Myocardial infarction and mortality caused by methylergonovine

Abstract

Methylergonovine is an ergot alkaloid commonly used for the prevention and treatment of postpartum and postabortion hemorrhage caused by uterine atony. Ergot alkaloids may cause coronary artery spasm (1,2), but serious cardiac complications related to their administration are very rare. To date, only seven cases of myocardial infarction related to ergot alkaloids have been reported (3). We report here another case of myocardial infarction and cardiac arrest resulting from the injection of methylergonovine. This tragic case is also the first mortality associated with the use of methylergonovine. A 38-year-old woman, para 3-0-0-3, came to our hospital for an artificial abortion. An ultrasonography revealed a gestational sac compatible with 5 weeks of gestation. She had been occasionally hypertensive in the past 4 years but had received no regular treatment. She had no history of chest pain or heart disease. She was not diabetic, did not smoke and had no hyperlipidemia. She did not have a family history of other cardiovascular diseases except for hypertension. Her first pregnancy was uneventful, but her blood pressure was sometimes high in the following two pregnancies, increasing to 180/100 mmHg, but was normal most of the time. The woman was referred to a cardiologist to evaluate her anesthetic risk. Her blood pressure was 160/100 mmHg. Electrocardiogram (EKG) was normal. A D&C (dilatation & curettage) was performed 4 days later after her blood pressure had been controlled with verapamil (Isoptin SR, 240 mg/day; Knoll) and valsartan (Diovan, 80 mg/day; Novartis). During the operation, her vital signs, including blood pressure, were normal. The operating resident, failing to notice her hypertensive history, ordered an intravenous injection of 0.2 mg methylergonovine and 10 IU intramuscular oxytocin according to our routine. The operation lasted 10 min and was uneventful. However, 5 min later, when she was observed in the recovery room, she complained of chest pain, and then became unresponsive with cardiac arrest. Despite vigorous resuscitation, she died 70 min later. An autopsy revealed myocardial infarction. There was no evidence of stroke, thromboembolism, atherosclerosis, aortic dissection or left ventricular hypertrophy. Methylergonovine induces contractions of uterine and vascular smooth muscles. Its vasoconstrictive action is less than that of other ergot alkaloids, and it produces hypertension less frequently (1). The normal response of coronary arteries to ergot alkaloids is a diffuse 15–20% decrease in diameter (4). Despite the common use of ergot alkaloids, cardiac complications related to them are extremely rare. Taylor and Cohen first reported a postpartum woman who sustained coronary artery spasm and myocardial infarction after receiving ergonovine (5). Since then, only seven cases have been reported, including four cases related to delivery and three cases related to D&C. Although the pathophysiology of severe coronary vasospasm is unclear, hypertension and obesity (157 cm, 70 kg) in this case may be risk factors. Racial differences may play a role (6) because, including this case, six cases were Asians. In addition, methylergonovine is better given intramuscularly. Intravenous administration may, albeit rarely, produce serious adverse effects if the methylergonovine is not diluted and administered slowly (over 1 min). This case demonstrates the need for a judicious use of ergot alkaloids, especially in women at risk of coronary artery disease. Physicians should be alert to this rare but potentially life-threatening complication. Oxytocin, having fewer and less severe adverse effects, should be the drug of choice over ergot alkaloids for prophylactic use in obstetrics.