Author Interviews, Heart Disease, JAMA, Stroke / 14.03.2017
Appropriate Anticoagulation Underutilized in Atrial fibrillation
MedicalResearch.com Interview with:
Dr. Ying Xian MD PhD
Department of Neurology,
Duke Clinical Research Institute
Duke University Medical Center
Durham, North Carolina
MedicalResearch.com: What is the background for this study?
Response: Atrial fibrillation (AF) is the most common arrhythmia. AF increases the risk for stroke and accounts for 10% to 15% of all ischemic strokes. While the burden of AF-related stroke is high, AF is a potentially treatable risk factor. Numerous studies have demonstrated that vitamin K antagonists, such as warfarin, or non-vitamin K antagonist oral anticoagulants (NOACs), reduce the risk of ischemic stroke. Based on these data, current guidelines recommend adjusted-dose warfarin or NOACs over aspirin for stroke prevention in high-risk patients with Atrial fibrillation.








Dr. Jonathan Hsu[/caption]
Jonathan Hsu, MD, MAS, FACC, FAHA, FHRS
Assistant Professor
Cardiac Electrophysiology, Division of Cardiology
University of California, San Diego (UCSD)
MedicalResearch.com: What is the background for this study?
Response: Atrial fibrillation (AF) is the most common cardiac arrhythmia worldwide and imparts significant stroke risk. In patients with AF determined to be at intermediate to high risk for thromboembolism, anticoagulation with warfarin (a vitamin K antagonist) or the newer non-vitamin K antagonist oral anticoagulants clearly reduces morbidity and mortality compared to aspirin. We sought to evaluate practice patterns of cardiovascular specialists in the United states to determine how often AF patients at risk for stroke are prescribed aspirin over oral anticoagulation, and predictors of this practice.
Dr. T. Jared Bunch[/caption]
T. Jared Bunch, MD
Director of Heart Rhythm Research
Medical Director for Heart Rhythm Services
Intermountain Healthcare System
MedicalResearch.com: What is the background for this study? What are the main findings?
Dr. Bunch: Approximately 6 years ago we found that patients with atrial fibrillation experienced higher rates of all forms of dementia, including Alzheimers disease. At the time we started to ask the questions of why this association existed. We know that atrial fibrillation patients experience higher rates of stroke. These patients are placed on blood thinners, most commonly warfarin, to lower risk of stroke which at the same time expose that patient to a higher risk of intracranial bleeding. One possibility to explain the association was that perhaps dementia in the manifestation of many small clots or bleeds in the brain that in total lead to cognitive decline. If this is the case, then the efficacy and use of anticoagulation is very important in atrial fibrillation patients.
We conducted additional studies that showed this to be the case. In patients with no history of dementia, managed long-term with warfarin anticoagulation, those that had levels that were frequently too higher or too low that resulted in poor times in therapeutic range, experienced significantly higher rates of dementia. The risk was highest in younger atrial fibrillation patients that were less than 80 years of age. We then found that in atrial fibrillation patients that were frequently over anticoagulated and also use an antiplatelet agent, aspirin or plavix, the dementia rates nearly doubled. At this point we raised the question if atrial fibrillation increased the risk beyond anticoagulation, or does anticoagulation efficacy drive most of the risk. This question formed the background of the current study.





Prof. De Caterina[/caption]
Prof. Raffaele De Caterina M.D., Ph.D
University Cardiology Division G. d'Annunzio University
Medical Research: What is the background for this study? What are the main findings?
Dr. De Caterina: There is uncertainty on how to predict bleeding upon treatment with anticoagulants, because bleeding risk scores and thromboembolic risk score fare very similarly in predicting bleeding, making the net clinical benefit difficult to assess in the single patient. Here we find that a history of bleeding – even minor bleeding – has an important prognostic value on the risk of future bleeding – virtually all sorts of future bleeding, with the notable exception of intracranial hemorrhage. Some novel oral anticoagulants (NOACs), such as apixaban, studied here, reduce the risk of major bleeding, and appear to benefit independent of the bleeding history.
Dr. Martinelli[/caption]
MedicalResearch.com Interview with:
Ida Martinelli MD, PhD
A Bianchi Bonomi Hemophilia and Thrombosis Center
Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico
Milan, Italy
Medical Research: What is the background for this study? What are the main findings?
Dr. Martinelli: Hormonal therapies are associated with an increased risk of venous thromboembolism. Patients with acute deep-vein thrombosis or pulmonary embolism require anticoagulation, but women of childbearing potential require also an adequate contraception, as oral anticoagulants cross the placenta potentially leading to embryopathy or fetal bleeding. This study was aimed to evaluate the safety of hormonal therapies together with anticoagulant therapies in terms of recurrent venous thrombosis and uterine bleeding. We demonstrated for the first time that women who take oral anticoagulants can safely use hormonal therapies, as their risk of recurrent venous thromboembolism or uterine bleeding is not increased.
Dr. Barnes[/caption]
MedicalResearch.com Interview with:
Geoffrey Barnes, MD, MSc
Clinical Lecturer
Cardiovascular Medicine and Vascular Medicine
University of Michigan Health System
Medical Research: What is the background for this study?
Dr. Barnes: Although warfarin has been the primary anticoagulant used for stroke prevention in atrial fibrillation for over 60 years, four new direct oral anticoagulants (DOACs) have been introduced into the market since 2010. Dabigatran, which directly inhibits thrombin, was found to have better prevention of ischemic stroke and a significant reduction in hemorrhagic stroke (bleeding strokes) for patients with 





