BAV does NOT mean a systemic connective tissue disease

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PathFinder

Well-known member
Joined
Dec 5, 2006
Messages
165
Location
Bulgaria
I have not written for a long, but today I wanted to see how is it going here, and looking to the new forum-part BAV and CTD, I decided to put this thread.

OK, bicuspid aortic valve is a congenital defect of the aortic valve. Logicaly, we can not expect how a defect will be localized to a isolated area of tissue, which is the same as structure as the entite thoracic aorta. That's why, it is not so surprisingly, that the transverse aorta is affected by the congenital defect.

There are some speculations about, whther there is a disruption of the haemodynamics during embryonal period, leading to disseparation of the leaflets of the valve. This defective form, leads to constant vibrations causing disfunction of the endothelium of the aortic wall and respectively destruction of the wall structures. The outcomes are aneurysms and dilations. Some trials have proved the potencial of this theory.

However, there are to many signs of pathological status of the aortic ascendence, root and arch. Something more - there are many evidences of aneurysms of some arteries in the nech and head in patients with BAV. And finally - there is already a prooved defficiency of microfibril Fibrillin-1 in the aorta and the pulmonary artery of the BAV patients. In conclusion, these facts show us a realtion to a serious connective tissue disorder at histological and molecular level.

Here I nees to make some remarks of what I have read after my surgery:

- Fibrillin is a major component of the extracellular matrix in the great arteries. Its mutations causes the aneurysmal formation in the Marfan disease. Studies already showed the deficiency of Fibrillin in the BAVs. But many aothors suggest, that it is only defficient in the great arteries, not mutant. This defficiency may be caused by other factors, like alterations of the signaling pathways, encoding the gene FBN-1, encoding the major proteine.

- If there is a Fibrillin defficiency, why the BAV patients don't show another signs of systemic connective tissue disease in general? Because the defficiency is suspected to be systemic only for a area of the body - this area is shown to be the arteries of the outflow track (aorta and pulmonary artery) and the great and some more specificaly arteries in the neck and the head (but only in some subjects).

- The last suggests a system, responsible for that area of defective development by the bAVs. And this is the neural crest. The cardiac neural crest, which is an organ functioning in the embryons, delivers the cells migrating and forming the aortic valve commissures, root, make the separations of the aorta with the pulmonary artery, forms the endothelium of these arteries, the aortic arch with its branches and forms the muscular and sometimes occular arteries in the neck abd head.
Trials with removal of the neural crest from the embryo, shows 100% cardiac defects as patent ductus arteriosus (seen in some BAVs), aortic misdevelopment, arch misdevelopment and variety of head/neck maldevelopments.

This led the scientists to investigate the possible role of the neural crest in the BAV disease. This investigations are particular to the aortic coarctation (disease 50% - 70% accompanied by BAV) where are sometimes seen thyroid diseases and common arterial dissectins or aneurysms in the brain (very common 10-15% of cases). May be some more serious defect in the neural crest is responsible to the coarctation phenotype of the aortic pathology with thyroidal, parathyroidal and neck diseases (all of which are related to the neural crest).

This partly explanes why there is connective tissue disorder, but generally "localized" to the great arteries above the heart.

- eNOS, or endothelial nytric oxide synthase. Major factor in cardiac development. Trials with defficiency of eNOS in mice shows something revolutionary in searching the culprite gene. For first time, there are seen mice with bicuspid aortic valve. Some other gene defects may cause ventrucular or other septal defects, but the most important facts, is the appearance of a BAV in mice, lacking eNOS. You all, guys see what shall I say as a cosequence - all the mice with BAV develope aneurysms.

Of great interest it will be for us, if I add something interesting here. Variations of the eNOS genes cause occular migraines, seen in may be half of the BAV patients...

***

If you let me comment other discussions I have read, I will put some thoughts.

There is arising evidence of the heritable nature of many BAVs. More than 10%-35% of the cases show familial clustering.

HOWEVER, almost all the great investigators of the BAV reach the conclusion, that BAV may have many different causes, of many different genes, giving to the disease many different phenotypes.

Some autopsies of BAV patinents show no evidence of regurgitation or stenosis in people 90 years and beyound. There are seen asymptomatic cases of BAV in people over 100 years old!

So, there are heterogenous phenotypes. The BAV isn't even always the same - there are different types of fusion of the commissures (right and left; right and noncoronary; left and noncoronary; no raphes in the three cases; raphes in the three cases). This account of at least 5 phenotypes only in the BAV type. What may we say then about the aortic phenotypes. Many develope proximal aortic dilation; many have dilated root and normal aorta; many have "all-iclusive" program; many do not anything at all. Some develope stenosis, some regurgitation, some don't even have echocardiographic evidence of haemodynamic alteration!

Some BAV are related to Connective tissue diseases of autosomal dominant penetrance, as Marfan, Ehler Dahnlos, Turner syndromes. This is may be a consequence of the influence of these systemic disorders to a list of genes, potentialy encoding the process of forming the BAV (5-10%in the Marfan; 5-10% in EDS; 85-90% in Turner).

some other BAVs are replaced in totally healthy sportists, like Schwarzenegger or Kanu. The first is the greatest bodybuilder ever, the second became a soccer player of the world for the year over ten years ago - and that was after a BAV repair in USA... Does they look like persons with connective tissue disease? No. They just have one of the great variety of bAV phenotypes. Kanu is still a professional player in first league, despite his old age. Schwarzenegger has a familial occurence of BAV - his father and brother have it.

In talking about connective tissue diseases, a study in 2007 compared mitral valve prolapse persons with BAV persons for Body Mass Index. While the MVPs showed independently relation to very low BMI, the BAV persons didn't show any evidence of relation to some kind of heterogenous BMI.

Plus - Some cardiac defects are seen in BAVs, but the percentage is small and usually they are free of cardiac issues, except for those, caused by valve dysfunction.



Ok. that's from me now, thank you for reading my thread.
 
That was very interesting, thanks! I had (I do love that word, had) a BAV and no other problems beyond the advanced stenosis that was choking it. My arch and root were (and still are after 2 years) fine.

I wonder if they will someday find that valve defects are actually fairly common....like near-sightedness! I guess we'll have to echo the whole population to see. It would be intersting if whomever makes these latest, fancy machines might choose a suburb or small town and just echo everyone and start some statitstics like that.

BTW. I don't know how often you are checking in, but please catch up on a fairly new member, AaronJ. He is your age and facing AVR and is pretty keen on getting a lot of good information prior to his surgery. He has just learned a lot more about his condition, and I know he would value some exchange with someone his age who has been through this.

Stop in more often!

:D Marguerite
 
Hello Pathfinder--Thanks for all the interesting information. A quick question... When you were talking about connective tissue disorders related to BAV, you mentioned Marfan as being 5-10%. Does this mean that 5-10% of people with Marfan have a BAV? I'm very interested if and how BAV and Marfan are related and haven't found much in my internet searches. My son has many of the Marfan characteristics--will find out in Sept. at the geneticist followup if there are enough now to constitute a Marfan diagnosis. Really wondering to what extent BAV and Marfan go together--could be coincidental since BAV is the most common heart defect, as you say often found in the general healthy population. A percentage of people with Marfan will be bound to have it... Wish I was a geneticist! I'd love to hear where the 5-10% number came from. Thanks and glad you are doing well!
 
To Francie12

To Francie12

Yes, there is some percentage of Marfan patients, who suffer the BAV defect along with the other craps :( And this additionally suggest the variativity of the genes, responsible for formation of a BAV. A systemic connective tossie disease has a greater chance to involve defects of such genes, as compared to the general population. That's why Marfans, Ehler Dahnlos, Turner and other autosomal dominant disorders have some percent of relation to BAV, variating from 5-10% by Marfan and EDS, through 50-75% by coarctation, to 85% by Turner syndrome (which is entirely female disease, becouse of its chromosome penetrance). These percents are much much greater, than that seen in the general population. As for the percent of the BAV patients, who suffer prooved connective tissue diseases: over 7% of BAVs have coarctation; and very less than 1% of them have classical CTD (BAV is found approx. in 200 perons of 10 000, and Marfan, EDS and others are found in 1-2 persons in 10 000). However a little percentage of the BAVs have some other symptoms of CTD, which don't cover all the points for diagnosing a known syndrome. They may be well related to some of the factors I mentioned above.

Again - BAV shows many signs leading to the conclusion, that many different genes and proteines are responsible for the defect. It suggests a strong heterogeneity, with variety of phenotypes, penetrance (inheritance) and even each BAV may be an sign of very diferent pathogenesis and morphology.
 
for the Turner syndrome

for the Turner syndrome

The 85%, which I mentioned in the Turner disease is for BAV or coarctation or another cardiac malformations. May be half of them, or 40% will be for the presence of BAV at all. There is no clear estimation how many of them will have BAV, because of the variation in studies (from 14% to 50%).
 
sorry dude but I'm thinking BAV is definitely systemic. Of course there's varying levels of systemic effects, just like there is with a cold/flu. That's just my two cents here.

I guess as long as I'm just shouting out anectdotes, why not mention myself: I have eye problems, my right arm and hip pop out of the socket pretty randomly, I have rosacea (which is effected by blood vessels), hypertension... I just don't think it stays in the aorta.
 
Degrees of genetic abnormalities?

Degrees of genetic abnormalities?

I found your post very interesting, Ivo. I've noticed in your other posts that you apparently closely research your information.

Your post and the replies reminded me of a brief experience I had last week. I was in a large store with a small cafe within the store and the girl running the cafe had Downs Syndrome but she was obviously only mildly affected, for lack of a more correct or knowledgeable way of expressing it, and she seemed quite capable of doing her job correctly; I saw no supervisor. It reminded me that there are great varying degrees within that disorder.

It thus makes sense to me that many genetic abnormalities (including bicuspid issues) also may have different degrees of and/or within the disorder; that is my opinion.

Different causes seems possible to me also. I only know a bit about cleft palates but they have different degrees and apparently have different causes also.
 
about sources

about sources

Google is you ONLY source? Interesting information, but, I'd hope for better references.
Google id the tool, medical sites are the job.

As to the opinion of AaronJ,
If you read my thread again, you will see the paragraph about the Febrillin-1 defficiency. Trials demonstrate, that lack of that proteine does NOT occur only in the aorta, but also in the main pulmonary artery. This suggest a systemic defficiency, respectively a systemic connective tissue disorder. However, there are two types of "systemic" diseases: those, which involve the entire body with all the organs and systems and the other type is "systemic" disease, which is not localized to one organ, system or area, but involve more ones and is systemic for those specifical organs and systems.

And again, there are ofcourse cases of more serious and widely affective connective tissue defects by patints with BAV. However, if you read the largest sudies of Bicuspid aortic valve disease you will see some interesting facts:

-BAV is not associated with any specifical body habbitus, or mass index, or anything (in general) - all the systemic CTD are associated with habbitus deformation.

-There is NOOOOO statistical difference in the general blood pressure of the BAV patients and normal population! I have read so many studies and NONE of them shows any statistical difference.

-BAV is statisticaly NOT affected of occular problems, such as myopia. If there are many patients with BAV who are nearsighted, I will personaly count 10 000 healthy persons and will compare the percentage of myopic people in that population, with that seen in BAVs.

-BAV DOESN'T show affected skin fibroblasts or any other histological abnormalities, related to Fibrillin defficiency, as seen in Marfan, despite its prooved defficiency in the general BAV aorta. The same thing is observed about the collagen or other proteines.

And finally,
Don't associate everything, happening to your body to a systemic connective tissue disease!!! I will give one last example: striae distensae or stretch marks are associated with all kinds of connective tissue diseases. I wanted to see how many of my friends have it - the answer is 45 from 47......... Then I checked the largest study of occurance of stretch marks in the population. It is made by a South Korean Medical institute (or something), and the results were surprising: 88% of the teenage boys have stretch marks and 80% of the girls. What, do they all have CTD? :D
 
In regards to Arnold Schwarzenegger, his first Ross didn't work because the surgeon didn't recognize that the bicuspid valve was part of the larger connective tissue disease. The second surgeon did and changed how the replacement was performed.

This information came from Dr. Paul Stelzer, who now uses the information gained in assessing patients for the likelihood of success with the Ross procedure.

Scoliosis is mentioned as related to BAV, and it has held true in my family. My uncle, who died from aortic stenosis, had a severe case of it throughout his adult life.
 
Actually, if you use scholar.google, you get all the scientific articles, and they are very good.

It's kind of funny being quoted twice on this comment :eek:. It wasn't really meant to mean much, which I tried to convey with the smilies :p;). I was teasing Pathfinder; Google is a search engine, not really a source. Apparently you can get to the sources that way. I'm not much on reading scientific articles, nor do I typically use Google, so it was totally meant in a joking manner. I apologize for the misunderstanding.

Wise
 
You sound like you think information google obtains for you may not be reliable--like, say, Wikipedia. But google does not exist to provide information. Google is a search engine, which finds sites for you that MAY provide the information you need.

As with literature research since, probably, the ancient Greeks, no one but you can decide how much weight you give to a certain source. But that's true, whether google locates it for you on the internet or you schlep down to the brick-and-mortar library.
 
I think you need to consider the 2 types of BAV that I know of, those with apparent fused leaflets and those like mine that are true 2 leafets.
rckrzy1's comment is consistent with what I have learned. When I asked, my cardiologist (who teaches this stuff to medical students) told me in effect that the form of BAV with connective tissue disorder and the form of BAV without are not different degrees of the same disease, but are different diseases.

Of course there are wide variations in severity within each disease, but merely being more or less severe or having no apparent indicia of the connective tissue disease do not distinguish the two.

That's just what I heard.
 
rckrzy1's comment is consistent with what I have learned. When I asked, my cardiologist (who teaches this stuff to medical students) told me in effect that the form of BAV with connective tissue disorder and the form of BAV without are not different degrees of the same disease, but are different diseases.

Of course there are wide variations in severity within each disease, but merely being more or less severe or having no apparent indicia of the connective tissue disease do not distinguish the two.

That's just what I heard.
Very interesting! I recall Adam previously mentioning that some have fused leaflets and not actual genetically malformed bi-leaflets. That makes sense that the two situations could be different in their makeup, of course, particularly if the fusing develops over time.

So perhaps one group is less--or even not--likely to develop connective tissue issues?
 
So perhaps one group is less--or even not--likely to develop connective tissue issues?

If so, which is which? It's not intuitively obvious to me.
 
Thanks Ivo - from the small abstract

Thanks Ivo - from the small abstract

"RESULTS We identified three morphologies: Type 1, fusion of right and left coronary cusp (N=152); Type 2, right and non-coronary fusion (N=39); and Type 3, left and non-coronary fusion (N=1). Comparing Type 1 and 2 BAV, there were no significant differences in age, height, weight, blood pressure, or aortic valve function. Type 1 was more common in men (69 vs. 45%,). The aortic sinuses were larger in Type 1, while Type 2 had larger arch dimensions. Myxomatous mitral valves were more common in Type 2 BAV (13% vs. 2.6%, p < 0.05). Three aortic shapes were defined: normal (N), sinus effacement (E), and ascending dilation (A). Comparing Type 1 to Type 2 BAV, shape N was more common in Type 1 (60% vs 32%), and Type A was more common in Type 2 (35% vs 54%,), Type E was rare (p<0.01 across all groups).

CONCLUSION A comprehensive BAV phenotype includes aortic shape. Type 1 BAV is associated with male gender and normal aortic shape but a larger sinus diameter. Type 2 leaflet morphology is associated with ascending aorta dilation, larger arch dimensions and higher prevalence of myxomatous mitral valve disease."
 
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