The use of oral anticoagulants in patients with myocardial infarction (MI) has been shown to have beneficial effects in terms of reduction in mortality.
Oral anticoagulants in MI
Investigators & study design
International Anticoagulant Review Group54
This was a review of 9 well designed trials involving patients with MI
2205 male and 282 female patients
Long-term oral anticoagulant treatment after infarction
Of the men under the age of 55 years, 91% were alive after 2 years vs. 85% in the control group not receiving the anticoagulant (p<0.01)
In men over the age of 55 years, 75% were alive at the end of 3 years vs. 69% in the control group (p<0.05).
The overall reduction in mortality was 20%.
Sixty Plus Reinfarction Study Research Group55
This was a randomized double-blind multicentre clinical trial.
878 patients over 60 years of age, who had suffered a MI and were on oral anticoagulant therapy for
Half of the patients received placebos instead of the anticoagulant; the others continued anticoagulant therapy. All were followed for 2 years.
2-year incidence of recurrent MI was 15.9% in the placebo group and 5.7% in the anticoagulant treated group (p=0.0001).
The incidence of intracranial events was 5.6% in the placebo group and 3.1% in the group on anticoagulants (p=0.18).
No fatal extracranial hemorrhages were seen.
Hurtado L et al.56
300 patients with acute MI
Group I - anticoagulant treatment with heparin and acenocoumarol Group II - did not have anticoagulant therapy
The incidence of persistent angina, arrhythmias, pulmonary embolism and reinfarction was not different for both groups.
The mortality was slightly higher in group II.
Of the patients who died, the autopsy demonstrated fresh thrombi in all cases of both groups; in addition, in most of the patients of group II, hemorrhage of the coronary artery wall was found.
Two-dimensional echocardiographic assessment of anticoagulant therapy in left ventricular thrombosis early after acute myocardial infarction Tramarin R et al., Eur Heart J, 1986; 7(6): 482-92.
This study was designed to assess, by two-dimensional echocardiography, the effects
of anticoagulant therapy on left ventricular thrombosis detected after acute myocardial infarction.
Randomized, assessor-blind, comparative study
38 patients with left ventricular thrombi detected by two-dimensional echocardiology
within 5 weeks (mean 4) of the onset of infarction.
17 patients each from both the groups were restudied 15 days, 3 months and one year later to evaluate the changes in size of thrombi using echocardiography. A significant decrease in ventricular thrombus size was taken as a greater than or equal to 5 mm reduction of thickness in the apical views.
There was a significant reduction in the dimension of the thrombi in the acenocoumarol group (P < 0.001). In Group A, 9 patients showed a complete resolution of thrombus at the 15 day study; at one year, thrombus had resolved in 15 and persisted unchanged in size in 2patients. Among 17 patients of group B at the 15 day study, two had resolution of thrombus and 15 were unchanged; at the one year examination thrombus was resolved in 4, decreased in size in 4 and persisted unchanged in 9 patients.
Recommendations for oral anticoagulant therapy in ischemic heart disease are as follows57:
For post‐myocardial infarction (MI) patients at low or moderate risk, aspirin alone is recommended (Grade 2B);
For post-MI patients at high or low risk, in whom international normalized ratio (INR) can be rigorously monitored, one of two alternatives is recommended: aspirin with moderate-dose vitamin K antagonists (INR 2.0–3.0, target 2.5) or high-dose vitamin K antagonists for 4 years (INR 3.0–4.0, target 3.5) (Grade 2B);
For high-risk post-MI patients, including those with extensive anterior MI, severe heart failure, intracardiac thrombi documented by echocardiography or history of thromboembolic events, combined moderate intensity oral anticoagulant therapy (INR 2.0–3.0) and low‐dose aspirin (<100 mg/day) is recommended for 3 months following MI (Grade 2A).