<International Circulation>：Transcatheter aortic valve replacement (TAVR) has now become an important treatment for severe and symptomatic aortic stenosis. Because the patients undergoing TAVR are older and have more complications, the situation is complicated. Would you please share us the antiplatelet treatment strategies recommended in the guidelines for patients after TAVR ?
Prof. Roxana Mehran: Thank you for that important question. Transcatheter aortic valve replacement is increasing in the number of procedures. It is becoming the treatment of choice for most patients with severe aortic stenosis spanning from low to even very high risk patients as an alternative to surgical aortic valve replacement. In many ways, it is a great option for extremely high risk and intermediate to high risk and even low risk patients. As such, it is really important that we understand if there is a need for any antiplatelet regimens after TAVR. When we first started using TAVR, most patients went on aspirin/clopidogrel therapy for three months, and the guidelines are saying 3~6 months aspirin/clopidogrel. Those patients requiring an oral anticoagulant should receive that but judiciously. Obviously, triple therapy would be difficult in these patients. Usually, aspirin is dropped in these patients. But over the years now, after the important POPular TAVI trial, where they looked at both with or without oral anticoagulation, less seems to be more, and the need for dual antiplatelet therapy comes into question. The GALILEO study really did evaluate the role of a novel oral anticoagulant, rivaroxaban, in a modified dose, in patients undergoing TAVR versus an antiplatelet strategy. The trial was stopped early due to more harm in the anticoagulation group. It is important to understand these are extremely high-risk patients. Although we deem them low risk for surgery, the average age is over 70 (up to 80) meaning they are at very high risk for bleeding complications, so we need to understand how to tailor therapy for these patients. For now, it seems that less is more and a single antiplatelet regimen is what is being used. The guidelines, however, have not been updated, which leaves room for some prospective randomized trials in the future to evaluate the role of dual antiplatelet therapy versus single.
<International Circulation>：：Atrial fibrillation is one of the common complications of TAVR patients. It is extremely important to choose a reasonable treatment plan to balance the risk of stroke and bleeding. What is the safety and effectiveness of combined oral anticoagulation and antiplatelet drugs after TAVR? Would you please share us your opinion?
Prof. Roxana Mehran: In patients who require oral anticoagulants because they have atrial fibrillation, the risk of stroke is really high, so balancing the risk of stroke versus bleeding and choosing the right combination therapy in these patients is crucial. In most cases, we are making sure the oral anticoagulant that is given to the patient is a novel oral anticoagulant because that is what they are usually treated with, and making sure that we minimize bleeding by not adding too much of an antiplatelet regimen. If the patient had a stent just before the procedure, or needs a stent, there has to be at least a short period of antiplatelet treatment. But less is more, especially in these patients with oral anticoagulants. We have to make sure we don’t ration the anticoagulation treatment because it is really important for stroke prevention. The other thing for stroke prevention is the use of cerebral embolic protection devices during the procedure. The data is not really clear whether there is stroke reduction, but there is a very large clinical trial underway right now examining cerebral embolic protection devices in TAVR.
<International Circulation>：In recent years, studies have shown that biological valves after TAVR will produce subclinical thrombosis, which is manifested as a decrease in valve leaflet activity. What kind of anticoagulant treatment plan should be taken for this part of patients to prevent thrombosis?
Prof. Roxana Mehran: The incidence of valve thrombosis or restricted valve leaflet mobility is not rare in the order of 10-15% when we start to see increasing gradient and decreased valve motility, especially on 4D CT. That is the sort of work that Raj Makkar did at Cedars-Sinai across all valves, also surgical valves, showing that if you give anticoagulants you can resolve this. In fact, in the GALILEO 4D CT substudy, we did show that rivaroxaban was associated with a reduced incidence of valve immobility or valve thrombosis or valve-related issues, but remember that GALILEO was stopped because of the bleeding issue. So we still need to work hard on finding the balance, and the rules of subclinical valve thrombosis and subclinical valve leaflet decreased mobility needs to be investigated, because we don’t really know. Some of the substudies did show some level of subclinical valve thrombosis or valve decreased mobility, and its effect on the long term durability of the valve is something we need to look out for, but for now, it seems from the early follow-up that we don’t have a full answer on what to do, but some of these anecdotal experiences in retrospective data have shown that giving oral anticoagulants to these patients can resolve the mobility issue, which tells us there is some thrombin-, platelet-, or thrombus-related activity going on in the valve at that place. Again, we need to continue to evaluate this topic.
<International Circulation>：In the future, how to optimize the antithrombotic regimen after TAVR ?Would you please share us your opinion?
Prof. Roxana Mehran:As I said, the future is extremely bright for TAVR and TAVR pharmacology. We are working very hard there. The ATLANTIS trial is coming, which should be extremely informative. In ATLANTIS, apixaban is being evaluated for the full dose, with or without atrial fibrillation, in patients undergoing TAVR. We are really looking out for that study hopefully being reported at ACC. The ENVISAGE study, which is in patients with atrial fibrillation and evaluating the role of a novel oral anticoagulant, edoxaban, compared to warfarin in these patients undergoing TAVR. And so far so good. We are waiting for the results. These are both large scale studies. There are larger registry-based studies being planned. I believe we need to find the optimal treatment for who, why, when and how. There is a lot of future research that will hopefully evaluate this.
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