A. Pieter Kappetein, MD, PhD; Gilles Montalescot, MD, PhD


June 06, 2014

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Dual Antiplatelets or Oral Anticoagulation?

Gilles Montalescot, MD, PhD: Hello. I'm Gilles Montalescot, an interventional cardiologist in Paris at the Pitié-Salpêtrière Hospital. We will have a discussion with Pieter Kappetein from Rotterdam about transcatheter aortic valve implantation (TAVI) and what we should do in terms of antiplatelet, anticoagulation therapy before, during, and after the procedure. What is best for the patients without data. What do you think? What should we do before and during?

A. Pieter Kappetein, MD, PhD: I'm a surgeon very much involved with the TAVI program. In surgery we already struggle with it, because if we have a patient with a mechanical heart valve it's pretty clear: We give them Coumadin [warfarin]. When a patient gets a bioprosthetic heart valve, it's less clear. We give them aspirin and we give them [warfarin] for 3 months. There are a lot of hospitals that only give them aspirin after the procedure. There is still debate in the surgical world on how we should anticoagulate patients with bioprosthetic heart valves.

We were one of the first centers in Europe and the first center in The Netherlands to do TAVI, and we were really in the dark. What should we use? The strategy comes more from the drug-eluting stents world. We started to give them clopidogrel because this valve has a stent. Then, of course, we learned that if you don't anticoagulate them, it may have some negative effects, more peripheral embolism. But whether clopidogrel is the right approach, we still don't know.

Dr. Montalescot: You would use mostly aspirin and clopidogrel after the procedure?

Dr. Kappetein: Yes. We give them aspirin and clopidogrel for at least 3 months. That's how we currently treat patients. But, of course, there are always patients who are not mainstream patients. Some patients have atrial fibrillation (AFib). Some have percutaneous coronary intervention (PCI) during the TAVI procedure or just before the TAVI procedure, so they are already on anticoagulation therapy. We may continue it or the clopidogrel much longer, especially in those patients who get PCI during the procedure or just before. We give them clopidogrel for at least 6 months.

Dr. Montalescot: I think that reflects what we see elsewhere. Aspirin and clopidogrel is the leading treatment after TAVI. More than 50% of patients apparently receive this dual-antiplatelet therapy. We see 10% of patients on warfarin, usually those with high-risk AFib. We also see patients on both, antiplatelet and anticoagulation, because they have AFib, and some form of antiplatelet therapy because of the TAVI or coronary artery disease -- whatever it is. I'm impressed by the complication rates: about 10% of patients experience major bleeding during the first month. Aspirin and clopidogrel is not very good in terms of safety. It makes you bleed as much as the anticoagulation. We know that from the ACTIVE study.[1]

Dr. Kappetein: Absolutely. Also, the procedure by itself, of course, is quite invasive. The sheaths are still pretty large. When you puncture the groin in the femoral artery, there's quite a big hole there. You hope that it will stop the bleeding. The bleeding events have decreased over the years, to be honest. Of course, when we started it was with 21 French catheters, and now it's 18 French. It has come down but there still is risk for those patients.

Dr. Montalescot: But you're a surgeon. Do you start the treatment before the procedure?

Dr. Kappetein: No, no. We always start it after the procedure. We never give them a bolus or anything.

What About Atrial Fibrillation?

Dr. Montalescot: We have a high rate of AFib occurring during the procedure and immediately after. Are you concerned about that, or do you give aspirin and that's good enough?

Dr. Kappetein: No. I think it is a concern because it may take some days before they hit normal sinus rhythm again. In surgery, about 30% of the patients are in AFib after the surgery. If the AFib lasts more than 24 hours, we usually start anticoagulation. If it's within 24 hours, we still give the aspirin and they start to use [warfarin]. We only start heparin when they have it for more than 24 hours.

Dr. Montalescot: Do you get the coronary patients on dual-antiplatelet therapy when they have TAVI?

Dr. Kappetein: The patient who gets that procedure is on both aspirin and clopidogrel.

Dr. Montalescot: But if they have been on dual-antiplatelet therapy before the procedure, would you take them to the OR or to the cath lab on therapy? They're going to bleed.

Dr. Kappetein: They're going to bleed. You have to stop it then. Nobody really knows the best way to bridge; normally we put them on heparin and we stop the clopidogrel, but whether that's the right approach, we don't know.

Dr. Montalescot: Is bivalirudin a good option?

Dr. Kappetein: That's an interesting point. There's now a study underway, BRAVO [Effect of BivaliRudin on Aortic Valve Intervention Outcomes],[2] which is trying to see whether that's the right therapy to bridge them around the procedure instead of heparin and whether that will decrease the bleeding events. It has currently recruited about 400 to 500 patients. They still have a couple of months to go before they can report the results of that study. It will be very interesting to see whether it decreases the bleeding events.

Dr. Montalescot: That's one option. The other option that we see being tested is ticagrelor in TAVI. Instead of having dual-antiplatelet therapy, we might have a single stronger agent and try to prevent complications with ticagrelor.

Dr. Kappetein: Do you think that's promising?

Dr. Montalescot: It's an option. I think in terms of safety it's probably as good as aspirin and clopidogrel. We'll see. My concern is that we may need more anticoagulation and less antiplatelet therapy. We have the new oral anticoagulants. They have not been tested in TAVI. We are going to start one study with apixaban against standard of care after TAVI. It makes sense because we have so many patients with AFib, with strokes after TAVI. It would make sense to test anticoagulation in these patients against dual-antiplatelet therapy or against warfarin. Sometimes you need warfarin. So, we will stratify at the time of randomization; you have to pick antiplatelet therapy/anticoagulation for the control arm. In the study arm everybody will get apixaban.

Dr. Kappetein: Is one drug more promising than the other one?

Dr. Montalescot: Apixaban is nice because this is the only new oral anticoagulant that has shown a reduction in stroke and peripheral embolism, a reduction in bleeding, and a reduction in mortality.[3] We hope to see all of that in this study of 1500 patients.

Dr. Kappetein: That's, of course, the advantage of the drug because it reduces both strokes and bleeding. Normally that's a tradeoff with more bleeding events, more anticoagulation, and thereby less strokes, but this works in the same direction.

Dr. Montalescot: We'll see. I think we need more data. This is fallow territory; there are no data. Everybody's sense is yes, but we need to wait for the results.

Dr. Kappetein: When do you expect the results of the study?

Dr. Montalescot: Oh, we are just starting. You will have to wait. We need to enroll the patients first.

Dr. Kappetein: What number of patients do you need?

Dr. Montalescot: The study will be 1500 patients.It's a European study. If you have centers in your country, you are welcome.

Dr. Kappetein: The number of procedures per center is still limited, so you need quite a lot of centers.

Dr. Montalescot: High-volume centers and a lot of centers to reach the goal.

Dr. Kappetein: What is currently your advice on clopidogrel use? If centers are still on the old regimen, what would you suggest?

Dr. Montalescot: I understand that warfarin is difficult and probably risky in many circumstances, so I can accept dual-antiplatelet therapy because it's simple. But whether it is safer, I'm not sure about that. Aspirin and clopidogrel has a safety profile that is quite comparable to what we get with well-controlled warfarin treatment. We expect better safety with the new agents. I think anticoagulation is better for those exposed to AFib and for the types of patients, of course, that are exposed to stroke and AFib. We need to test it. It's too early to say publically to go for the new agent because we have no data.

Dr. Kappetein: In the surgical world there is always the discussion about the introduction of self-management of the INR and self-management of the [warfarin], that they reduce bleeding events.

Dr. Montalescot: It would make sense except that the population is very old. It's probably more difficult to get adequate anticoagulation when you need to address treatment on the basis of self-controlled INR when you are 85 years old. That's the advantage of the new oral anticoagulants: You don't actually measure anything; you just take your pills.

Dr. Kappetein: Pradaxa (dabigatran) was tested in mechanical heart valves.

Dr. Montalescot: Mechanical heart valves is a different field, where the new agents are in trouble because we have one study which was not good.[4] I'm afraid that we are not going to see new data anytime soon.

Dr. Kappetein: Will there be another company that tries this again?

Dr. Montalescot: I cannot imagine that. We are stuck with warfarin. I hope this was useful to all of you who are practicing interventional cardiology or surgery and doing TAVI. The bottom line is that we don't know what to do. We expect to have more data. Thank you.

Dr. Kappetein: Thank you.


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