DrCumming wrote:drsclafani wrote:DrCumming wrote:
In this case, we had an excellent venographic and IVUS outcomes but ended up with an occluded vein.
So, was the residual stenosis with 10mm ok? Should this have been the end point? Or with the 12mm balloon should we have stopped at a lower pressure? When limiting balloon pressure to 10 ATM or less I have not seen any occlusions like this. Yet, I have also dilated many veins with > 20 ATM and had good outcome but more occlusions as well.
mike, i dont think it is the pressure that is the problem. it is using high pressures with a balloon too large. I average 13 ATM in the last 150 cases.
yes, this was a combination of too much pressure and too large of a balloon.
i typically have been limiting pressure to less than 6 atm. this case was the first time in probably 3 months of going over 15 atm.
for the sake of uniformity, i describe the dilatation based upon the diameter of the balloon. But, you know this, I use CSA measurements to select the balloon. Generally i have found that a balloon with a 50% increase in CSA compared to the vein is not a problem as the vein is compliant as flow increases and decreases the vein enlarges and shrinks.
I think that when you eliminating the waist of a valve problem with only 5 Atmospheres of pressure, you are using a balloon was too small.
my balloon selection is all high pressure balloons, so i have atlas and conquest balloons. I use 40 mm length because the shorter balloon often slips beyond the stenosis. My average pressure is over 13 atmospheres. When i first started, following the suggestions of Sinan to use large balloons, I had thromboses like everyone. I dont think it was the pressure, it was in mis-sizing the balloons. Sinan suggested using 18 mm for women and 22 mm for men, but once i started using this formula of 25-75% over CSA to select the balloon, The complications rate really dropped quite low. the only thromboses have been two patients who stopped their month of thrombin inhibitor and anti-platelet inhibition without discussing with me and two minor dissections that remained patent. That is in the last 100 patients. I find that acceptable.
I do not seem to be getting those two month recurrent symptoms now. Followup venography has shown most veins remain widely patent.
So to summarize my opinions
1. Large balloons are necessary because opening the valve requires it
2. high pressure is necessary because opening the valves requires it
3. Too large a balloon with high pressure results in excess injury to the vein wall, and may result in thrombosis
4. Too small a balloon will NOT open the valve completely and result in higher restenosis rates.
5. too low pressure will not open many of these stenoses. The choice is not a larger balloon but higher pressure with the proper sized balloon.
6. multiple inflation sometimes leads to opening the stenosis when one or two do not.
7. If you have to exceed burst pressure of the balloon, it is often better to concede and accept less than optimal results and bring patient back in three months or so. Often a second angioplasty succeeds at lower pressure
8. short term anticoagulation with antithrombin agent and antiplatelet agent is essential to avoid thromboses
I have always been disturbed by the illustrations shown by zamboni in his papers that show small balloon angioplasty and valves that never were completely opened. It just does not make sense to me to not open the valve. I really dont think that you can open the valves with low pressure. Effacing the waist in the balloon requires high pressure most of the time