This study focuses on people who have peripheral artery disease or a dysfunctional arteriovenous fistula and will be treated as part of routine standard care with a device called the Serranator PTA Serration Balloon Catheter (Serranator). The Serranator is approved by the U.S. Food and Drug Administration (FDA). It is a type of balloon catheter that includes the technology to score the lesion to enhance the balloon effect, which helps open up the blood vessel. The study will collect information about the safety and effectiveness of the Serranator; the data will be included in a registry about the device. Study procedures include collecting post-surgery information from medical records about how well the surgery using the Serranator PTA Serration Balloon Catheter worked for the procedure and how the patient felt following the surgery. Researchers aim to confirm the performance and safety of the Serranator when used to treat a lesion in the blood vessel. This will be evaluated as a part of standard of care with an angiogram (a type of imaging to view the vessels and determine how it worked). Safety will also be assessed by tracking adverse events (unwanted effects or injuries).