tzootsi wrote:Hi Dr Sclafani,
What is your take on Dr. Moguel's report?
Dr Moguel wrote:The liberation treatment, consisting on balloon angioplasty of the three major veins draining the brain (both left jugulars and azygous), is frequently complicated by a new narrowing of the vein in the same segment that was previously dilated.
I don't agree that restenosis is frequent, although it certainly does occur. Re-stenosis of valvular stenosis does occur but restenoses are more likely of the vein itself, rather than the abnormal valve. There are some who say there are wandering stenoses, or recurrent stenoses in different locations. These likely represent venous injuries that most commonly can be avoided by selecting the correct size balloon, restricting dilatation to the area of the venous injury and limiting the time that the balloon is inflated to a few seconds.
Dr Moguel wrote:The restenosis is a usual common phenomenon after any kind of angioplasty on any kind of blood vessels; all vascular specialists are very familiar with it. This complication comes after the injury done in the vessel, followed by an exaggerated response from the body to heal it, creating a hard scar. It is very similar to the scarring that occurs after a surgery, where some patients can develop harder and prominent scars.
I agree that restenosis is common in arterial angioplasty but the key is that the intention of arterial angioplasty is to injure the artery. Most angioplasty is done on arteries and these REQUIRE an injury, tearing the intimal and media of the artery to accomplish widening of the artery at the leve of a plaque. Restenosis also occurs commonly in patients with end staged renal disease, which is the most common reason for venous angioplasty. Veins do not tolerate tears as well as arteries and that is why we see so many thromboses reported after venoplasty for dialysis vein stenoses . When there is adventitial injury or significant tearing of the vessel, thrombus forms and then neointima deposits. This results in fibrin scar and intimal hyperplasia. Once this occurs, we have developed a different type of stenosis than that usually seen in MS which is usually a valvular stenosis or a hypoplasia of the vein.
In my view, the key to reducing restenosis is to AVOID over-dilation of the vein at high pressures. Overdilation causes perforation of the thin walled vein, leading to external hemorrhage and scar formation. Dilating the valve to a reasonable size should not typically require overstretch of the vein to a point that results in perforation of the vein. THIS SHOULD BE AVOIDED.
Dr Moguel wrote:The angiographic restenosis is defined by, of course, an angiography that finally reveals that a new narrowing exists.
Restenosis requires that a stenosis be seen at the point of the prior stenosis. Stenosis at any other location is not restenosis, but an iatrogenic stenosis, typically caused by overstretch of the vein leading to tear.
Since the valve is the most common part of the vein that is injured, it is usually possible to dilated the valve stenosis without exceeding the normal compliance (dilation) of the vein wall itself. Sometimes the valve resists stretch, perhaps because the annulus of the valve is hyoplastic. I have learned the hard way that exceeding size and pressure tolerances in order to try to dilate a recalcitrant, resistant valve stenosis leads to wall tear, wall dissection, and subsequent thrombosis or "hard" stenosis of the adjacent vein wall. I think that a few less vigorous angioplasties spaced a few months apart will be safer and more effective. An alternative to consider is surgical venoplasty or valvulotomy
Dr Moguel wrote:Sometimes the angiography is not enough but a direct measurement can disclose the problem, such as direct pressure register or other image modality like ultrasound, magnetic resonance, computed tomography or optical coherence tomography.
Pressures are not particularly reliable. I would not rely upon MRV or CTV. ultrasound is a reasonable screen for stenosis. not sure what OCT shows in this case.
Dr Moguel wrote:At this time no one is able to know how frequent is the restenosis after a correction of a chronic cerebro-spinal venous insufficiency (CCSVI) because all patients are treated overseas with a lack of follow up by image tests, so there is only a rough estimate by the recurrence of the symptoms which has been called “clinical restenosis” in other well known vascular scenarios.
I agree with Dr Moguel. It is very frustrating to try to follow patients. However clinical symptoms are the most important reflection of restenosis. I think clinical outcome is more important than angiographic stenosis anyway. Symptom relief is the only thing that has convinced me to perform these treatments.
Dr Moguel wrote:Multiple sclerosis patients are looking for a repeated vein angioplasty (two, three or more times) but they face the following problems:
Possible hard tissue responsible for the restenosis. This causes a narrowing sometimes impossible to open even at the highest pressure that a balloon can get, leading sometimes to the balloon burst.
Restenosis on restenosis. The treatment of a restenosis has an even higher restenosis risk than the first treatment, creating a vicious circle.
I agree as long as we are talking about vein restenosis and not valvular restenosis. REstenosis resulting for venous tear, leads to scar formation and angioplasty of scar requires more tearing, more blood leakage and more scar AND MORE RESTENOSIS. . That is one of the major reason for recurrent stenoses seen in treating dialysis venous access. ANGIOPLASTY FOR VALVULAR STENOSIS IN MS IS NOT THE SAME as treatment of vein wall restenosis.
Dr Moguel wrote:The first problem requires many times the help of a special balloon that is armed with four surgical micro-blades attached to its longitudinal surface (Flextome, Boston Scientific). These micro-blades work while the balloon is fully inflated, as seen in the figure below. Through this endovascular microsurgery, this balloon is able to open the vessel with a minimal lesion and less pressure than is used with a conventional balloon.
The second problem (restenosis after restenosis) is a challenge because of its very high prevalence. It occurs as a result of an exaggerated response from the body, to the damage after the elongation of the tissues during balloon inflation. AT the present time the best tool to reduce this risk is based on the attachment of certain drugs in stents or balloons. These drugs are directed to reduce the cell replication that causes the restenosis.
i do not think that higher pressure increases risk of restenosis PROVIDED the balloon size necessary to expand the valves does not exceed the stretchability of the surrounding vein wall. Cutting balloons have been advocated by some. However cutting balloons lead to tear of the vein wall. My use of them stopped quickly after a couple of vein wall injuries that led to thrombosis. I am concerned that cutting balloons will ultimately be shown to be too damaging to the wall and necessarily lead to restenosis. Perhaps the use of drug eluding balloons will reduce this scar formation but I need to see some proof that they can reduce restenosis caused by cutting balloons before i use them. .
Dr Moguel wrote:
The actual better way of reducing restenosis without the use of stents are the medicated, also called drug eluting or drug delivering balloons that are capable of deploying the drug in the inner surface of the blood vessel. The actual drug is Paclitaxel, which is part of the treatment of several cancers but the dose in the balloon is very small so it is enough to act locally without any collateral systemic effect. The balloons that we use are Paclitaxel added (Freeway, Eurocor) and it can be consulted on the link http://www.eurocor.de/products/freeway_ ... formation/
An example taken from a patient with severe restenosis is shown below.
These balloons were made for restenosis of smaller arteries. How well they work in the jugular veins remains to be seen. I am looking forward to some reports that show efficacy. If I see that I would use them in patients with restenosis.
Dr Moguel wrote: Note in this figure how a severe restenosis is present in a left jugular vein, two years after a successful liberation treatment. The patient had important recovery but a year after she had recurrence of symptoms suggesting a clinical restenosis.
The new narrowing is pointed with the red arrow; a cutting 8x20mm (Flextome) balloon is inflated at low pressure, followed by a medicated 8x20mm balloon (Freeway) inflated at low pressure in the same site.
The vein is finally dilated with a 14x20mm non-compliant conventional balloon (Atlas, Bard products), showing a very good result.
The first attempt to dilate this vein using only the normal balloon was not successful even at a pressure of 20 atmospheres which is the highest that this balloon is capable to afford without bursting.
Unfortunately, I did not see the images. So I cannot comment on the nature of the restenosis or its cause. If there was extravasation on the post angioplasty images, I will expect recurrent stenosis. I can't predict the effectiveness if no perforation occured.
Dr Moguel wrote:This case exemplifies the complexity of the treatment for restenosis which is a challenge for every endovascular specialist and the hospital staff as well as the availability of different kinds of therapeutic tools that should include the cutting and the medicated balloons.
I agree with Dr Moguel that treatment of true restenosis of the vein wall will be very complicated. Repeat angioplasty for valvular stenosis is not a failure, but part of the natural history of some valvular stenosis. Non-valvular stenosis is often a complication of angioplasty and it will also require ongoing care to maintain benefits patients have. This is not failure. We replace the brake linings of our autos periodically, that does not make repairing brakes a failure.
We need to convince payors (I am convinced) that many patients derive symptomatic benefit from venoplasty and that these procedures are worthwhile. The stress of financial drains for repeated angioplasty should not be born by patients alone.