Anticoagulation Interruption and the New ACC/AHA Guidelines on AF

Samuel Z. Goldhaber, MD; Seth Bilazarian, MD


May 28, 2014

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Cataract Surgery and Colonoscopy

Samuel Z. Goldhaber, MD: Hello. This is Dr. Sam Goldhaber for the ClotBlog at on Medscape speaking to you from the American College of Cardiology Scientific Symposium in Washington, DC. Today, I have a special guest and a special friend, Dr. Seth Bilazarian. Seth, welcome to the ClotBlog.

Today I wanted to discuss with you a problem that you and I get calls and emails about over and over again, and that is how to safely interrupt anticoagulation. There are several different levels that we can quickly talk about, including cataract surgery and colonoscopy, but then we can go into the more nitty gritty area of what do we do with patients who have mechanical heart valves. Let's start with cataract surgery. Do you ever instruct your patients to interrupt their anticoagulation?

Seth Bilazarian, MD: It's a great question. I think that I agree with you. It is a real problem. It is a frequent problem. I would say that my practice gets questions about interruption about 3 or 5 times a week, and I would expand it to not just anticoagulation but also antiplatelet therapy. Both are similar in terms of safely balancing the risk of interruption vs collaborating with the proceduralist in terms of making it safe to do the procedure that's planned. The cataract surgery scenario is an interesting one. In my experience, most cataract surgeons don't even ask anymore, but in my community one cataract surgeon was repeatedly asking and I had to make the extra effort to reach out to the surgeon and say, "Is this really necessary? Do you understand that the interruption has a hazard that we can estimate based on the patient's CHADS2 score? Please do not interrupt." This cataract surgeon was very pleasant and said that's not a problem, but it required a little bit of education and my reaching out proactively with my patient to make a change in the behavior of a proceduralist.

Dr. Goldhaber: Plus, there are no blood vessels in the cataract.

Dr. Bilazarian: Right. On one hand it's easy, but it highlights for our audience that sometimes we have to actually advocate for our patients in terms of this interruption period.

Dr. Goldhaber: I guess dental procedures are also a very common issue where we have to work with the oral surgeon. How do you handle those?

Dr. Bilazarian: Similarly. In most cases, we're talking about surgeries with a low risk for bleeding, but then of course it would have to be added to what is the level of risk of the patient's interruption. The patient with a higher CHADS2 score might be a case where I really advocate with the oral surgeon that we consider either a very brief interruption or no interruption at all. How about yourself?

Dr. Goldhaber: I usually try for no interruption or just getting the international normalized ratio (INR; if it's warfarin) below 2.0 depending on how elaborate the surgery is going to be in the oral cavity.

Dr. Bilazarian: How comfortable are the surgeons you deal with in reinitiating warfarin the night before surgery as a strategy to limit the time of interruption on the other end of the surgery? Is that something that you have implemented in your own practice?

Dr. Goldhaber: I don't think reinitiation of anticoagulation the night before surgery is something that my surgeons feel at all comfortable with. Generally, I don't try to go down that route.

Dr. Bilazarian: Okay.

Dr. Goldhaber: I think the most common issue we have to deal with is colonoscopy because our patients over 50 are going to undergo colonoscopy.

Dr. Bilazarian: At least they should.

Dr. Goldhaber: They should at least once every 10 years. Then if they have even an adenoma, they're going to be screened once every 3 years. If they have a family history, it's once every 5 years or so. Volume-wise, I get a lot of calls about colonoscopy. How do you handle that?

Dr. Bilazarian: You and I have covered this in the past, and you helped educate me to persuade colonoscopists to take patients on without stopping anticoagulation in the patient with a higher CHADS2 score. But, in general, we have interrupted. We could try to convince medical subspecialists like our gastroenterology colleagues to start the warfarin the night before to shorten the period of interruption. That is something that I have thought about; but, like you, I have not yet taken it on. I haven't taken that fight to the gastroenterologist, but it seems like it would be a strategy that would be valuable in reducing the interruption period.

Dr. Goldhaber: Of course, if we use novel oral anticoagulants (NOACs), we don't have to go down that route either.

Dr. Bilazarian: Exactly.

Dr. Goldhaber: As we increase our use of the NOACs, that won't be as much of a problem. Generally with NOACs, we wouldn't have to interrupt more than 2 days, but with warfarin it's 4 to at most 5 days of anticoagulation.

Dr. Bilazarian: Right, and it's not just on the front end but on the back end; reinitiation of NOACs provides almost immediate safety in terms of protection from stroke and systemic embolization, whereas with warfarin we still have the 2, 3, or maybe even 7-10 days to get patients back up to a therapeutic INR. It's a real struggle in terms of trying to minimize this time.

Dr. Goldhaber: Let's turn to the new American College of Cardiology (ACC)/American Heart Association (AHA) guidelines on atrial fibrillation[1] that were just released. You and I are still digesting the 120 or so pages of material. What did they say about anticoagulation interruption, particularly with respect to patients who have mechanical heart valves?

Dr. Bilazarian: The guidelines didn't give us much to hold onto as clinicians or to facilitate us giving strong advice to both our patients and the proceduralists that we're dealing with except in the area that you described. In patients who need anticoagulation for atrial fibrillation and a mechanical heart valve, the guidelines did give us a recommendation. It's a class I recommendation (level of evidence C) to use either heparin or low-molecular-weight heparin as a bridging strategy. Beyond that, they left it very vague about bridging patients who did not have a mechanical valve.

Dr. Goldhaber: Doesn't that depend on whether it's warfarin or one of the NOACs?

Dr. Bilazarian: They didn't specifically say that. It's an interesting point that you make, understanding that NOACs would leave us with a shorter time. The guidelines didn't specifically say that we shouldn't bridge with it.

Dr. Goldhaber: Because if we stopped an NOAC just before the procedure, there wouldn't really be time to bridge.

Dr. Bilazarian: Sure, but of course NOACs would not be used in patients with mechanical heart valves. I guess that's the reason why that's probably not covered.

Dr. Goldhaber: Right, that is also a good point. NOACs might be used in atrial fibrillation.

Dr. Bilazarian: Yes, exactly. As a clinician, being able to point to a document, a consensus document, and say to our physician colleagues or our patients that this is the best recommendation that we have on how to handle this problem of interruption would have been helpful. We didn't get it from this document.

Dr. Goldhaber: It would be great to have an NOAC that was effective and safe with mechanical heart valves, too.

Dr. Bilazarian: Yes, but we're not recommending that to our audience at all.

Dr. Goldhaber: No -- in fact, that's something that we shouldn't be doing right now. Now, looking through the new guidelines, what else struck you as particularly informative?

Dr. Bilazarian: On the topic of anticoagulation, I think those were the major highlights. The only other one that I thought was useful for busy clinicians -- when we get these calls about interruption, it takes time to get to the electronic record, to review the chart, to reassess the CHADS2 score. If a patient is on an NOAC, to find out what the creatinine is, there are a variety of assessments about how to make the best recommendation. Of course, we can default to the simple position of just stopping everybody 5 days before surgery, but I don't think that's in the best interest of the patient. I'm advocating (I assume you would agree) that we should try to tailor the recommendations for the patients, both for surgery and their risk for systemic embolization and stroke. The question that remains is: How should we do that? I don't really know other than saying that this reassessment is valuable. The ACC/AHA guideline document that we're discussing does state that periodic reassessment is very reasonable. I think that it is reasonable. As our patients age and the fall risk may change or the creatinine may change or other issues may change, I think we should certainly do that reassessment. As much as it's an annoyance to do this assessment, it is of value for our patients.

Dr. Goldhaber: I think it's a good idea. It's a good way for us to use the annual cardiovascular exam to good purpose.

Dr. Bilazarian: I agree with you completely. Let me ask: Do you think that we are now at a point or may be coming to a point where we are able to assess a patient's risk for stroke during interruption? We have data from ROCKET AF,[2] and we have unpublished [in a peer-reviewed journal] data from the ARISTOTLE[3] trial that do help us understand that basically the risk during interruption is similar to the patient's risk based on the CHADS2 score. Do you think that we're getting to a point where we can inform our procedural colleagues that our patient will have, for example, a risk of 3% during this period of interruption? Should that be part of our consent process? It's a radical idea that I came up with that I think we are not doing, but if we are interrupting patients and they are on these drugs for good reason (I am presuming they are), interrupting them obviously puts them at hazard. How should we approach that?

Dr. Goldhaber: I think the ENGAGE-AF TIMI 48 trial[4] with edoxaban came up with the new paradigm for giving low-dose edoxaban during these transition periods. We have to study that more and see how that pans out. There may be lessons to be learned from using that type of strategy and perhaps adopting it for some of the other NOACs.

Dr. Bilazarian: Okay. At the end of the day, to summarize, your view on this is that NOACs, as we have discussed previously, are much easier in this whole transition and are preferred from that standpoint. I think that we know that a minority of our patients are on NOACs nationally. I think penetration is still in the single digits. We still have to deal with warfarin as the primary therapy.

Dr. Goldhaber: I think warfarin still commands 70%-75% of the anticoagulation market, but my hope is that with programs such as the one we're doing now, we're going to increase awareness of the need for anticoagulation in patients with relatively low CHA2DS2-VASc scores; and as use increases, more of those patients newly starting anticoagulation will be on the NOACs because I think the NOACs are particularly advantageous in avoiding this very messy bridging. What I don't like about bridging with low-molecular-weight heparin is that the instructions (even if they are put in the electronic medical record) are often very confusing and not followed. Secondly, despite the best of intentions, there often seems to be more bleeding with low-molecular-weight heparin bridging. Third is this tricky issue about how to restart; and when you restart, do you restart with a low preventive dose of low-molecular-weight heparin and wait until the patient is fully anticoagulated? How do you avoid problems that plague the electrophysiology community such as pocket hematoma with low-molecular-weight heparin? I think the more we can get away from bridging with low-molecular-weight heparin probably the better.

Dr. Bilazarian: Right. As you said, the 2 strategies that could potentially reduce our bridging use would be NOACs or continued warfarin; for device implantation, continuing warfarin seems to be the best strategy.

Dr. Goldhaber: Right. Harking back to what you said earlier, some of the younger generation of gastrointestinal interventionalists will accept a patient with a low-ish ongoing level of anticoagulation.

Dr. Bilazarian: Let me ask you, Sam: How do you manage a vexing problem about how to discuss this with a patient, a patient who you care about, who you know well, who is getting a procedure that is necessary and is on a needed anticoagulant? The patient may call the office and say, "The doctor wants me off the anticoagulation for another 2 weeks." Because they trust you, the patient will call and ask if it's okay.

Dr. Goldhaber: First of all, it's not professional for the proceduralist to instruct the patient about anticoagulation and tell the patient to contact me to see if I agree. The proceduralist should be calling or emailing you or me directly. That way, the patient is no longer the middleman.

Dr. Bilazarian: I agree. That would be ideal.

Dr. Goldhaber: But it happens all the time. The first thing I say to the patient is that I'm going to let you step back, and I will contact the proceduralist. We will work something out, and we will be back in touch with you. Usually when I get that type of call (which I get several times a week), I want to first reduce the patient's anxiety and put the patient to the side so I can have direct communication with the proceduralist. If the proceduralist has said to stay off antiplatelet therapy for 2 weeks or stay off anticoagulation for 2 weeks, I usually go over issues such as what the half-life of the drug is and the biological effect of the antiplatelet agents or the anticoagulants, and we can usually come up with a much shorter interruption period that's more biologically based. That's how I approach it.

Dr. Bilazarian: I think that's a great review, and I really appreciate your insights in that regard. That's certainly something I will adopt. The next question that comes about is: "Is it okay to interrupt?" We understand that in medicine there are no definites, but that's really what the patient wants. They want a reassurance that nothing will happen. We have to say no. We can't say it's okay.

Dr. Goldhaber: I think that's our job -- to reassure the patients and to really communicate well with our proceduralists. Seth, thank you very much. This is Dr. Sam Goldhaber signing off for the ClotBlog.


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