Access flow volume (Qa) and survival in a haemodialysis population: an analysis of 5208 Qa measurements over a 9-year period

Abstract

Background Aim of the study was to determine associations between characteristics of arteriovenous access (AVA) access flow volume (Qa, mL/min) and four year freedom from cardiovascular mortality (4yr-CVM) in hemodialysis (HD) patients. Methods HD patients who received a primary AVA between January 2010 and December 2017 in one center were analyzed. Initial Qa was defined as the first Qa value obtained in a well-functioning AVA by a two-needle dilution technique. Actual Qa was defined as access flow at a random point of time. Changes in actual Qa were expressed per 3-month periods. CVM was assessed according to the ERA-EDTA classification. The optimal cut-off point for initial Qa was identified by a receiver operating characteristic curve. A joint modelling statistical technique determined longitudinal associations between Qa characteristics and 4yr-CVM. Results A total of 5208 Qa measurements (165 patients, male n = 103; age 70±12 years, autologous AVA n = 146, graft n = 19) were analyzed. During follow-up (Dec 2010-Jan 2018, median 36 months), 79 patients (48%) died. An initial Qa < 900 mL/min was associated with an increased 4y-CVM risk (HR: 4.05; 95% CI [1.94-8.43], P<0.001). After 4 years, freedom from CVM was 34% lower in patients with a Qa < 900 mL/min (53 ±7% vs. Qa ≥ 900 mL/min: 87 ±4%, P <0.001). An association between increases in actual Qa over 3-month periods and mortality was found (HR: 4.48 per 100mL/min, 95% CI [1.44-13.97], P =0.010) indicating that patients demonstrating increasing Qa were more likely to die. By contrast, actual Qa per se was not related to survival. Conclusions Studying novel arteriovenous access Qa characteristics may contribute to understanding excess CVM in HD patients.

Association Between Blood Flow Rate of Arteriovenous Access and Mortality in Prevalent Haemodialysis Patients: A Five-Year Prospective Study

“…In our study, the baseline QA of AV access was an independent predictor for all-cause mortality in prevalent HD patients. There are few published studies on the association between the QA of AV access and mortality in HD patients [14,[18][19][20]. Wu et al conducted a retrospective observational cohort study including 378 prevalent HD patients and showed that a lower QA level (<1000 ml/min) of AV access (85% AVF) was an independent predictor of both short-term and longterm all-cause mortality; in addition, they identified the QA value of 1020 ml/min as the most discriminatory cut-off point for all-cause mortality [18].…”

“…Wu et al conducted a retrospective observational cohort study including 378 prevalent HD patients and showed that a lower QA level (<1000 ml/min) of AV access (85% AVF) was an independent predictor of both short-term and longterm all-cause mortality; in addition, they identified the QA value of 1020 ml/min as the most discriminatory cut-off point for all-cause mortality [18]. A recent retrospective cohort study of 165 HD dialysed through an AV access (88.5 % AVF) identified a baseline QA of 900 mL/min as the optimal cutoff value for cardiovascular mortality and showed that HD patients having an initial QA<900mL/min were almost 4 times more likely to die from a cardiovascular event in the first 4 years after starting HD compared with the remaining patients [20].…”

“…In fact, the QA value and HD adequacy improves after successful elective AV access treatment for stenosis [17] and, therefore, the risk of death can return to baseline level. But, outside these extreme values, we have little information regarding the significance of QA levels in AV accesses without stenosis on the mortality risk of HD patients in a stable clinical condition and absence of haemodynamic disturbance [14,[18][19][20]. The aim of this study is to analyze all-cause mortality of prevalent HD patients and its relationship with AV access function (QA value).…”

A scoping review on surgical reduction of high flow arteriovenous haemodialysis access

“…Qa increases over 3 months periods as calculated using a joint-modelling technique did show a significant association with increased cardiovascular mortality. 96 It remains uncertain whether AVA reduction in HFA patients decreases (cardiovascular) mortality. Interestingly, 4 years survival in 10 patients undergoing Qa reductive surgery was 100% compared to 55% in 155 patients who did not.…”

Studies on high flow and hand ischaemia associated with an upper extremity haemodialysis access

“…Qa increases over 3 month periods as calculated using a joint-modelling technique did show a significant association with cardiovascular mortality. 96 It remains uncertain whether AVA reduction in HFA patients decreases (cardiovascular) mortality. Interestingly, four year survival in 10 patients undergoing Qa reductive surgery was 100% compared to 55% in 155 patients who did not.…”