Did stopping ultrasound surveillance during COVID-19 result in an increase of the dialysis access thrombosis rate?

Purpose: The COVID-19 pandemic resulted in cessation and subsequent reduction of routine care including the outpatient ultrasound surveillance of AVF. This un-planned service disruption allowed evaluation of effectiveness of US surveillance in reducing AVF/AVG thrombosis.

Methods: This study was a secondary data analysis of monthly access patency for all in-centre patients receiving haemodialysis using an AVF or AVG over a 2-year period (April 2019-March 2021). The study included 298 patients with age, access type, patency and COVID status measured as variables. Thrombosis rates for the 12 months prior to COVID-19 and then during the first 12 months of the pandemic were also measured. Statistical analysis to assess mean and standard deviation for relevant variables was used. A value of <0.05 was deemed significant.

Results: At the end of the study an increase in thrombosis rate (%) in the non-surveillance year was observed ((1.20) thrombosis/patient/year in the surveillance group vs (1.68) thrombosis/patient/year in the non-surveillance group). Monthly mean of thrombosed access during surveillance ( = 3.58, 95% CI 2.19-4.98, SD = 2.193) and non-surveillance ( = 4.92, 95% CI 3.52-6.31, SD = 2.19); (7148) = 2.051, = 0.038.

Conclusion: Reduction in routine Ultrasound surveillance following the COVID-19 pandemic was associated with a significant increase in access thrombosis rate. Further research is needed to unpick whether the associations seen were directly due to service changes, associated with COVID-19 or other factors during the pandemic. This association was independent of SARS-CoV-2 infection status. Clinical teams should consider alternative service delivery options including out-reach, bedside surveillance to balance risks of access thrombosis versus reducing the risk of nosocomial infection with hospital visits.