Acute aortic dissections during pregnancy are rare (incidence 0.0145/1000) but life-threatening.1 Signs and symptoms mimic pathologies such as pulmonary embolism and preeclampsia that have significantly higher incidence in the obstetric population (3–40/1000 and 50/1000, respectively), which often leads to delayed diagnosis.2 Prompt recognition of an acute aortic dissection is critical as mortality in the general population has been shown to increase 1% to 2% per hour and reach approximately 25% in the first 24 hours if unrecognized.2,3
The following case report describes an acute type A aortic dissection in a postpartum woman without a history of a connective tissue disorder. Written HIPAA authorization and informed consent were obtained for the publication of this case report, and the article adheres to applicable EQUATOR guidelines.
CASE DESCRIPTION
A 35-year-old G4P0121 woman presented to labor and delivery triage at 34w5d with headache, intermittent visual floaters, and substernal chest pain radiating to her jaw and back. Her past medical history was significant for chronic hypertension, preeclampsia in a previous pregnancy, and Cesarean delivery. During an evaluation for chronic hypertension 1 year prior, a transthoracic echocardiogram (TTE) showed an aortic root measurement of 3.41 centimeters (cm), 2.27 cm/meter(m)² when indexed for size and was considered normal.
In the weeks leading up to delivery, the patient presented to triage several times for worsening hypertension. Preeclampsia evaluation was negative; therefore, she was treated for an exacerbation of chronic hypertension, prescribed increased doses of nifedipine, and discharged home. The day before delivery, she presented to triage with a headache, a blood pressure of 161/96 mm Hg, and visual floaters. Admission was recommended for delivery planning in the setting of chronic hypertension with superimposed preeclampsia with severe features at a gestational age >34 weeks. The patient declined admission, so she was discharged with a new prescription of labetalol in addition to nifedipine. She returned to triage the next afternoon with complaints of chest pain, systolic blood pressures in the 160s, and blurred vision. She was found to have a newly elevated protein-to-creatinine ratio (uPCR) of 1.28 (uPCR of ≥0.3 used as a surrogate marker for proteinuria in preeclampsia). She was admitted for delivery, and a magnesium infusion was started. Intravenous antihypertensive medications were not administered.
For her complaint of chest pain, an electrocardiogram (ECG) and serum troponin T generation 5 were obtained. ECG confirmed normal sinus rhythm, serum troponin was normal, and the patient’s chest pain improved with a gastrointestinal cocktail comprised of lidocaine 4% viscous solution and aluminum-magnesium-simethicone. The chest pain was deemed noncardiac due to the resolution of symptoms and negative evaluation. Platelet count was normal, and coagulation studies were not completed. She subsequently underwent an uneventful repeat Cesarean delivery under spinal anesthesia and was transferred to the postpartum floor.
The patient remained mildly hypertensive postpartum, and on postoperative day 1, she again complained of chest pain. A repeat troponin was ordered and was mildly elevated to 14 nanogram (ng)/liter (L) (normal <14 ng/L), so cardiology was consulted. The cardiologist attributed the patient’s symptoms and elevated troponin to demand ischemia related to persistent hypertension, but a TTE was ordered to further evaluate a new diastolic murmur appreciated on examination. The TTE was completed on postoperative day 2 and diagnosed an aortic type A dissection (Figure 1). While the operating room was being prepared, a computed tomography angiography (CTA) of the chest was obtained for operative planning (Figure 2). Following imaging, the patient was brought to the operating room emergently for an aortic type A dissection repair on cardiopulmonary bypass with deep hypothermic circulatory arrest. Surgical repair involved replacement of the ascending aorta and hemiarch, and repair of the aortic valve by resuspension of the noncoronary and right coronary cusp commissures. Postoperatively, the patient remained intubated and was transferred to the intensive care unit. Her postoperative course remained uneventful, and she was discharged home on postoperative day 5. Five months postpartum, the patient is at home, back to baseline function, and neurologically intact.
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Figure 1.: Transthoracic echocardiogram—parasternal long axis (still image) with the dissection flap in the ascending aorta highlighted by the red arrow. AV indicates aortic valve; RV, right ventricle; LA, left atrium; LV, left ventricle.
Figure 2.: Axial image from the CT angiographic acquisition of the chest with the dissection flap in the ascending aorta highlighted by the red arrow. CT indicates computed tomography.
Months after discharge, she underwent genetic testing for aortopathy and was found to have a heterozygous variant within the MYLK gene.
DISCUSSION
During pregnancy, hormonal changes result in fragmentation of the reticulin fibers, diminished amounts of acid mucopolysaccharides, and loss of the normal corrugation of elastic fibers. These changes combined with increased blood volume, stroke volume, and heart rate can lead to structural changes predisposing patients to aortic dissection.4 The literature supports an increased incidence of aortic dissection in pregnant patients with a history of connective tissue disorders associated with aortopathies such as Marfan’s syndrome, Ehlers-Danlos syndrome, bicuspid aortic valve, and Loeys-Dietz syndrome.5 Women with an aortic root diameter of >4.0 cm, history of previous dissection, coarctation of the aorta, hypertension, and drug abuse are also predisposed to aortic dissections.6 What is less understood is the risk of aortic dissection in pregnant patients in the absence of risk factors. Our patient denied a history of connective tissue disorder, had a normal trileaflet aortic valve, and did not have a dilated aortic root on previous imaging. However, she did have chronic hypertension, preeclampsia, and presented to triage with chest pain. The case emphasizes the importance of considering aortic dissection in any pregnant patient complaining of persistent chest pain, especially in the setting of hypertension and a new diastolic murmur, as was seen in our patient.
Patients with aortic dissection often present with acute onset, severe chest or interscapular pain, myocardial ischemia, acute neurological findings, new diastolic murmurs, or heart failure secondary to acute aortic insufficiency or tamponade.7 Diastolic murmurs are always pathologic, indicative of a valvular abnormality, and require prompt assessment. However, the majority of parturients with chest pain do not have an aortic dissection. The differential diagnosis includes pulmonary embolus, arrhythmias, cardiomyopathy, acute coronary syndrome, costochondritis, and gastroesophageal reflux.8
It can be challenging to diagnose an aortic dissection. Early diagnostic tests for chest pain, including ECG, cardiac troponins and chest radiograph, may not always be revealing. Acute ST elevation or depression on ECG was only present in 49.7% of patients with aortic dissections.9 Elevated cardiac troponins were only present in 26.8% of patients with acute aortic dissection and may actually delay in-hospital diagnosis as providers initiate treatment for acute coronary syndrome.10 Chest radiograph may show mediastinal widening or pleural effusion. However, one study determined that these findings were present in only 37.4% of type A aortic dissections, and in 12.4% of patients, there was no abnormality noted.11
With respect to diagnostic imaging for acute aortic dissection, CTA is typically the modality of choice due to advantages of rapid, accurate results and assistance with surgical planning. Attempts to limit ionized radiation exposure to the fetus may delay ordering such tests in pregnant patients who are often young, healthy, and deemed low risk for this pathology, but providers should never delay potentially lifesaving imaging for fear of almost negligible fetal radiation. TTE offers a safe alternative but may be limited by the total aorta visualized and the ability to obtain high-quality images. Images are largely dependent on patient body habitus and sonographer expertise. Transesophageal echocardiography (TEE) may be useful in the diagnosis of thoracic aortic dissections, especially those involving the ascending aorta, with a >95% sensitivity and specificity, but is limited by the need for patient sedation and sonographer expertise. Magnetic resonance angiography (MRA), although highly sensitive and specific, is rarely used for emergent cases due to time restraints.12,13
Management of acute aortic dissection in pregnancy adds an additional layer of complexity but should never delay surgical repair, which would only lead to increased maternal morbidity and mortality. Timing of delivery with respect to repair requires a multidisciplinary approach focused on maternal health and often guided by fetal gestational age. Anesthetic management of a parturient with an acute aortic dissection should minimize stress on the dissected aorta by reducing wall tension, mean arterial blood pressure, heart rate, and circulating catecholamines.
Several weeks postpartum, the patient underwent genetic testing for aortopathy and was found to have a heterozygous variant within the MYLK gene. This gene is autosomal dominant, associated with thoracic aortic aneurysms and dissections, and has been recorded as having an incidence of 0.01%. Aortic dissections have not been reported in individuals affected with MYLK-related conditions in the absence of a bicuspid aortic valve.14
In summary, this case supports the concept that physiologic changes in pregnancy enhance an individual’s predisposition to aortic dissection even in the absence of other, well-established risk factors. It is critical to consider this diagnosis in any parturient complaining of persistent chest pain, especially in the setting of hypertension and a new diastolic murmur. Emergent CTA or sonography must be considered to decrease delays in definitive management and to minimize maternal morbidity and mortality.
DISCLOSURES
Name: Mercades A. Meuli, DO.
Contribution: This author is the primary author, participated in the care of this patient, completed a literature search, and wrote and edited the paper.
Name: Anne Shapiro, DO.
Contribution: This author helped edit the paper.
Name: Brett H. Cronin, MD.
Contribution: This author helped obtain images and edit the paper.
Name: Kelsey A. Pinson, MD.
Contribution: This author helped edit the paper.
Name: Erin I. Martin, MD.
Contribution: This author helped edit the paper.
This manuscript was handled by: Jennifer Banayan, MD.
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