We know that restrictions in veins are hard to stretch open. It is essential to use a balloon that is large enough compared to the patient’s veins. Also, the balloon has to be inflated for long enough to give the tissue enough time to stretch open. Moreover, you must be able to apply enough pressure to the balloon to allow sufficient force to be developed to break the fibres that are causing the narrowing or deformation.
The average diameter of the jugular vein is 12 to 14 mm. The pressure needed to force open a restriction in a vessel can easily reach 10 to 14 atmospheres. These are very high pressures, for which it is essential to have a balloon that retains its own diameter and does not burst at these pressures.
Images too, including the final results.
1. Contrast injected into the vessel flows away via collaterals; limited narrowing but probably the valve system is not opening completely
2. Balloon with a dent where the restriction is
3. Balloon completely opened out; here this was at 14 atmospheres
4. Follow-up image after use of the balloon: good drainage of contrast back to the heart; vessel is wide open.
In practice, during the inflation of a well-chosen balloon, you see that it inflates first in front of and behind the deficit. By well-chosen, I mean its diameter compared to the vessel. A dent remains in the balloon at the position of the narrowing or stenosis. Then the pressure in the balloon is increased until this dent disappears (usually 12 to 14 atmospheres, and sometimes more). Next you look at the pressure meter you used to inflate the balloon, and you usually see some pressure drop happening as a few more fibres part. Then you apply a little more pressure back to that where the balloon became fully open. Finally you maintain this for a minute or two until the situation is stable without pressure drop.
Contrasting with Dr. Sclafani's methods, Dr. De Letter is keeping the balloon inflated for a few minutes. Dr. Sclafani keeps the inflation duration short.
Dr. De Letter centers the balloon over the stenosis. Dr. Sclafani places the shoulder of the balloon at the healthy vein just past the stenosis.
Dr. De Letter says that his usual atm is 12 -14 and sometimes more. Not sure what Dr. Sclafani's usual is but he too uses the high pressure balloons that are the main point of what Dr. De Letter is discussing.
There are of course other differences such as the use of IVUS to measure precisely the size of the vein. I am also not sure about the part where the pressure drops in the balloon, because the stenosis gave way, so Dr. De Letter increases the pressure to where it had been at.
I prefer Dr. Sclafani's methods because of the higher priority to minimizing damage to the veins. We saw too many occlusions and complications last fall, now suspected to be due to aggressive ballooning. (And even one is one too many. Impossible standard but still.)
I like that Dr. De Letter has laid out the images and explained his procedure so clearly. The differences that I point out are up for debate as to what is right and what is less right.
Dr. De Letter also focuses on the importance of a well-chosen balloon. This is indeed important.