very large study shows learning curve is at 400 patients

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

very large study shows learning curve is at 400 patients

Postby Cece » Wed Aug 14, 2013 12:39 pm

http://www.jvascsurg.org/inpress
Feasibility and safety of endovascular treatment for chronic cerebrospinal venous insufficiency in patients with multiple sclerosis

Tommaso Lupattelli, MD Giovanni Bellagamba, MD, Elena Righi, MD, Vincenzo Di Donna, MD, Isac Flaishman, MD, Rita Fazioli, MD, Francesco Garaci, MD, Paolo Onorati, MD
Received 8 January 2013; accepted 28 May 2013. published online 14 August 2013.

Objective
Chronic cerebrospinal venous insufficiency (CCSVI) is a recently discovered syndrome mainly due to stenoses of internal jugular (IJV) and/or azygos (AZ) veins. The present study retrospectively evaluates the feasibility and safety of endovascular treatment for CCSVI in a cohort of patients with multiple sclerosis (MS).

Methods
From September 2010 to October 2012, 1202 consecutive patients were admitted to undergo phlebograpy ± endovascular treatment for CCSVI. All the patients had previously been found positive at color Doppler sonography (CDS) for at least two Zamboni criteria for CCSVI and had a neurologist-confirmed diagnosis of MS. Only symptomatic MS were considered for treatment. Percutaneous transluminal angioplasty was carried out as an outpatient procedure at two different institutes. Primary procedures, regarded as the first balloon angioplasty ever performed for CCSVI, and secondary (reintervention) procedures, regarded as interventions performed after venous disease recurrence, were carried out in 86.5% (1037 of 1199) and 13.5% (162 of 1199) of patients, respectively. Procedural success and complications within 30 days were recorded.

Results
Phlebography followed by endovascular recanalization was carried out in 1999 patients consisting of 1219 interventions. Balloon angioplasty alone was performed in 1205 out of 1219 (98.9%) procedures, whereas additional stent placement was required in the remaining 14 procedures (1.1%) following unsuccessful attempts at AZ dilatation. No stents were ever implanted in the IJV. The feasibility rate was as high as 99.2% (1209 interventions). Major complications included one (0.1%) AZ rupture occurring during balloon dilatation and requiring blood transfusion, one (0.1%) severe bleeding in the groin requiring open surgery, two (0.2%) surgical openings of the common femoral vein to remove balloon fragments, and three (0.2%) left IJV thromboses. The overall major and minor complication rates at 30 days were 0.6% and 2.5%, respectively.

Conclusions
Endovascular treatment for CCSVI appears feasible and safe. However, a proper learning curve can dramatically lower the rate of adverse events. In our experience, the vast majority of complications occurred in the first 400 cases performed.

As patients, perhaps we should choose IRs who have treated over 400 patients?
That's not a guarantee of no complications but if it means a lower risk of complications, then that's good.
It would be nice also if clinical trials adopted the same standard and were run only by IRs with that sort of experience under their belt.

I wonder if the 14 azygous stents were necessary.
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Re: very large study shows learning curve is at 400 patients

Postby 1eye » Wed Aug 14, 2013 1:42 pm

I doubt anyone would stent a vein if it wasn't necessary. Dr. Zamboni's data covers the head outflow quite well. His measurements can be translated into pressure gradients if one uses a fixed value of viscosity and vein segment lengths. The azygus vein is still a big unknown. We haven't connected it with specific symptoms.

I think there may be some major rerouting of normal flows, brought on by both stenosis and reflux, which might even turn out to be a bigger problem than suspected, based on his diagrams. Maybe there is a steady state of reflux in some people in the prone position that is as bad or worse than stenoses.

Obviously, as is done in cardiac stenting and catheter investigations, a common practice must be assisting and observing, so that while a doctor is going through that curve, somebody else is calling the shots. It must be that way already for a lot of procedures. That way nobody gets used for target practice.

I think his paper shows heavy use of collateral veins in the prone position. Is the result a lot less smooth muscle control? I think D. Sclafani is limiting his ballooning to jugulars, at least in the neck. Maybe the less robust veins that are nature's afterthoughts get stretched to an unhealthy large diameter, worsening with time. Enough to give a body insomnia. Or sleep standing up.
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Re: very large study shows learning curve is at 400 patients

Postby Cece » Wed Aug 14, 2013 3:55 pm

additional stent placement was required in the remaining 14 procedures (1.1%) following unsuccessful attempts at AZ dilatation

Sometimes when a vein is dilated then goes right back to how it was, it's because it's not a true stenosis. Intravascular ultrasound would have clarified.

For no stents to have been used in the jugular veins in 1999 patients, probably there was error there too, and some patients would've met the criteria for stent placement if such standardized criteria were in use.

But it's a good article showing very very low number of complications in a high number of patients, and the author's conclusions reaffirm what we've been saying here about there being a learning curve when it comes to performing jugular and azygous angioplasty of these particular malformations.

What you describe in your last paragraph, 1eye, sounds like what I have: extra large emissary veins, extra large vertebral vein, extra large azygous vein, all in poor compensation for my previously blocked jugular veins. I don't sleep standing up but I sleep at an angle. :)
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Re: very large study shows learning curve is at 400 patients

Postby 1eye » Wed Aug 14, 2013 8:05 pm

In the CCSVI patient diagram (figure 2) of the Zamboni model study, the vertebral veins show 0 flow, and everything (or a lot of what is rerouted - more than either jugular had in the healthy patient) goes through Qc-p, the collateral flow. These veins have no valves. They are parallel to the jugulars, and somehow are getting a lot of the flow. I think Q12 on the right side is a lot of what is left after the stenosis gets in the way, reducing the right jugular down to QJ1=35. instead of 650. The left jugular seems to be smaller in this patient, so the reversed collateral flow at Q12 is a bit less. The main difference seems to be the rerouting to Qcp on the right, all the way up to 668. That must be stretching the collaterals a lot compared to the healthy patient. Something about these veins must be different, to cause illness. Maybe the endothelium has been stretched too thin.

But why 0 flow in the VVs? That must affect sugar and oxygen to the vertebrae... Reflux can't be a problem there, can it?

The healthy face seems to have more flow. That is reflected in the common result of the procedure, where faces have regained colour.
"Try - Just A Little Bit Harder" - Janis Joplin
CCSVI procedure Albany Aug 2010
'MS' is over - if you want it
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Re: very large study shows learning curve is at 400 patients

Postby 1eye » Thu Aug 15, 2013 5:31 am

Cece wrote:http://www.jvascsurg.org/inpress
...The feasibility rate was as high as 99.2% (1209 interventions). Major complications included one (0.1%) AZ rupture occurring during balloon dilatation and requiring blood transfusion, one (0.1%) severe bleeding in the groin requiring open surgery, two (0.2%) surgical openings of the common femoral vein to remove balloon fragments, and three (0.2%) left IJV thromboses. The overall major and minor complication rates at 30 days were 0.6% and 2.5%, respectively.

Conclusions
Endovascular treatment for CCSVI appears feasible and safe. However, a proper learning curve can dramatically lower the rate of adverse events. In our experience, the vast majority of complications occurred in the first 400 cases performed.

As patients, perhaps we should choose IRs who have treated over 400 patients?

That's not a guarantee of no complications but if it means a lower risk of complications, then that's good.

It would be nice also if clinical trials adopted the same standard and were run only by IRs with that sort of experience under their belt...

That's what I was getting at with the comment about assisting and observing: if we could get 400 patients' worth of experience without doing any procedures, that would be great. I think what this paper is concluding is that a "proper learning curve" is necessary and long. Doctors can expect a higher rate of complications in the first 400 procedures, so to avoid this, some mentor-ship must occur, at the expense of not performing solo work for that number of assists. Perhaps that is uncommon in an outpatient setting, but I don't see a way around it.

Perhaps what is needed is slow dilatation that can be done very gradually, over, time and using a series of increments of dilatation which includes many small changes. That can be done if a port-like "doorway" can be installed through which to insert the catheter on multiple separate visits. Problems might include keeping infection out, and wear and tear on major leg veins. My mother had such a device for her dialysis, but that was on a smaller scale, I think.

Anyway this is an important study because it looks like the first of its kind on this scale. The 1-month patency may be misleading, if there is a much higher rate of restenosis at say, 1 or 2 years. However, it seems very hopeful with the 1-month restenosis rate being as low as 13.5 %. These being veins, the dangers probably go up with the number of procedures, so it is critical to get it right the first time, without stents, avoiding the need for long-term drug therapy.

Stents in veins might be less successful than arterial ones. Those are nothing to write home about, either, I understand.
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CCSVI procedure Albany Aug 2010
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Re: very large study shows learning curve is at 400 patients

Postby Cece » Thu Aug 15, 2013 6:11 am

1eye wrote:That's what I was getting at with the comment about assisting and observing: if we could get 400 patients' worth of experience without doing any procedures, that would be great. I think what this paper is concluding is that a "proper learning curve" is necessary and long. Doctors can expect a higher rate of complications in the first 400 procedures, so to avoid this, some mentor-ship must occur, at the expense of not performing solo work for that number of assists. Perhaps that is uncommon in an outpatient setting, but I don't see a way around it.

A way around it: CCSVI being taught in medical school and treated in residency.
We're not there yet! :smile:
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