#5014 VALIDATION AND APPLICABILITY OF A MONITORING SYSTEM FOR VASCULAR ACCESS IN HAEMODIALYSIS: A MULTICENTRE STUDY
Authors: Rotondi Silverio , Satta Ersilia , Romano Carmine , Iannone Achille , Romano Massimo , Korreschi Kamela , Mazzaferro Sandro 
Published: June 2023

Abstract

Background and Aims
Routine systems for monitoring vascular access (VA) performance are lacking. We recently showed that with a VA triage system it is possible to improve the average value of a number of VA efficiency parameters and that the VA triage score was associated with clinical outcomes. The triage categorization is generated monthly by a scoring system which is based on a number of parameters (blood flows, VA pressure values, end HD circuit clots and a dedicated score of the external VA examination, KT/V) recorded at each session by the staff on a dedicate electronic spreadsheet. According to threshold values, triage classified each VA in Green (G), Yellow (Y) or Red (R), thus indicating the VA performance and the clinical risk of complication linked to VA. In our open label single centre study, with three years of follow-up, the average VA score improved significantly and G VA associated with lower mortality, compared to the Y and R VA. Aims: To validate the ability of the triage system to early identify VA with increased risk of complications.

Methods
In this interventional prospective, blinded multicentre study, each centre used the VA triage electronic spreadsheet without knowledge of the generated triage. After six months of system implementation, two years of follow-up (01/01/2020 - 01/12/2021) were planned to record VA related events. Two external reviewers evaluated the records. A minimum of three months VA follow up was necessary for patients enrolment.

Results
From 18 HD centres we enrolled 757 patients, aged 64,5±15,5 y.o.; 27% diabetics; HD since 24,4±32,4 months; 369 (48,7%) with arteriovenous fistula (AVF) and 388 (51,3%) with permanent central venous catheter (CVC). During 11,4±5,6 months of follow-up (range 3-23), 108537 HD sessions were recorded on the triage electronic spreadsheet, with 214 total clinical events and an event free time of 224,5 ±172 days (range 4-713). The VA related events were 150 (70,1%) during 16,3±2,2 months of follow up (range 3-23) with an event free time of 230±160 days (range 11-713). The VA Triage was: 60% Green, 35% Yellow and 5% Red. In the 369 patients with AVF the VA Triage was: 61% Green, 36% Yellow and 3% Red; The AVF Triage Green group showed: lower incidence of VA related events respect to the AVF Triage Yellow and Red group (30% vs 48%; P: 0.05); higher time-free from VA events (AVF Green vs AVF Yellow-Red: log-rank test: 0.04). Similar results were confirmed in the CVC groups: VA events incidence Triage Green 15% vs Triage Yellow-Red 40% (p: 0.001; time-free from VA events log-rank Test 0.001).

Conclusion
Our VA triage system identifies 40% of vascular accesses as yellow-red triage. These VA were not identified as at elevated clinical risk by the dialysis staff and only the Triage system was able to highlight them as critical. Notably the VA access with Yellow and Red Triage independently from the VA typology had an higher risk of clinical complications that according to the time survival curve could be detectable roughly 237,8 days before the event developed. The Triage system was able to identify early the VA with increased clinical risk and it may be a useful tool to prevent VA complication.