Oral contraceptives and myocardial infarction: report of three cases and review of the literature.

3 additional cases of actue myocardial infarction involving premenopausal women (ages 22-39 years) who were receiving oral contraceptives are reported and the literature is briefly reviewed. The women had been taking oral contraceptives for periods of 3 months 10 months and 4 years respectively. In a majority of all reported cases the patients had received oral contraceptives for periods of 5 months to 8 years. Most of the myocardial infarctions have been located anteriorly. In 2 of the authors cases a characteristic single smooth proximal lesion and lack of collateral vessels as shown by arteriograms supported the diagnosis of an acute coronary artery thrombosis as the cause of the myocardial infarction. Clinical and laboratory studies ruled out other conditions associated with precocious coronary artery thrombosis such as polycythemia vera sickle cell anemia disseminated lupus erythematosis and polyarteritis vera. In a recent study by others an estimated 2.7 times increased risk for myocardial infarction exists in patients in the 30-39 year old age group and a 5.7 times increased risk in the 40-44 age group of those using oral contraceptives. The greater the number of risk factors for coronary artery disease including the use of oral contraceptives the higher the risk. The combined effect of these risk factors appears to be synergistic rather than additive. Many actors seem to be involved. Platelet adhesions platelet sensitivity to adenosine diphosphate platelet numbers and aggregation with estrogens have been blamed. Patients with Blood Group A have had 3 times more thromboembolic complications with oral contraceptives than those with Blood Group O. Estrogens have been noted to have a direct effect on the blood vessel walls in rabbits. From autopsy studies oral contraceptives were thought to have caused endothelial and intimal hyperplasia of veins and arteries followed by thrombotic occlusion. Pure progestational compounds have not been found to be satisfactory contraceptives.