Native arteriovenous fistula blood flow and resistance during hemodialysis

doi:10.1053/ajkd.2003.50032

American Journal of Kidney Diseases

Volume 41, Issue 1, January 2003, Pages 132-139

https://doi.org/10.1053/ajkd.2003.50032 Get rights and content

Abstract

Background: Measurement of vascular access flow (Qa) has been proposed as the ideal method for surveillance of native fistulae. However, debate exists about the influence of blood pressure (mean arterial pressure [MAP]) on Qa during dialysis. Methods: During three consecutive dialysis treatments, 10 patients had paired measurements of Qa and MAP performed at 30, 60, 120, 180, 210, and 240 minutes. Access resistance (AR; in peripheral resistance units, PRUs) was calculated from MAP and Qa values. Results: Overall pooled coefficients of variation (CVs) for MAP, Qa, and AR were 8.4%, 12.3%, and 12.9%, respectively. A significant reduction in Qa and MAP occurred throughout the dialysis treatment (Qa, 104 mL/min; P = 0.008; MAP, 10.4 mm Hg; P = 0.007). Mean percentages of change in Qa for the first third compared with the middle and last thirds of the session were −4.6% ± 11.15% (SD) and −9.6% ± 10.5%, respectively. Thus, Qa varied between 11.4% and −30.6% from baseline during the last hour of dialysis treatments. A stronger correlation between MAP and Qa was seen in radiocephalic (r² = 0.55; P < 0.0001) compared with brachiocephalic fistulae (r² = 0.06; P = 0.023). Mean AR was unchanged during the dialysis session (0.23 PRU; P = 0.358). AR for radiocephalic fistulae was significantly greater compared with brachiocephalic fistulae (6.03 ± 3.90 versus 3.00 ± 1.11 PRU; P < 0.0001). Conclusion: Qa could decrease up to 30% from baseline, potentially impairing the ability of Qa to predict impending vascular access failure. AR remained stable during the treatment and may be a more useful measure of vascular access performance as part of an access surveillance program. Am J Kidney Dis 41:132-139. © 2003 by the National Kidney Foundation, Inc.

Section snippets

Study protocol

We prospectively evaluated 10 stable chronic hemodialysis patients. Nine patients usually performed their own dialysis at home. However, their dialysis was currently being performed in the hemodialysis unit at Monash Medical Centre (Melbourne, Australia) because the patients were either retraining on new dialysis machines or undergoing a routine medical assessment. All patients underwent thrice-weekly 4-hour hemodialysis treatments. Each patient was studied during three consecutive dialysis

Results

Basic demographics of study participants are listed in Table 1.

. Basic Demographics of Study Participants

No. of patients	10
Age (y)	49 ± 13.8
No. of men	6
No. of antihypertensives prescribed (per patient)
0	7
1	1
2	2
Access type
Radiocephalic fistula	5
Brachiocephalic fistula	4
Saphenous vein forearm loop	1
Predialysis BP (mm Hg)
Systolic	157 ± 18.5
Diastolic	87 ± 12.3
MAP	96.9 ± 14.1
Interdialytic weight gain (kg)	1.4 ± 0.53

Mean age was 48 years, and there were six men and four women in the group. Causes of end-stage

Discussion

The ability of Qa surveillance to predict access thrombosis will depend, in part, on hemodynamic conditions at the time of the test. Because trends in Qa are important in determining the presence of a hemodynamically significant stenosis and heightened risk for thrombosis, variability not just during a given treatment, but also from one treatment to the next is important.¹⁵

To quantify this variability, we measured Qa not just at multiple times during one treatment session, but also during three

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Cited by (24)

KDOQI Clinical Practice Guideline for Vascular Access: 2019 Update
2020, American Journal of Kidney Diseases
Citation Excerpt :
In summary, the use of surveillance methods in addition to clinical monitoring in AVF appears to increase the rate of detection of AVF stenosis and the rate of AVF intervention. Several previous studies have examined the effect of surveillance in addition to clinical monitoring in AVG.351,360,364,369 Most of the studies did not specifically examine the rate of detection of stenosis but, rather, a clinical outcome of thrombosis or patency.
The National Kidney Foundation’s Kidney Disease Outcomes Quality Initiative (KDOQI) has provided evidence-based guidelines for hemodialysis vascular access since 1996. Since the last update in 2006, there has been a great accumulation of new evidence and sophistication in the guidelines process. The 2019 update to the KDOQI Clinical Practice Guideline for Vascular Access is a comprehensive document intended to assist multidisciplinary practitioners care for chronic kidney disease patients and their vascular access. New topics include the end-stage kidney disease “Life-Plan” and related concepts, guidance on vascular access choice, new targets for arteriovenous access (fistulas and grafts) and central venous catheters, management of specific complications, and renewed approaches to some older topics. Appraisal of the quality of the evidence was independently conducted by using a Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach, and interpretation and application followed the GRADE Evidence to Decision frameworks. As applicable, each guideline statement is accompanied by rationale/background information, a detailed justification, monitoring and evaluation guidance, implementation considerations, special discussions, and recommendations for future research.
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Evaluation of fistula blood flow and resistance by regression analysis (multiple letters)
2003, American Journal of Kidney Diseases
Diagnostic accuracy of ultrasound dilution access blood flow measurement in detecting stenosis and predicting thrombosis in native forearm arteriovenous fistulae for hemodialysis
2003, American Journal of Kidney Diseases
Citation Excerpt :
The pooled CV for Qa measurements and the regression equation between mean Qa values and their SDs obtained in our study indicate that assay reproducibility accounts for up to 16% of Qa measurement variability, even under standardized conditions in which hemodynamic variability is minimized. Qa variability was lower in our study than that reported for grafts,23 but similar to what others reported in AVFs,4 who found pooled CVs similar to ours for MAP (7.9% versus 8.2%), Qa (9.5% versus 7.9%), and MAP/Qa (11.9% versus 11.2% for Qa/MAP in our study) in hemodynamically stable subjects during the first hour of dialysis. Despite the relatively high variability, Qa measurement shows an excellent diagnostic performance in detecting access dysfunction; this finding is explained partially by the high prevalence of stenosis and thrombosis in our unselected forearm AVF population, a situation that usually ensures good performance, even for tests with less than ideal diagnostic accuracy.
Vascular access surveillance by ultrasound dilution blood flow rate (Qa) measurement is widely recommended; however, optimal criteria for detecting stenosis and predicting thrombosis in arteriovenous fistulae (AVFs) are still not clearly defined.
In a blinded trial, we evaluated the accuracy of single Qa measurement, Qa adjusted for mean arterial pressure (Qa/MAP), and decrease in Qa over time (dQa) in detecting stenosis and predicting thrombosis in an unselected population of 120 hemodialysis subjects with native forearm AVFs (91 AVFs, located at the wrist; 29 AVFs, located at the midforearm). All AVFs underwent fistulography, which identified greater than 50% stenosis in 54 cases.
Receiver operating characteristic curve analysis showed that dQa, Qa, and Qa/MAP have a high stenosis discriminative ability with similar areas under the curve (AUCs), ie, 0.961 ± 0.025, 0.946 ± 0.021, and 0.912 ± 0.032, respectively. In the population as a whole, optimal thresholds for stenosis were Qa less than 750 mL/min alone and in combination with dQa greater than 25% (efficiency, 90%); however, the best threshold depended on anastomotic site; it was Qa less than 750 mL/min for an AVF at the wrist and Qa less than 1,000 mL/min for an AVF in the midforearm. Qa was the best predictor of incipient thrombosis (AUC, 0.981 ± 0.013) with an optimal threshold at less than 300 mL/min (efficiency, 94%). Pooled intra-assay and interassay variation coefficients were 8.2% for MAP, 7.9% for Qa, and 11.2% for Qa/MAP.
Our study shows that ultrasound dilution Qa measurement is a reproducible and highly accurate tool for detecting stenosis and predicting thrombosis in forearm AVFs. Neither Qa/MAP nor dQa improve the diagnostic performance of Qa alone, although its combination with dQa increases the test's sensitivity for stenosis.
Guidelines on vascular access for hemodialysis from the brazilian society of angiology and vascular surgery
2023, Jornal Vascular Brasileiro

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: Address reprint requests to Kevan R. Polkinghorne, FRACP, Department of Nephrology, Monash Medical Centre, 246 Clayton Rd, Clayton, Melbourne, Victoria 3168, Australia. E-mail: [email protected].

: 0272-6386/03/4101-0015$35.00/0

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Original Investigations: Dialysis TherapiesNative arteriovenous fistula blood flow and resistance during hemodialysis

Abstract

Section snippets

Study protocol

Results

Discussion

Kidney Int

Kidney Int

Am J Kidney Dis

Am J Kidney Dis

Kidney Int

Am J Kidney Dis

Am J Kidney Dis

Prolongation of hemodialysis access survival with elective revision

Clin Nephrol

Screening for subclinical stenosis in native vessel arteriovenous fistulae

J Am Soc Nephrol

Clinical practice guidelines for vascular access. Canadian Society of Nephrology

J Am Soc Nephrol

Original Investigations: Dialysis Therapies
Native arteriovenous fistula blood flow and resistance during hemodialysis