To observe early safety and performance of the Shockwave Medical Lithoplasty® System (specifically, Lithoplasty® Catheters: 2.5 x 60mm, 2.75 x 60mm, 3.0 x 60mm, 3.25 x 60mm, and 3.5 x 60mm) in subjects to demonstrate that the Shockwave device can safely and effectively deliver localized pulsatile mechanical energy for balloon dilation of calcified, stenotic, infrapopliteal arteries.

Shockwave Medical, Inc. intends to conduct a prospective, single-arm, multi-center, clinical study designed to evaluate the early safety and performance of the Shockwave Lithoplasty® System in subjects with moderate to heavily calcified peripheral arteries with 2.5mm to 3.5mm reference vessel diameter at the target site. The Shockwave Lithoplasty® System is indicated for lithotripsy-enhanced, low-pressure balloon dilation of calcified, stenotic peripheral arteries in patients who are candidates for percutaneous therapy. Up to twenty subjects will be enrolled and treated with Lithoplasty® System.

Inclusion Criteria:

1. Subject is able and willing to comply with all assessments in the study.
2. Subject or subject's legal representative have been informed of the nature of the study, agrees to participate and has signed the approved consent form.
3. Age of subject is >18.
4. Rutherford Clinical Category 1 - 5.

Angiographic Inclusion Criteria:

1. Single or multiple target lesion(s) is/are located in a de novo artery distal to the trifurcation vessels and extends to and ends above the ankle
2. Target vessel reference diameter is between 2.5mm and 3.5mm by visual estimate
3. Target lesion with diameter stenosis ≥50% by investigator via visual estimate
4. If inflow disease >50% proximal to the trifurcation vessels is present, and it can be treated with POBA, stent or Lithoplasty and without complications.
5. Target lesion is ≤150mm in length
6. Subject has at least one patent tibial vessel (>50%) with run-off to the foot.
7. No evidence of aneurysm or acute thrombus in target vessel.
8. Any presence of calcification within the target lesion as assessed by imaging (radiograph, CT or angiography).

Exclusion Criteria:

1. Rutherford Clinical Category 6.
2. Target lesion is within only lower extremity vessel with < 50% stenosis.
3. Gangrene of the lower extremity.
4. Planned major amputation of the target leg.
5. Previously implanted stent in the treatment lesion
6. Target lesion length exceeds 150mm.
7. Patient has chronic total occlusion of target lesion.
8. Patient has significant stenosis (>50% stenosis) or occlusion of inflow tract (e.g., iliac or common femoral) not successfully treated with POBA, stent or Lithoplasty and without complications.
9. Patient in whom antiplatelet, anticoagulant, or thrombolytic therapy is contraindicated.
10. Patient has known allergy to contrast agents or medications used to perform endovascular intervention that cannot be adequately pre-treated.
11. Patient has known allergy to urethane, nylon, or silicone.
12. Patient is pregnant or nursing.
13. Patient is participating in another research study involving an investigational agent (pharmaceutical, biologic, or medical device) that has not reached the primary endpoint.