There have been a number of reports of MI during pregnancy. It is known that pregnancy predisposes to dissection of the aorta and other arteries, perhaps because of the accompanying connective tissue changes. The risks are particularly high in patients with Marfan, Ehlers-Danlos, or Loeys-Dietz syndromes. The risk is highest in the third trimester, and coronary dissection, thrombosis, and atherosclerosis have about equal prevalence. The most frequent cause in one study was coronary dissection, and it has a peak incidence in the early postpartum period. Paradoxical emboli through a PFO to the coronary arteries have been implicated in a few instances. Clinical management is essentially similar to that of other patients with acute infarction, unless there is a connective tissue disorder. If nonatherosclerotic dissection is present, coronary intervention may be risky, as further dissection can be aggravated. In most instances, conservative management is warranted. At times, extensive aortic dissection requires surgical intervention. The 2011 European guidelines suggest Marfan patients are particularly susceptible to further aortic expansion during pregnancy when the aortic diameter is more than 4.5 cm (greater or equal to 27 mm/m2) and pregnancy be discouraged in these situations. Some data, however, suggest that there is an increased risk of dissection during pregnancy even when the aortic root is at 4.0 cm, since pregnancy appears to have a small, but significant, influence on aortic growth even at this size. The earlier 2010 ACC/AHA/AATS guidelines suggest elective repair is reasonable when the aortic root is greater than 4.0 cm in women with Marfan syndrome contemplating pregnancy; as the review notes, half of women with Marfan syndrome and this large of an aorta will need surgery since they are at risk for rupture or life-threatening aortic root growth during pregnancy.
Acute infarction during pregnancy is associated with an 8% maternal mortality and 56% incidence of premature delivery. If PCI is required, it is recommended that a bare metal stent be used to minimize antiplatelet usage. There are data that clopidogrel is safe, but ticagrelor, prasugrel, bivalirudin, and glycoprotein IIb/IIIa inhibitors should not be used. Statins and ACE inhibitors are also contraindicated in pregnancy.