long,
The questions you ask are a little too specific to give exact answers.
1) The aortic root is measured at different places. The radiologist/cardiologist that will interpret your scan will be able o give your measurements and if you lie in the range of normal. Generally, The mean normal value for the aortic root annulus in men is 2.6 cm and for the proximal ascending aorta 2.9 cm . The upper normal limit for the ascending aorta is 2.1 cm/m2. A value beyond 4 cm is regarded as an aneurysm, a lower value as ectasia. The normal value for the descending aorta is 1.6 cm/m2 for BSA, and aneurysm is present when a value of 3 cm is exceeded.
The aortic diameter gradually increases over time. The normal expansion rate over a period of about 10 years is between 1-2 mm and the expansion may be greater for patients with an aorta that is larger than normal
2) An anuerysm is usually defined by a dimension greater than 4 cm.
3) This number is the general cutoff. If defined on a reliable imaging modality with good images, I cant think of an alternative explanation.
4) No Idea. There probably isnt a difference between the 2.
5) No idea. The ratio we do sometimes refer to would be the ascending aorta and descending aorta. The descending aorta is smaller then the ascending aorta because it contains less blood after the branches from the aorta that go to the head come off. The ratio of ascending to descending aorta should normally be about 3:2 but the descending aorta can become relatively larger with age in comparison to the ascending.
6) They are the same for the general population.
Good luck. There is really no way a Dr. can know what is normal for you. Watch it, and if it doesn't get larger, you could be perfectly fine.
I know EXACTLY what you are going through. We were going to go to Cleveland Clinic last summer to see someone who specialized in this. But, a person would have to be God to know what really is normal for a person. Doctors have their general guidelines, but there are occasions where normal is above 3.7.
Seriously, read the research and you will feel a whole lot better. But, you will not really know until you have stayed at 4.0 for a long time with no change. I'm no Dr., but I've been to numerous Marfan conferences while we thought my husband had Marfan. He spent TEN years of his life thinking he had Marfan, when he just had a larger aorta than what most people have, but it is normal for him.
How old are you and how did you discover your aorta size??
If 3.7 is the high end of normal, 2cm more at age 52 is NOT that big of a deal. If you do not have any characteristics of Marfan, or if aortic dilitation/dissection doesn't run in you family, I really believe you are worrying about nothing.
If your valve is fine and you don't have symptoms, you are probably normal. If you are concerned, have your Dr. put you on a low dose of beta blocker, to keep your BP low. And, avoid heavy lifting. If you have high blood pressure or use cocaine, this could also cause the aorta to enlarge.
My husband is 53 and has had the same measurement for over 10 years!! If they are telling you the root is 3.9, that is where it is at the ascending aorta, on the way to the arch. There, the high end normal number is 3.7. You are very close---don't worry!! I believe that part is valsalva.
This is when people should worry.....when it gets to 5.0!! And even then, a few years back, they wouldn't consider doing surgery until 5.5-6cm. You will be long gone before yours gets to that point!
smitty70, if your ascending aorta is at 6.2 cm, according to everything I have read (I'm no doctor), you are at high risk for aortic dissection. I'm certain your cardiologist knows this and will advise you appropriately. If surgery is indicated, make certain you get a surgeon with a great deal of experience in aortic aneurysm repair. Cleveland Clinic is a good place to start.