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Assessment of The Effect of Apixaban in AF

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ClinicalTrials.gov Identifier: NCT03199521
Recruitment Status : Completed
First Posted : June 27, 2017
Last Update Posted : February 7, 2019
Sponsor:
Collaborator:
University of Hertfordshire
Information provided by (Responsible Party):
Prof Diana Gorog, East and North Hertfordshire NHS Trust

Brief Summary:
This study will assess the effect of apixaban on thrombotic status in patients with atrial fibrillation.In addition it will compare apixaban to aspirin and warfarin on their effect on endogenous fibrinolysis.

Condition or disease Intervention/treatment
Atrial Fibrillation Embolism Thrombosis Other: Thrombin generation assays, Thromboelastography (TEG), and Global Thrombosis Test (GTT)

Detailed Description:

Patients with an irregular heart rhythm called atrial fibrillation (AF) have an increased risk of forming blood clots inside the heart, that can then fragment and break off, travelling through the circulation to the brain, where it can cause blockage of the small blood vessels resulting in a stroke. Most patients with AF are prescribed blood thinning medications in an attempt to prevent such clot formation. The body has the ability through enzymes circulating in blood, to dissolve a clot once formed, such that even if a clot is formed, it is rapidly dissolved and no lasting damage is sustained. This is known as endogenous fibrinolysis. If this defence system is faulty or suboptimal, there is an increased risk of clot formation, resulting in stroke or heart attack. Currently, there are no available tablets to favourably modify this defence system of endogenous fibrinolysis. The investigators will assess how this defence system functions in patients with AF who are on different blood thinners. Then the investigators will also assess a group of patients before and during treatment with a relatively new blood thinner called apixaban, to assess the effect of this on the stickiness of blood and the ability of the blood to dissolve clots (endogenous fibrinolysis). All the blood thinners will be prescribed for clinical indications, not as part of the research. The research aspect of the study is that we will perform a blood test to assess endogenous fibrinolysis.

Understanding the effect of apixaban on endogenous fibrinolysis raises the possibility that apixaban, rather than other blood thinners, may be of particular use in patients with impaired fibrinolysis who are at particularly high risk of clots due to inefficient endogenous fibrinolysis.


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Study Type : Observational
Actual Enrollment : 240 participants
Observational Model: Cohort
Time Perspective: Prospective
Official Title: Assessing The Effect of Apixaban on Endogenous Fibrinolysis in Patients With Non-Valvular Atrial Fibrillation
Actual Study Start Date : June 1, 2017
Actual Primary Completion Date : January 2, 2019
Actual Study Completion Date : January 2, 2019


Group/Cohort Intervention/treatment
Atrial Fibrillation newly diagnosed, starting apixaban
Patients will undergo the global thrombosis test (GTT), thromboelastography (TEG) and thrombin generation assays before and after stabilisation(4 weeks) of their anticoagulation. This will allow to compare the effect of apixaban on endogenous fibrinolysis before and after treatment.
Other: Thrombin generation assays, Thromboelastography (TEG), and Global Thrombosis Test (GTT)
Global Thrombosis Test (GTT): assesses formation of the blood clot and how easily can this be broken down once formed) Thromboelastography (TEG) :assesses the properties of a blood clot and how easily can be broken down Thrombin generation assays: assesses the formation of a blood clot and the potential of thrombolysis via the introduction of different buffer solutions

Atrial fibrillation on stable warfarin treatment
Patients will undergo the global thrombosis test (GTT), thromboelastography (TEG) and thrombin generation assays on stable anticoagulation treatment. This will allow to compare the effect of apixaban against warfarin on endogenous fibrinolysis on stable treatment.
Other: Thrombin generation assays, Thromboelastography (TEG), and Global Thrombosis Test (GTT)
Global Thrombosis Test (GTT): assesses formation of the blood clot and how easily can this be broken down once formed) Thromboelastography (TEG) :assesses the properties of a blood clot and how easily can be broken down Thrombin generation assays: assesses the formation of a blood clot and the potential of thrombolysis via the introduction of different buffer solutions

Atrial Fibrillation on stable aspirin treatment
Patients will undergo the global thrombosis test (GTT), thromboelastography (TEG) and thrombin generation assays on stable anticoagulation treatment. This will allow to compare the effect of apixaban against aspirin on endogenous fibrinolysis on stable treatment.
Other: Thrombin generation assays, Thromboelastography (TEG), and Global Thrombosis Test (GTT)
Global Thrombosis Test (GTT): assesses formation of the blood clot and how easily can this be broken down once formed) Thromboelastography (TEG) :assesses the properties of a blood clot and how easily can be broken down Thrombin generation assays: assesses the formation of a blood clot and the potential of thrombolysis via the introduction of different buffer solutions




Primary Outcome Measures :
  1. Assessing the effect of apixaban on endogenous fibrinolysis in patients wth atrial fibrillation [ Time Frame: Change of endogenous fibrinolysis from baseline at 4 weeks ]
    Measuring endogenous fibrinolysis before and after apixaban


Secondary Outcome Measures :
  1. Comparing the effect of apixaban to warfarin and aspirin on endogenous fibrinolysis in patients with atrial fibrillation [ Time Frame: 12 months ]
    Compare the effect on endogenous fibrinolysis as measured by occlusion time and lysis time (seconds) of stable apixaban, warfarin and aspirin treatment in patients with atrial fibrillation with the GTT,TEG,thrombin generation assays


Biospecimen Retention:   Samples Without DNA
plasma


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Ages Eligible for Study:   18 Years and older   (Adult, Older Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   No
Sampling Method:   Probability Sample
Study Population
Patients with non-valvular atrial fibrillation. Participants will be recruited via inpatient and outpatient clinical areas.
Criteria

Inclusion Criteria:

  1. Age >18 years
  2. Diagnosis of NVAF (nonvalvular atrial fibrillation)
  3. Requiring anticoagulation or antiplatelet therapy for thromboprophylaxis of stroke and systemic embolism
  4. No contra-indications to apixaban (except for those patients taking part in baseline cross-sectional study where this inclusion criterion does not apply)
  5. Patient does not meet any of the exclusion criteria below

Exclusion Criteria:

  1. Patient unwilling or unable to give informed consent
  2. Patient already taking antiplatelet or anticoagulant therapy (except for those patients taking part in baseline cross-sectional study, where this exclusion criterion does not apply)
  3. Patient who, in the opinion of the investigator, has significant hepatic or renal impairment likely to cause a bleeding diathesis
  4. Patient needing systemic high dose steroids or immunosuppression that may impact on platelet function
  5. Patient with ongoing active alcohol or substance abuse or demonstrates signs or clinical features of active substance abuse
  6. Patient with any major bleeding diathesis or blood dyscrasia at baseline (platelets<70 x 109/l, Hb<80 g/l, INR >1.4 (international normalized ratio), APTT (activated partial thromboplastin time ) > x 2UNL (upper normal limit) , leucocyte count< 3.5x 109/l, neutrophil count<1x 109/l).
  7. Patient currently involved in another investigational trial of a medicine or medical device

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT03199521


Locations
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United Kingdom
Hertfordshire Cardiology Centre, East and North Hertfordshire NHS Trust
Stevenage, United Kingdom, SG14AB
Sponsors and Collaborators
East and North Hertfordshire NHS Trust
University of Hertfordshire

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Responsible Party: Prof Diana Gorog, Professor,University of Hertfordshire, East and North Hertfordshire NHS Trust
ClinicalTrials.gov Identifier: NCT03199521     History of Changes
Other Study ID Numbers: No 1.1 Apr 2017
CV185-622 ( Other Grant/Funding Number: BMS/Pfizer European Thrombosis Investigator Initiated Research Program )
RD2017-03 ( Other Identifier: East and North Hertfordshire NHS Trust )
First Posted: June 27, 2017    Key Record Dates
Last Update Posted: February 7, 2019
Last Verified: February 2019
Individual Participant Data (IPD) Sharing Statement:
Plan to Share IPD: Yes
Keywords provided by Prof Diana Gorog, East and North Hertfordshire NHS Trust:
apixaban
endogenous fibrinolysis
warfarin
aspirin
thrombotic status
Additional relevant MeSH terms:
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Atrial Fibrillation
Thrombosis
Embolism
Embolism and Thrombosis
Arrhythmias, Cardiac
Heart Diseases
Cardiovascular Diseases
Pathologic Processes
Vascular Diseases
Aspirin
Warfarin
Apixaban
Thrombin
Anti-Inflammatory Agents, Non-Steroidal
Analgesics, Non-Narcotic
Analgesics
Sensory System Agents
Peripheral Nervous System Agents
Physiological Effects of Drugs
Anti-Inflammatory Agents
Antirheumatic Agents
Fibrinolytic Agents
Fibrin Modulating Agents
Molecular Mechanisms of Pharmacological Action
Platelet Aggregation Inhibitors
Cyclooxygenase Inhibitors
Enzyme Inhibitors
Antipyretics
Anticoagulants
Factor Xa Inhibitors