CHICAGO – Coronary dissection, a rare and sometimes fatal condition, surpassed atherosclerosis as the most common cause of pregnancy-associated acute myocardial infarction in a retrospective analysis of 150 women.
Pregnant women also appear to be at increased risk of coronary dissection during coronary angiography and percutaneous coronary intervention, leading to death in one patient, coronary artery bypass grafting in four, and multiple stenting in two.
Patrice Wendling/IMNG Medical Media
Dr. Uri Elkayam
Moreover, standard treatment with thrombolytic agents may actually increase the risk of hemorrhage and further progression of the dissection in pregnant patients, Dr. Uri Elkayam explained at the annual meeting of the American College of Cardiology.
"Because of this, we are ready now to come up with some strong recommendations that we hope will be reflected in the guidelines that the approach to heart attack in pregnancy should be different than that recommended in the general population," said Dr. Elkayam, professor of medicine in the cardiovascular medicine division at the University of Southern California in Los Angeles and director of the Heart Failure Program at USC Medical Center and University Hospital.
Although the European Society of Cardiology recently published guidelines for the management of cardiovascular diseases during pregnancy (Eur. Heart J. 2011;32:3147-97), neither the American College of Cardiology nor the American Heart Association has specific guidelines.
The analysis included 150 cases of myocardial infarction during pregnancy or the 12 weeks after delivery that were identified in the literature, consulted on, or cared for by the research team since 2005. The women’s average age was 34 years, and 75% were at least 30 years old.
The cause of acute MI was coronary dissection in 56 of the 129 women who had angiography, with 10 dissections occurring in the third trimester and 41 postpartum. Atherosclerotic coronary artery disease, the most common cause of acute MI in the general population, was identified in only 35 women, followed by intracoronary thrombus without evidence of atherosclerosis in 22, normal coronary anatomy with possible spasm in 16, documented spasm in 3, and takotsubo cardiomyopathy in 1. Four of the 22 patients with intracoronary thrombus did not undergo an angiogram.
Coronary dissection, which is thought to occur during pregnancy because of hormonally mediated weakening of the walls of coronary arteries, was managed with bypass surgery in 41.5% of patients, stenting in 38%, medication without coronary intervention in 22%, and a Bentall procedure in 1%.
Percutaneous coronary intervention (PCI) was performed in 40% of all patients and coronary angiography in 79%.
The use of thrombolytic therapy is relatively contraindicated in pregnancy due to the risk of bleeding. In addition, thrombolytic therapy may not be effective in women with normal coronaries, spasm, or coronary dissection, and in the last group it can even be detrimental, Dr. Elkayam observed.
"Thrombolytic therapy should therefore be considered second choice to primary PCI in patients with ST-segment elevation MI during pregnancy, especially during the third trimester, [in] the peripartum and early postpartum periods when the incidence of dissection is high," he suggested.
The use of angiography to determine the cause of the MI and guide therapy is recommended in pregnant women with ST-segment elevation MI and in other high-risk MI patients, but because of the increased risk of iatrogenic coronary dissection, stable and low-risk non-STEMI patients should be treated noninvasively during pregnancy and postpartum, Dr. Elkayam recommended.
Most women in the current analysis did not present with traditional cardiovascular risk factors. Only 9% had diabetes, 15% had hypertension, and 20% had hyperlipidemia, although one-fourth were smokers.
Maternal mortality was 7%, down from 20% during 1922-1995 and 11% during 1996-2005, as previously reported by the researchers (Ann. Intern. Med. 1996;125:751-62; J. Am. Coll. Cardiol. 2008;52:171-80). In spite of the decreased rate of maternal death, women who experience a pregnancy-related MI are three to five times more likely to die than nonpregnant women of comparable age, he said.
Fetal deaths, driven largely by maternal mortality, were also lower at 5%, compared with 12% and 9% in the previous analyses.
Still, Dr. Elkayam stressed that women should not avoid becoming pregnant because of fears of an MI, as the incidence is extremely low, at one in 16,000 deliveries. Although maternal and fetal mortality have been decreasing, the number of women with cardiac problems in pregnancy is rising due to older maternal age at first pregnancy; a spike in age-related cardiovascular risk factors such as diabetes, obesity, and hypertension; and mostly, improved treatment of congenital heart disease, allowing more women to reach childbearing age.
"In general, most patients with mild and even moderate cardiac problems can become pregnant and have children safely," he said in an interview. "Patients are often getting information that is not realistic, usually exaggerating the risk. The reality is such that most physicians are not interested in really managing this problem, and so oftentimes women with heart disease will get advice not to become pregnant."