All vascular access guidelines recommend monitoring and surveillance protocols to prevent vascular access complications in hemodialysis units. However, in the case of second generation screening techniques which determine access blood flow measurement (QA), there is a huge controversy about it´s efficiency. Although multiple observational studies find a decrease in the thrombosis rate and an increased primary assisted patency survival related to the use of these techniques, a recently published meta-analysis find contradictory results in the randomized controlled trials, affirming that the measurement of QA is useless in grafts and questionable in native arteriovenous fistulae (AVF). We have designed a multicenter, prospective, open label, controlled, randomized trial, to prove the usefulness of the QA measurement using two complementary second generation techniques, Doppler ultrasound and Transonic dilution method, compared to the classical monitoring and surveillance methods. The primary endpoint will be a reduction in the thrombosis rate with an increased assisted primary patency survival, and a cost effectiveness economic analysis. As secondary endpoints we will analyze the impact over non-assisted primary patency survival and secondary patency survival.
Definition: Multicenter, prospective, open label, controlled, randomized trial, to prove the usefulness of the QA measurement using two complementary second generation techniques, Doppler ultrasound and Transonic dilution method, compared to the classical monitoring and surveillance methods. For Patient Registries: Clinical data repository (CDR) paper notebook will contain all baseline patient characteristics and the information related to vascular access. These data will be collected by the different investigators and reviewed and included in data base by the study´s monitor. This information will be included in a centralized computer database (SPSS 15.0 computer system) and encoded in order to preserve patients´ confidentiality.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
PREVENTION
Masking
NONE
Enrollment
212
Doppler ultrasound and transonic dilution method technique will be performed in the experimental group quarterly. QA will be measured by both techniques and haemodynamic repercussion stenosis will be evaluated by doppler ultrasound.
Effective blood flow, venous pressure, arterial pressure, at the beginning and at the end of the dialysis session
Predialysis physical examination of AVF every dialysis session.
Weekly ktv measurement using biosensors. In patients who have been dialyzed in monitors with no biosensors, ktv will be measured monthly using monocompartimental Daugirdas equation
Quarterly recirculation with urea method.
Hospital Universitario Infanta Sofia
San Sebastián de los Reyes, Madrid, Spain
Centro de Diálisis Los Enebros
Madrid, Spain
Hospital Universitario Gregorio Marañon
Madrid, Spain
Dialcentro
Madrid, Spain
Clinica Fuensanta
Madrid, Spain
Improved primary patency rate in arteriovenous fistulae with the use of doppler ultrasound and transonic dilution method
Differences in assisted primary patency rates (thrombosis free access survival) in AVF between the two groups: control group in which classical monitoring and surveillance techniques are applied and experimental group in which Doppler ultrasound and transonic were performed every three months in addition to classical methods. Cost efficacy analysis in both groups will be done, measuring all vascular access (VA) related health care spending (VA hospitalization costs, central venous catheter (CVC) placements, surgeries and endovascular procedures will be recorded).
Time frame: Up to 3 years follow up
Compared non-assisted primary patency rates (intervention free access survival) and secondary patency rates (access survival until abandonment) between the two groups.
Time frame: Up to 1 year follow up
Evaluate the efficacy and efficiency of second generation methods
It will be evaluated the positive and negative predictive value of each second generation technique, doppler ultrasound and Transonic dilution method. The accuracy of these techniques will be compared to determine which one show more benefits detecting pathology of AVF.
Time frame: Up to 2 years follow up
Reproducibility in Doppler ultrasound technique
There will be always two observers for each doppler ultrasound (same observers for same AVF). Differences among different quarterly measures in stable AVF will be evaluated, as well as the differences between the two observers in QA measurement.
Time frame: Up to 3 years follow up.
Possible influence of different baseline items in the risk of thrombosis of native AVF
It will be evaluated if there is any influence of age, body mass index, use of antiplatelet therapy, anticoagulant therapy or the use of pentoxifylline in the risk of thrombosis of AVF
Time frame: Up to 3 years follow up
Compared non-assisted primary patency rates (intervention free access survival) and secondary patency rates (access survival until abandonment) between the two groups.
Time frame: Up to 2 years follow up
Evaluate the efficacy and efficiency of second generation methods
It will be evaluated the positive and negative predictive value of each second generation technique, doppler ultrasound and Transonic dilution method. The accuracy of these techniques will be compared to determine which one show more benefits detecting pathology of AVF.
Time frame: Up to 3 years follow up
Compared non-assisted primary patency rates (intervention free access survival) and secondary patency rates (access survival until abandonment) between the two groups.
Time frame: Up to 3 years follow up
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