| Backgroud: Restenosis remains the major limitation of the long-term success of coronary angioplasty. The introduction of stents has significantly reduced the incidence of restenosis, but these results were obtained in selected patients with relatively large vessels( diameter >3.0mm ). Coronary stenting has initially been limited to such artery because of the increased risk of subacute thrombosis obsearved in small vessels. Some investigations showed higher restenosis rate in the patients with small stent implantation. However, with the development of the new stent techniques and new drugs, the insights about the small stent implantation has been changed in recent years. But it still needs further experimental and clinical provements. A few preliminary studies of coronary stents implantated in vessels < 3.0 nun have provided conflicting results. Therefore , the purpose of this study was to assess the effectiveness of the small stent implantation in plasma platelet function and some vasoactive substances .Methods and Objectives: Circulating GMP-140, TXA2, MPAR, ET-1 and AT II levels at different timepoints before and after CAG or PTCA&Stent were measured in 20 palients for (CAG) and 39 patients for PTCA&Stcnt at the paired sampling site: the coronary sinus and peripheral femoral blood. All patients had-6-angiographically significant coronary artery disease ( ^75% at least one epicardial artery) . According to the type of stent, the 39 patients were devided into two groups : Small Stent(SS) group and Non small Stent(NSS) group. The study aim to investigate the safty of CAG and feasibility of small stent group by means of evaluating the time course of plasma platelet function and vasoactive substences. Results:1. Both in CAG groups and in two PTCA&Stent groups, the changes of all indexes in peripheral femoral artery were less than those in coronary sinus, but the tendency of two sites is similar.2. In CAG group, no significant change was found in plasma GMP-140,TXA2, MPAR, ET-1 and AT II after CAG.3. In PTCA&Stent groups, the fluctuation of plasma concentrations of platelet function (GMP-140, TXA2, MPAR) were compatible. They all exhibited dramatically increase at the timepoint of immediately after stenting (P<0.05). The levels of GMP-140 and MPAR dropped to the pre-oparetion level at 10 minute after stenting, while TXE$2 did so at 24 hours after stenting.4. The plasma parameters of platelet function in SS group has no significant changes compared with NSS group.5. In NSS group, the plasma concentration of ET-1 was dramatically decreased immediately after stenting (P<0.05) , increased at 6 hours after stenting, and then decreased again at 12 hours. Compared with the NSS group, the ET-1 levels were higher at timepoints of post-stenting immediately, and 10 minutes, 12 hours, 24 hours after stenting (P<0.05) .6. The plasma level of AT II in SS and NSS group were almost alike. They all increased significantly immediately after stenting (P<0.05), and arrived at the-7-peak at 12 hours after stenting. Then dropped to the pre-oparetion level at 24 hours. Conclusions:1. Measurement results with the sample of peripheral femoral blood was less sentitive than those of Cs, but still reflect the tendency of the changes in Cs,2. Coronary angiograph is a highly safe interventional diagnosis technique, which has no adverse effects on platelet activation and endothelial injury.3. A transient increase of platelet activation exists during the stent placement, which may contribute to the thrombosis after stenting. So the application of potent anti-platelet and anti-coaggregation drugs is vital for stent implantation , especially for small stent implantation.4. With the usage of potent anti-thrombus drugs , the immediate success of small stent implantation was high, and the risk of thrombosis was low.5. The implantation of stent may cause the delayed increase of ET-1 and immediately increase in AT II level.These may get involved in the formation ofin-stent...
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