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Occult bleeding in three different antithrombotic regimes after myocardial infarction. A WARIS-II subgroup analysis
Mette Hurlen1, Lars Eikvar, Ingebjørg Seljeflot
1Ullevål University Hospital, Norway. mehu@uus.no
Insights
Long-term treatment with warfarin and aspirin did not cause anemia or iron deficiency. Occult bleeding was temporary and not clinically significant, with macroscopic bleeding being the main concern.
Area of Science:
- Cardiology
- Hematology
- Pharmacology
Background:
- Warfarin and aspirin are effective in preventing myocardial infarction (MI) recurrence.
- Bleeding risk is a significant concern with these antithrombotic agents.
- This study investigated occult bleeding and iron deficiency in patients on these therapies.
Purpose of the Study:
- To compare the incidence of occult bleeding and iron deficiency.
- To evaluate long-term effects of different antithrombotic regimens after MI.
- To assess the clinical significance of occult bleeding detected through screening.
Main Methods:
- 267 MI survivors were randomized to aspirin, warfarin, or combination therapy.
- Occult bleeding in feces and urine was screened at 3 months.
- Hemoglobin and iron metabolism were monitored at baseline, 3 months, and 4 years.
Main Results:
- Occult bleeding occurred in 7.1% of fecal tests and 10.9% of urine tests, with no significant intergroup differences.
- Most positive occult bleeding tests were transient; only 2 cases of malignancy were found.
- Hemoglobin and iron status remained within normal limits across all groups throughout the 4-year follow-up.
Conclusions:
- Long-term aspirin and/or warfarin therapy at studied doses did not lead to anemia or iron deficiency.
- Occult bleeding was generally a temporary finding with limited clinical importance.
- Macroscopic bleeding events are clinically significant; routine occult bleeding screening has limited value.
Introduction:
Warfarin, aspirin, and the combination of these, have all proven to be efficacious in preventing future events after myocardial infarction. The accompanying bleeding tendency is a concern. The aim of the present study was to compare the occurrence of occult bleeding and iron deficiency during these treatment modalities.
Methods:
The 267 patients who had survived a myocardial infarction were randomly assigned in the Warfarin Aspirin Reinfarction Study to treatment with aspirin 160 mg/day, or warfarin (INR 2.8-4.2), or aspirin 75 mg/day plus warfarin (INR 2.0-2.5). The patients were screened for the occurrence of occult bleeding in faeces and urine after 3 months. Haemoglobin and iron metabolism parameters were measured at baseline, after 3 months, and at the end of the 4 years follow-up.
Results:
The number of occult bleeding in faeces was 19 (7.1%) and in urine 29 (10.9%). There were no intergroup differences (p=0.45 and 0.39, respectively). In the occult bleeders, a second test showed 3 (1.1%) positive samples in faeces and 9 (3.4%) in urine. Further investigation revealed 2 cases of malignant disease. Haemoglobin and iron status variables were all within normal limits after 3 months and after 4 years in all treatment groups.
Conclusions:
Long-term treatment with aspirin, warfarin, or both, in the present doses and levels of anticoagulation did not lead to anemia or iron deficiency. The occurrence of occult bleeding in faeces and urine was a temporary phenomenon in most patients. Only macroscopic bleedings during these treatment modalities were of clinical importance, and screening for occult bleeding was of limit value.
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