Case Study

Reducing the Risk of Stroke in Atrial Fibrillation: A Personal and Professional Perspective

Matthew P. Latacha, MD, FACC, FHRS

Methodist Health System

Omaha, Nebraska

Matthew P. Latacha, MD, FACC, FHRS

Methodist Health System

Omaha, Nebraska

Case Description

The patient was an 84-year-old female with hypertension, dyslipidemia, and persistent atrial fibrillation (AFib). She was diagnosed in the days before direct-acting oral anticoagulants (DOACs), and therefore, was treated with warfarin. Her CHA2DS2-VASc score was 4 due to age over 75, female sex, and hypertension, giving her an estimated annual risk of stroke of 4.8% per year.1 Every week, she called her grandson, an internal medicine resident, giving him her INR and a host of reasons why she did not want to take warfarin, telling him it made her tired, cold, weak, and short of breath. She was an incredibly independent woman who emigrated to the United States from the Ukraine after surviving the Eastern Front of World War II. She owned her apartment building and always insisted on living on the top floor, despite her age. She walked up those stairs several times a day for decades, but nonetheless, convinced her physician she was a “fall risk,” so her warfarin was stopped. Although she was initially happy with this decision, she ended up suffering a large middle cerebral artery stroke. She never fully regained consciousness, and passed away in hospice care.

This patient was my grandmother, and I use this case as an illustration, because all of us who care for patients with atrial fibrillation have heard the same story countless times. Whenever I am asked to talk or write about atrial fibrillation, people tend to want to learn about the “sexier” aspects of it, such as the newest ablation strategies, device-based therapies, 3D mapping systems, etc. Discussing stroke prevention in AFib simply does not inspire the awe that images of ablation catheters and left atrial reconstructions do. But I would argue that it is one of — if not the most — important aspects of AFib care. What could be more important than preventing a potentially disabling or even deadly stroke? Many of our AFib patients fear stroke more than death. Fortunately, with new technologies for AFib detection and stroke reduction, this aspect of care is now as exciting as the advances seen in ablation catheters and mapping systems.

Discussion

Stroke is a tremendous problem in the United States. One out of every 20 deaths, or 140,000 a year in the U.S., are attributed to stroke. There is a stroke every four seconds in the U.S., and someone dies from stroke every 40 minutes. Stroke is a leading case of disability in the U.S., at a cost of $34 billion each year. The vast majority (87%) are ischemic, with AFib being the greatest culprit of these.2 To that end, we at Nebraska Methodist Hospital and Methodist Physicians Clinic take the primary and secondary prevention of stroke in AFib patients very seriously, and have made it our goal to improve both the detection and treatment of AFib, as well as provide both pharmacologic and non-pharmacologic based treatment options for atrial fibrillation patients.

When a patient has known AFib, the indications for anticoagulation are relatively straightforward. As we will discuss below, weighing the risks and benefits of oral anticoagulation (OAC) is not always easy. The risk of stroke can be easily calculated using the CHA2DS2-VASc scoring system. If a patient has a score of 0, the risk of stroke is low. If the score is 1, aspirin (at least for now) or OAC is indicated.1 If the score is 2, the annual stroke rate is 2.2% per year, and greater OAC is indicated. However, what about the patient with stroke of no clear etiology, also referred to as cryptogenic stroke?

It turns out that the risk of atrial fibrillation in cryptogenic stoke is quite high.3 Monitoring these patients for atrial arrhythmias is critical. Various methods are available, from the simplest (a 24-hour Holter monitor), to more prolonged methods such as an implantable loop recorder (ILR). As is so frequently the case in life, the more you look, the more you find. Accordingly, the diagnostic yield of an ILR is much higher than that of monitoring for a shorter time period.4 At Nebraska Methodist Hospital, we treat cryptogenic stroke patients in a multidisciplinary fashion, with neurology and cardiology/electrophysiology. We recently updated the EMR order set for cryptogenic stroke patients to include an EP consultation for an ILR. This has truly streamlined the process. As I implant the patient with a local anesthetic, I am generally able to have the device placed very quickly after I get the call, without having to hold up the patient’s discharge. Interestingly, the incidence of “silent AFib” in patients without a previous diagnosis of atrial fibrillation, but with risk factors for stroke as indicated by an elevated CHA2DS2-VASc score, can be as high as 40%.4 These data could fundamentally change the way we approach these patients, by suggesting that perhaps those that present with a stroke consistent with a cardioembolic source and other CHA2DS2-VASc risk factors should simply be anticoagulated, even if AFib has never been documented.

While oral anticoagulation with either warfarin or a novel oral anticoagulant (NOAC) such as apixaban, rivaroxaban, or dabigatran remains the first line of therapy for stroke reduction in AFib patients, these medications have limitations as well. Warfarin is notoriously difficult to manage and reverse. Many patients also find the dietary issues difficult to manage (for example, my grandmother always brought a bag of leafy greens to every meal to keep her green vegetable intake steady). With their ease of use, lack of dietary restrictions, and reliability, NOACs have been a substantial improvement, but there are still issues with compliance.5 NOACs are also reversible, but the reversing agents are not always readily available. NOACs are ultimately still anticoagulants — thus, bleeding remains an issue. The clinical characteristics that make up the HAS-BLED score, a risk calculator for bleeding in anticoagulated patients, are very similar to the CHA2DS2-VASc.5 Age, hypertension, and a history of stroke/TIA are risk factors for both stroke and bleeding. Thus, an anticoagulation paradox exists, meaning that many of those who would benefit the most from anticoagulation are at the highest risk of bleeding from them.

The prevailing thought with regard to stroke in AFib patients is that the vast majority of strokes originate from the left atrial appendage (LAA), which was the rationale behind the development of the WATCHMAN LAA Closure Device (Boston Scientific), which essentially closes the LAA. The device is catheter delivered, and after being successfully deployed, endothelializes and excludes the LAA from the circulation, thus reducing the risk of stroke without the need for OAC. The WATCHMAN device has been proven to be as effective as warfarin for reducing the risk of stroke with a 72% reduction in bleeding and a mortality benefit as well.6,7

Nebraska Methodist Hospital adopted this technology in Spring 2018. While most centers include an electrophysiologist, interventional cardiologist, and imaging cardiologist for the transesophageal echocardiogram (TEE) used in the screening of patients, implant, and follow-up, our institution takes a different approach. We are somewhat unusual in that all three of us trained together, which I feel has truly allowed us to do these procedures with a team approach. The screening TEE, intraprocedural TEE, and post TEE are all done by the same cardiologist. The three of us do every case together, and all three of us must agree that the device deployment and placement looks good before the patient leaves the lab. We have a wonderful coordinator who helps to identify patients, meets with them before and after the implant, and serves as a contact person for any patient questions or issues that might arise. On “Anticoagulation Liberation Day” (as we call it), patients undergo a 45-day post-procedure TEE, and if the device looks good with no leaks, OAC is discontinued. A patient generally undergoes TEE in the morning, then sees me in the afternoon in clinic. This is always an exciting day for our patients, as they get to shed the worries and costs associated with OAC, but can feel secure knowing they are still protected from a stroke.

We have learned quite a bit as we have moved forward with our LAA closure program. The first is that the LAA is like a fingerprint, meaning that no two are alike, and despite trying to lump them into somewhat nebulous terms such as “windsock”, “broccoli”, or “chicken wing,” these are gross oversimplifications. When we evaluate a patient for LAA closure, we realize each one is a unique puzzle, so as a team, we decide how to best approach it. Another thing we have learned is just how many people would benefit from this device. We often see patients with multiple admissions and endoscopies for gastrointestinal bleeding. We also see frequent falls in patients on OAC and dual antiplatelet therapy for stents (the “triple threat” of cardiology). I continue to see referrals for ablation in order to get patients off anticoagulation, despite guidelines recommending against this.8

As a new technology, our greatest obstacle to serving eligible patients has been simply to get those who care for these patients to think about it. Our WATCHMAN team continues to do “lunch and learn” events with primary care groups, hospitalists, and gastroenterologists. We have also involved our device technicians, who are often the first caregivers to diagnose atrial fibrillation in our device patients.

Conclusion

It is amazing how much has changed in the field of stroke prevention in the ten years since my grandmother suffered a lethal stroke from atrial fibrillation. Would she have been more willing to take a NOAC? Would she have benefited from LAA occlusion? Fortunately, we now have so much more to offer to the millions of patients just like her. As we continue to confront the AFib epidemic before us, I can confidently say that we are better armed. 

Disclosure: Dr. Latacha has no conflicts of interest to report regarding the content herein.   

References

1. January CT, Wann LS, Alpert JS, et al. 2014 AHA/ACC/HRS guideline for the management of patients with atrial fibrillation: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines and the Heart Rhythm Society. J Am Coll Cardiol. 2014;64:e1-76.

2. Stroke Facts. CDC. Published September 7, 2017. Available at https://www.cdc.gov/stroke/facts.htm. Accessed December 6, 2018.

3. Gladstone DL, Spring M, Dorian P, et al. Atrial fibrillation in Patients with Cryptogenic Stroke. N Engl J Med. 2014;370:2467-2477.

4. Sanna T, Diener H, Passman RS, et al. Cryptogenic stroke and underlying atrial fibrillation. N Engl J Med. 2014;370:2478-2486.

5. Lip GY. Implications of the CHA(2)DS(2)-VASc and HAS-BLED Scores for thromboprophylaxis in atrial fibrillation. Am J Med. 2011;124(2):111-114.

6. Jackevicius CA, Tsadok MA, Essebag V, et al. Early non-persistence with dabigatran and rivaroxaban in patients with atrial fibrillation. Heart. 2017;103(17):1331-1338.

7. Holmes DR Jr, Kar S, Price MJ, et al. Prospective randomized evaluation of the Watchman Left Atrial Appendage Closure device in patients with atrial fibrillation versus long-term warfarin therapy: the PREVAIL trial. J Am Coll Cardiol. 2014;64(1):1-12.

8. Price MJ, Reddy VY, Valderrábano M, et al. Bleeding Outcomes After Left Atrial Appendage Closure Compared With Long-Term Warfarin: A Pooled, Patient-Level Analysis of the WATCHMAN Randomized Trial Experience. JACC Cardiovasc Interv. 2015;8(15):1925-1932.

9. 2017 HRS/EHRA/ECAS/APHRS/SOLAECE Expert Consensus Statement on Catheter and Surgical Ablation of Atrial Fibrillation. Heart Rhythm Society. Published May 12, 2017. Available at https://bit.ly/2BU6Kd3. Accessed December 6, 2018.

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