Lower Arm Arteriovenous Fistula Research Articles

#1922 Patterns and 2-year outcomes of preemptive vascular access creation in France

Abstract Background and Aims Most studies on clinical practices regarding the type and the timing of vascular access creation are limited to patients on kidney replacement therapy (KRT) from North American settings. Our aim was to describe patterns of preemptive vascular access creation in patients under nephrology care in France, and to assess the subsequent risks of hemodialysis (HD) initiation with arteriovenous (AV) access use, HD initiation with central venous catheter (CVC) use, initiation of other KRT modality, and competing death. Method From 2013 through 2016, the CKD-REIN cohort included 3033 adult patients with CKD stages 3 to 5 from 40 outpatient nephrology clinics in France, nationally representative geographically and in terms of facility legal status (public, private not for profit, and private for profit). Participants were followed for 5 years or until initiation of kidney replacement therapy (KRT) or death, whichever came first. Patients who underwent a first vascular access creation during follow-up were eligible for this analysis. We described the type, anatomical site and timing of the first vascular access created, as well as patients’ associated characteristics. The number and type of subsequent accesses were also described. Among patients who underwent AV fistula creation first, we used the cumulative incidence functions to estimate the 2-year probabilities of HD initiation with AV access use (independently of its type or order), HD initiation with CVC use, initiation of other KRT modality, and death. Results Over a median follow-up of 5.0 years (interquartile range [IQR], 4.6 to 5.2), 535 patients (18% of the total population) underwent a first vascular access creation. 408 patients (75%) had an AV fistula as their first vascular access, 7 patients (1%), an AV graft, and 127 patients (24%), a CVC. AV fistulas were predominantly located in the lower arm (76%). The median eGFR levels at access creation were 13 (IQR, 10 to 16), 12 (10 to 14) and 9 (6 to 13) ml/min/1.73 m2 for AV fistula, AV graft, and CVC, respectively. Groups defined by their first vascular access did not differ with regards to diabetes status, but patients who received AV fistula as their first vascular access stood out for being younger and having less cardiovascular comorbidities than their counterparts who received AV graft or CVC (Table 1). In contrast to the 7 patients with first AV graft who did not have any subsequent access creation, 22% of those with first AV fistula had at least one subsequent access creation before initiating KRT. The subsequent access was a fistula in 49% of cases (54% of them in the lower arm), a CVC in 48% and a graft in 2%. The 2-year cumulative incidences of HD initiation with AV access use, HD initiation with CVC use, preemptive kidney transplantation and pre-KRT death were 61%, 14%, 2% and 5%, respectively (Fig. 1); 18% of patients undergoing a first AV fistula creation did not experience any event within two years, and 25% did not start HD. No patients received peritoneal dialysis as other KRT modality. Conclusion In this nationwide description of patterns of preemptive vascular access creation, we highlight that lower arm AV fistula is largely prioritized, even after a first failed AV fistula creation. This may contribute to the higher use of AV fistula among HD patients in France compared to North American countries. Most patients who undergo a first AV fistula creation eventually start hemodialysis with an AV access within 2 years of this creation, but 1 out of 4 do not start HD at all (because of death, preemptive transplantation, or stable kidney function). Novel tools assisting clinical decision making in preemptive AV fistula creation are needed.

NT-pro-BNP as marker for cardiac strain that may be caused by high-output arteriovenous shunting in a haemodialysis patient. A case report

BackgroundAn arteriovenous fistula (AVF) is the first choice when considering access for haemodialysis (HD). When a forearm AVF fails an upper arm AVF is a frequent subsequent dialysis access option. The latter may cause cardiac strain. NT-pro-B-type natriuretic peptide (NT-NT-proBNP) is a marker used to estimate volume overload and cardiac strain.This case report shows the benefit of using longitudinal individual follow-up of pre-dialysis NT-proBNP in clinical practice to detect changes in cardiac condition that may be due to high-output AVF.Case presentationAn 18 years old patient performed HD via an upper arm AVF before he was admitted to our unit. NT-proBNP was above the upper detection level of 70,000 ng/L. Echocardiography revealed a left-ventricular cardiac insufficiency. Interdialytic weight gain (IDWG) was above 5%. He was instructed to lower fluid intake and IDWG towards 2%. Four months later NT-proBNP surpassed 70,000 ng/L again. Flow in the brachial artery was at 3034 ml/min. Reconstructive surgery of the AVF did not reduce flow and NT-proBNP in the long run. Clinically, he worsened to NYHA class III-IV. It was decided to close the upper arm AVF and to replace it with a lower arm AVF leading to a reduced artery flow of 1344 mL/min. The clinical condition successively recovered and NT-proBNP decreased to 7000 ng/L.ConclusionsPre-dialysis NT-proBNP should be considered as a suitable routine marker for cardiac strain such as caused by high-output AVF besides variables such as IDWG. Brachial artery flow besides AVF flow measurement is helpful.

Predicting arterio-venous fistula failure by urea-method derived access blood flow in chronic hemodialysis patients.

Dialysis access is an essential part of hemodialysis. Determining the access blood flow (Qa) can help predict arterio-venous fistula thrombosis. Qa determination by the urea method, which was previously described in the past is simple and is available in most of the dialysis units but was not be able to predict arterio-venous fistula thrombosis. To compare the efficacy of Qa determination by the urea method and by ultrasound dilution methods in predicting arterio-venous fistula failure. Qa was measured by urea method and by ultrasound dilution simultaneously, every 3 months for a period of 1 year, in stable chronic hemodialysis patients with arterio-venous fistula. Arterio-venous fistula failure determined by clinical parameters and confirmed by Doppler ultrasound before sending the patient for interventional angioplasty. This study enrolled a total of 16 patients, with 63% being male, 75% with lower-arm arterio-venous fistula and around 43% with previously done angioplasty. 59-Qa measurements were done, and 6 patients underwent angioplasty (one patient for severe upper limb edema, one for access thrombosis, and four for access dysfunction). Qa determination by the urea method had non-significantly lower Qa, (745 mL/min (interquartile range: 509-1143) and 779 mL/min (interquartile range: 530-1160), (p = 0.58)) and high correlation (r = 0.83, p < 0.001) to Qa by ultrasound dilution. The cut-off criteria with its sensitivity and specificity in predicting the access failure were 440 mL/min, 66.67%, and 96.15% for Qa determination by the urea and 400 mL/min, 66.67% and 90.38% for Qa by ultrasound dilution, respectively, with no difference in the area under the receiver operating characteristic curve. Measurement of Qa determination by the urea method is well correlated with Qa by ultrasound dilution and can be used to predict vascular access failure.

The impact of haemodialysis arteriovenous fistula on haemodynamic parameters of the cardiovascular system.

BackgroundSatisfactory vascular access flow (Qa) of an arteriovenous fistula (AVF) is necessary for haemodialysis (HD) adequacy. The aim of the present study was to further our understanding of haemodynamic modifications of the cardiovascular system of HD patients associated with an AVF. The main objective was to calculate using real data in what way an AVF influences the load of the left ventricle (LLV).MethodsAll HD patients treated in our dialysis unit and bearing an AVF were enrolled into the present observational cross-sectional study. Fifty-six patients bore a lower arm AVF and 30 an upper arm AVF. Qa and cardiac output (CO) were measured by means of the ultrasound dilution Transonic Hemodialysis Monitor HD02. Mean arterial pressure (MAP) was calculated; total peripheral vascular resistance (TPVR) was calculated as MAP/CO; resistance of AVF (AR) and systemic vascular resistance (SVR) are connected in parallel and were respectively calculated as AR = MAP/Qa and SVR = MAP/(CO − Qa). LLV was calculated on the principle of a simple physical model: LLV (watt) = TPVR·CO2. The latter was computationally divided into the part spent to run Qa through the AVF (LLVAVF) and that part ensuring the flow (CO − Qa) through the vascular system. The data from the 86 AVFs were analysed by categorizing them into lower and upper arm AVFs.ResultsMean Qa, CO, MAP, TPVR, LLV and LLVAVF of the 86 AVFs were, respectively, 1.3 (0.6 SD) L/min, 6.3 (1.3) L/min, 92.7 (13.9) mmHg, 14.9 (3.9) mmHg·min/L, 1.3 (0.6) watt and 19.7 (3.1)% of LLV. A statistically significant increase of Qa, CO, LLV and LLVAVF and a statistically significant decrease of TPVR, AR and SVR of upper arm AVFs compared with lower arm AVFs was shown. A third-order polynomial regression model best fitted the relationship between Qa and LLV for the entire cohort (R2 = 0.546; P < 0.0001) and for both lower (R2 = 0.181; P < 0.01) and upper arm AVFs (R2 = 0.663; P < 0.0001). LLVAVF calculated as % of LLV rose with increasing Qa according to a quadratic polynomial regression model, but only in lower arm AVFs. On the contrary, no statistically significant relationship was found between the two parameters in upper arm AVFs, even if mean LLVAVF was statistically significantly higher in upper arm AVFs (P < 0.0001).ConclusionsOur observational cross-sectional study describes statistically significant haemodynamic modifications of the CV system associated to an AVF. Moreover, a quadratic polynomial regression model best fits the relationship between LLVAVF and Qa, but only in lower arm AVFs.

Investigating clinical predictors of arteriovenous fistula functional patency in a European cohort.

BackgroundArteriovenous fistula (AVF) failure to mature (FTM) rates contribute to excessive dependence on central venous catheters for haemodialysis. Choosing the most appropriate vascular access site for an individual patient is guided largely by their age, co-morbidities and clinical examination. We investigated the clinical predictors of AVF FTM in a European cohort of patients and applied an existing clinical risk prediction model for AVF FTM to this population.MethodsA prospective cohort study was designed that included all patients undergoing AVF creation between January 2009 and December 2014 in a single centre (Belfast City Hospital) who had a functional AVF outcome observed by March 2015.ResultsA total of 525 patients had a functional AVF outcome recorded and were included in the FTM analysis. In this cohort, 309 (59%) patients achieved functional AVF patency and 216 (41%) patients had FTM. Female gender [P < 0.001, odds ratio (OR) 2.03 (CI 1.37–3.02)] and lower-arm AVF [P < 0.001, OR 4.07 (CI 2.77–5.92)] were associated with AVF FTM. The Lok model did not predict FTM outcomes based on the associated risk stratification in our population.ConclusionsIn this European study, female gender was associated with twice the risk of AVF FTM and a lower-arm AVF with four times the risk of FTM. The FTM risk prediction model was not found to be discriminative in this population. Clinical risk factors for AVF FTM vary between populations; we would recommend that units investigate their own clinical predictors of FTM to maximize AVF functional patency and ultimately survival in dialysis patients. Clinical predictors of AVF FTM may not be sufficient on their own to improve vascular access functional patency rates.