Cardiovascular Comorbidity and Late Referral Impact Arteriovenous Fistula Survival

Abstract

Abstract. Autologous arteriovenous fistulas (AVF) have the best 5-yr patency and the lowest complication rate among hemodialysis vascular accesses. However, maturation requirements to optimize survival are unknown. A longitudinal cohort study was conducted to ascertain risk factors for failure, maturation time, and survival of the first AVF. All patients who initiated hemodialysis between January 1, 1997, and December 31, 2002, in three centers were included in this study. Analysis was restricted to patients who received an AVF. Cox regression was used to estimate the association between predictors of interest and primary and secondary AVF survival. Of the 535 patients enrolled (mean age, 66.5 yr; 57.8% male; 26.7% diabetic), 513 (96%) received an AVF. Patients who initiated with catheters (47%) cannulated their AVF earlier (median maturation period, 0.78 versus 1.80 mo; P Ͻ 0.001). Median primary and secondary survivals were longer than 50 and 72 mo, respectively. After adjustment for confounding factors, cardiovascular disease (hazard ratio [HR], 1.84; 95% confidence interval [CI], 1.26 to 2.67), utilization earlier than 1 mo after placement (HR, 1.94; 95% CI, 1.34 to 2.82), and referral within 3 mo of dialysis start (HR, 1.55; 95% CI, 1.04 to 2.32) were associated with a reduction in primary AVF survival. Presence of cardiovascular disease (HR, 2.21; 95% CI, 1.38 to 3.55), maturation time Ͻ15 d (HR, 2.12; 95% CI, 1.20 to 3.73), and presence of catheters at hemodialysis initiation (HR, 1.79; 95% CI, 1.13 to 2.84) were associated with lower secondary AVF survival. It is concluded that cardiovascular disease, late referral, temporary catheters, and early cannulation are associated with impaired AVF survival. It is recommended that AVF be allowed to mature at least 1 mo before cannulation.Creation and maintenance of a well-functioning vascular access (VA) remains one of the most challenging problems in delivering adequate hemodialysis (HD) therapy. As compared with arteriovenous grafts and permanent cuffed central venous catheters, native arteriovenous fistulas (AVF) are viewed as being superior, because of the much smaller number of procedures associated with use and longer overall survival (1). However, AVF are not readily utilizable after placement, and early cannulation has been shown to be associated with shorter survival (2). Indeed, the optimal maturation period to make cannulation easier and improve AVF survival is not established, although it is common practice to delay utilization after insertion to allow enlargement and "arterialization" of the vein. This maturation process is expected to result in adequate blood flow through the fistula and in lower risk of local hemorrhage at the cannulation site, wall damage, fibrosis, and final occlusion. The current National Kidney Foundation's Dialysis Outcomes Quality Initiative guidelines endorse this practice and recommend that initial use be delayed for at least 4 wk after surgery, although this guidance is based on opinion (3), and a shorter maturation time ...

Hemodialysis Arteriovenous Fistula Patency Revisited

“…Although a larger sample size may have resulted in a significantly increased risk for primary functional patency loss in aging or female hemodialysis patients, older patients and women were not at significantly increased risk for fistula abandonment in our population (20). All other factors including obesity or cardiovascular disease did not reduce functional AVF survival (21,22).…”

Comorbidities Do not Influence Primary Fistula Success in Incident Hemodialysis Patients

“…Historically, AVF are more commonly used in European centers, as recently demonstrated in the Dialysis Outcomes and Practice Patterns Study (DOPPS) (19). Higher rates of primary fistula success have also been reported in European centers (11), which may be due to lower rates of patient comorbidity, including diabetes, congestive heart failure, and peripheral vascular diseases (7). The results of the DOPPS I survey suggest that the preference of the medical directors of dialysis units in North America might also contribute to underuse of AVF (20); however, AVF are still underused in North American centers despite most medical directors' and vascular access surgeons' preference for AVF, as noted in the recent DOPPS II study (7).…”

“…Preexisting cerebrovascular disease, older age, and commencement of dialysis before access creation were noted to be associated with higher primary fistula failure in their study. Ravani et al (11) noted that cardiovascular disease and late referral to nephrologists were associated with lower primary AVF success in patients from northern Italy.…”

Fistula First Initiative

“…FFI recommends a policy to allow new AVF to develop for at least 8 to 12 wk before cannulation. Although there has been debate regarding the use of maturation time policies and its impact on AVF survival (30,98), there is a unanimously agreed-on need to determine "cannulation readiness" by clinical examination (99,100) and not solely on time from AVF creation. Clinical examination (101) by experienced nurses has been able to predict AVF maturity 80% of the time (96) and is reinforced by the FFI.…”

“…Central stenosis has been reported in 40% (58,59) of patients who undergo venography and, importantly, may preclude later AVF creation or hamper its maturation. Indeed, it has been well documented that patients who have had a CVC placed before AVF creation have reduced AVF survival compared with patients who did not receive a CVC (27,30,38).…”