title: Efficacy and safety of a novel nano-porous polymer-free sirolimus-eluting stent in pigs.
abstract: BACKGROUND
  Drug-eluting stents represent a major advance in interventional cardiology. However, the current drug-eluting stents have significant limitations. One of the major problems is very late stent thrombosis, which is likely caused by inflammation and a hypersensitivity reaction related to a polymer on the stent. A polymer-free sirolimus-eluting stent with a unique nano-porous surface has been developed. This study aimed to evaluate this novel polymer-free sirolimus-eluting stent for its efficacy and safety in a pig model.
  
  
  METHODS
  Stents were directly coated with sirolimus (a drug concentration of 2.2 µg/mm(2) on the stent surface). The polymer-free sirolimus-eluting stents (PFSES) were compared to standard polymer-coated sirolimus-eluting stents (PCSES) and bare-metal stents (BMS) in 18 pigs.
  
  
  RESULTS
  At one month the degree of neointimal hyperplasia was similar between the two sirolimus-eluting stent groups and was significantly less compared to BMS ((1.93 ± 0.51) mm(2), (1.57 ± 0.69) mm(2) vs. (4.45 ± 1.05) mm(2), P < 0.05) At three months, PFSES maintained the low level of neointima ((2.41 ± 0.99) mm(2) vs. (4.32 ± 1.16) mm(2), P < 0.05), whereas PCSES had developed significant neointimal proliferation similar to BMS. The inflammation level was significantly higher in PCSES when compared with BMS three months post-implantation (2.50 ± 0.55 vs. 0.83 ± 0.75, P < 0.05) whereas PFSES showed a low level of inflammation comparable to PCSES (1.33 ± 0.52 vs. 2.50 ± 0.55, P < 0.05).
  
  
  CONCLUSIONS
  The PFSES is effective and safe, and appears to be superior to standard PCSEs.
authors.affiliation: Heart Center of Peking University First Hospital, Beijing 100034, China.
authors.forename: Ming
authors.initials: M
authors.lastname: Chen
authors.affiliation: Heart Center of Peking University First Hospital, Beijing 100034, China.
authors.forename: Bo
authors.initials: B
authors.lastname: Zheng
authors.affiliation: Heart Center of Peking University First Hospital, Beijing 100034, China.
authors.forename: Zheng
authors.initials: Z
authors.lastname: Wu
authors.affiliation: Heart Center of Peking University First Hospital, Beijing 100034, China.
authors.forename: Hong-Yu
authors.initials: HY
authors.lastname: Peng
authors.affiliation: Heart Center of Peking University First Hospital, Beijing 100034, China.
authors.forename: Xin-Gang
authors.initials: XG
authors.lastname: Wang
authors.affiliation: Heart Center of Peking University First Hospital, Beijing 100034, China.
authors.forename: Bin
authors.initials: B
authors.lastname: Zhang
authors.affiliation: Heart Center of Peking University First Hospital, Beijing 100034, China. Email: cm6141@sina.com.
authors.forename: Yong
authors.initials: Y
authors.lastname: Huo
mesh_terms: D000818:Animals; D054855:Drug-Eluting Stents / Q000009:adverse effects*; D058426:Neointima / Q000517:prevention & control; D011108:Polymers / Q000737:chemistry*; D020123:Sirolimus / Q000627:therapeutic use*; D013552:Swine
chemical_list: D011108:Polymers; D020123:Sirolimus