Pregnancy-Associated Acute Myocardial Infarction

Abstract

T he incidence of coronary artery disease (CAD) in women of child-bearing age is low, and acute myocardial infarction (AMI) is uncommon. 1,2 Pregnancy, however, has been shown to increase the risk of AMI ≈3-fold compared with the risk in non-pregnant women of similar age. 2-5 Although previous studies have provided some data related to the incidence of pregnancy-associated MI (PAMI), clinical characteristics, risk factors, and outcome 1,2,4 more information is needed on the mechanisms of AMI, the efficacy and safety of standard therapy, and the applicability of guideline recommendations designed for the general AMI population, to women with PAMI. The aim of this study was therefore to review contemporary data on PAMI in an attempt to provide recommendations for the management of this condition. Methods A literature search for cases with AMI related to pregnancy was performed using PubMed and Google Scholar. References from these studies were cross-checked to obtain additional studies that may have been missed by the original search. All original articles were obtained online or by interlibrary communication. Articles published in languages other than English were translated by medical translators. A total of 134 cases published in the literature from 2006 to 2011 not included in a previous review 4 were included in this study. 6-124 In addition, 7 cases presented at the First International Congress on Cardiac Problems in Pregnancy in 2010 (Valencia, Spain) and 9 patients treated or consulted by the authors were also included in the analysis. Recommendations were made on the basis of available clinical information, with the understanding that the cases published in the literature and reviewed by us do not represent all the patients who developed PAMI during the period of the study and that reporting may therefore be incomplete and biased. Results One hundred fifty patients with PAMI were included in the study (Table 1). The age ranged from 17 to 52 years; the mean age was 34±6 years; 75% of the patients were >30 years of age; and 43% were >35 years. Reported risk factors for CAD included smoking in 25% of the patients, dyslipidemia in 20%, hypertension in 15%, and diabetes mellitus and a family history of CAD in 9% each. The type and timing of AMI are shown in Figure 1. Data on the type of AMI were available in 139 of the patients. Of these, 105 (75%) presented with ST-segment-elevation MI (STEMI) and the rest with non-STEMI (NSTEMI). The majority of the patients developed AMI during either the third trimester of pregnancy (STEMI, 25%; NSTEMI, 32%) or the postpartum period (STEMI, 45%; NSTEMI, 55%). The myocardial infarct involved the anterior wall of the left ventricle (LV) in 69% of the patients, the inferior wall in 27%, and the lateral wall in 4%. Table 2 shows the mechanisms of AMI. Coronary angiogra-phy was performed in 129 patients and demonstrated coronary dissection (CD) in 56 patients (43%), atherosclerotic disease in 27%, a clot without angiographic evidence for atherosclerotic disease in 22 patients (17%), and normal coronary anatomy in 14 patients (11%), Three of these patients were diagnosed with takotsubo cardiomyopathy, and noniatrogenic coronary spasm was documented in 2 patients The majority of patients who developed CD presented in the postpartum period (73%) and the third trimester (21%); similarly, most patients (78%) who were found to have normal coronary anatomy presented in late pregnancy or the postpartum period, whereas women with athero-sclerotic disease presented equally throughout the 3 gestational trimesters and the postpartum period. One of the patients with AMI resulting from documented spasm and the 3 patients with Takotsubo cardiomyopathy presented during the postpartum period. CD involved the left anterior descending artery (LAD) in 39 patients, the left main (LM) segment in 24 patients, the left circumflex artery (LCx) in 14 patients, and the right coronary artery (RCA) in 12 patients. Thirty-four patients had dissection limited to 1 coronary artery (LAD, 19; LM, 9; LCx, 1; and RCA 5); 14 women had dissection involving 2 vessels (LM, 9; LAD, 12; LCx, 5; and RCA, 2); and 8 women had involvement of ≥3 vessels (LM, 6; LAD, 8; LCx, 8; and RCA, 5). LV function is shown in Figure 2. Information on LV ejection fraction measured by either echocardiography or contrast angiography was available in 97 patients and was reported to be ≤40% in 54% of the cases, ≤30% in 24% of cases, and ≤20% in 9% of cases. Complications (Table 3) included heart failure or cardio-genic shock in 38% of the patients, ventricular arrhythmias in 12%, and recurrent angina or AMI in 20%. The incidence of maternal mortality was 7% (9 patients), and the causes were