Associations between Hemodialysis Access Types and Clinical Outcomes: A Systematic Review
Hemodialysis: Facts and Data
Over 1.5 million people worldwide are treated with hemodialysis. Hemodialysis is marked by persistently high mortality, morbidity, and healthcare use. Effective hemodialysis requires repeated and reliable access to the bloodstream through a central venous catheter (required when the AV fistula or graft fails to sufficiently mature for dialysis or becomes occluded by thrombosis) or a surgically created AV communication.
AV fistula or AV graft for hemodialysis?
Clinical practice guidelines recommend an AV fistula as the preferred vascular access for hemodialysis, but quantitative associations between vascular access type and various clinical outcomes remain controversial. Low rates of fistula use have led to initiatives, such as Fistula First in the United States, which aim to achieve the clinical and organizational changes needed to increase fistula use.
Vascular access thrombosis and infection occur frequently, however, and are the leading cause of dialysis-related morbidity.
Association between types of vascular access (AV graft, fistula and central catheter) and the risks – a study review
This study included 62 cohort studies comprising over 500,000 participants. It evaluated the associations between different types of vascular access (AV fistula, AV graft, and central venous catheter) and the risks of death, infection, and major cardiovascular events.
The results showed that in comparison with people with AV fistulas, those using catheters or grafts ran a higher risk of all-cause mortality or fatal infections. Those with catheters were also at a higher risk of cardiovascular events. It must, however, be recalled that fistulas have a high risk of maturation failure, often require several interventions to attain suitability for hemodialysis, and are frequently impossible or not attempted in patients with a poor prognosis.
The data showed that people who are successful in the creation and use of a fistula have better clinical outcomes. Given, however, that approximately 40% of fistulas fail to attain maturity for dialysis and may require repetitive interventions to achieve function, any indiscriminate recommendation of fistula first may result in the inappropriate use of resources and services.
Can AV fistulas or AV grafts improve clinical outcomes?
Although data has suggested that a successful fistula or graft improves clinical outcomes, we could not identify specific patient characteristics that might predict smaller absolute benefits of a fistula over a graft or catheter. This therefore leaves the question open regarding who may or may not benefit from aggressive fistula promotion.
In summary, several important clinical outcomes are associated with the type of vascular access used for hemodialysis. The most adverse events have been observed in people using catheters, while the lowest risks have been observed in those using fistulas.
Future research should focus on defining the characteristics of patient populations in which there may be an uncertainty between different access options, including patients who do not achieve a functioning fistula.
VasQ for fistula failure
Our product VasQ™ is designed to overcome the aforementioned problems by improving maturation and patency rates. It provides external support thereby addressing the root causes of fistula failure:
- It regulates flow by constraining and shaping optimal geometrical parameters of the fistula.
- It reinforces and shields the vulnerable perianastomotic vein against high pressure, wall tension, and flow levels.