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Warfarin After Anterior ST-Elevation Myocardial Infarction

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details. Identifier: NCT00662467
Recruitment Status : Completed
First Posted : April 21, 2008
Last Update Posted : April 21, 2008
Information provided by:
McMaster University

Brief Summary:

Following severe heart attacks involving the front wall of the heart (anterior myocardial infarction), patients are at risk of developing blood clots in the main pumping chamber that can cause a stroke. In the past, studies have shown that a blood thinner (warfarin) can decrease the risk of stroke and clot formation if administered to patients after an anterior myocardial infarction.

However, in today's current practice, certain heart attack patients are commonly treated with two blood-thinning medications (aspirin and clopidogrel) to prevent recurrent heart attacks.

Thus, a clinical problem is created as physicians are not clear how to treat patients after an anterior myocardial infarction who are at risk of a clot but require aspirin and clopidogrel to keep their blood vessels open. Adding warfarin to the combination of aspirin and clopidogrel will possibly decrease the risk of stroke but increase the risk of bleeding. Currently, there is no good evidence to help guide physicians. As demonstrated by a survey done at the Hamilton Health Sciences, there is a fifty/fifty split between physicians who use dual (aspirin and clopidogrel) versus triple (aspirin, clopidogrel, and warfarin) therapy in the treatment of similar patients as described above.

The purpose of this study is to address the bleeding and stroke complications in patients after a severe anterior myocardial infarction. Half of the eligible patients will receive dual therapy and half will receive triple therapy. We will compare the incidence of stroke, blood clots, and bleeding complications between the two groups at 3 months.

Condition or disease Intervention/treatment Phase
Myocardial Infarction Drug: aspirin + clopidogrel Drug: aspirin + clopidogrel + warfarin Not Applicable

Detailed Description:


Left ventricular mural thrombus (LVT) remains a common complication after anterior ST-elevation myocardial infarction (STEMI) with a reported incidence ranging from 12- 17%. Previous studies from the pre-thrombolytic era have shown that warfarin therapy significantly reduces the incidence of LVT and embolic events in patients post anterior STEMI. However, the risk/benefit ratio of warfarin therapy in the setting of early revascularization and dual antiplatelet therapy with aspirin and clopidogrel remains unknown.


To compare the incidence of death, MI, stroke, embolic events, LVT, and bleeding complications at 3 months in patients with an anterior STEMI and ejection fraction less than 40% treated with ASA and clopidogrel alone versus those treated with aspirin, clopidogrel, and warfarin (triple therapy group).

Sample Size:

This is a pilot project to help establish the feasibility of conducting a full scale externally funded study. As such sample size calculations are not applicable. The primary aim of the study is to determine the safety and feasibility of conducting a large-scale trial, and this pilot project in not expected to reveal a statistically significant difference between the 2 groups.


All patients will be randomized to either aspirin and clopidogrel alone or to triple therapy with aspirin, clopidogrel and warfarin. The randomization process will be centralized and computer generated. Patients with a clear indication for oral anticoagulation such as atrial fibrillation, LV thrombus, mechanical heart valve, or DVT/PE will not undergo randomization but will be followed as part of a registry of patients on triple therapy. All patients will remain on the allocated therapy for 3 months at which time outcomes will be determined.

Study interventions:

Patients will be treated with either ASA and clopidogrel alone (dual therapy) or with aspirin, clopidogrel and warfarin (triple therapy) in combination for 3 months. Patients in the triple therapy arm will be bridged with intravenous unfractionated heparin, low molecular weight heparin, or fondaparinux until their INR is therapeutic, and will be followed by the thrombosis service for the duration of the study.

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Study Type : Interventional  (Clinical Trial)
Actual Enrollment : 20 participants
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: None (Open Label)
Primary Purpose: Treatment
Official Title: Warfarin After Anterior ST-Elevation Myocardial Infarction
Study Start Date : November 2006
Actual Primary Completion Date : January 2008
Actual Study Completion Date : January 2008

Resource links provided by the National Library of Medicine

Arm Intervention/treatment
Active Comparator: 1
aspirin and clopidogrel
Drug: aspirin + clopidogrel
Dual therapy

Experimental: 2
aspirin, clopidogrel, and warfarin
Drug: aspirin + clopidogrel + warfarin
Triple therapy

Primary Outcome Measures :
  1. Combined death, MI, embolic event (TIA, stroke, non-cns emboli), Major Bleeding, and LVT (as determined by echocardiography) at 3 months [ Time Frame: 3 months ]

Secondary Outcome Measures :
  1. Individual endpoints of LVT at discharge and at 3 months (determined by echocardiography), death, MI, stroke, TIA, non-CNS emboli, and minor bleeding [ Time Frame: 3 months ]

Information from the National Library of Medicine

Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study. To learn more about this study, you or your doctor may contact the study research staff using the contacts provided below. For general information, Learn About Clinical Studies.

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Ages Eligible for Study:   18 Years to 85 Years   (Adult, Older Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   No

Inclusion Criteria:

  • Anterior STEMI
  • An ejection fraction less than 40% as per initial LV angiography or echocardiogram
  • Randomization possible within hospital admission if anticoagulated with no interruption > 24 hours
  • Patient able and willing to give informed consent to participate in this trial

Exclusion Criteria:

  • history of intracranial hemorrhage
  • history of GI bleed last 6 months
  • hemoglobin < 90 g/L
  • platelet count < 100 x 10exp9/L
  • ischemic stroke last 30 days
  • intracranial tumor or aneurysm
  • significant pericardial effusion
  • severe renal failure (creatinine > 250 mmol/L).

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 identifier (NCT number): NCT00662467

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Canada, Ontario
Hamilton Health Sciences-Hamilton General Hopsital
Hamilton, Ontario, Canada, L8L 2X2
Sponsors and Collaborators
Hamilton Health Sciences Corporation
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Principal Investigator: Jon-David R Schwalm, MD, FRCPC McMaster University
Principal Investigator: Mayraj Ahmad, MD, FRCPC McMaster University
Antman EM, Anbe DT, Armstrong PW, Bates ER, Green LA, Hand M, Hochman JS, Krumholz HM, Kushner FG, Lamas GA, Mullany CJ, Ornato JP, Pearle DL, Sloan MA, Smith SC Jr, Alpert JS, Anderson JL, Faxon DP, Fuster V, Gibbons RJ, Gregoratos G, Halperin JL, Hiratzka LF, Hunt SA, Jacobs AK; American College of Cardiology; American Heart Association Task Force on Practice Guidelines; Canadian Cardiovascular Society. ACC/AHA guidelines for the management of patients with ST-elevation myocardial infarction: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines (Committee to Revise the 1999 Guidelines for the Management of Patients with Acute Myocardial Infarction). Circulation. 2004 Aug 31;110(9):e82-292. Erratum in: Circulation. 2005 Apr 19;111(15):2013-4. Circulation. 2007 Apr 17;115(15):e411. Circulation. 2010 Jun 15;121(23):e441.

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Responsible Party: Dr. J-D Schwalm, McMaster University Identifier: NCT00662467    
Other Study ID Numbers: 06-281
First Posted: April 21, 2008    Key Record Dates
Last Update Posted: April 21, 2008
Last Verified: April 2008
Keywords provided by McMaster University:
Myocardial Infarction
Additional relevant MeSH terms:
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Myocardial Infarction
ST Elevation Myocardial Infarction
Pathologic Processes
Myocardial Ischemia
Heart Diseases
Cardiovascular Diseases
Vascular Diseases
Anti-Inflammatory Agents, Non-Steroidal
Analgesics, Non-Narcotic
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
Purinergic P2Y Receptor Antagonists
Purinergic P2 Receptor Antagonists