Case Report

A 30-year-old woman (gravida 2, para 1) at 33 weeks of gestation with acute onset of dyspnea and chest pain was referred to our Emergency Department. Her plasma D-dimer was elevated (1.35 mg/L), and her chest x-ray revealed a normal heart shadow and no widening of the mediastinum. Acute aortic dissection of the descending aorta extended to the bifurcation of abdominal aorta; the fetus was verified by aortic computed tomography angiography ( Figure 1 ). The patient had a negative history of vascular events, hypertension, or previous vascular surgery. Marfan syndrome was diagnosed. She was admitted to the intensive care unit, and the condition of the fetus was monitored closely. Emergency cesarean delivery was performed with general anesthesia, followed by intravenous infusion with nicardipine and nitroglycerin for control of blood pressure during the perioperative period. The patient was discharged in stable condition on day 8 after delivery; the infant male was discharged 1 month later. Both the patient and her infant son recovered well during the 3-month follow-up period. Repeated aortic computed tomography angiography was arranged and revealed the stable condition of Standford type B aortic dissection ( Figure 2 ).

Aortic computed tomography angiograms

A, An acute aortic dissection with a false lumen. B, A dissection from the descending aorta and the fetus in the uterine cavity.

Chang. Aortic dissection managed with medication during pregnancy. Am J Obstet Gynecol 2013.

Aortic computed tomography angiograms

A, An aortic dissection from the descending aorta through the abdominal aorta. B, A reformed image of Stanford type B aortic dissection.

Chang. Aortic dissection managed with medication during pregnancy. Am J Obstet Gynecol 2013.

Comment

Patients with Marfan syndrome have a mutation in the fibrillin-1 gene. The connective tissue disorder often affects the cardiovascular system and may cause aortic root dilation and aortic dissection. Abnormal biophysical properties of the aorta have been observed in patients with Marfan syndrome that lacked aortic enlargement. Immer et al showed that aortic root enlargement (>4 cm) during pregnancy in patients with Marfan syndrome or bicuspid aortic valve disease was associated with a considerable risk of aortic dissection. Both the absolute diameter of the aortic root and the rapidity of aortic dilation are critical factors and should be considered. However, a recent prospective study of 127 patients with Marfan syndrome indicated that pregnancy is relatively safe with an aortic root diameter <45 mm. The aortic root diameter was 37 mm in our pregnant patient with Marfan syndrome, which resulted in a favorable prognosis.

Aortic dissection, although rare in young woman, is associated most frequently with pregnancy in the third trimester, which places both the mother and the fetus at high risk. The third trimester is the period of maximal hyperhemodynamic stress; there are maximal increases in heart rate, stroke volume, cardiac output, left ventricular wall mass, and end-diastolic dimensions. In addition, estrogen reportedly inhibits collagen and elastin deposition in the aorta, and progesterone accelerates the deposition of noncollagen proteins in the aorta. These hormonal effects lead to fragmentation of the reticular fibers, diminished acidic mucopolysaccharide content, and reduced corrugation of the elastic fibers of the aortic wall. Because these modifications occur in every pregnancy, it is assumed that aortic dissection may have other etiologic factors, such as an inherent defect in the aortic wall and abnormal aortic root diameters. However, because some pregnant women with aortic dissection may have an aortic diameter <40 mm, we recommend close and careful monitoring of all pregnant women with Marfan syndrome.

Currently, there is no standard treatment for aortic dissection in pregnancy. In the third trimester of gestation, especially at >30 weeks, emergency cesarean delivery and subsequent cardiac surgery may represent the best option to save the lives of the mother and her child. In a recent study, minimizing surgical repair of acute type B dissection in pregnant patients with stable blood pressure with antihypertensive drugs resulted in favorable outcomes with lower risks. Thus, we prescribed only antihypertensive drugs for our pregnant patient with Marfan syndrome instead of performing the aortic repair surgery. Aortic dissection generally occurs as a hypertensive emergency, and the prime consideration of medical management is strict blood pressure control. The target blood pressure should be a mean arterial pressure of 60-75 mm Hg or the lowest blood pressure that can be tolerated by the patient. Another factor is to reduce the shear-force of ejection of blood from the left ventricle. Beta blockers are first-line treatment for patients with acute and chronic aortic dissection. In acute dissection, rapidly acting, titratable parenteral agents (such as propranolol or labetalol) are preferred. Calcium channel blockers can be used in the treatment of aortic dissection, particularly if there is a contraindication to the use of beta blockers. The calcium channel blockers that typically are used are verapamil and diltiazem because of their combined vasodilator and negative inotropic effects. Vasodilators such as sodium nitroprusside can be considered for patients with ongoing hypertension; however, vasodilators should never be used alone because they generally cause reflex tachycardia. Hence, we prescribed combined calcium channel blockers plus vasodilator drugs for the refractory hypertension. If the individual has persistent hypertension with the maximum doses of 3 different classes of antihypertensive agents, involvement of the renal arteries in the aortic dissection plane should be considered.

Current pharmacologic therapies for aortic dilation and dissection consist of agents that generally are used to reduce blood pressure and the inotropic state of the heart, which diminishes the cyclic repetitive forces that are exerted on the aortic wall and reduces the risk of aortic dilation. Although these pharmacologic agents may offer some benefit for the reduction of the aortic aneurysm expansion rate, the underlying cause of the progressive aortic degradation in Marfan syndrome is left untreated, which serves only to prevent or delay aortic complications. Recent studies on the transforming growth factor-β signaling pathway and the inflammatory mechanisms in aortic disease with a mouse model have suggested new pharmacologic treatment strategies for Marfan syndrome. These strategies use doxycycline, statins, and angiotensin II receptor blockers with the angiotensin II receptor type 1 blocker approach that focuses more on the prevention of aortic wall disease rather than on the delay of such effects.

Pregnancy is a risk factor for the development of aortic aneurysm and dissection in women with Marfan syndrome; it is has been shown that dissection can develop both before and after labor. Patients with Marfan syndrome with an aortic root diameter >40 mm should undergo preconception counseling for surgical aortic repair before pregnancy. Patients with Marfan syndrome with an aortic aneurysm should be evaluated closely and continuously during pregnancy by multidisciplinary specialists to prevent possible aortic dissection that could be fatal for both the mother and the fetus.