Background: Arteriovenous fistula (AVF) stenosis is an important complication in hemodialysis (HD) patients. Prediction of survival after percutaneous transluminal angioplasty (PTA) is also crucial for close-up monitoring and early correction. The impact of post-angioplasty access flow rates on AVF survival was controversial. The authors conducted a prospective study to assess the relationships between post-angioplasty access flow rate and AVF survival.

Materials and Methods: The cohort study in hemodialysis patients undergoing PTA for AVF stenosis at Srinagarind Hospital was performed between January 2012 and September 2022. Intra-access flow rates were measured by an ultrasound dilution technique during 2 weeks after PTA and followed every 3 to 6 months. Comparison of incidence rates and median survival times of AVF between the different access flow groups were conducted. Risk factors of AVF re-stenosis were evaluated by the Cox proportional hazard model.

Results: 62 patients with 94 PTA procedures (1 to 7 procedures/patient) were enrolled. The mean post-angioplasty intra-access flow rate was 726±327 ml/min. The incidence of AVF dysfunction was 1.05 per 1,000 patients-days (95% CI: 0.82 to 1.35) and the median post-angioplasty survival time was 341 days (95% CI: 233 to 802). Multivariable analysis demonstrated that comparisons with <500 ml/min group, hazard ratios (HR) of AVF failure in 501 to 750 and >750 ml/min groups were 0.43 (p=0.003) and 0.29 (p<0.001). The other risk factors were upper arm AVF (HR 2.58), a previous angioplasty procedure (HR 1.86), and body mass index (HR 0.90 for every increase 1 kg/m²).

Conclusion: Higher intra-access flow was associated with higher post-angioplasty AVF survival rate. The intra-access flow of less than 500 ml/min was associated with unacceptable survival times and a very high risk for AVF failure. Monitoring and surveillance for detection of early AVF re-stenosis are encouraged to strengthen the successful correction with high access flow and extended the usage duration.

Keywords: Arteriovenous fistulae; Percutaneous transluminal angioplasty; Post-angioplasty patency; Intra-access flow; Hemodialysis