LOOKING FOR PARAMETER for aneurysm Repairthat was posted on the site

[heartman77]

HI all....someone a while back posted the parameters for when it is appropriate to repair and aortic aneurysm, partly based on a persons height and size of the aneurysm.
There were also a few examples given using people of different heights and other circumstances. Anyone know where i could find that? I tried a search but could not come up with it. Thanks all......

 

[Lynlw]

I searched this forum for formula and found a couple i'll give the link and 1st post of the thread if that helps
http://www.valvereplacement.org/for...ze-Body-Surface-Calculation&highlight=formula
What about the Aortic Size / Body Surface Calculation?

I have read about the Aortic Size/Body Surface calculation. I saw it mentioned in this article (http://emedicine.medscape.com/article/424904-overview). Going by my height and weight 6'4'' roughly 195 lbs, my body surface is calulated at 2.19 m2. 4.9 cm/2.19 is only 2.24 on that and according to that article this translates into a low risk. "In addition, relative aortic size in relation to body surface area may be more important than absolute aortic size in predicting complications. Using the aortic size index of aneurysm size divided by body surface area, patients are stratified into 3 groups: less than 2.75 cm/m2 are at low risk (4%/y), 2.75-4.24 cm/m2 are moderate risk (8%/y), and greater than 4.24cm/m2 are high risk for rupture (20%/y)."

Any thoughts on using that sort of calculation vs. absolute size?

http://www.valvereplacement.org/for...AV-Aneurysm-Surgery-Forumla&highlight=formula

I've been trying to find this formula for a while now.

An aorta that is enlarged and forming an aneurysm can be repaired, but at Cleveland Clinic we more often replace the damaged section with a section of plastic tubing that is sewn into position. The timing for repair of an aortic aneurysm is critical. When the valve is faulty and the aorta has enlarged to greater than 4.5 cm, we repair the aorta at the same time we repair or replace the valve. If the aorta has enlarged but the valve is still good, the optimal time to repair the aorta varies. At Cleveland Clinic, we have developed a special mathematical formula we use to determine this, based on the patient’s height and weight and the size of the aorta - surgery is usually recommended when the aortic cross sectional area in square centimeters, divided by the patient's height in meters is more than 10.
Source: http://my.clevelandclinic.org/heart/...e_disease.aspx

If I understand this correctly and my calculations are correct, here are two examples:

I am 6'5" tall, which is 1.96 meters. Currently my ascending aorta is at 4.5 cm diameter, which calculates to a cross sectional area of 15.9 cm2. 15.9 divided by 1.96 = 8.1 which is less than 10, not time yet for surgery.

If and when my ascending aorta reaches 5.0 cm in diameter it will then have a cross sectional area of 19.6 cm2. 19.6 divided by 1.96 = 10, which is the recommended trip point for surgery on my aorta.

I'm a taller than average person. Based on a person that is, say 5'10 inches tall, the calculations are different. A person that height will have a calculated formula factor of 8.9 when her aneurysm is at 4.5, still not yet time for surgery. However, when her aneuysm reaches 4.7 cm, her formula factor rises to 9.8, and when the aneurysm is 4.8 cm across, her forumla factor is then 10.2, and surgery would be recommended according to the Cleveland Clinic formula.


there also was this thread talking about the CCf formula http://www.valvereplacement.org/for...ula-Can-someone-help-please&highlight=formula

 

[mecretired]

Heartman--haven't heard from you in quite some time. Do you have an aortic aneurysm that may need surgery? Can't help you with a size formula as my ascending aorta was 5.4 when they found I had an aneurysm. Mary

 

[Greg a]

I searched this forum for formula and found a couple i'll give the link and 1st post of the thread if that helps
http://www.valvereplacement.org/for...ze-Body-Surface-Calculation&highlight=formula
What about the Aortic Size / Body Surface Calculation?

I have read about the Aortic Size/Body Surface calculation. I saw it mentioned in this article (http://emedicine.medscape.com/article/424904-overview). Going by my height and weight 6'4'' roughly 195 lbs, my body surface is calulated at 2.19 m2. 4.9 cm/2.19 is only 2.24 on that and according to that article this translates into a low risk. "In addition, relative aortic size in relation to body surface area may be more important than absolute aortic size in predicting complications. Using the aortic size index of aneurysm size divided by body surface area, patients are stratified into 3 groups: less than 2.75 cm/m2 are at low risk (4%/y), 2.75-4.24 cm/m2 are moderate risk (8%/y), and greater than 4.24cm/m2 are high risk for rupture (20%/y)."

Any thoughts on using that sort of calculation vs. absolute size?

http://www.valvereplacement.org/for...AV-Aneurysm-Surgery-Forumla&highlight=formula

I've been trying to find this formula for a while now.

An aorta that is enlarged and forming an aneurysm can be repaired, but at Cleveland Clinic we more often replace the damaged section with a section of plastic tubing that is sewn into position. The timing for repair of an aortic aneurysm is critical. When the valve is faulty and the aorta has enlarged to greater than 4.5 cm, we repair the aorta at the same time we repair or replace the valve. If the aorta has enlarged but the valve is still good, the optimal time to repair the aorta varies. At Cleveland Clinic, we have developed a special mathematical formula we use to determine this, based on the patient’s height and weight and the size of the aorta - surgery is usually recommended when the aortic cross sectional area in square centimeters, divided by the patient's height in meters is more than 10.
Source: http://my.clevelandclinic.org/heart/...e_disease.aspx

If I understand this correctly and my calculations are correct, here are two examples:

I am 6'5" tall, which is 1.96 meters. Currently my ascending aorta is at 4.5 cm diameter, which calculates to a cross sectional area of 15.9 cm2. 15.9 divided by 1.96 = 8.1 which is less than 10, not time yet for surgery.

If and when my ascending aorta reaches 5.0 cm in diameter it will then have a cross sectional area of 19.6 cm2. 19.6 divided by 1.96 = 10, which is the recommended trip point for surgery on my aorta.

I'm a taller than average person. Based on a person that is, say 5'10 inches tall, the calculations are different. A person that height will have a calculated formula factor of 8.9 when her aneurysm is at 4.5, still not yet time for surgery. However, when her aneuysm reaches 4.7 cm, her formula factor rises to 9.8, and when the aneurysm is 4.8 cm across, her forumla factor is then 10.2, and surgery would be recommended according to the Cleveland Clinic formula.


there also was this thread talking about the CCf formula http://www.valvereplacement.org/for...ula-Can-someone-help-please&highlight=formula

Heartman joined in 2010 and the first link was 2009 I think you NAILED it with links two and three good call Lyn

 

[normofthenorth]

The general principle -- that a 5cm-diameter AR may be fine for a huge person, but scary huge for a tiny person -- makes perfect sense, as does the desire to compensate for body size when judging possibly excessive AR size. But the two formulas I see in Lynn's posts are VERY different, and neither one seems "obviously logical" to me. The first -- dividing AR diameter by (est'd) body surface area -- finds a ratio between a linear measurement (in cm) and a "second-order" area (in cms SQUARED). Assuming they chose the constants so it seems reasonable at "average" body size (surface area), I'd expect it to be on the alarmist side for small people and on the falsely reassuring side for big people.

IOW, it seems to me that assuming we're all roughly the same shape, while we differ a lot in size, is closer to the truth than most competing assumptions (including the assumption that's embedded in that formula, and in the other one). If that's true, then a person who's twice as big in every dimension (height, width, and depth) than another person, would be expected to have an Aortic Root that's also twice as big in every dimension, including the diameter that's being measured. But that "twice as big in every dimension" person will have FOUR TIMES the surface area as the other person, so an AR that's only TWICE as big would seem small in that formula. And conversely, a person who's HALF as big in every dimension including AR diameter, would always need emergency surgery for a (non-existent) aneurysm.

The second formula Lynn found, from Cleveland Clinic, seems to divide the AR area by the patient's height. (The text also mentions the patient's weight, but when the formula is presented, there's no mention of weight.) That formula seems to vary from my simplified assumption in the opposite direction -- it divides a second-order AR AREA (in cm SQUARED) by a simple first-order linear measurement (in m), height. If their target numbers are reasonable for a person of average height, then I'd expect them to be rushing big guys under the knife, and leaving small people (kids and women?) to "ripen", maybe until they rupture.

I can see an argument for a different simplification than mine above (that we're all roughly the same shape): Assuming that our "normal" Aorta size is optimized for the flow of blood we need to nourish our body's tissues, with identical blood flow rates through our Aortas (e.g., in cms/minute), then our AR areas should normally vary with our body weights, or roughly as the CUBE of our height. If it started with body height, that would lead to a formula that divides AR diameter SQUARED by body height CUBED, as the best way to compensate and decide whose AR is "scary big". Or it could just compare AR area with body weight -- though I doubt that anorexics or obese people experience changing AR size to compensate for their weight loss/gain, so starting with height might be a better idea.

Of the two, the CC formula (at least as stated in Lyn's clip) seems the nuttier. Of course, I'm criticizing some fancy folks here, so I may be missing something. E.g., CC might include weight in their formula after all. . . But for sure BOTH these formulas can't make sense, except in the middle of the range.

 

[heartman77]

Lynn...that was the post i had seen.....Thanks so much......i had saved it to a text file on ome of my computers but lost it when that particular computer crashed and had to be reformatted......thanks again so much....I really appreciate it.........Warm Hugs.........Michael

 

[camgough]

I am 30 yrs, 6 foot and 195 lbs. My ascending aneurysm was 6.7 cm when it was found (bicuspid aorta valve). 6 weeks later had valve sparing aortic root replacement surgery with a Dacron graft, then 3 weeks later a Medtronic pacemaker. Heart block post op, but happy to be alive!