Aneurysms: Overview of Abdominal Aortic Aneurysms
Guest: Dr. Jay Robison – Vascular Surgery
Host: Dr. Pam Morris – Cardiologist
Dr. Pam Morris: Hi, I am Dr. Pam Morris and I am here today with Dr. Jay Robison who is a professor of surgery and a vascular surgeon at the Medical University of South Carolina. We are talking today about aortic aneurysms. Dr. Robison, we hear a lot about cerebral aneurysms, aneurysms of the heart, aortic aneurysms. Surely, these share some common features.
Dr. Jay Robison: Well, all of them are related to a weakness in the tissue structure, usually in the artery wall itself, in the cerebral aneurysms, but especially in the aortic area. We are not really quite sure what causes this. But, if you liken it to a balloon under pressure, it gets more and more pressure and more and more distended and, eventually, it can actually stretch so far as to burst or pop. Aortic aneurysms actually are a leading cause of death in men over the age of 65 in this country. They are not necessarily related. People with cerebral aneurysms do not necessarily have a high risk of having aortic aneurysms.
Now, aortic aneurysms are not necessarily inherited but there are tendencies in families to have aortic aneurysms. They are more common in males than they are in females. The most common aortic aneurysm is really below the level of the kidney arteries, in the abdomen. That is the most common aneurysm that we actually encounter and deal with.
Dr. Pam Morris: Do we have any understanding of what some of the risk factors are for aneurysms?
Dr. Jay Robison: Well, the risk factors for aortic aneurysms are the same as for other atherosclerotic processes, interestingly. Smoking is a major risk factor for aortic aneurysm development, family history, as I mentioned. High blood pressure is certainly one of the risk factors, and maybe also high lipids or high cholesterols; seems to have some impact on the development of aortic aneurysms. We really just do not know exactly what causes this weakness in the wall of the aortic aneurysms. There is a lot of research that is going on about it, but we really do not know exactly the etiology. But, all of those risk factors do seem to contribute in some way.
Dr. Pam Morris: Do plaque and aneurysms seem to go hand in hand, or are they different processes?
Dr. Jay Robison: I think they are different processes. Although the risk factors are similar and we used to think that it was an atherosclerotic process, it probably is not exactly the same process. Although, patients with aortic aneurysms can have some degree of atherosclerosis, there are certainly a number of other atherosclerotic manifestations of disease that patients with aortic aneurysms have, such as coronary artery disease.
Dr. Pam Morris: Are there any symptoms or warning signs of an aneurysm? How would a patient know if they are at risk for developing an aneurysm?
Dr. Jay Robison: Actually, they may not know that they have an aneurysm. A lot of times, these are found on a routine screening examination for something else: i.e. an abdominal ultrasound examination for suspected gall bladder disease, or on a CAT scan, or on an x-ray performed for kidney problems or for a back problem. So, these can sometimes be silent. In fact, they are very frequently a silent process.
Occasionally somebody will come in and they will have a routine screening test. They will have a screening test done at their church, or their doctor would think that because they have some of these risk factors and they are over a certain age, then maybe a screening test would be a good idea for them. They have it done and, low and behold, they have a small aneurysm that needs to be investigated, or studied or followed.
Dr. Pam Morris: Now, you mentioned a small aneurysm. Is there a size at which an aneurysm becomes more of a problem for an individual?
Dr. Jay Robison: Absolutely. Not all aneurysms are dangerous aneurysms. These things grow over a slow long period of time. Aneurysms that are very large, as you might imagine like a balloon, the very large aneurysms are the ones that are most prone to rupture. The ones that are very small are not particularly dangerous, we do not think. For the most part, those aneurysms may not need to be fixed unless they become symptomatic in some way.
Dr. Pam Morris: Let’s talk for a moment about how you diagnose an aneurysm.
Dr. Jay Robison: Sometimes the aneurysms can be actually felt on a physical examination by your physician. Other ways to make that diagnosis are on the ultrasound examination which is a painless examination using an ultrasound probe done in a radiology office or a vascular laboratory. Sometimes the diagnosis is made by CT scan which gives a very accurate measurement of the size of the aneurysm. Usually an abdominal aorta is about the size of your thumb. When it gets about twice that size, that is the size that we worry about becoming an aneurysm. When it gets to be three times that size, or about 5.5 cm, that gets to be in the danger range of rupturing. Not all aneurysms that size will rupture. In fact, if you just look at the natural history of aneurysms that size, over time only about one out of three may actually burst or rupture, over time, over a five-year period. But, that is about the size that the risk of rupture exceeds the risk of surgery or intervention. So, 5 to 5.5 cm, depending on if you are a man or a woman, is about the size that we consider for repair.
Dr. Pam Morris: How do you know how often to monitor a patient for an aneurysm?
Dr. Jay Robison: If it is a small aneurysm, say, less than 4 cm in diameter, then we will follow those usually on a yearly basis because the rate of growth is pretty slow. If it is enlarging over a period of time, since the last examination, then we may follow them every six months. Or, if it looks to be a particularly dangerous growth rate, then we will follow them even more frequently, but usually every 6 to 12 months.
Dr. Pam Morris: One question that I get asked quite often is, you know, there are the ultrasound vans that go around screening for carotid disease, for aneurysms as well. Are there any screening guidelines for when an individual should be screened for an aneurysm?
Dr. Jay Robison: Medicare has recently agreed to pay for a one-time screening, especially for men over the age of 65 who have one of these risk factors. Otherwise, for patients that have a strong family history, I think that men especially should have an abdominal ultrasound, probably beginning at about age 50 to 55 because they are going to be a higher risk for having an aneurysm.
Dr. Pam Morris: Well, Dr. Robison, thank you for discussing with us today the importance of abdominal aortic aneurysms. I would like to come back in another podcast and talk with you more about treatment of aortic aneurysms. Thank you.
Dr. Jay Robison: Sure, Pam. Thanks.
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