1. To perform an observational analysis to determine if mean translesional gradient measurements (TLG) are associated with differences in clinical outcomes in patients with femoropopliteal arterial disease and claudication.
2. Hypothesis: Patients stratified by a residual translesional gradient </= 11 mmHg after peripheral revascularization or angiography alone will have better clinical outcomes than patients with TLG > 11 mmHg as assessed by six minute walk (6MW), walking impairment questionnaire scores (WIQ), ankle brachial index and need for repeat procedure at 6 months.

The role of measuring translesional pressure gradients(TLG) in peripheral arterial disease lesions below the iliac artery is unclear. In a previous study the investigators demonstrated that a pressure wire can be effectively used to measure gradients in the femoropopliteal (FP) arterial bed showing good correlation between TLGs recorded with exercise ankle brachial index and walking impairment scores. However there is a no evidence that effectively modifying the gradient or having a high residual gradient after revascularization or just with medical therapy correlates with worse clinical outcomes.

This is a prospective, single center, observational clinical study to evaluate whether measurement of mean residual TLG at the time of angiography and/or immediately after endovascular revascularization are associated with clinically important outcomes in patients with claudication symptoms.

Prior to angiography they will be asked to complete an ankle brachial index evaluation, baseline six minute walk test and walking impairment questionnaire. Arterial access should be obtained in the contralateral common femoral artery to the symptomatic limb if feasible. Angiographic images are to be obtained, interpreted and clinical decisions regarding endovascular treatment are to be made per treating physician's discretion prior to obtaining translesional pressure gradients. In patients whose angiogram does not meet exclusion criteria and do not have a chronic total occlusion (CTO) a baseline TLG will be obtained. A 0.014" pressure wire/catheter to measure pressure will be inserted. After baseline calibration in the superficial femoral artery, the wire will be inserted past the narrowest lesion into the popliteal vessel. Intra-arterial adenosine 100-200 mcg will be given for hyperemia and measurements are to be recorded. If an intervention is planned, repeat measurements are to be obtained at the end of the procedure. If no intervention is planned this will be the residual or final TLG recorded. If baseline measurement are unable to obtained due to a CTO then only a post intervention residual TLG will be obtained and included in analysis. The operator will be blinded to the pre and post TLG measurements by turning the display monitor away from the procedure table and towards the recorder situated in the procedure room when measurements are being obtained.

Patients will follow up within two weeks post angiography for routine scheduled follow up and will obtain repeat ABI, WIQ, and six minute walk if they underwent revascularization. Treating physicians and study coordinators collecting these test measurements will be blinded to TLG measurements but not to angiography and treatment. Patients will again be evaluated at 6 months follow up with repeat ABI, WIQ and six minute walk.

Inclusion Criteria:

• Signed informed consent
• At least 18 years old
• Unilateral lower limb claudication Rutherford class 2-4
• Subjects must be able to complete screening six minute walk, walking impairment questionnaire, and baseline ankle brachial index
• Estimated survival ≥1 year in the judgment of the primary operator
• Documented symptomatic femoropopliteal (FP) atherosclerotic disease with at least moderate angiographic stenosis in the symptomatic lower extremity
• Subjects with multilevel disease can be screened and enrolled after treatment of other non FP PAD

Exclusion Criteria:

• Life expectancy less than 12 months or other medical co-morbid condition(s) that could limit the subject's ability to participate in the trial, limit the subject's compliance with the follow-up requirements, or impact the scientific integrity of the trial
• Severe Bilateral claudication
• Known hypersensitivity or contraindication to contrast dye that, in the opinion of the investigator, cannot be adequately pre-medicated
• Known hypersensitivity to adenosine or moderate to severe asthma
• Pregnancy
• Serum Creatinine >2.5
• Vascular graft, aneurysm or postsurgical stenosis of the target vessel
• Documented untreated severe iliac or below-the knee stenosis with < 2 vessel run-off in leg with femoropopliteal stenosis or untreated bilateral symptomatic peripheral arterial disease

Patients with claudication symptoms and femoropopliteal disease referred for peripheral angiography and possible revascularization.