< International Circulation >: Would you please introduce the possible mechanisms of late stent thrombosis?

《国际循环》：支架内晚期血栓的可能机制是什么？

Dr. Liliana R. Grinfeld: The possible mechanisms for the late stent thrombosis are not thoroughly discovered yet， but， we have known lots of useful information already， one of which is that late stent thrombosis is not as common in drug eluting stents as in bare metal stents; In addition， late stent thrombosis is very rare condition with a incidence below 0.5% per year， however it’s a very serious complication， because 80% or more will encounter acute myocardial infarction whose mortality is around 30%.

There are many considerations about the drug eluting stents， for instance， stents are not covered by endothelium for a long time. The islands of no coverage could be one of the reasons for late stent thrombosis. Another is that the patients might develop new lesions immediately before or after the procedures. Though some of these lesions are distant from the stent， the thrombosis may involve the stent indeed. Besides， an unusual condition is that instant restenosis emerged， and then some factors facilitate the thrombosis to a serious illness. In a word， those are the main reasons for the late thrombosis.

Dr. Liliana R. Grinfeld: 支架内晚期血栓形成的可能机制还不是十分清楚。但我们目前也已经知道了很多情况：第一，药物洗脱支架的晚期血栓形成发生率较裸金属支架低；第二，支架内晚期血栓形成的发生率比较低，并不是一个常见情况，每年通常低于0.5%或者更低。尽管这是一种发生率低的并发症，但是其严重程度很高。因为80%的患有支架内晚期血栓形成的患者患有心肌梗死，病死率在30%左右。总的来说，其病死率很高，但是发生率很低。因此，对药物洗脱支架，有很多考虑初衷，第一是支架长期时间内没有被覆内皮细胞，有很多“小岛”没有被覆，也许这是原因之一。另外一个原因是，有些患者在支架置入后马上就出现新的病变，或许支架置入为新的病变发生创造了新的条件，有些病变远离支架，但是血栓形成却在支架附近；另外一种情况较少发生，并且不发生在所有的支架上，这种情况就是支架再狭窄，这种情况下血栓形成会变成非常严重的疾病。这些是晚期血栓形成的主要原因。

< International Circulation >: How to prevent and treat the problem of late stent thrombosis in DES or BMS? 

《国际循环》：如何预防和处理支架内晚期血栓问题?

Dr. Liliana R. Grinfeld: The prevention of the late stent thrombosis is a crucial issue between 3 month and 1 year after PCI. One year later， it’s called very late stent thrombosis. As for the late stent thrombosis， what you have to do first is keeping full-dose injection and complete medication， eg. clopidogrel and aspirin. Up to now， the guidelines recommend one year at least. In some cases， like multiple stents for multi-segment lesion， you should tell the patients to take clopidogrel for more than one year， and another important point to mention is that people may be resistant to clopidogrel and aspirin， if they are at high risk for late stent thrombosis which means long stents， diabetes， low ejection fraction， or previously late stent thrombosis history in bare metal stent or drug eluting stent， you should continue their anti-platelet therapy and try to find out whether they do have resistance to those drugs.

Dr. Liliana R. Grinfeld: 支架内晚期血栓形成的预防通常在3个月和1年间，1年后，通常称为支架内非常晚期血栓形成。对于支架内晚期血栓形成，通常你需要做：第一，保证充足和充分的内科药物治疗，氯吡格雷和阿司匹林，到目前为止，我们通常将药物治疗时间定为1年，或长或短，现在指南上也说至少1年。在有些情况下，比如放置了很多支架，如多节段病变，对于这些病例，你可以让患者服用1年以上的氯吡格雷，这是非常重要的。我们也知道有些患者有氯吡格雷和阿司匹林抵抗，如果你的患者目前处于支架内血栓形成高风险状态，比如多支架、糖尿病、此前曾发生过支架内晚期血栓形成，无论裸金属支架或药物洗脱支架，所有这些患者发生支架内晚期血栓形成的风险都很高，所以对于这些患者，你应该保证抗血小板治疗，同时判定是否对药物产生抵抗。

< International Circulation >: Would you like to review the status of AMI treatment in Latin America?

《国际循环》：您可以概述拉丁美洲急性心肌梗死的治疗现状吗？

Dr. Liliana R. Grinfeld: In Latin America， the treatment for acute myocardial infraction is mainly anti-thrombosis therapy with aspirin， because we don’t have enough catheterization rooms， if in very high risk， patients are transferred to the hospitals with primary angioplasty capability. Finally， no more than 5% to 15% patients will have primary angioplasty， about 50% will be dealt with anti-thrombosis， and 20%~30% overall do not have any treatment. So it is a task that we are working on to have more treatments for more patients. In the future， we are going to open new cath labs in order to do more primary angioplasty， but， right now it is not the first choice because of the lack of both catheterization rooms and qualified doctors.

Another task we have to work on is prevention for all patients from progression of late stent thrombosis， from the occlusions of the stent， from repeated surgery for more lesions， and from more treatment procedures. So prevention is for everyone. In acute myocardial infarction， we think it very important that people have to know that if chest pain occured， they should immediately go to the hospital， and beforehand， we must give more instuctions to them， such as doing clinical checkups every year if more than 40 years old， no use of cholesterol， well controlling of body weight mass. 

Dr. Liliana R. Grinfeld:对于拉丁美洲而言，急性心肌梗死的治疗目前仍主要以抗血栓治疗为主，因为我们没有足够的导管室条件。对于血栓形成，主要使用阿司匹林。高危患者一般转院至可进行血管成形的医院，大约5%~15%的患者可接受一期血管成形术，剩下的患者，也即50%的患者接受抗血栓治疗，整个拉丁美洲范围内，大约20%~30%的患者无法接受治疗。应该缩小其中的差距，但至少目前为止，一期血管成形术不是首选治疗，主要原因是缺少硬件条件及受训人员。

《国际循环》：谢谢，这意味着将重点从治疗转向预防？

Dr. Liliana R. Grinfeld: 我们对每个患者均采取预防策略，以防止支架内晚期血栓形成进展，防止支架内堵塞，防止曾接受手术的患者因病变再次接受手术，所以预防是针对每个患者的。对于急性心肌梗死，我们意识到需要研究，我们告诉患者出现胸痛时该如何做，马上去医院。当然，在此之前，我们会建议年龄在40岁以上的人群做每年做健康体检，比如心电图。并且强调不要应用胆固醇，注意降低体重等等。所有这一切构成了我们的预防策略。