NKF KDOQI GUIDELINES
I. CLINICAL PRACTICE GUIDELINES FOR VASCULAR ACCESS
More than 300,000 individuals in the United States rely on a vascular access to receive hemodialysis (HD) treatment.1 Vascular access continues to be a leading cause for hospitalization and morbidity in patients with chronic kidney disease (CKD) stage 5.2 Appropriate care of HD patients with CKD stage 5 requires constant attention to the maintenance of vascular access patency and function. An ideal access delivers a flow rate to the dialyzer adequate for the dialysis prescription, has a long use-life, and has a low rate of complications (eg, infection, stenosis, thrombosis, aneurysm, and limb ischemia). Of available accesses, the surgically created fistula comes closest to fulfilling these criteria. Studies over several decades consistently demonstrate that native fistula accesses have the best 4- to 5-year patency rates and require the fewest interventions compared with other access types.3-5 However, in the United States between 1985 and 1995, the growth of the CKD Stage 5 HD program was accompanied by decreased use of native fistulae and increased use of grafts and cuffed central catheters for permanent HD access.5,6 In 1995, the United States Renal Data System (USRDS) reported, for the 1990 incident cohort of patients, that insertion of polytetrafluoroethylene (PTFE) grafts occurred almost twice as often as construction of native accesses.6 Significant geographic variation in the ratio of native fistula construction to graft placement also was noted.
The substitution of grafts for fistulae increased patient care costs, in part because of the increased number of procedures needed to maintain patency of grafts compared with native fistulae.7 A review of Medicare billing showed that the first-year total yearly costs for patients initiating HD therapy using a fistula were lowest ($68,002) compared with grafts ($75,611) and catheters ($86,927).8 Although the second-year total yearly costs were lower for all groups, catheters still resulted in the highest costs at $57,178 compared with $54,555 for grafts and $46,689 for fistulae. Similarly, in a single-center Canadian study, the cost of vascular access–related care was lower by more than 5-fold for patients who began the study period with a functioning fistula compared with those treated with a long-term catheter or graft.9
Before the first dissemination of the Dialysis Outcomes Quality Initiative (DOQI) recommendations on vascular access in 1997, many studies showed that practice patterns were contributing to patient morbidity and mortality, as well as costs. The failure of access was noted to be a major cause of morbidity for patients on HD therapy, with a number of reports indicating that a high percentage of hospitalizations for patients with CKD stage 5 were caused by vascular access complications.6,7,10-12 The USRDS reported that HD access failure was the most frequent cause of hospitalization for patients with CKD stage 5,6 and, in some centers, it accounted for the largest number of hospital days.13 Reports also indicated a decreasing interval between placement of a vascular access and a surgical procedure needed to restore patency,7,12 with significant costs to restore patency.6,13 Since then, a study using data from the USRDS Morbidity and Mortality Study Wave 1 showed that patients receiving catheters and grafts have greater mortality risk than patients dialyzed with fistulae.14 In patients with and without diabetes mellitus, cause-specific analyses found higher infection-related deaths for cuffed central catheters. In patients without diabetes, relative risks (RRs) were 1.83 (P < 0.04) with catheters and 1.27 (P < 0.33) with arteriovenous (AV) grafts (AVGs). In patients with diabetes, the RR was even higher than in those without diabetes: RR of 2.30 (P < 0.06) for catheters and RR of 2.47 (P < 0.02) for grafts compared with fistulae. Cardiac cause of death was highest in patients with central venous catheters (CVCs). A number of subsequent epidemiological studies, both in the United States15,16 and abroad,17 reaffirmed that greater use of fistulae was associated with reduced mortality and morbidity.
It was shown that an aggressive policy for monitoring hemodynamics within an AVG or AV fistula (AVF) to detect access dysfunction may reduce the rate of thrombosis (see Clinical Practice Guideline [CPG] 4). Thus, much access-related morbidity and associated costs might be avoided. The number of interventions required to maintain access patency may be decreased further by the use of fistulae rather than AVGs. Studies showed that the number of access events is 3- to 7-fold greater in prosthetic bridge grafts than in fistulae,3,18 thereby contributing to the increased cost of grafts. Whether utilization of such interventions to reduce thrombosis rates ultimately prolongs the useable life of the access are unknown and should not be the sole outcome measure. Thrombosis is associated with additional risks to the patient that are not present with simple percutaneous angioplasty (PTA).19
The National Kidney Foundation (NKF) issued the Kidney Disease Outcomes Quality Initiative (KDOQI) CPGs for Vascular Access in an effort to improve patient survival and quality of life (QOL), reduce morbidity, and increase efficiency of care. Vascular access patency and adequate HD are essential to the optimal management of HD patients with CKD stage 5. The first is a necessary prerequisite for the second. To improve QOL and overall outcomes for HD patients, 2 primary goals were originally put forth in the vascular access guidelines20:
We believe these goals still apply, with the emphasis on placement of the functioning fistula. The Centers for Medicare & Medicaid Services (CMS) has actively collected data on 3 Clinical Performance Measures (CPMs) derived from the original and revised KDOQI Guidelines for Vascular Access. The failure to “adequately” increase the number of fistulae among either incident or prevalent HD patients during the past 6 years2 or to reduce the use of catheters led to a CMS mandate that the ESRD networks develop Quality Improvement Projects (QIPs) on Vascular Access. These have been distilled into 3 key points: avoid central catheterization, thus avoiding loss of central patency; maintain existing access by detecting impending failure, followed by prompt intervention; and maximize creation of fistulae as the best long-term access. Out of these concepts has grown the National Vascular Access Improvement Initiative (NVAII), emphasizing a fistula-first approach. Recently, the target for fistula creation was set as 65% by 2009. The Work Group acknowledges the importance of increasing the number of fistulae in use, but believes that the emphasis should be shifted from the fistula construction rate to the rate of usable fistula accesses. This shift in emphasis is important to minimize wasted time and effort and reduce the primary failure rate and salvage procedures.
A number of barriers need to be overcome to achieve the goals set for vascular fistula construction; chief among these is the late referral of patients for permanent access placement, reflected in patient hospitalizations. In some regions, up to 73% of patients are hospitalized for initiation of HD therapy, almost invariably for dialysis catheter access placement.21 Unexpectedly, the modest increases in fistula use rates have been accompanied by increases in the use of catheters.2 Early referral of patients with CKD stage 5 to a nephrologist is absolutely essential to allow for access planning and thus increase the probability of fistula construction and maturation, thereby decreasing the need for catheter placement.
To achieve these objectives, the current Work Group has developed and revised the vascular access practice guidelines and strategies for implementation and has made a concerted effort to differentiate guidelines from recommendations. At the core of these guidelines is the goal of early identification of patients with progressive kidney disease and the identification and protection of potential fistula construction sites—particularly sites using the cephalic vein—by members of the health care team and patients.
After access has been constructed, dialysis centers need to use a multifaceted continuous quality improvement (CQI) program to detect vascular accesses at risk, track access complication rates, and implement procedures that maximize access longevity. Vascular access databases that are available to all members of the vascular access team (VAT) are crucial. The Work Group has developed explicit guidelines regarding which tests to use to evaluate a given access type and when and how to intervene to reduce thrombosis and underdialysis. The Work Group believes that the guidelines are reasonable, appropriate, and achievable. Attainment of these goals will require the concerted efforts of not only practicing nephrologists, but also nephrology nurses, access surgeons, vascular interventionalists, patients, and other members of the health care team.
In this update of the Vascular Access Guidelines, the Work Group did not perform a comprehensive review of all the guidelines. Seven topics underwent systematic review, and these are identified. The other guidelines were unified and consolidated. More recent references, including reviews, were included when appropriate.
|© 2006 National Kidney Foundation, Inc.|