Patency and Durability of Stent Grafts Placed in the Dialysis Circuit Cannulation Zone J Vasc Interv Radiol 2024 Jan;35(1):86-91. doi: 10.1016/j.jvir.2023.09.015. Epub 2023 Sep 23.
From the Department of Interventional Radiology, Shamir Medical Center (formerly Assaf Harofeh), Israel, Tel Aviv University, Tel
Currently, the use of SGs in the cannulation zone is considered off-label. In study ,40 pts, 26 AVA, 14 AVG. SGs placed residual stenosis, perforation, aneurysm, and thrombosis.
Retrospective, single-center study. Only Covera Vascular Covered Stents used
Mean follow-up was 332 days (range, 28–661 days). All SGs successfully cannulated for hemodialysis. No cases of stent fracture or stent infection were observed during follow-up. The primary-assisted patency was 89% (SD ± 5.2) and 78% (SD ± 7.6) at 6 and 12 months, respectively.
Can’t argue with the results. We should compare the primary and assisted patency at 6 months and 12 months with those of a regular AVG since functionally that is what placing a stent graft in the cannulation area does.
Providing a photo of stent graft course with a line on the skin.to dialysis team is important. ___________________
Catheter Clamp over Hydrophilic Guide Wire Central Venous Catheter Exchange Technique for Air Embolism Prophylaxis in an In Vitro Model. J Vasc Interv Radiol 2024; 35:122–126. https://doi.org/10.1016/j.jvir.2023.09.007
I do believe in having ex vivo models to study such phenomenon. “ With −7 mm of pressure applied by the wall vacuum, a mean of 48.0 mL (SD 9.3) of air was introduced with open exchange and a mean of 20.6 mL (SD 4.7) of air was introduced with closed exchange. With −11 mm Hg of pressure applied to the model, 97.8 mL (SD 11.9) of air was introduced with open exchange and 37.8 mL (SD 6.3) with closed”.
Air embolism is rare but when it occurs. can be lethal The literature suggest that about 200-500 ml or more of air has to enter the venous system but the amount is a function of position and the rate at which it enter. 300 to 500 mL of gas introduced at a rate of 100 mL/sec can be acutely fatal for human, Other factors such as state of hydration (volume) can effect venous pressure (which can n become negative) and influence rate of air entry .
Per UpToDate , small amounts of air can be removed from the pulmonary vascular bed by gas diffusion across the arteriolar wall and into the alveolar spaces. However, the capacity of the lung to remove gas is limited to 50 mL or so, so larger amount can produce pulmonary outflow tract obstruction. Venous air embolism is a serious and under-recognized complication associated with the insertion of central venous catheters [11,45-47], hemodialysis catheters [48,49], pulmonary artery catheters [50], and with intravenous injections, particularly contrast injection [51,52].
What is the consensus about the differences in air volume entering the “venous system, ie 48 vs 20 ml for -7 mm , and 98 vs 38 at -11 mm Hg. Second how long doe it take to exchange the catheter over a guywire, , certainly not 1 second, The loner the period the more air can enter, However the ability of the “lung to remove air” is not present in the experimental set up.
Just my thoughts. Other opinions welcome At this point of my career, I have not placed a catheter in over 12 years. Technology changes