LV Thrombus Pilot Study for Comparing Enoxaparin Vs. Warfarin

A Prospective Randomized Trial Comparing Enoxaparin to Warfarin for the Prevention of LV Thrombus Formation After Anterior Wall Myocardial Infarction: A 60 Patient Pilot Study

To prospectively evaluate the utility of enoxaparin vs. oral warfarin in reduction of echocardiographic indices of LV mural thrombus. The primary outcome is the presence of LV mural thrombus at 3.5 months. The secondary outcome is cost analysis comparing the two arms.

Patients with anterior Q-wave MIs and ejection fractions<=40% will be enrolled within the first 4 days of infarction. Patients will be randomized to receive either enoxaparin 1mg/kg (maximum 100mg) subcutaneously every 12 hours for one month or heparin followed by oral warfarin for 3 months.

Clinical and safety evaluations, 2-D echocardiograms at baseline and at 3.5 months and cost analysis will be performed.

Inclusion Criteria:

• Age 18 to 80

• Anterior myocardial infarction with:

  1. Pathological Q-waves in at least 3 contiguous anterior precordial leads, assumed to be new
  2. CK peak>5 times the upper limit of normal with positive MB bands

• Ejection fraction <=40% or anterior dyskinesis or documented LV Thrombus

• MI onset < 7 days from randomization

Exclusion Criteria:

• Inability to give written informed consent
• Medical conditions that would prohibit discharge within 48 hours with the exception of need for anticoagulation
• Cardiogenic shock, rest angina unresponsive to medical therapy or serious ventricular arrhythmia in the 24 hours prior to randomization
• Patients scheduled for surgical procedure in the next 4 months that would prevent use of enoxaparin or warfarin
• Anemia: Baseline Hgb<=9 gm for women, <=10 gm for men or platelet count<100,000
• Renal insufficiency (creatinine >2.0 mg/dl)
• Serious liver disease as reflected by INR>1.3
• Stroke within past 6 months or a prior documented intracranial or subarachnoid hemorrhage
• Active bleeding or major surgery within 2 weeks prohibiting the use of anticoagulants
• Acute pericarditis
• Women of childbearing potential unless pregnancy test negative
• Cardiac or non-cardiac condition with expected survival< 6 months
• Severe peripheral vascular disease
• Patients who undergo cardiac surgery, including CABG, as a result of their index myocardial infarction
• Allergy to aspirin, heparin or warfarin, pork or pork products
• History of recurrent thromboembolic disease or a history of Protein C, Protein S, antithrombin III deficiency or known bleeding disorder.
• Current use of warfarin or need for chronic anticoagulation
• Current participation in other trials using investigational drugs or devices
• Prior enrollment in this trial