| Background It has been more than one decade since intracoronary stenting (ICS) was successfully used in therapy of coronary artery diseases,which has prominent efficacy on decreasing late-stage in-stent restenosis (RS) and preventing acute post-angiopiastic complications. However, the main complications after ICS ,such as coronary vasoplasm, subacute intrastent thrombosis, especially, RS, limit its therapeautic roles. Someones have discovered that magnetic fields may effectively inhibit endothelin-1 (ET-1) release from some special neurons and the activity of coagulation system, additionally, improve fibrinolysis function. Moreover, other cardiologists have found they play significantly roles in inhibiting proliferation of vascular smooth muscle cells , as probably has an important preventive effects on the development of RS.Methods and Objective 38 hospitalized patients from July to November, 2000 were enrolled in our study. All of them were proved by means of coronary angiography to have at least one culprit branch with diameter stenosis of 75% or more, and randomly implanted non-magnetic stents(NMS,n=18) and magneticones (MS, n=20). Coronary sinus blood was drawed at different time points before PICA and after ICS for the analysis of plasma ET-1 level, tissue-type plasminogen activator (t-PA), plasminogen activator inhibitor-1 (PAI-1) and thrombin activities.Those patients were continuously followed up for 6 months after the discharge in order to find RS. The diagnostic conteria of RS mainly include recurrence of chest pain and > 50% reduction of the lumen diameter of target vessels .Through the analysis of the above parameters and the results of follow-up, we aimed at discovering some protective mechanisms of intracoronary magnetic stents in patients undergoing intervational therapy.Results 1. The postoperational concentrations of endothelin-1 in MS group were kept on a lower level, especially at 3 h(P<0.01), while the ones in NMS group were elevated, especially immediately after stenting (PO.Ol); furthermore, the endothelin-1 levels in both of the groups restored to the baseline at 6 h.2. The t-PA activities in the two groups were lowered immediately after stenting. However ,the t-PA activity in MS group almost recovered to the basal level at 6 h ,in contrast with that of NMS group still being on a lower one (P<0.05).3. The PAI-1 activities in both of the groups were markedly elevated immediately after stenting(P<0.01). Nevertheless, the one in MS group was restored to the pre-PTCA level at 6 h .4. In contrast to no significant changes in NMS group , the decreases of post-intervational thrombin activity in MS group were siganificantly: (0.31 ?.14) and (0.23 + 0.11) vs(0.45 + 0.12)U /ml (PO.05, P<0.01 , respectively).5. As a result of 6-month follow-up, no complications occurred in MS group while 4 patients suffered from RS in NMS group (22.2%,P<0.05) and wererehospitalized to receive angioplasty. Conclusions1. Magnetic stents may effectively lower the postintervational endothelin-1 concentrations and thrombin activity in coronary sinus plasma of the patients undergoing PICA and immediately intracoronary stenting .2. Intracoronary magnetic stents may improve fibrinolysis function in the coronary arteries undergoing angioplasty.3. Intracoronary magnetic stents may play an important role in preventing the development of RS. |
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