Abstract Body (Do not enter title and authors here): Case Description:
A 26 yo woman with Marfan Syndrome (MFS, FBN1), ectopia lentis, aortic dilation and no family history of MFS or aortic dissection was evaluated for preconception counseling. She was asymptomatic, and the size of her aortic root (~4cm) and ascending aorta (~3.5cm) had been stable for over 5 years. She was counseled that risk of cardiac events during her pregnancy is high, but lower compared to those with aortic sizes >4.5cm. Once pregnant, she was followed closely with imaging every trimester (MRA at 25 weeks gestation showed stable aortic sizes). Cardio-obstetric recommendations included: CARPREG II score: 2, mWHO class: III, consideration of assisted second stage due to aortic root dilation. She was counseled on symptoms of aortic dissection and to seek emergency care should those symptoms arise. At 27 weeks gestation, she presented to the ED with intense chest and neck pain, shortness of breath, and headache. Emergent CT showed aortic root (4.1cm) and proximal ascending aortic dissection with propagation into the left main coronary artery (Figure 1). She underwent emergent C-section followed by aortic root and ascending aorta replacement and mechanical aortic valve replacement due to severe regurgitation. She was discharged in stable condition 8 days after an uncomplicated post-operative recovery. Her baby is recovering in the NICU.

Discussion:
While risk of aortic dissection in women with MFS is higher during pregnancy, recent studies suggest relative safety with aortic root diameters up to 4.5cm. Our case highlights that even at “lower risk” aortic sizes, aortic dissection remains an important risk for such women. Educating patients and providers about the acute symptoms of aortic dissection and forming an action plan for timely intervention can be lifesaving. Furthermore, some genetic mutations (e.g. TGBR1/2 or SMAD3) and sequence variants within the FBN1 gene may pose a higher risk of aortic dissection at smaller aortic diameters. Our patient’s pathogenic FBN1 mutation (-c.2114-5T>G, previously classified as a VUS) highlights the importance of genetic testing: prophylactic surgery at sizes <4.5cm may be considered with high-risk genetic variants or a family history of aortic dissection.