What Nephrologists Need to Know About VasQ
What is the ideal access for haemodialysis?
AVFs are the preferred options for dialysis access with lower complication rates, more established longevity, and lower overall costs than prosthetic AV grafts or central venous catheters. The Fistula First initiative in the US has resulted in a significant increase in AVF prevalence, although it has also uncovered a high early fistula failure rate largely as a result of non-maturation.
Although native AVFs have a low rate of complications and improved longevity of use when functional, they suffer from relatively poor early patency rates with more than half being unsuitable for dialysis use after one year.
An inability to increase inflow often results from perianastomotic stenosis and venous neointimal hyperplasia, which are both related to endothelial and smooth muscle cell activation in the area of the anastomosis and are capable of inducing AVF stenosis.
Turbulent flow has been identified as a driver for neointimal hyperplasia and as a cause of stenosis. However, it has been suggested that a laminar flow could be protective and could serve as a predictor for successful maturation in a newly formed AVF.
The ideal access for haemodialysis should deliver a sustained flow rate sufficient for long-term utilisation along with a low rate of significant complications and minimal requirement for assistance and should be designed to maintain maturation and patency.
Information for nephrologists: About the VasQ device
The VasQ is a nitinol implant, externally surrounding and supporting the vein and artery near the junction site without being in contact with the blood flow. It is an innovative device which attempts to address the root causes of AVF failure by minimising flow disturbances around the area of the anastomosis. This device targets the two main fistula failure mechanisms; namely, turbulent flow around the area of connection and increased venous wall tension which results from arterial circulation conditions.
The VasQ implantation procedure is seamlessly integrated into a standard end-to-side fistula procedure and does not affect ongoing surgical practice.
A preliminary study has shown the device:
- To be safe — with no documented device-related adverse events or SAEs.
- To have good unassisted maturation rates at 1, 3, and 6 months.
- To have high primary patency rates and high mean access flow rates.
These early results may promise the VasQ implant’s good performance in the future.
How does the VasQ device work?
Although the factors involved in maturation are currently unclear, it would appear that the greatest increase in patent access flow occurs close after AVF construction and depends on optimal haemodynamics.
Some remodelling is necessary in order to accommodate a markedly increased flow resulting from the arteriovenous anastomosis.
The aim of the VasQ is to target those perianastomotic areas prone to the development of neointimal hyperplasia. The use of external supports is expected to positively influence early failure rates which are often due to juxta-anastomotic stenosis in brachiocephalic fistulas.
In this respect, VasQ has proved efficient with promising results, and this influences local haemodynamics and the geometry of the anastomosis in brachiocephalic AVFs.
However, more extensive and longer-term studies are required in order to confirm these early encouraging results. Read more >>>