[Antithrombotic therapy after myocardial infarction: arguments for the use of acetylsalicylic acid and coumarin derivatives]

Patients who survived myocardial infarction and who are being treated with the current optimal therapy (antithrombotics, statins and beta-blockers), have a 10-20% chance of death, re-infarction and stroke within in the first year. A possible explanation for this could be an increased activation and generation ofthrombin for at least 6 months following the cardiovascular event preceding preventative therapy. Acetylsalicylic acid and clopidogrel do not affect activation by thrombin of the platelet aggregation and the clotting cascade. The additional use of cumarin derivatives could therefore reduce the chance of recurring thrombotic events, and subsequently improve prognosis. Since the nineteen-nineties several randomised trials have been conducted to study the clinical relevance ofcumarin derivatives both with and without acetylsalicylic acid, in patients who had had a myocardial infarction. The conclusions of these studies were not unambiguous. If the international normalized ratio (INR) was kept > 2 for a long period, by means of frequent check-ups and effective dosage adjustment, the chance of death, recurrent myocardial infarction or stroke was 30-50% lower than when acetylsalicylic acid only was used. The risk of bleeding was raised by 2-4 times, but there were no life-threatening episodes of bleeding. In view of the recent development of anticoagulant agents, for which monitoring seems to be becoming unnecessary, identification of patients who would benefit most from a combined antithrombotic strategy is warranted