vascular remodeling

A forum to discuss Chronic Cerebrospinal Venous Insufficiency and its relationship to Multiple Sclerosis.

vascular remodeling

Postby Cece » Fri Oct 28, 2011 11:49 am

http://circ.ahajournals.org/content/104/1/91.full
Although balloon angioplasty (percutaneous transluminal angioplasty, PTA) is a well-accepted method to reduce arterial stenosis, an important disadvantage of the method is the restenosis that develops in 30% to 50% of the patients.1 Although it has been accepted that intimal hyperplasia causes the restenosis,2 it recently became clear that restenosis after PTA is caused mainly by shrinkage of the vessel wall ("constrictive vascular remodeling").

Vascular remodeling has been observed in physiological conditions in response to changes in shear stress (SS), where it is aimed at restoring the original values of SS.3 Although it has been postulated that this mechanism is of importance in vascular remodeling after PTA, experimental data underlying this theory are currently lacking.1 This is of importance, because it has been shown that the endothelium plays an essential role in vascular remodeling.4 Immediately after PTA, the endothelium is disrupted and the regenerated endothelial layer is dysfunctional.5 Furthermore, because the vascular tissue is damaged after PTA, factors not involved in vascular remodeling during more physiological conditions might become of importance. Hence, the first question addressed in the present study was whether vascular remodeling after PTA is controlled by SS and if so, to which reference value the SS values will be restored during the remodeling process. To that end, we developed a method based on a combination of intravascular ultrasound (IVUS) and computational fluid dynamics that enables us to calculate regional SS over time.

The vessel wall responds to increments in blood pressure, at an unchanged flow, by increasing vessel wall thickness.6 The wall stresses (WS) calculated before and after these pressure elevations appear to be similar, implying that WS is normalized during these conditions. PTA increases local WS, and the constrictive vascular remodeling may be a consequence of WS normalization. Therefore, the second aim of the present study was to evaluate the existence of a WS feedback loop in constrictive vascular remodeling after PTA.

WS is wall stress, which can be determined using the LaPlace formula.
SS is shear stress.
The conclusion of the article was that both wall stress and shear stress control vascular remodeling after angioplasty.
I am not sure how to apply this but we do not want negative vascular remodeling reducing the size of our veins after angioplasty.
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Re: vascular remodeling

Postby Cece » Fri Oct 28, 2011 11:53 am

http://circ.ahajournals.org/content/99/1/30.full
The positive results obtained with probucol suggest that the restenosis process is associated with oxidative stress. The powerful antioxidant effects of probucol18 may have prevented endothelial dysfunction,19 LDL oxidation,20 and macrophage and metalloproteinase21 activation. This could have limited smooth muscle cell activation, migration, and proliferation; matrix degradation; and deposition of new collagen fibers. By ultimately limiting smooth muscle cell contraction, collagen formation and cross-linking, and endothelial dysfunction, probucol may have modified vascular remodeling and allowed greater vessel enlargement. Specific inhibition by probucol of the secretion of interleukin-122 may also have decreased secretion of metalloproteinases23 and modified matrix remodeling.

An article on the effect of probucol, a powerful antioxidant, in reducing restenosis possibly due to vascular remodeling.
What I take from this, for something we can do as patients, is that an endothelial health program may be of especial importance in the months following angioplasty.
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Re: vascular remodeling

Postby cheerleader » Fri Oct 28, 2011 1:12 pm

Cece wrote:An article on the effect of probucol, a powerful antioxidant, in reducing restenosis possibly due to vascular remodeling.
What I take from this, for something we can do as patients, is that an endothelial health program may be of especial importance in the months following angioplasty.


You're right...It really is important, Cece. Antioxidants are essential after treatment, but there's so much more. President Bill Clinton had a heart bypass surgery, and a leg vein was used in his surgery. The vein later suffered stenosis, and needed to be stented, then the stents became bent and occluded and he needed more angio. Clinton wanted to know, what could he do to keep that vein open and flowing? He consulted the top cardiac docs, and they recommended a program similar to the Endothelial Health Program.
C reactive protein levels are the key. High numbers indicate endothelial dysfunction. But there are ways to reduce this.

Here is Sanjay Gupta interviewing President Clinton---
http://www.cnn.com/2011/HEALTH/08/18/bi ... index.html

it's possible to keep vessels healthy and flowing, but it takes commitment to exercise, diet, nutrition and lifestyle. Wish there was one magic pill, but there isn't.
http://www.ccsvi.org/index.php/helping- ... ial-health
cheer
Husband dx RRMS 3/07
dx dual jugular vein stenosis (CCSVI) 4/09
http://ccsviinms.blogspot.com
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Re: vascular remodeling

Postby CureOrBust » Fri Oct 28, 2011 3:51 pm

would they hurry up and just make dissolve-able stents already! :!!
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Re: vascular remodeling

Postby Cece » Fri Oct 28, 2011 4:08 pm

Cure, I am apparently going to disagree with you on every thread, but it is nothing personal. :oops:

The dissolvable stents take 18 months to dissolve. All the complications we are seeing with stents are happening within the first 12 months. I can't see the benefit. If the stent is already occluded or grown over with intimal hyperplasia, it no longer can dissolve the way it was intended.
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Re: vascular remodeling

Postby CureOrBust » Fri Oct 28, 2011 5:53 pm

Cece wrote:Cure, I am apparently going to disagree with you on every thread, but it is nothing personal. :oops:
No, please disagree with me whenever you see I am wrong, or even think I MAY be wrong! I do a lot of speed reading here (followed by half thoughts), and have no medical training. I really believe and appreciate being corrected, and find i learn best when I first get it wrong; makes life that little harder, but easier knowing it to be true. I truly sense there is no malice. :X

Has there been any thought given to the ability to re-balloon an area still encased in a metal stent as opposed to a half dissolved, dissolvable stent? I would guess a broken/streatched metal stent in a vein could be more problematic than a stent that would eventually dissolve into the tissue? or could it help the vein be more patent?
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