**2.1 Epidemiology of hemodialysis vascular access**

Due to reduced AVF use and increased AVG (70% in 1993 40) and catheter use in the United States from the mid-1980's-1990's, the National Kidney Foundation in 1997, in an effort to improve vascular access outcomes, published the first Kidney Disease Outcome Quality Initiative (K/DOQI) clinical practice guidelines for vascular access to optimize the care of vascular access in hemodialysis patients using evidenced and opinion-based guidelines 41. Since these initial clinical practice guidelines have been published, we have seen the creation of the Fistula First Breakthrough Initiative (FFBI) 42-45 and two more revised K/DOQI clinical practice guidelines and performance measures for vascular access 19,46, which have clearly impacted and improved hemodialysis vascular access management. The most recent report from the 2009 United States Renal Data System (USRDS) has showed an AVF prevalence of 50% 47, a marked improvement since 2004 (39% AVF prevalence), 2000 (30% AVF prevalence), and 1998 (26% AVF prevalence)48 in the United States. In contrast, AVF prevalence in Europe and Japan, reported from the Dialysis Outcomes and Practice Patterns Study (DOPPS) has been historically much higher, ranging from 57-91% 20.

While the K/DOQI guidelines and FFBI have clearly played an instrumental role in meeting the initial target goal of 50% AVF prevalence (new goal 66% 19,42), the prevalence of CVC use continues to remain between 20-30% in the United States 42. Furthermore, this trend of increased catheter use has also been observed in other countries, such as Spain, France, Belgium, Germany, and Italy 20. This is likely due to an increase in the number of AVFs that have failed to mature for dialysis use in recent years 14,16.

### **2.2 Clinical significance and economic implications of hemodialysis vascular access dysfunction**

When patients develop vascular access dysfunction, due to an immature AVF or thrombosed AVF or AVG, they are often consigned to CVC use for prolonged periods. Because dialysis with a catheter is associated with increased morbidity and mortality 49-55, CVC use has significant clinical implications such as increased risk of bacteremia which has been reported to occur at a frequency ranging from 2.5 to 5.5 episodes per 1000-catheter

Arteriovenous grafts (made from polytetrafluoroethylene, a synthetic fluoropolymer of tetrafluoroethylene) are advantageous because of short maturation time and relative ease to cannulation compared to AVFs 12,17-19. Until recently, AVGs were the most common access used in hemodialysis patients in the Unites States 20. However, the main disadvantages of AVGs are development of recurrent venous stenosis, requiring frequent interventions to

Tunneled central venous catheters have the advantage of immediate use, multiple sites for insertion, and the ability to provide access for hemodialysis for a period of months, permitting time for AVF or AVG maturation, in patients who require immediate hemodialysis 19,25-28. However, the main disadvantages are the high risks of morbidity and mortality caused by

**2. Epidemiology and clinical significance of hemodialysis vascular access** 

Due to reduced AVF use and increased AVG (70% in 1993 40) and catheter use in the United States from the mid-1980's-1990's, the National Kidney Foundation in 1997, in an effort to improve vascular access outcomes, published the first Kidney Disease Outcome Quality Initiative (K/DOQI) clinical practice guidelines for vascular access to optimize the care of vascular access in hemodialysis patients using evidenced and opinion-based guidelines 41. Since these initial clinical practice guidelines have been published, we have seen the creation of the Fistula First Breakthrough Initiative (FFBI) 42-45 and two more revised K/DOQI clinical practice guidelines and performance measures for vascular access 19,46, which have clearly impacted and improved hemodialysis vascular access management. The most recent report from the 2009 United States Renal Data System (USRDS) has showed an AVF prevalence of 50% 47, a marked improvement since 2004 (39% AVF prevalence), 2000 (30% AVF prevalence), and 1998 (26% AVF prevalence)48 in the United States. In contrast, AVF prevalence in Europe and Japan, reported from the Dialysis Outcomes and Practice Patterns

While the K/DOQI guidelines and FFBI have clearly played an instrumental role in meeting the initial target goal of 50% AVF prevalence (new goal 66% 19,42), the prevalence of CVC use continues to remain between 20-30% in the United States 42. Furthermore, this trend of increased catheter use has also been observed in other countries, such as Spain, France, Belgium, Germany, and Italy 20. This is likely due to an increase in the number of AVFs that

**2.2 Clinical significance and economic implications of hemodialysis vascular access** 

When patients develop vascular access dysfunction, due to an immature AVF or thrombosed AVF or AVG, they are often consigned to CVC use for prolonged periods. Because dialysis with a catheter is associated with increased morbidity and mortality 49-55, CVC use has significant clinical implications such as increased risk of bacteremia which has been reported to occur at a frequency ranging from 2.5 to 5.5 episodes per 1000-catheter

infection 7,29-33, catheter thrombosis 19,34-37, and central venous stenosis 37-39.

Study (DOPPS) has been historically much higher, ranging from 57-91% 20.

have failed to mature for dialysis use in recent years 14,16.

**2.1 Epidemiology of hemodialysis vascular access** 

**1.1.2 Arteriovenous graft** 

**dysfunction** 

**dysfunction** 

maintain patency, and graft infection 19,21-24.

**1.1.3 Tunneled central venous catheter** 

days 6,56, increased risk of 1-year mortality 49, and 60-70% higher risk of subsequent AVF failure 32,57. The cost of treating one CVC-related bacteremia in the United States has been estimated to be as high as \$45,000 per episode with an average of \$22,000 per bacteremic episode 58.
