[The efficacy of tetramethylpyrazine-eluting stents on inhibiting neointima formation in porcine coronary arteries].
OBJECTIVE
The aim of this study was to investigate the mechanism and efficacy of tetramethylpyrazine-eluting stents (TES) on inhibiting neointima formation in porcine coronary arteries.


METHODS
TES was prepared by tetramethylpyrazine spray-coated in bare metal stents (BMS). Pigs were implanted with TES or BMS (n = 7 each), respectively. Quantitative coronary angiography (QCA) and intravascular ultrasound (IVUS) were performed before, immediately after stenting and at 28 days after stenting. Coronary arteries segments (5 cm) before and post stenting area (5 cm) as well as at stenting location were harvested at 28 days post stenting for histopathological examinations (inflammation, vascular smooth muscle cells proliferation and apoptosis).


RESULTS
Follow up QCA at 28 days showed that percentage diameter stenosis were significantly lower in the TES group than that in the BMS group [(10.0 +/- 2.1)% vs (60.2 +/- 23.5)%, P = 0.01]. The lumen area determined by IVUS was similar between the two groups and there was no in-stent thrombosis in TES or BMS treated animals. Internal elastic lamina area was significantly larger while the neointimal area [(1.51 +/- 0.45) mm(2) vs (4.60 +/- 1.39) mm(2), P = 0.04] was significantly smaller in the TES group than that in the BMS group. Histopathological assessments showed fewer inflammatory cells in the stented-coronary artery walls than those at the border zones of stenting in both groups. The number of proliferating cells were significantly decreased while apoptotic cells were significantly increased in the TES group compared with the BMS group (all P < 0.05).


CONCLUSIONS
TES could effectively reduce in-stent restenosis in this porcine model by attenuating vascular smooth muscle proliferation and enhancing vascular smooth muscle apoptosis post stenting.
Chen
Li-Juan
LJ
Department of Cardiology, Zhong Da Hospital, Southeast University, Nanjing 210009, China.
Feng
Yi
Y
Ding
Shu
S
D000818:Animals; D023903:Coronary Restenosis / Q000517:prevention & control*; D003331:Coronary Vessels / Q000473:pathology; D004195:Disease Models, Animal; D004311:Double-Blind Method; D054855:Drug-Eluting Stents; D011719:Pyrazines / Q000008:administration & dosage*; D013552:Swine; D017539:Tunica Intima / Q000187:drug effects* / Q000473:pathology
D011719:Pyrazines; C017953:tetramethylpyrazine