[Myocardial infarction during pregnancy]

Up to now 136 cases of myocardial infarction during pregnancy have been reported, and angiography revealed normal findings in 47%. In these cases coronary spasms have been discussed as the major mechanism of the disease. In isolated cases coronary artery dissection may also present with a normal coronary angiography. The case of a 31-year-old pregnant women who developed myocardial infarction during a caesarean section under spinal anaesthesia gives rise to the assumption that an early stage of coronary artery disease may be the third cause that has to be considered. Probably as a consequence of phases of tachycardia and hypertension during the course of anaesthesia, the patient developed a myocardial infarction that she survived without sequelae. While coronary angiography showed normal coronary vessels, an intravascular ultrasound study (IVUS) demonstrated an atheroma in the left main coronary artery with a ruptured fibrous cap. Laboratory screening for risk factors of coronary artery disease (CAD) showed hypercholesterinemia, increased factor VII activity and hyperfibrinogenemia. Platelet aggregation was not inhibited by acetylsalicylic acid. It was pointed out recently that even in asymptomatic patients, plaques may be present in coronary vessels indicating an early stage of CAD that cannot be diagnosed by angiography. Plaque rupture is often triggered by hypertension and may lead to myocardial infarction, instable angina pectoris, or sudden ischemic death. As IVUS is a new diagnostic tool that allows diagnoses of even early stages of CAD we believe that myocardial infarction during pregnancy is more often caused by plaque rupture than may be expected according to the current literature.