Is Surveillance Useful? A New Spanish RCT Confirms its Value
The value of vascular access surveillance has been widely debated over the past decade. Some studies attest to its usefulness for identifying stenoses. Others question its value. Although all vascular access clinical guidelines recommend monitoring and surveillance protocols to prevent vascular access thrombosis, randomized clinical trials (RCT) have failed to consistently demonstrate the benefits of flow-based surveillance. Thus, the controversy over the value of surveillance continues.
A randomized controlled trial (RCT) published in September’s Journal of Vascular Surgery now adds credence to the value of regular surveillance of hemodialysis patients. First presented at the 9th Congress of Vascular Access Society, in Barcelona, Spain this past spring, a group of Spanish clinicians conducted a randomized controlled trial (RCT) in five Madrid hospitals. In parallel groups of 98 patients each with AV fistulas, they compared flow-based techniques that included ultrasound dilution and Doppler ultrasound with classical monitoring and surveillance methods. When flow was ≤ 500 ml/min and had decreased by at least 25% or if a hemodynamically significant stenosis was present, the patient was referred for fistulography, surgery or close clinical observation. Thrombosis rate, assisted primary patency rate, primary and secondary patency rates were measured.
The results demonstrated a significant reduction in the thrombosis rate in the experimental group after one year (0.022 thrombosis/patient/year of risk as compared to 0.099 thrombosis/patient/year at risk in the control group). The assisted primary patency rate was significantly higher in the flow surveillance group than in the control group. Those undergoing angioplasty and surgery were higher in the experimental group compared to the control group, but thee was no significant difference in non-assisted primary patency rates between the two groups. There was non-significant improvement in the secondary patency rate in the QA (experimental) group.
From these results, the clinicians concluded that vascular access surveillance, combining Doppler Ultrasound and Indicator Dilution methods, shows a reduction in thrombosis rate and an increased assisted patency rate in AVFs after one year.
Aragoncilla I et al, “The impact of access blood flow surveillance on reduction of thrombosis in native arteriovenous fistula: a randomized clinical trial,” J Vasc Access. 2015 Sep 18.