The Disrupt PAD III study was designed as a randomized controlled trial (RCT) with an additional observational registry component. The registry, referred to as the Disrupt PAD III Observational Study (PAD III OS), was a global, prospective, multi-center, single-arm registry of the Shockwave Peripheral Intravascular Lithotripsy (IVL) System. The objective of this study was to assess the real-world acute performance of IVL in the treatment of calcified, stenotic, peripheral arteries that may not qualify for inclusion in the RCT. The study was designed to enroll a maximum of 1500 subjects from up to 60 global sites with a minimum of 200 subjects treated with the S4 IVL catheter, a line extension designed to treat smaller diameter peripheral vessels, including calcified below-the-knee (BTK) lesions.

Subjects were required to have target lesions in the iliac, femoral, ilio-femoral, popliteal, or infra-popliteal arteries with at least moderate calcification as determined by the investigator, defined as calcification within the lesion on both sides of the vessel assessed by angiography. Adjunctive therapies such as atherectomy, specialty balloons, and stents were allowed. Subjects were followed through discharge.

Inclusion Criteria:

Subjects were required to meet ALL of the following inclusion criteria in order to be included in this clinical study:

1. Subjects intended to be treated with Shockwave Medical Lithoplasty for de-novo or restenotic lesions of the femoral, ilio-femoral, popliteal, and infra-popliteal arteries.
2. Subjects presenting with claudication or CLI by Rutherford Clinical Category 2, 3, 4, 5, or 6 of the target limb.
3. Age of subject is > 18.
4. Subject of subject's legal representative have been informed of the nature of the study, agrees to participate and has signed the approved consent form.
5. Calcification is at least moderate defined as presence of fluoroscopic evidence of calcification: 1) on parallel sides of the vessel and 2) extending > 50% the length of the lesion if lesion is ≥50mm in length; or extending for minimum of 20mm if lesion is <50mm in length.

Exclusion Criteria:

Subjects that met ANY of the following exclusion criteria were not included in this clinical study:

1. Subjects with any medical condition that would make him/her an inappropriate candidate for treatment with Shockwave Lithoplasty as per Instructions for Use (IFU) or investigator's opinion.
2. Subject already enrolled in other investigational (interventional) studies that would interfere with study endpoints.

All patients presenting to the study sites with known PAD requiring an interventional procedure were evaluated for eligibility and participation in the study. If a patient met the baseline pre-procedure screening of inclusion and none of the exclusion criteria for the protocol version current at time of screening, and was willing to participate in the study, written consent was obtained. No study-specific requirements were performed prior to obtaining informed consent.