Patient with stenosis and angioplasty
This patient has a fistula. As you can see, the readings were consistently above the .55 ratio threshold (dashed red line) The sudden drop-off resulted from an angioplasty performed on May 8th. The trend is increasing again, indicating the need for another intervention.

Note: the vertical green lines are the average VAPR values for each treatment. The vertical red lines show when an alert was issued. The blue line is a moving average used to indicate trends.

Patient with developing fistula
This patient has a new fistula that is maturing well, and we see a reverse trend. Initially, the patient was alerting on both sides of the access, but as the access became better developed the alerts dropped off and blood flow rate increased.

The importance of trend analysis and testing the access with every treatment is evident in this scenario, as it can confirm that a fistula is maturing as expected. If the access was not maturing and the alerts continued, the graphs would provide clinicians with an early indication of a problem and allow them to promptly refer the patient for intervention.

Patient with failing access
This patient had an access revision on May 22nd that was not completely successful in correcting the problem within the access. The VAPR continued to increase and an angioplasty was performed on August 21st with poor results. This patient’s access will require additional revision or replacement.