Warfarin After Anterior ST-Elevation Myocardial Infarction

April 18, 2008 updated by: Hamilton Health Sciences Corporation

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.

Study Overview

Status

Completed

Conditions

Intervention / Treatment

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.

Study Type

Interventional

Enrollment (Actual)

20

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • Canada
    • Ontario
      • Hamilton, Ontario, Canada, L8L 2X2
        • Hamilton Health Sciences-Hamilton General Hopsital

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

18 years to 85 years (ADULT, OLDER_ADULT)

Accepts Healthy Volunteers

No

Genders Eligible for Study

All

Description

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).

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: TREATMENT
  • Allocation: RANDOMIZED
  • Interventional Model: PARALLEL
  • Masking: NONE

Arms and Interventions

Participant Group / 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

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Time Frame
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
3 months

Secondary Outcome Measures

Outcome Measure
Time Frame
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
3 months

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Hamilton Health Sciences Corporation

Investigators

  • Principal Investigator: Jon-David R Schwalm, MD, FRCPC, McMaster University
  • Principal Investigator: Mayraj Ahmad, MD, FRCPC, McMaster University

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start

November 1, 2006

Primary Completion (ACTUAL)

January 1, 2008

Study Completion (ACTUAL)

January 1, 2008

Study Registration Dates

First Submitted

April 8, 2008

First Submitted That Met QC Criteria

April 18, 2008

First Posted (ESTIMATE)

April 21, 2008

Study Record Updates

Last Update Posted (ESTIMATE)

April 21, 2008

Last Update Submitted That Met QC Criteria

April 18, 2008

Last Verified

April 1, 2008

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • 06-281

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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