#2867 EARLY DETECTION OF VASCULAR ACCESS STENOSIS USING NEPHROFLOW

Abstract

Abstract Background and Aims The monitoring programs for vascular access make it possible to detect access dysfunction and indicate the need to perform an imaging test to confirm the presence of stenosis and proceed with its treatment. Measurement of arteriovenous fistula (AVF) flow using biosensors is a simple and reproducible method of vascular access assessment. AVF flow (QA) drops below 500 ml/min or a reduction of more than 25% in previous flow are considered predictors of stenosis and/or thrombosis. A stenosis with a high risk of thrombosis is defined as that which presents a decrease of more than 50% in the vascular lumen and a stenosis/prestenosis Peak Systolic Velocity ratio > 2, with additional criteria (residual diameter < 2 mm and/or QA (ml/ min) < 500 (native AVF) or and/or decrease in QA > 25% if QA < 1,000 ml/min. Method We performed AVF flow measurement using the NephroFlow biosensor in prevalent hemodialysis patients. Results Sixty-one patients were studied, all with native or prosthetic AVF. Of which 42 men and 19 women. The distribution of AVFs was: 38 brachiocephalic (62%), 16 radiocephalic (26%) and 6 brachial-axillary prostheses (10%) 1 brachial-basilic (2%). The data was collected for 24 months. The mean follow-up time for the AVF was 16 months. In 17 patients (30%), flow was detected below 25% compared to previous controls or a decrease in QA <500 ml/min. In these patients, echo-doppler was performed, showing in 15 cases stenosis with a high risk of thrombosis that was treated with angioplasty. In 1 patient, echo-doppler detected only insufficiency of the artery, and no stenosis was observed in fistulography. In 1 patient, there was a significant drop in flow (from 830 to 451 ml/min), which later recovered 650 ml/min with ultrasound without significant alterations, so an endovascular procedure was not performed. During the study period, 1 fistula thrombosis occurred in a patient who had already detected a drop in flow but could not repair it in time. At the end of the study, of the 61 patients analyzed, 51 patients continued with the technique and the flows remained stable or even increased. In the other 10 patients, 9 left due to transplantation or death and 1 patient had a new thrombosis and the AVF could not be repaired. Conclusion In hemodialysis units, the measurement of AVF flow using biosensors should be protocolized together with Doppler ultrasound to achieve better monitoring of vascular access, managing to detect and treat early stenosis with a high risk of thrombosis.