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Warfarin After Anterior ST-Elevation Myocardial Infarction
This study has been completed.
First Received: April 8, 2008   Last Updated: April 18, 2008   History of Changes
Sponsored by: Hamilton Health Sciences
Information provided by: McMaster University
ClinicalTrials.gov Identifier: NCT00662467
  Purpose

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 Intervention
Myocardial Infarction
Drug: aspirin + clopidogrel
Drug: aspirin + clopidogrel + warfarin

MedlinePlus related topics: Blood Thinners Heart Attack
Drug Information available for: Acetylsalicylic acid Warfarin Clopidogrel Clopidogrel Bisulfate Warfarin sodium Warfarin potassium
U.S. FDA Resources
Study Type: Interventional
Study Design: Treatment, Randomized, Open Label, Active Control, Parallel Assignment, Safety/Efficacy Study
Official Title: Warfarin After Anterior ST-Elevation Myocardial Infarction

Further study details as provided by McMaster University:

Primary Outcome Measures:
  • 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 ] [ Designated as safety issue: No ]

Secondary Outcome Measures:
  • 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 ] [ Designated as safety issue: No ]

Enrollment: 20
Study Start Date: November 2006
Study Completion Date: January 2008
Primary Completion Date: January 2008 (Final data collection date for primary outcome measure)
Arms Assigned Interventions
1: Active Comparator
aspirin and clopidogrel
Drug: aspirin + clopidogrel
Dual therapy
2: Experimental
aspirin, clopidogrel, and warfarin
Drug: aspirin + clopidogrel + warfarin
Triple therapy

Detailed Description:

Rationale:

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.

Purpose:

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.

Design/Methodology:

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.

  Eligibility

Ages Eligible for Study:   18 Years to 85 Years
Genders Eligible for Study:   Both
Accepts Healthy Volunteers:   No
Criteria

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).
  Contacts and Locations
Please refer to this study by its ClinicalTrials.gov identifier: NCT00662467

Locations
Canada, Ontario
Hamilton Health Sciences-Hamilton General Hopsital
Hamilton, Ontario, Canada, L8L 2X2
Sponsors and Collaborators
Hamilton Health Sciences
Investigators
Principal Investigator: Jon-David R Schwalm, MD, FRCPC McMaster University
Principal Investigator: Mayraj Ahmad, MD, FRCPC McMaster University
  More Information

Publications:
Nihoyannopoulos P, Smith GC, Maseri A, Foale RA. The natural history of left ventricular thrombus in myocardial infarction: a rationale in support of masterly inactivity. J Am Coll Cardiol. 1989 Oct;14(4):903-11.
Asinger RW, Mikell FL, Elsperger J, Hodges M. Incidence of left-ventricular thrombosis after acute transmural myocardial infarction. Serial evaluation by two-dimensional echocardiography. N Engl J Med. 1981 Aug 6;305(6):297-302.
Meltzer RS, Visser CA, Fuster V. Intracardiac thrombi and systemic embolization. Ann Intern Med. 1986 May;104(5):689-98. Review.
Küpper AJ, Verheugt FW, Peels CH, Galema TW, Roos JP. Left ventricular thrombus incidence and behavior studied by serial two-dimensional echocardiography in acute anterior myocardial infarction: left ventricular wall motion, systemic embolism and oral anticoagulation. J Am Coll Cardiol. 1989 Jun;13(7):1514-20.
Chiarella F, Santoro E, Domenicucci S, Maggioni A, Vecchio C. Predischarge two-dimensional echocardiographic evaluation of left ventricular thrombosis after acute myocardial infarction in the GISSI-3 study. Am J Cardiol. 1998 Apr 1;81(7):822-7.
Nayak D, Aronow WS, Sukhija R, McClung JA, Monsen CE, Belkin RN. Comparison of frequency of left ventricular thrombi in patients with anterior wall versus non-anterior wall acute myocardial infarction treated with antithrombotic and antiplatelet therapy with or without coronary revascularization. Am J Cardiol. 2004 Jun 15;93(12):1529-30.
Stratton JR, Lighty GW Jr, Pearlman AS, Ritchie JL. Detection of left ventricular thrombus by two-dimensional echocardiography: sensitivity, specificity, and causes of uncertainty. Circulation. 1982 Jul;66(1):156-66.
Vaitkus PT, Barnathan ES. Embolic potential, prevention and management of mural thrombus complicating anterior myocardial infarction: a meta-analysis. J Am Coll Cardiol. 1993 Oct;22(4):1004-9.
Weinreich DJ, Burke JF, Pauletto FJ. Left ventricular mural thrombi complicating acute myocardial infarction. Long-term follow-up with serial echocardiography. Ann Intern Med. 1984 Jun;100(6):789-94.
Chen ZM, Jiang LX, Chen YP, Xie JX, Pan HC, Peto R, Collins R, Liu LS; COMMIT (ClOpidogrel and Metoprolol in Myocardial Infarction Trial) collaborative group. Addition of clopidogrel to aspirin in 45,852 patients with acute myocardial infarction: randomised placebo-controlled trial. Lancet. 2005 Nov 5;366(9497):1607-21.
Sabatine MS, Blake GJ, Drazner MH, Morrow DA, Scirica BM, Murphy SA, McCabe CH, Weintraub WS, Gibson CM, Cannon CP. Influence of race on death and ischemic complications in patients with non-ST-elevation acute coronary syndromes despite modern, protocol-guided treatment. Circulation. 2005 Mar 15;111(10):1217-24.
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. No abstract available. Erratum in: Circulation. 2005 Apr 19;111(15):2013-4.

Responsible Party: McMaster University ( Dr. J-D Schwalm )
Study ID Numbers: 06-281
Study First Received: April 8, 2008
Last Updated: April 18, 2008
ClinicalTrials.gov Identifier: NCT00662467     History of Changes
Health Authority: Canada: Ethics Review Committee

Keywords provided by McMaster University:
Myocardial Infarction
Hemorrhage
Thromboembolism
Clopidogrel
Aspirin
Warfarin

Study placed in the following topic categories:
Anti-Inflammatory Agents
Anticoagulants
Heart Diseases
Myocardial Ischemia
Cyclooxygenase Inhibitors
Vascular Diseases
Fibrinolytic Agents
Cardiovascular Agents
Ischemia
Warfarin
Hemorrhage
Thromboembolism
Fibrin Modulating Agents
Necrosis
Aspirin
Analgesics, Non-Narcotic
Clopidogrel
Platelet Aggregation Inhibitors
Anti-Inflammatory Agents, Non-Steroidal
Peripheral Nervous System Agents
Analgesics
Antirheumatic Agents
Infarction
Myocardial Infarction

Additional relevant MeSH terms:
Anti-Inflammatory Agents
Molecular Mechanisms of Pharmacological Action
Myocardial Ischemia
Hematologic Agents
Physiological Effects of Drugs
Fibrinolytic Agents
Necrosis
Fibrin Modulating Agents
Pathologic Processes
Aspirin
Sensory System Agents
Therapeutic Uses
Anti-Inflammatory Agents, Non-Steroidal
Cardiovascular Diseases
Analgesics
Myocardial Infarction
Anticoagulants
Heart Diseases
Cyclooxygenase Inhibitors
Vascular Diseases
Enzyme Inhibitors
Cardiovascular Agents
Warfarin
Ischemia
Pharmacologic Actions
Analgesics, Non-Narcotic
Clopidogrel
Platelet Aggregation Inhibitors
Peripheral Nervous System Agents
Infarction

ClinicalTrials.gov processed this record on May 07, 2009