RISK FACTORS FOR ARTERIOVENOUS FISTULA THROMBOSIS IN HEMODIALYSIS PATIENTS

Introduction:

Functional vascular access remains the most important issue in hemodialysis (HD) patients. Prevention of vascular access complications and maintaining arteriovenous fistula (AVF) patency for long-term use has high priority in dialysis therapy. The aim of the study was to determine the risk factors for arteriovenous fistula (AVF) thrombosis in HD patients.

Methods:

In this multicenter longitudinal prospective cohort study data were collected over a period of one year. The clinical parameters followed were hemodialysis time per week (hours), high ultrafiltration rate (UF>3% body weight), intradialytic hypotension frequency, comorbidities (diabetes mellitus-DM and heart failure-HF), AVF localization (distal or proximal), time before the first AVF cannulation (weeks), AVF time patency (months), blood flow, venous pressure, cannulation technique, AVF recirculation and HD adequacy parameter (eKt/V). The group of patients with AVF thrombosis was compared with other patients without AVF thrombosis. Statistical analysis was performed by SPSS, analysis of variance and chi square tests were performed for comparisons of means and frequencies, and Cox regression analysis for predictors of AVF survival.

Results:

Of total 397 HD patients (247M and 150F) with the average age 61,75±12,07 years in 39 HD patients (9,8%) AVF thrombosis was determined over a period of one year. The group of patients with AVF thrombosis in comparison to group of patients without AVF thrombosis had statistically significant lower AVF time patency (33,1±48,2 vs 57±56,7 months; p=0.012), lower blood flow (278,7±41,8 vs 297,5±42,5 ml/min; p=0.009) and greater AVF recirculation (9,8±11,3% vs 4,9±5,2%; p<0.001). The frequency of AVF thrombosis was significantly higher in patients with intradialytic hypotension in comparison to patients without hypotension (21,9% vs 7,5%; p<0.001). The frequency of AVF thrombosis was the highest in patients with blood flow below or equal 200 ml/min in comparison to patients with blood flow 201-300 ml/min and over 300 ml/min (30% vs 11,8% vs 6%; p=0,016). The frequency of AVF thrombosis was the highest in patients with venous pressure below or equal 100 mmHg in comparison to patients with venous pressure 101-200 mmHg and over 200 mmHg (50% vs 10,7% vs 0%; p=0,023). The frequency of AVF thrombosis was the highest in patients with antegrade bevel down cannulation in comparison to patients with antegrade bevel up cannulation and retrograde cannulation (18,8% vs 8% vs 0%; p=0,019). There was no statistically significant difference in AVF thrombosis frequency regarding age, sex, DM, heart failure, AVF localization and high UF rate. Statistically significant risk factors for AVF thrombosis by Cox regression analysis (Chi-square=59,675; p<0.001) were AVF recirculation equal or over 10% (HR=4,513; p<0.001), intradialytic hypotension (HR=3,367; p<0.001), blood flow equal or below 200 ml/min compared to blood flow over 300 ml/min (HR=21,065; p<0.001) and blood flow 201-300 ml/min compared to blood flow over 300 ml/min (HR=2,93; p=0.005) (Figure 1) and antegrade bevel down cannulation compared to antegrade bevel up cannulation (HR=2,43; p=0.012).

Conclusions:

Avoidance of intradialytic hypotension, timely correction of AVF recirculation and malfunction, and improvement of cannulation practice guidelines are the most important factors for prevention of AVF thrombosis and long-term AVF patency. 

I have no potential conflict of interest to disclose.

I did not use generative AI and AI-assisted technologies in the writing process.