When should an Abdominal Aortic Aneurysm be repaired?

So people often wonder at what size do we need to repair an abdominal aortic aneurysm. There was a really good study called the UK Small Aneurysms Trial that looked at the outcomes of just monitoring a small aneurysm, and by small aneurysm I mean less than 5.5cm across in terms of diameter as compared to operating on the aneurysm while it was still in the small category as opposed to the large category. And I found that there's no benefit in operating if an aneurysm was lower than five and a half centimeters in size as measured with ultrasound across the width of the aneurysm from front to back. So generally speaking, we wouldn't offer an operation for an aneurysm less than five and a half centimeters if it was in the abdominal aorta in the belly. And actually an even higher threshold it was higher up in the chest or upper abdomen, as the risk-benefit ratio of surgery is different in those areas. So the long and short of it is if it's the abdominal water, 5.5cm would be what we would consider the threshold for treatment.