Prospective, Multi-center, Single-arm Study of the Auryon Laser System for Treatment of Below-the-Knee (BTK) Arteries

Inclusion Criteria: 1\. Subject is 18 years of age or older. 2. Critical limb ischemia (CLI) in the target limb from the distal segment (P3) of the popliteal artery to the ankle joint prior to the study procedure with Rutherford Category 4-5 in the target limb from the distal segment (P3) of the popliteal artery to the ankle joint prior to the study procedure. 3\. Patient has signed approved informed consent. 4. Patient is willing to comply with the follow-up evaluations Angiographic Inclusion Criteria 1. Target lesions(s) must be viewed angiographically and have ≥50% stenosis. More than one lesion can be included in the same vessel. 2. Only 1 target vessel is included in the study. 3. Intraluminal crossing of the lesion. If this is not certain, IVUS may be used to verify this per operator's discretion. Target Lesion reference vessel diameter (RVD) between 1.5 mm - 4.5 mm. by investigator estimate. 4\. Target lesion is denovo or restenotic. \- Exclusion Criteria: 1. Target lesion is in a vessel graft or synthetic graft. 2. Subjects requiring dialysis. 3. Subject is unable to understand the study or has a history of non-compliance with medical advice. 4. Subject is unwilling or unable to sign the Informed Consent Form (ICF) 5. Subject is currently enrolled in another clinical investigational study that might clinically interfere with the current study endpoints. 6. Subject has a known sensitivity to contrast media and the sensitivity cannot be adequately pre-medicated for. 7. Subject has a CVA or TIA within 4 weeks prior to the Auryon procedure. 8. Planned Use of another debulking device or specialty balloons before or after the Auryon laser during the index procedure 9. Patient has any planned surgical intervention or endovascular procedure ≤14 days after the index procedure or had these procedures in the past 14 days 10. Life expectancy of less than one year judged by the investigator 11. Patient unable to take anticoagulant or antiplatelet agents 12. Platelet count less than 80,000K or bleeding disorders 13. Subject is suspected of having an active systemic infection. 14. Patient enrolled once already in the protocol 15. Planned major amputation of either leg. 16. Acute limb ischemia 17. Current Covid-19 Infection or history of Covid-19 in the past 30 days. 18. Subject is pregnant or planning on becoming pregnant. 19. Vulnerable patients who are unable to give informed consent on their own Pregnant and Vulnerable Populations. There will be no female patients who are pregnant or any vulnerable populations enrolled in the study. 20. Subject experiencing ongoing cardiac problems that per the investigator judgment would not make the subject ideal per the procedure 21. Subject has evidence of intracranial or gastrointestinal bleeding within the past 3 Angiographic Exclusion Criteria 1\. Failure to treat clinically significant inflow lesions in the contralateral iliac, ipsilateral iliac, femoral, or P1-P2 segments of the popliteal arteries with ≤ 30 % residual stenosis, and no serious angiographic complications (e.g., embolism) 2. Failure to successfully treat significant non-target infra-popliteal lesions prior to treatment of the target lesion. Successful treatment is defined as obtaining ≤ 50 % residual stenosis with no serious angiographic complications (e.g., embolism). 3\. Failure to successfully cross the guidewire across the target lesion; successful crossing is defined as tip of the guidewire distal to the target lesion in the absence of flow limiting dissections or perforations. 4\. In-stent restenosis. \-