Preclinical study of a biodegradable polymer-based stent with abluminal sirolimus release.
BACKGROUND
Bioabsorbable polymer stents with drug elution only on the abluminal surface may be safer than durable polymer drug-eluting stents.


OBJECTIVE
To report the experimental findings with the Inspiron™ stent - a bioabsorbable polymer-coated stent with sirolimus release from the abluminal surface only, recently approved for clinical use.


METHODS
45 stents were implanted in the coronary arteries of 15 pigs. On day 28 after implantation, angiographic, intracoronary ultrasonographic and histomorphological data were collected. Five groups were analyzed: Group I (nine bare-metal stents); Group II (nine coated with bioabsorbable polymer on the luminal and abluminal surfaces); Group III (eight stents coated with bioabsorbable polymer on the abluminal surface); Group IV (nine stents with bioabsorbable polymer and sirolimus on the luminal and abluminal surfaces); and Group V (ten stents with bioabsorbable polymer and sirolimus only on the abluminal surface).


RESULTS
The following results were observed for Groups I, II, III, IV and V, respectively: percentage stenosis of 29 ± 20; 36 ± 14; 33 ± 19; 22 ± 13 and 26 ± 15 (p = 0.443); late lumen loss (in mm) of 1.02 ± 0.60; 1.24 ± 0.48; 1.11 ± 0.54; 0.72 ± 0.44 and 0.78 ± 0.39 (p = 0.253); neointimal area (in mm(2)) of 2.60 ± 1.99; 2.74 ± 1.51; 2.74 ± 1.30; 1.30 ± 1.14 and 0.97 ± 0.84 (p = 0.001; Groups IV and V versus Groups I, II and III); and percentage neointimal area of 35 ± 25; 38 ± 18; 39 ± 19; 19 ± 18 and 15 ± 12 (p = 0.001; Groups IV and V versus Groups I, II and III). Injury and inflammation scores were low and with no differences between the groups.


CONCLUSIONS
The Inspiron™ stent proved to be safe and was able to significantly inhibit the neointimal hyperplasia observed on day 28 after implantation in porcine coronary arteries.
Instituto do Coração, Hospital das Clínicas, Faculdade de Medicina, Universidade de São Paulo, São Paulo, SP, Brasil.
Celso Kiyochi
CK
Takimura
Instituto do Coração, Hospital das Clínicas, Faculdade de Medicina, Universidade de São Paulo, São Paulo, SP, Brasil.
Carlos Augusto Homem M
CA
Campos
Instituto do Coração, Hospital das Clínicas, Faculdade de Medicina, Universidade de São Paulo, São Paulo, SP, Brasil.
Pedro Henrique Magualhães Craveiro
PH
Melo
Instituto do Coração, Hospital das Clínicas, Faculdade de Medicina, Universidade de São Paulo, São Paulo, SP, Brasil.
Julliana Carvalho
JC
Campos
Instituto do Coração, Hospital das Clínicas, Faculdade de Medicina, Universidade de São Paulo, São Paulo, SP, Brasil.
Paulo Sampaio
PS
Gutierrez
Scitech Produtos Médicos Ltda, São Paulo, SP, Brasil.
Thiago Francisco Costa
TF
Borges
Scitech Produtos Médicos Ltda, São Paulo, SP, Brasil.
Luciano
L
Curado
Lasertools Tecnologia Ltda, São Paulo, SP, Brasil.
Spero Penha
SP
Morato
Instituto do Coração, Hospital das Clínicas, Faculdade de Medicina, Universidade de São Paulo, São Paulo, SP, Brasil.
Francisco Rafael Martins
FR
Laurindo
Instituto do Coração, Hospital das Clínicas, Faculdade de Medicina, Universidade de São Paulo, São Paulo, SP, Brasil.
Pedro Alves
PA
Lemos Neto
D020341:Absorbable Implants; D000818:Animals; D001704:Biopolymers; D020099:Coated Materials, Biocompatible; D017023:Coronary Angiography; D003331:Coronary Vessels / Q000000981:diagnostic imaging / Q000187:drug effects*; D016503:Drug Delivery Systems / Q000379:methods; D054855:Drug-Eluting Stents; D007166:Immunosuppressive Agents / Q000008:administration & dosage*; D008422:Materials Testing; D012016:Reference Values; D015203:Reproducibility of Results; D020123:Sirolimus / Q000008:administration & dosage*; D013552:Swine; D013997:Time Factors; D014463:Ultrasonography
D001704:Biopolymers; D020099:Coated Materials, Biocompatible; D007166:Immunosuppressive Agents; D020123:Sirolimus