ABSTRACT
BACKGROUND: Early identification of dysfunctional arteriovenous hemodialysis (HD) vascular access (VA) is important for timely referral and intervention. METHOD: We retrospectively calculated the VA risk score using Vasc-Alert surveillance software technology from HD treatment sessions in 2 satellite HD units over 18 months. We included in the analysis HD patients dialyzing with arteriovenous fistula or graft (AVF/G) with available Vasc-Alert data for≥ 2 months. For group one (eventful) which included patients who developed vascular access thrombosis or stenosis over the study period, we collected Vasc-Alert risk score 2 months prior to the event, and for group two (uneventful) over 5 consecutive months. Vasc-Alert technology utilizes routinely collected data during HD to calculate the VA risk score and triggers an alert if the score is ≥7 in 3 consecutive dialysis sessions. Patients with> 2 alerts (vascular access score ≥ 7) per month were considered to have positive alerts. RESULTS: From 140 HD patients, 81 patients dialyzed via AVF/G. 77/81 had available Vasc-Alert data and were included in the final analysis. Out of 17 eventful patients, 11 (64.7%) had positive alerts 2 months prior to the vascular event. Out of the 60 patients without vascular events, 20 patients (33.3%) had positive alerts. Vasc-Alert's sensitivity and specificity for vascular events were 64.7% and 66.6% respectively. Within the 6 patients with thrombosed access, 2 patients (33.3%) detected by Vasc-Alert were not detected with clinical monitoring. CONCLUSION: Vascular access risk score can be a useful non-invasive vascular access surveillance method to assist clinical decision-making.
ABSTRACT
INTRODUCTION: Arteriovenous grafts (AVG) for haemodialysis (HD) access are recommended as a second line modality due to higher morbidity and mortality rates than arteriovenous fistulae (AVF). Smoking is already established as a risk factor in lower extremity bypass graft failure used for peripheral vascular disease, but its effect on AVGs remains unclear. We aimed to investigate the relationship of smoking on AVG outcomes. METHODS: A 3 year (01/08/2015-01/08/2018) multi-centre retrospective study was carried out on patients receiving an AVG for HD. Data included patient demographics, medical history, operation, type of graft, postoperative course and primary and secondary patency rates. Statistical analyses performed were Kaplan-Meier curves and Cox's proportional hazard regression. RESULTS: Fifty-five AVGs were performed (1052 AVF performed) in this period. The most common complication was thrombosis (38.9%). Primary patency at 6, 12 and 24 months were 55%, 45% and 44% respectively. Secondary patency at 6, 12 and 24 months were 63%, 56% and 54% respectively. Smoking was found to be a poor prognostic factor for primary (HR 3.734 (1.818-7.668 95% CI) p < 0.001) and secondary patency (HR 6.238 (2.729-14.257) p < 0.001). Smoking was also significantly associated with graft thrombosis (HR 5.741 (2.380-13.848 95% CI) p < 0.001). DISCUSSION: Primary patency rates are lower than previous reports whilst secondary patency is equivalent. Smoking results in a greater risk of thrombosis and poorer primary and secondary patency. This is recognised in vascular surgical grafts, but has not been previously described in AVGs for HD access. Smoking is a modifiable risk factor and as AVGs are typically used for end-stage vascular access patients. Pre-operative strategies to promote smoking cessation, including patient education and prehabilitation should be employed to improve outcomes.
