In Marfan syndrome, aortic dilation greater than which measurement is associated with higher risk and may prompt surgical consideration?

• A. 40 mm
• B. 35 mm
• C. 50 mm
• D. 45 mm

Answer: (A)

In Marfan syndrome the aorta is more susceptible to dilation and rupture because of weakened connective tissue. As the aorta enlarges, the risk of dissection or rupture increases, so clinicians identify a diameter at which prophylactic surgery should be considered before catastrophe occurs. For patients with Marfan, this threshold is around 4.0 cm (40 mm) of the ascending aorta, because dissection risk rises earlier than in the general population. If the aorta grows rapidly (for example, more than about 0.5 cm per year) or there are additional risk factors such as a family history of dissection, the consideration for surgery may occur at or below this size. Therefore, 40 mm is the size at which surgical consideration is prompted in this context. Smaller sizes like 35 mm are generally not the typical trigger, while larger sizes such as 45 or 50 mm are thresholds more commonly referenced for other populations or with different risk factors.