Evaluation of anticoagulent therapy in coronary thrombosis with myocardial infarction
MacFadyen, William Agnew Laws
1. The reported incidence of coronary thrombosis is increasing and with lengthening of the span of life and ageing of the population will probably continue to increase.2. Thrombo-embolic complications contribute significantly to the mortality from and invalidism following episodes of myocardial infarction.3. A fundamental upset of the coagulation system appears probable in cases of coronary thrombosis. Further investigation is indicated to confirm this clotting tendency and to elucidate its cause.4. The anticoagulants, heparin and dicumarol, are effective, experimentally and clinically, in the prophylaxis and treatment of intravascular thrombosis and embolism.5. In 905 cases of myocardial infarction treated with anticoagulants the death rate was 14.1% as compared with a death rate of 27.3% in 572 similar cases receiving conventional therapy only.6. Thrombo-embolic complications occurred in 8 of 805 cases of myocardial infarction receiving anticoagulants and in 23.6% of 572 cases not so treated.7. In 813 cases of myocardial infarction treated with anticoagulants there were minor haemorrhagic manifestations in 47, severe haemorrhages in 2 and no fatalities attributable to the anti-:coagulants.8. Regular, preferably daily, estimations of prothrombin time are essential for the control of dicumarol therapy and Quick's is the method of choice. It is suggested that the general use in this country of the Russell viper venom method is responsible for current unfavourable impressions of dicumarol therapy.9. In the absence of specific contraindications and provided there are adequate laboratory facilities combined heparin-dicumarol therapy should be applied in the author's opinion, to all cases of coronary thrombosis with myocardial infarction.10. Simple methods of avoiding the inconvenience, in heparin therapy, of repeated venepuncture have been described.11. Both heparin and dicumarol have considerable disadvantages. Vigorous search should be made for an anticoagulant which is entirely satisfactory in clinical use.