Optical Coherence Tomography (OCT) Evaluation Of Stents Coated With Extract From Tripterygium Hypoglaucum (Levl.) Hutch After PCI

Objective:Percutaneous Coronary Intervention (PCI) is a main means of treatment of coronary heart disease. As important advance in the clinical application of drug-eluting stent(DES ) , sirolimus-eluting stent and paclitaxel-eluting stent has effectively reduced the rate of in-stent restenosis.But the risk of late thrombosis and possibility of restenosis have become the main barrier to the development of drug-eluting stent. So the study of drugs in preventing restenosis after PCI is a hot medical topic at present. Tripterygium Hypoglaucum (Levl.) Hutch (THH) plays an effective role in anti-inflammation and immunity, inhibiting the proliferation of smooth muscle cells and neointimal. This study evaluates the efficiency of extract from tripterygium hypoglaucum (Levl.) hutch (TH-1)eluting stent on anti-restenosis from the quantitative coronary angiography and optical coherence tomography equipment.Methods:This study intends to use 20 healthy Diannan small ear pigs, 4-6 months old, weight 25-35Kg, male or female. Animals were divided at random into 5 groups: Bare metal stent, low dose of TH-1 eluting stent (0.14?g/mm2), middle dose of TH-1 eluting stent(0.70?g/mm2), high dose of TH-1 eluting stent (2.8?g/mm2) and sirolimus eluting stent.Each pig was fed clopidogrel (300mg) and aspirin (300mg) for 1 day before PCI. After coronary artery angiography, each pig was implanted into the same type stents, the diameter ratio of artery to stent is 1.1-1. 2:1. After that, we made use of optical coherence tomography (OCT) technique to observe the stent position,made sure each support beam completely stick to the vascular wall. Each pig was injected heparin sodium 6000IU one time, 2 times per day for 7 days, clopidogrel (75mg/d) and aspirin(100mg/d) for 28 days. Animals underwent angiographic study afer 28 days, optical coherence tomography was applied to measuring reference artery diameter, minimum stent diameter, neointimal thickness, stent area,lumen area, neointimal area and calculating degree of coronary artery stenosis, narrow degree. Make comparison for bare metal stent group, low dose of TH-1 eluting stent, middle dose of TH-1 eluting stent, high dose of TH-1 eluting stent and sirolimus eluting stent to observe if there is any difference in statistics.Results:The results the measurement of quantitative coronary angiography after stent implantation 28 days testify that the narrow degree of middle dose of TH-1 eluting stent group is similar to sirolimus eluting stent group (P>0.05), and less than bare metal stent group, low dose and high dose of TH-1 eluting stent group (P<0. 05). OCT results testify that the narrow degree and neointimal area of middle dose of TH-1 eluting stent group and sirolimus eluting stent group is similar (P>0. 05). less than bare metal stent group, low dose and high dose of TH-1 eluting stent group (P<0. 05). Lumen residual area of Middle dose of TH-1 eluting stent group and sirolimus eluting stent is similar(P>0. 05), and all obviously larger than bare metal stent group, low dose and high dose of TH-1 eluting stent group (P<0. 05).Conclusion:(1) TH-1 eluting stent could significantly inhibit the neointimal proliferation.(2) TH-1 eluting stent group (0.70 ?g/mm2) and sirolimus eluting stent group have similar function in prevention restenosis after PCI.(3) High or low dose of (TH-1) eluting stent could not effectively prevent restenosis after PCI.