Hi there,
I think the term you're referring to is an abdominal
aortic aneurysm, which is a dilation of the
aorta, which is the large blood vessel that comes off the heart and gives blood to all of the vessels in the abdomen.
Aneurysms do not cause symptoms, but the main risk is that they can rupture and this usually leads to death, as patients will bleed to death. The risk of rupture is increased and usually repair is recommended when the aneurysm reaches 5.0 cm in women and 5.5 cm in men. We also will usually recommend repair if the aneurysm is growing more than 0.5cm every 6 months.
If she's not going to have surgery, which is very reasonable in her situation, the only treatment is making sure her blood pressure is well controlled. If the aneurysm ruptures, just know that she'll likely pass away from this, which is ok if that is what she would want. It's impossible to predict when or even if it will rupture, but from many studies, we know that the risk increases significantly after the size reaches 5.0 cm in women.
I hope this answers your questions. Please feel free to contact me should you have any further questions.