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    Poor Control Of Anticoagulant Therapy Leads To Increased Adverse Events For Patients With Atrial Fibrillation
    By News Staff | November 8th 2012 11:52 AM | Print | E-mail | Track Comments

    Twelve-month data from the Global Anticoagulant Registry in the FIELD (GARFIELD) show that the poor management of stroke prevention therapy is widespread in clinical practice, which may lead to elevated rates of mortality, stroke and bleeding among individuals with newly diagnosed atrial fibrillation (AF).

    The data presented today at the American Heart Association (AHA) Scientific Sessions evaluated clinical outcomes, such as stroke, major bleeding and mortality, in relation to patient risk profiles and antithrombotic treatments in a representative worldwide AF population. Of the 9,971 patients observed, only 5,724 (57 percent) were treated with a vitamin K antagonist (VKA). Of those patients, 57 percent were not treated effectively, with a poorly controlled International Normalized Ratio, or INR, a measure of how long it takes the blood to clot.

    In this analysis, only 24.5 percent of patients received well-controlled VKA therapy in clinical practice. In the first year from diagnosis with AF:

    Up to two percent of the population has AF, a common condition in which the two upper chambers of the heart (the atria) quiver rather than beat rhythmically and can lead to life-threatening complications, including stroke. AF-related stroke remains a major and increasing clinical and societal burden, despite the availability of effective preventive treatment.

    "These first 12-month data from GARFIELD demonstrate a high mortality rate in patients with newly diagnosed atrial fibrillation," said Professor Ajay Kakkar, Director of the Thrombosis Research Institute, London, Professor of Surgery, University College London and Chair of the GARFIELD Steering Committee. "We know that anticoagulation can improve patient outcomes in AF, but if it is not controlled properly, as appears often to be the case in actual practice, patients may be put at increased risk for poor clinical outcomes. Further insights into real world outcomes will be provided in the second year of follow-up."

    Of 10,537 patients enrolled in GARFIELD Cohort 1, follow-up data were available for 9,971 patients. 

    "The high death rate and stroke rate from AF are highlighted in this real-life cohort," said Samuel Z. Goldhaber, MD, Professor of Medicine, Harvard Medical School, Senior Staff Cardiologist, Brigham and Women's Hospital, and Member of the GARFIELD Steering Committee. "GARFIELD provides us with the take home message that there remains a wide gap between anticoagulation guidelines and actual clinical practice. Our challenge is to redouble our efforts in clinician education and implementation of proven measures to prevent stroke in AF patients."

    The GARFIELD Registry is an observational, multicenter study of men and women with newly diagnosed AF and one or more additional risk factors for stroke. The program is conducted by the Thrombosis Research Institute, London. It will prospectively follow 50,000 newly-diagnosed AF patients from at least 1,000 centers in 35 countries in the Americas, Eastern and Western Europe, Asia, Africa and Australia.

    GARFIELD is the largest prospective registry of patients with AF at risk of stroke. It seeks to describe the real-life burden of this disease, providing insights into the impact of thromboembolic and bleeding complications, antithrombotic treatment patterns and potential opportunities for improving clinical outcomes amongst a representative and diverse group of patients. This should help physicians and healthcare systems appropriately adopt innovation to ensure the best outcomes for patients and populations.

    Four key design features ensure a comprehensive and representative description of AF:

    Included patients have been diagnosed with non-valvular AF within the past six weeks, have at least one additional risk factor for stroke, and are candidates for anticoagulant therapy to prevent blood clots leading to stroke. It will be left to the investigators' clinical judgment to identify patients' stroke risk factor(s). Patients will be included whether or not they receive anticoagulant therapy so current and future treatment strategies and failures can be properly understood in relation to patients' stroke risk profile and co-morbidities.

    Data will be collected over a six-year period, and will include the following outcomes: thromboembolic stroke; transient ischemic attacks (TIA, or "mini-strokes"); blood clots affecting other areas of the body; bleeding events; therapy persistence; rate and reason for discontinuation; medical consultations and hospitalizations; need for urgent and elective interventions; cardiovascular morbidity and all-cause mortality.

    Among patients treated with anticoagulant therapy, additional outcomes data will include the frequency and timing of monitoring required to maintain a safe and therapeutically-effective level of anticoagulation and interventions needed to manage complications due to anticoagulation therapy.

    The GARFIELD Registry is made possible through an unrestricted research grant from Bayer Pharma AG.

    The Burden of AF

    Up to two percent of the global population has AF, and it is estimated that its prevalence will at least double by 2050 as the population ages. Around 4.5 million people in the European Union and 2.2 million people in the United States have AF, and estimates suggest that by 2014 more than 12 million people in the Asia-Pacific region will have AF.[1],[2],[3],[4]AF confers a 5-fold increase in the risk of stroke, and one in five of all strokes is attributed to this arrhythmia. Ischemic strokes in association with AF are often fatal, and those patients who survive are left more frequently and more severely disabled, and more likely to suffer a recurrence than patients with other causes of stroke.

    In consequence, the risk of death from AF-related stroke is doubled and the cost of care is increased by 50%.[5] The condition occurs when parts of the atria emit uncoordinated electrical signals that cause the chambers to pump too quickly and irregularly, not allowing blood to be pumped out completely.[6] As a result, blood may pool, clot and lead to thrombosis, which is the number one killer in both the developed and developing world.

    If a blood clot leaves the left atrium, then it could potentially lodge in an artery in other parts of the body, particularly in the brain. A blood clot in an artery in the brain leads to a stroke. Ninety-two percent of fatal strokes are caused by thromboses.[7] People with AF also are at high risk for heart failure, chronic fatigue and other heart rhythm problems.[8],[9] Stroke is a major cause of long-term disability worldwide - each year 5 million sufferers are left permanently disabled.[10]

    References:

    [1] Jamil-Copley S; Kanagaratnam P. (12/6/10). Stroke in atrial fibrillation-hope on the horizon? J R SOC INTERFACE. 8/16/12. 

    [2] The Lancet Neurology.Stroke prevention: getting to the heart of the matter. 8/16/12. 

    [3] Thrombosis Advisor.Thrombosis Facts. 8/16/12. 

    [4] Chinese Medical Journal 2004 ; 117 ( 12) : 1763-176. 

    [5] European Society of Cardiology. Guidelines for the Management of Atrial Fibrillation. 8/16/12. 

    [6] National Heart Lung and Blood Institute. What is Atrial Fibrillation. 8/16/12.

    [7] Thrombosis Research Institute. About TRI. 11/6/12. 

    [8] Rockson SG, Albers GW. Comparing the guidelines: anticoagulation therapy to optimize stroke prevention in patients with atrial fibrillation. J Am CollCardiol 2004;43(6):929-35.

    [9] American Heart Association. Why is AF a Problem?. 8/16/12. 

    [10] World Heart Foundation. The Global Burden of Stroke. 8/16/12.