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Health See other Health Articles Title: Treating AF: Reducing Stroke Risk With Ablation Ileana L. Piña, MD, MPH: Hello. I am Ileana Piña from Albert Einstein College of Medicine and Montefiore Medical Center in the Bronx, New York, and this is my blog. I am thrilled to have Hugh Calkins here from Johns Hopkins University, who is now President of the Heart Rhythm Society (HRS). He is visiting New York to talk about arrhythmias and arrhythmia management, so we took the opportunity to bring him in so that he can tell us about an atrial fibrillation (AF) study[1] that is quite interesting. That is the conversation we are going to have today. Welcome. It is so nice of you to come by and spend some time with us. AF is so common, and I have talked to our audience before about issues with AF and how it is not just benign. Some say, "Oh yeah, they have AF. I will just control their heart rate." And that is it. But this study casts a different light on a procedure. Can you tell us a little bit about it? Hugh G. Calkins, MD: The study is a large registry from the Intermountain Health Center. I think we are all aware of this fantastic health center in Utah, where they have a very robust database. They use it to try to address questions that come up, so they looked at 10,000 patients without AF. Dr. Piña: In the community? Dr. Calkins: In the community in their database. They took 10,000 patients without AF and 5000 patients with AF who had undergone catheter ablation, and they looked at stroke risk during 3 years of follow-up. They showed that patients without AF had a relatively low stroke risk. For patients with AF, the stroke risk was significantly increased, and patients who had had catheter ablation of AF had a stroke rate that was very similar to that of the general population without AF. That was sort of the headline of the study, that perhaps catheter ablation of AF somehow reduces stroke risk in patients with AF. Who Is a Candidate for Ablation? Dr. Piña: Clinicians may say that they are going to refer their patients for ablation after they have tried the usual. You gave them digoxin, you gave them a beta-blocker, you gave them amiodarone. And they haven't converted. Who should be entered into an ablation type of study? Dr. Calkins: Who should get catheter ablation of AF? Despite this study, there is widespread agreement, and the HRS Expert Consensus Statement[2] clearly states that a desire to stop anticoagulation is not an appropriate indication for AF ablation. AF ablation is done to improve quality of life. That is the only proof we have. Yes, it may make people live longer. Yes, it may prevent strokes. Yes, it may reduce dementia. Yes, it may reduce heart failure. But the only proven benefit today is that if you have an AF ablation and the procedure is successful, there is significant improvement in quality of life. Dr. Piña: So the patients feel better? Dr. Calkins: Yes. If someone has asymptomatic AF, it would be inappropriate to do an AF ablation. If you look at the HRS Expert Consensus Statement, AF ablation is only indicated if someone has AF and an antiarrhythmic drug has failed, particularly if it is paroxysmal AF. That is an appropriate indication for AF ablation. However, in someone with no symptoms, that is not even mentioned as an indication for AF ablation. It would be inappropriate because the only reason you are doing it is for theoretical benefits that are unproven, and the procedure is not without risk. Is This Practice-Changing? Dr. Piña: Do you think this registry finding may get into the guidelines? Do you think it may change practice? Dr. Calkins: It is a very provocative question and the results of the study are very provocative. They start you wondering whether AF ablation reduces stroke risk and whether you can stop anticoagulation in the patient if you do an AF ablation. Dr. Piña: That is a huge question for our doctors out there. Dr. Calkins: I think the answer is that after AF ablation, everyone should be anticoagulated for at least 2-3 months. Then, at the 2- or 3-month point, all of the guidelines and consensus documents say that the decision of whether to continue anticoagulation should be based on stroke risk or the CHA2DS2-VASc score. Dr. Piña: Is gender part of that score? Dr. Calkins: Yes. There has been a shift from the CHADS2 to the CHA2DS2-VASc. The C is congestive heart failure, H is hypertension, A is age (it used to be over 75, but with the CHA2DS2-VASc it is > 65 years), D is diabetes, S is prior stroke, female gender, and vascular disease. If, after 3 months, someone is doing well but the CHA2DS2-VASc risk score is 3 or 4, it would be a mistake, in my opinion, to stop anticoagulation. That reflects the fact that we know that late reoccurrences can occur after AF ablation. Dr. Piña: We learned in AFFIRM[3] that when you converted patients and you stopped anticoagulation, the risk of stroke went up. Dr. Calkins: Exactly. We also know that if AF comes back after an AF ablation, it is more likely to be asymptomatic. And we know that over time, the patient's age and stroke risk score goes up. If you look at the study, it had these big headlines: "Does AF ablation reduce stroke risk? Isn't this wonderful?" I think it is easy to misinterpret the study to conclude that if my patient is doing well, I am going to stop anticoagulation, or if my patient doesn't want to take an anticoagulant, I am going to tell them to get an AF ablation to reduce stroke risk even if they are asymptomatic. That is a big mistake. This registry study clearly states that the results should not impact current recommendations and that they have to be verified. They also did not include an assessment of what anticoagulants these patients were on. Dr. Piña: We don't know from the registry? They didn't capture that? Dr. Calkins: Exactly. Everyone who had an AF ablation may still be on anticoagulation for all we know. Dr. Piña: But we don't know. Dr. Calkins: They just didn't have that data. Follow-up After Ablation Dr. Piña: If you had to give a recommendation to our audience, let's say that they send a patient to ablation and it is successful. Can they lower the international normalized ratio (INR)? What INR should they keep the patient at? And if not warfarin, can they put the patient on a thrombin inhibitor? Dr. Calkins: The answer is no. There are no data to show that you can lower the INR. What I would do is, at 3-month follow-up, assess the CHA2DS2-VASc score. If the score is 2 or greater, I would recommend to the patient that he continue anticoagulation indefinitely. Dr. Piña: With whatever they are on at that point? Dr. Calkins: With whatever they are on or, if they prefer, one of the novel new drugs. I would encourage them to shift at that point. There are some data showing that the best way to have a very low stroke risk at the time of AF ablation is to do the procedure on continued anticoagulation with warfarin, particularly if they are in AF all of the time.[4] That is the safest thing. There are centers or electrophysiologists who will transition a patient to warfarin before the procedure to get them ready. And then they do the procedure and keep the INR therapeutic. If you have tamponade, you can reverse it. Then at 3 months, you can say, "You are probably sick of warfarin. Let's go back to one of these novel new drugs that are much easier to take and more effective in reducing stroke risk." Dr. Piña: More expensive, though. Let's not forget that. Dr. Calkins: Perhaps, but it depends on whether you include the cost of their testing. The CABANA Trial Dr. Piña: And getting all their blood work in between. In another one of our programs, we talked about the CABANA trial. Tell us a little bit about CABANA. What is different about this registry vs CABANA? Dr. Calkins: CABANA is like AFFIRM. It is a prospective randomized clinical trial of 2 different strategies, and it is a very interesting study design. Study participants are patients with AF who have an increased risk for stroke and adverse events. They are older than 65 years of age or have stroke risk factors, and they get randomly assigned to treatment of AF with drug therapy or catheter ablation. They are looking long-term at the hard endpoints: Does ablation strategy improve mortality and lower stroke risk? AFFIRM was criticized because they tried a rhythm-control strategy but used antiarrhythmic drugs that weren't effective and caused proarrhythmia. Now, with CABANA, we have a strategy that doesn't have proarrhythmia and that is more effective. Therefore, we are going to see the benefit of AF ablation. Dr. Piña: You said that one arm of CABANA is drug protocols. Are they in a protocol form or can you use whatever you want? Dr. Calkins: You can use whatever you want. Dr. Piña: So, what would you use for your patients? Dr. Calkins: If a patient has minimal symptoms, they may just go with rate control. If not, I will usually start with an antiarrhythmic drug. Flecainide or propafenone is usually first. If that doesn't work, I use sotalol or possibly amiodarone. It is really wide open, what you choose and when you move from one to another. It is a very practical study looking at 2 strategies, and I think the results will be very important. We are all looking forward to them. Dr. Piña: I think more and more studies are looking at strategies as opposed to just this drug versus that drug or this procedure versus that procedure. In the heart failure world, we are starting to think that way as well. You guys were ahead of us on thinking about strategies of care. Is There a Gender Difference in AF? Dr. Piña: Let's talk a little bit about gender. A couple of years ago, there was a paper in JAMA [5] showing that new-onset AF, the incidence of AF, in women was associated with worse mortality. Do you want to comment on that? Do you think there is a gender difference -- that women tend to be sicker than men when they first present with AF? Dr. Calkins: That is an interesting question. Clearly, AF is far less common in women than in men. I think that is widely acknowledged. In terms of what their clinical course is, I certainly have not observed any huge difference in my practice. I know that when it comes to catheter ablation of AF, far fewer women get the procedure. Women who do get the procedure have a higher complication rate. Dr. Piña: That sounds similar to everything else we do with women. Dr. Calkins: We have struggled with why that is. Why are so few women getting AF ablation? Part of it is that fewer women have AF, but there is also the fact that a lot of women are the caretakers of their families, and they aren't willing to risk a complication. They feel that they have to take care of the family, so they shouldn't have this procedure. I also think that women tend to be more risk-averse whereas men say, "I just want it cured. Just fix it."Both of those things are reflective. The increased complication rate in women has been shown now in many different studies,[6-9] but it is not a huge difference. Dr. Piña: Is it primarily bleeding and vascular complications? Dr. Calkins: It is basically all different types. If you look at the overall cumulative complication rate, it is higher in women than in men, and that is something that no one fully understands. Dr. Piña: We see it in bypass surgery, ischemic heart disease, and heart failure, where women's prognoses are just as bad as the men's, even though women are supposed to have a better outlook than the men. You wonder whether they are waiting too long to go see somebody or whether there is a bias when referring them. We are not going to answer those questions today, but it is something for clinicians to think about. I hope CABANA enrolls a sufficient number of women to really make that point. I want to thank you for joining us today. I hope you have a very successful visit in New York. I want to thank our audience for watching us today. That article that we have been talking about was published in Heart Rhythm, which is the official journal of the Heart Rhythm Society. It will be an interesting paper to read for your practice, with all the caveats and observations that we have made here today. I hope this is helpful to your practice and for your patients. Thank you for joining me. This is Ileana Piña, signing off. Have a great day. Post Comment Private Reply Ignore Thread
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