Difficult cannulation may cause VAPR and AAPR results to be higher due to an inability to obtain optimal needle placement. These results may or may not be related to access stenosis depending on the cause of needle placement problems.

Scar tissue build up around the access can cause problems with needle placement. It can also cause access compression which may lead to elevated VAPR and AAPR results.

For patients with chronic access issues, baseline pressure readings may be above threshold whether or not they have stenosis. If the baseline is above threshold, it is important to monitor for upward trends in your patient’s results.