Vasc‑Alert is often compared to flow-based technologies such as the Transonic device and Fresenius On-Line Flow as incorporated in the K machine. While all three methods are deemed acceptable by the latest K/DOQI report on access site maintenance, there are indications that Vasc‑Alert is both more sensitive to changes in the growth of stenosis than flow based technologies, and seems to identify issues earlier than flow based technologies:

An independent study compared Vasc-Alert and Transonic and published at ASN in 2006.

This paper examines the sensitivity of both Vasc-Alert and Transonic to detect a change in stenosis. It examines 529 interventions and compares the readings taken before to the readings taken after an intervention. The ability to detect change is a marker for the growth of stenosis. Since the fact that an intervention creates a big change in the occlusion of the stenosis (decreasing the blockage), by presumption, the device that is more sensitive here, will also be more sensitive to detecting the growth of stenosis.

The conclusion is that Vasc-Alert is more sensitive to change in stenosis growth than Transonic. It also suggests that the performance of Transonic might be improved with more frequent measurements than once a month. A simple explanation of the study is also available.

An analysis of Transonic and Vasc-Alert results on the same patient population.

This analysis was internally derived from data provided by a dialysis center, which used both the Vasc-Alert and Transonic devices for a year. While this analysis does not have the same controls as a study, it does support the conclusions that Vasc-Alert:

• Vasc-Alert identifies more patients with issues, (74% vs. 52%)
  
  
• Vasc-Alert identifies patients with issues earlier, (74% vs. 18%)
  
  
• When Vasc-Alert alerts earlier, it does so with a longer lead-time. (38 vs. 26 days)
  
  

Operational Considerations for Pressure and Flow