Does aortic root dilation suggest aneurysm in thoracic or abdominal aorta?

[ArtistLike]

I just received the report from a cardiac calcium scoring CT scan, and while my calcium score is zero, the report notes that my aortic root is dilated up to 3.7cm.

I am a 42 year-old male. I had the CT scan performed because of recurring pain and tightness in my left arm/left side of my neck/jaw/chest that particularly follows any kind of exercise, and also because my family has a lot of cardiovascular problems. My father has had a triple-bypass surgery for severely blocked arteries, and he has an abdominal aortic aneurysm that so far has responded well to two non-open surgeries.

I have mast cell activation syndrome (MCAS), which causes a lot of mostly bothersome, but sometimes fairly severe inflammatory symptoms. I assume that this is related to that.

I understand that my next step will be to speak with my doctor and likely to follow up with a specialist.

The most immediate question I have is whether the heart CT scan I just had shows anything below the aortic root. If it doesn't, then I'm very curious what the likelihood may be that the aorta could be more widely dilated father down, and whether the bulging of the aortic root makes it more likely that the thoracic and abdominal aorta could be likewise/further dilated and potentially aneurysmal.

[CHIN_C]

The field of view of CT cardiac for calcium scoring can vary from institution to institution but is typically coned down to focus on the heart. This incidentally includes portions of the ascending and descending thoracic aorta and may include portions of the suprarenal abdominal aorta but does not include the infrarenal abdominal aorta where abdominal aortic aneurysms (AAA) commonly occur. If your doctor wants to screen for AAA, consider US Doppler, CTA, and/or MRA.

[ArtistLike]

Thank you for replying. I am scheduled late next month to have an ultrasound of both my abdomen and the area above it where my aortic root is located.

I was really wondering in the meantime though if having a dilated aortic root increases the likelihood of developing an AAA. In other words, are the two twos of aortic dilation typically caused by different underlying processes, or is it more likely that having a dilation in one part of the aorta increases the chances of having a dilation in a different part of the aorta, as well?

[CHIN_C]

Thoracic aortic aneurysms most often result from cystic medial degeneration. Cystic medial degeneration occurs normally to some extent with aging, but the process is accelerated by hypertension and atherosclerosis. Risk factors for cystic medial degeneration include Marfan syndrome, Ehlers-Danlos syndrome, or Turner syndrome; familial thoracic aortic aneurysm syndrome; bicuspid aortic valve; infection (e.g., syphilis) and/or inflammation (e.g., Takayasu's and giant cell arteritis).

Abdominal aortic aneurysms are much more common than thoracic aortic aneurysms. Smoking is the risk factor most strongly associated with abdominal aortic aneurysms, followed by age, hypertension, hyperlipidemia, and atherosclerosis. Sex and genetics also influence aneurysm formation. Men are 10x more likely than women to have an abdominal aortic aneurysm of 4 cm or greater. Those with a family history of abdominal aortic aneurysm have an increased risk of 30%, and their aneurysms tend to occur at a younger age and carry a greater risk of rupture than do sporadic aneurysms.

Source: https://www.ahajournals.org/doi/full/10.1161/01.cir.0000154569.08857.7a