implants; D000818:Animals; D020099:Coated Materials, Biocompatible / Q000009:adverse effects; D017023:Coronary Angiography; D003331:Coronary Vessels / Q000000981:diagnostic imaging* / Q000473:pathology* / Q000601:surgery; D054855:Drug-Eluting Stents / Q000009:adverse effects; D005260:Female; D066298:In Vitro Techniques; D008422:Materials Testing; D011091:Polyesters; D011474:Prosthesis Design; D020123:Sirolimus / Q000008:administration & dosage*; D013552:Swine; D014657:Vasculitis / Q000209:etiology
chemical_list: D020099:Coated Materials, Biocompatible; D011091:Polyesters; D020123:Sirolimus