title: Variable pump flow-based Doppler ultrasound method: a novel approach to the measurement of access flow in hemodialysis patients.
abstract: Decreasing vascular access flow (Qa) is an important predictor of future access thrombosis and malfunction for hemodialysis (HD) patients. Among all of the methods for determining Qa, the variable pump flow (VPF) Doppler method measures Qa according to the change in Doppler signal between the arterial and the venous needles under different pump flow. After this technique was combined with spectral analysis of Duplex Doppler imaging, the variable pump flow-based Doppler ultrasound method (VPFDUM) for Qa measurement was developed. This study compared the reproducibility and correlation of Qa measurements for three different methods-VPFDUM, ultrasound dilution method (UDM), and conventional Doppler ultrasound method (CDUM)-in 55 HD patients. The mean value of Qa by VPFDUM (870.8 +/- 412.0 ml/min) was close to that by UDM (868.6 +/- 417.9 ml/min) but higher than that by CDUM (either of the above values versus 685.1 +/- 303.6 ml/min; P < 0.005). The mean values of coefficient of variation were similar by VPFDUM (1.6%) and UDM (1.4%) but lower than that by CDUM (either of the above values versus 6.8%; P < 0.01). The correlation coefficient and intraclass correlation coefficient of the repeated Qa measurements by VPFDUM (0.985 and 0.993; P < 0.001) were also similar to those by UDM (0.992 and 0.995; P < 0.001) but slightly higher than those by CDUM (0.917 and 0.948; P < 0.005). Either the reproducibility of VPFDUM (r=0.98, P < 0.0001) or the correlation between VPFDUM and UDM (r=0.99, P < 0.0001) in Qa measurements is good. The unassisted patency of vascular access at 6 mo was significantly poorer in patients with Qa <500 ml/min than those with Qa >500 ml/min (13.6% versus 92.2%; P < 0.0001). In conclusion, VPFDUM is a noninvasive, accurate, and reliable procedure for Qa measurement and prediction of the prognosis of vascular access in HD patients.
authors.affiliation: Division of Nephrology, Taipei Veterans General Hospital, No. 201, Sec. 2, Shih-Pai Road, Taipei, Taiwan 112, Republic of China.
authors.forename: Chih-Ching
authors.initials: CC
authors.lastname: Lin
authors.forename: Chao-Fu
authors.initials: CF
authors.lastname: Chang
authors.forename: Hong-Jen
authors.initials: HJ
authors.lastname: Chiou
authors.forename: Ying-Chou
authors.initials: YC
authors.lastname: Sun
authors.forename: Shou-Shan
authors.initials: SS
authors.lastname: Chiang
authors.forename: Ming-Wei
authors.initials: MW
authors.lastname: Lin
authors.forename: Pui-Ching
authors.initials: PC
authors.lastname: Lee
authors.forename: Wu-Chang
authors.initials: WC
authors.lastname: Yang
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001166:Arteriovenous Shunt, Surgical; D005260:Female; D006083:Graft Occlusion, Vascular / Q000000981:diagnostic imaging; D006801:Humans; D007676:Kidney Failure, Chronic / Q000000981:diagnostic imaging* / Q000628:therapy*; D008297:Male; D008875:Middle Aged; D008954:Models, Biological; D012039:Regional Blood Flow; D006435:Renal Dialysis / Q000379:methods*; D015203:Reproducibility of Results; D018608:Ultrasonography, Doppler / Q000592:standards