Treatment of Chronic Deep Vein Thrombosis (DVT) and Post-Thrombotic Syndrome (PTS) With the EkoSonic Endovascular System

The study is designed to evaluate the safety and efficacy of ultrasound accelerated
thrombolysis using the EkoSonic® Endovascular System with standard infusion of a
thrombolytic drug for PTS and chronic DVT. Clinical effectiveness will be evaluated using a
standard measure of severity of post-thrombotic syndrome over a year.

Key Inclusion criteria:

1. Male or female ≥ 18 years of age and ≤ 75 years of age.

2. Proximal DVT (iliac vein, common femoral vein, deep femoral vein, femoral vein) that
was objectively diagnosed with duplex imaging and/or venography ≥ 6 months prior to
study screening.

3. Persistent chronic DVT causing restrictive flow, as confirmed by imaging, within 60
days prior to the study procedure.

4. Villalta score ≥8 for the affected limb within 30 days prior to the study procedure.

5. Failed a minimum of 3 consecutive months of conservative treatment (therapeutic
anticoagulation and compression stockings) according to the completed Adherence to
Conservative Treatment Form.

Key Exclusion Criteria:

1. Treated with mechanical thrombectomy within 2 weeks of the study thrombolysis
procedure.

2. Treated with thrombolysis drugs within 48 hours of the study thrombolytic procedure.

3. Life expectancy less than 1 year.

4. Body Mass Index (BMI) >40 kg/m2 or per Investigator's discretion subject is able
tolerate the procedure and be compliant with post-procedure increased physical
activity.

5. No flow in popliteal vein on duplex imaging

6. Isolated iliac vein only thrombus.

7. Thrombus extending ≥ 3 cm into the inferior vena cava (IVC). If central venous
occlusion, consider computed tomography (CT) or magnetic resonance venography (MRV).
For subjects with bilateral DVT, it is recommended that central imaging be performed
prior to treatment to evaluate the status of the IVC.

8. Active bleeding, recent (< 3 mo) gastrointestinal (GI) bleeding, active peptic ulcer,
severe liver dysfunction, bleeding diathesis.

9. Recent (< 3 mo) internal eye surgery or hemorrhagic retinopathy; recent (< 10 days)
major surgery, cataract surgery, trauma, cardiopulmonary resuscitation (CPR),
obstetrical delivery, or other invasive procedure.

10. History of stroke or intracranial/intraspinal bleed, tumor, vascular malformation,
aneurysm.

11. Active cancer (metastatic, progressive, or treated within the last 6 months).
Exception: subjects with non-melanoma primary skin cancers are eligible to
participate in the study.

12. Hemoglobin < 9.0 mg/dl within 24 hours prior to the procedure

13. International normalized ratio (INR) ≥ 1.5 ng/dl within 24 hours prior to the
procedure

14. Platelet count < 100,000 cells/mm3 or >700,000 cells/mm3 within 24 hours prior to the
procedure.

15. Creatinine outside the normal range for the treating institution and considered
clinically significant by the Investigator.

16. Uncontrolled hypertension, defined as systolic > 175 mmHg and a diastolic > 110 mmHg.

17. Use of clopidogrel, ticlopidine, or other thienopyridine antiplatelet drug within 7
days of the study procedurei.

18. In the judgment of the clinician, the subject is at high risk for catastrophic
bleeding.