Results for leg accesses will be slightly higher than arm accesses, because part of the calculation for VAPR uses the distance between the venous chamber and the access to calculate the measurement. When we make this calculation we use a constant based on the use of an arm access and the equipment in your clinic. Since this distance is larger with a leg access, the result can be elevated.

If you have a patient with a leg access that runs slightly above threshold but has no upward trend in VAPR results, it does not necessarily mean there is stenosis in the access. The most important factor in this case is to monitor for an upward trend in VAPR results.