| Objective Drug-eluting stents have been suggested to markedly decrease in-stent restenosis in 6 months, but they are noticed due to the late thrombogenicity. Tetramethylpyrazine -eluting stent (TES) is made up of bare-metal stent coating with Tetramethylpyrazine(TMP).It is not clear about its long-term effects and safety. The purpose of the present study was to investigate the intimal response and thrombogenicity in normal porcine coronary arteries by coronary angiography(CAG) and intravascular ultrasound(IVUS) and histomorphometry, further to evalute its biocompatibility.Methods Bare metal stents(BMS) were uniformly sprayed with TMP(200μg)and prepared for TMP -eluting stents. Fourteen coronary arteries in 14 pigs underwent stnet implantation. Seven TES were implanted in 7 pigs. Seven BMS for other 7 pigs. The stents were deployed with a stent-to-artery ratio of 1.1-1.2/1.0 in order to induce vascular wall injury. Quantitative coronary angiography(QCA) and intravascular ultrasound(IVUS) were performed before and immediately after the implantations and at the end point time of 28 days.The analysis on blood cell count ,27 biochemistry items ,blood pressure (BP), heart rate (HR), body weight (BW), status of behavior of pigs were evaluated before the implantation and at the point time of 1, 28 days. Stented-coronary ,stented-coronary related ventricular wall ,lung ,liver and kidney were collected after euthanasia of animals on the endpoint. Histopathology and histomorphometry had been done by H&E.Results All the stents were implanted into porcine coronary arteries successfully, However four pigs were died of cardiac tamponade or anesthesia. No bone marrow inhibition and hemolysis occurred , no damage to the function and metabolism of liver and kidney was discovered ,no significant difference was found in variation of HR , BP and BW between the two groups . No thrombosis was found in control and test groups. The stented-coronary wall wasn't found inflammation cell for each endpoint in both groups . No damage to stented-coronary related ventricular wall ,lung , liver and kidney due to TES implanted . It was showed that the follow-up vessel diameter was diminished markedly compared with the post-stenting vessel diameter in both groups(P<0.01)by QCA. Compared with the control group, the neointimal area was significantly reduced in the TES group (60.2±23.5% vs 10.0±2.1%, P=0.01) by IVUS analysis. It was showed that the injury score and the in-stent areas were similar in both groups(P>0.05)by histomorphometric detection, but the lumen area in the TES group was increased visibly (4.34±0. 93mm~2 vs 1.29±1.02mm~2, P=0.011), the neointimal area was reduced markedly (1.51±0.45mm~2 vs 4.60±1.39mm~2, P=0.004). Compared IVUS to histopathology have liner regression on data detection in two groups.Conclusions The histocompatibility and hemocompatibility of TES in porcine model in 28 days seems good and acceptable . Biocompatibility can be evaluated by IVUS and histopathology in a mini porcine... |
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