Although acute myocardial infarction (AMI) is rare in women of child-bearing age, pregnancy can increase a woman's risk of heart attack 3- to 4-fold, according to a study published in the July 15, 2008, issue of the Journal of the American College of Cardiology.
Since women today may delay having children until later in life, and advances in reproductive medicine enable older women to conceive, the occurrence of AMI associated with pregnancy is expected to increase.
The study, authored by Arie Roth, M.D., Tel Aviv University in Israel, and Uri Elkayam, M.D., University of Southern California (USC), is a follow up to their initial report released in 1995. The report is based on a review of 103 women with pregnancy-related AMI in the last decade and outlines key recommendations for the diagnosis and treatment of this condition in pregnant women that also considers the health and safety of the developing baby.
"It's extremely important that physicians who take care of women during pregnancy and after delivery be aware of the occasional occurrence of AMI in pregnancy and not overlook symptoms in these young patients," said Dr. Elkayam, who is a professor of Medicine and Obstetrics and Gynecology at USC. "Although many of the standard principles for diagnosing and treating AMI in non-pregnant patients also apply to pregnant women, two patients need to be treated-the mother and her baby-and the health status of both should play a major role in the selection of diagnostic and therapeutic strategies."
Some of the standard diagnostic tests and medications (e.g., ACE inhibitors, angiotensin II receptor blockers (ARBs) and warfarin) used to manage AMI can be harmful to the baby, whether in the womb or through breastfeeding; therefore, their use should take into account potential risks and benefits. There is also limited evidence about the efficacy and safety of other commonly used drugs such as thrombolytic and antiplatelet therapy and devices such as drug-eluting stents, mainly because pregnant patients are routinely excluded from clinical trials.
"The good news is that we've seen a significant drop in maternal deaths related to AMI during and immediately following pregnancy in the last decade," said Dr. Elkayam. "Our initial report indicated a mortality rate of 20 percent, and nearly 40 percent was reported by other studies. In contrast, the new data suggest that only 5 percent to 10 percent of expectant and new mothers who have a heart attack die as a result."
The authors attribute this improvement to increased awareness, more aggressive clinical approaches to treating AMI in general, including standardized hospital protocols for screening and diagnosis, as well as the application of these approaches to pregnant women.
"Interestingly, the mechanism of AMI is somewhat different when it occurs in association with pregnancy. One in four women had a weakening and separation of the walls of the coronary arteries (coronary dissection), which is a rare cause of heart attack in the general population," explains Dr. Elkayam. "Another 13 percent had normal coronary arteries. These findings signify the need to establish the cause of AMI in pregnancy in order to decide on appropriate therapy."