Résumé
Objective:To explore the association of access blood flow measured by ultrasound dilution and color Doppler ultrasound with patency loss of arteriovenous fistula (AVF).Methods:This was a bidirectional cohort study. The adult patients who underwent maintenance hemodialysis (MHD) with AVF in Peking University First Hospital from January 1, 2018 to July 31, 2020 were enrolled. AVF blood flow was measured by ultrasonic dilution method (Qa), and color Doppler ultrasound in cephalic vein and brachial artery. Patients were divided into low Qa (<500 ml/min), normal Qa (500-1 500 ml/min) and high Qa (>1 500 ml/min) groups according to baseline AVF blood flow measured by ultrasonic dilution method. Qa was monitored every 3 months within the first year. The endpoint events of follow-up were defined as AVF patency loss or death. The deadline of the follow-up was July 31, 2022. Linear regression analysis was used to assess the change trend of Qa. Fine and Gray competitive risk model was used to evaluate the cumulative incidence of AVF patency loss. The Cox proportional hazards regression model was used to evaluate the association between access AVF blood flow and patency loss.Results:A total of 163 patients were enrolled, with age of (57.0±13.7) years old and 110 males (67.5%). The median follow-up time was 45(22, 53) months. Forty-four patients (27.0%) had AVF failure, and 29 patients (17.8%) died. The cumulative incidence rates of AVF patency loss in patients with low Qa, low blood flow of brachial artery and cephalic vein (<500 ml/min), and in those with a downward trend of Qa were higher than those in patients with normal or high blood flow, and in those with a upward trend of Qa (Gray′s test, all P<0.05). After adjusted for age, sex, age of fistula, diabetes and vascular stenosis, multivariable Cox regression analysis results showed that baseline Qa<500 ml/min ( HR=3.508, 95% CI 1.382-8.905, P=0.008), baseline brachial artery flow<500 ml/min ( HR=2.413, 95% CI 1.058-5.503, P=0.036) and a downward trend of Qa ( HR=2.498, 95% CI 1.241-5.027, P=0.010) were independently associated with AVF patency loss. Conclusions:Patients with low baseline value or downward trend of AVF blood flow are at significantly higher risk of patency loss. The brachial artery measurement of AVF blood flow is the preference location for color Doppler ultrasonic.
Résumé
BACKGROUND: Prophylactic stenosis correction is important in the durability of the vascular access, and routine surveillance for the detection of stenosis has been widely recommended to allow preemptive intervention before thrombotic occlusion. The ultrasound dilution technique has been considering not only a popular and validated in vascular access surveillance, but also useful in the measurement of access recirculation and cardiac output. METHODS: Access flow, recirculation, and cardiac output of seventy-six hemodialysis patients with arteriovenous fistulae were measured by ultrasound dilution technique, followed by access flow measurement by color doppler ultrasound in sixty-four patients. Access stenosis was defined as 50% and more reduction in the diameter of vessels by color doppler ultrasound. Cardiac output of thirty-seven patients by echocardiography within a year was also analyzed. RESULTS: Access stenosis was diagnosed in six of sixty-four patients by color doppler ultrasound (9.4%). Access flow in the group with stenosis (621+/-322 mL/min) was lower than the group without stenosis (1, 005+/-633 mL/min), but no statistical significance was found. The access flow measured by ultrasound dilution technique was significantly correlated with color doppler ultrasound (r=0.436, p= 0.01). The cardiac output measured by ultrasound dilution technique was also significantly correlated with echocardiography (r=0.660, p=0.01). CONCLUSION: The data did not provide statistical significances for the detection of stenosis by ultrasound dilution technique. But this study suggests that ultrasound dilution technique is a useful method in the measurement of access flow, cardiac output and recirculation. We hope further prospective studies based on our data will be performed.