Case 2--2011: Acute myocardial infarction in a pregnant patient requiring coronary artery bypass graft surgery.

A 38-year-old gravida 6, para 3, abortus 2 woman (160 cm and 104 kg) at 37 weeks' gestation with an acute ST- elevation myocardial infarction was transferred from an outside hospital for further management. The patient's past medical history included Hashimoto thyroiditis, hypothy- roidism, exercise-induced asthma, depression, anxiety, mi- graine headaches, degenerative joint disease, and lichen sclerosis. Her past surgical history was significant for bilat- eral knee arthroscopies, a right-breast biopsy, and bilateral LASIK vision correction. Her obstetric history included 3 spontaneous vaginal deliveries and 2 spontaneous abortions at 8 weeks' and 13 weeks' gestation. The patient's daily home medications consisted of levothyroxine (350 g), flu- oxetine (20 mg), and prenatal vitamins. The patient's initial cardiac symptoms consisted of waking up at night with severe epigastric chest pain, diaphoresis, nausea, vomiting, and a tingling sensation in her left arm. She called her obstetrician and was advised to go to the emergency department at an outside hospital. Vital signs were normal, and fetal heart monitoring showed normal variability with a reas- suring pattern and the to codynamometer showed the absence of contractions. Her initial electrocardiogram (ECG) revealed ST elevations in leads I, aVL, V5, and V6, with ST depres- sions in leads III and aVF. Her cardiac enzymes were elevated, with a CK-MB of 7.0 (0.6-6.3) and troponin I of 0.18 (0.01-0.1). Her initial medical management included aspirin (324 mg orally), ondansetron (4 mg intravenously), morphine (2 mg intravenously), diazepam (5 mg orally), diphenhydramine (50 mg orally), and a nitroglycerin infu- sion ranging from 5 to 30 g/min. The patient was taken to the cardiac catheterization suite where a left-heart catheterization revealed moderate hypokine- sis of the anterior and lateral walls of the left ventricle, with an estimated left ventricular ejection fraction of 40%. Coronary angiography showed a normal left main coronary artery and 40% to 50% proximal stenosis of the left anterior descending (LAD) with associated haziness along with diffuse 60% steno- sis in the distal portion. There was TIMI III flow in all segments of the LAD and diagonal branches. The left circumflex and right coronary arteries were found to be codominant, with mild diffuse atherosclerosis. These results were interpreted as being consistent with spontaneous recanalization of a proximal LAD lesion. A transthoracic echocardiogram revealed a normal-sized left atrium and an enlarged, globular left ventricle with akinesis of the apical septum, apical lateral segment, midlateral seg- ment, anteroapical segment, and midseptum. The ejection frac- tion was estimated visually to be 25% to 30%. The right atrium and ventricle were normal in size. Doppler examination showed trace-to-mild mitral regurgitation and trace pulmonic regurgi- tation. The patient was medically managed in the intensive care unit (ICU), with an unfractionated heparin intravenous infu- sion, aspirin, and metoprolol. Statins and angiotensin-convert- ing enzyme inhibitors were not administered because of the patient's pregnancy. She continued to experience occasional 2/10 chest pain. Of note, when her nitroglycerin infusion rate was decreased after developing headaches, the patient experi- enced more severe chest pain. Serial cardiac enzymes showed continued elevations with a peak troponin I of 160.7 ng/mL and peak CK-MB of 686.3 ng/mL. It was believed that the patient