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

Prof. 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 as common in drug-eluting stents as in bare metal stents; In addition， late stent thrombosis is a very rare condition with an incidence below 0.5% per year， however it’s a very serious complication， because 70%  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 instent restenosis emerged， as one of factors that might facilitate the thrombosis and also that restenosis is a very serious illness.Also I have to mention that inadequate sent apposition to the vessel wall (which is poor technique)，also is one of the main reasons for these serious complication. In a word， those are some of the main reasons for the late thrombosis.

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

Prof. Liliana R. Grinfeld: The prevention of the late stent thrombosis is a crucial issue between 3 months 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 of clopidogrel and aspirin. Up to now， the guidelines recommend one year at least. In some cases， like multiple stents for multi-segment lesion， it could be wise tell our patients to take clopidogrel for more than one year. 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.

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

Prof. Liliana R. Grinfeld: In Latin America， the treatment for acute myocardial infarction is mainly thrombolytic  therapy and aspirin， because we don蒸 have enough catheterization rooms， in very high risk patients we try hard to transfer them to the hospitals with primary angioplasty capability. Finally， no more than 5% to 15% of patients will have primary angioplasty， about 50% will be dealt with thrombolysis， and 20%~30% overall do not have any revascularization treatment. So it is a task that we are working on to have more revascularization 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 of risk factors so we can prevent patients from progression of the atherosclerotic disease ansd also prevention of late stent thrombosis and occlusions ，also from the need to repeat surgery for new lesions， and the need for more  procedures . So prevention is for everyone and people should have annual check ups if they are over 40 years and younger if there is a trong family history of heart disease. In acute myocardial infarction， we think it is very important that people that have chest pain  should know that should immediately go to the hospital.