The purpose of this study is to test if dexamethasone, an anti-inflammatory medication approved by the US Food and Drug Administration (FDA), can be injected safely into the tissue around the blood vessel wall at the time of an angioplasty or atherectomy.

This is an investigator-initiated, single-arm, external pilot study to assess the safety and feasibility of perivascular administration of dexamethasone following endovascular superficial femoral and popliteal artery angioplasty or atherectomy.

Although dexamethasone is approved by the FDA for injection into blood, skin or joints, it has not been approved by the FDA for injection around blood vessels. The investigators want to find out if this procedure helps prevent re-narrowing of the blood vessel after angioplasty or atherectomy. The dexamethasone will be injected with a Bullfrog® Micro-Infusion catheter, which is an FDA-approved device for injecting medications into tissues around the blood vessel wall. The Bullfrog® Micro-Infusion catheter is similar to other balloon tipped catheters except that it contains a microneedle covered by a fold of semi-rigid balloon. Once the balloon is inflated, the microneedle is uncovered and a medication can be injected into the tissue around the blood vessel.

Inclusion Criteria:

• Patient is > 40 years and < 80 years of age
• Patient has severe, lifestyle-limiting claudication or critical limb ischemia (Rutherford classification 3-6)
• Patient has TASC II A, B or C disease, SFA revascularization is preferred over medical management, and endovascular approach is preferred revascularization strategy
• Patient has a resting ABI of <0.9 or an abnormal treadmill ABI. Patients with incompressible arteries must have a TBI <0.8
• Patient has at least 1 infra-popliteal run-off vessel with patency to the ankle without a >50% stenosis
• Successful crossing of the lesion with guidewire and successful atherectomy or angioplasty with residual stenosis <30% as compared to the reference vessels
• Atherectomy procedure does not result in embolization, arteriovenous fistula or perforation
• Patient agrees to return for a clinical assessment duplex ultrasound at 1, 3, 6, 9, 12 and 24 months (routine clinical care)

Exclusion Criteria:

• Patient is simultaneously participating in another investigational drug or device study
• Patient is pregnant or breast-feeding
• Patient has cancer, autoimmune disease, bone marrow or organ transplant, or other concurrent medical illness requiring immunosuppressive therapy
• Patient has end-stage renal disease and chronic kidney disease (eGFR<30)
• Patient has an active infection
• Patient has a known hypersensitivity or contraindication to heparin, contrast agents, excipients of Dexamethasone Sodium Phosphate Injection, USP, dexamethasone, or other glucocorticoids
• Patient has a life expectancy of less than one year