Eligibility Criteria:
1. Adults ≥ 18 years of age.
2. Symptomatic upper- or lower-extremity venous thrombosis.
3. Treatment with the FLOWRUNNER Aspiration System for venous thrombectomy as part of routine care.
4. Willing to participate, able to understand and able to voluntarily sign the Informed Consent Form (ICF) prior to the initial qualifying procedure (index procedure).
5. Willing and able to participate and comply with all protocol-required follow-up visits and assessments.
Exclusion Criteria:
1. Evidence of a chronic or previously undiagnosed extensive clot on the pre-procedure venogram that makes endovascular thrombectomy inappropriate. Indicators of chronic clot include significant venous narrowing, the presence of diffuse collateral vessels, partial recanalization, Inferior Vena Cava (IVC) hyperplasia, or other congenital anatomic anomalies of the IVC, iliac veins, or subclavian veins.
2. No available upper- or lower-extremity venous access site suitable for the procedure due to absence of appropriate access, severe anatomical obstruction, scarring, or prior surgical alteration that prevents safe catheter insertion or any condition that, in the investigator's judgement, makes upper- or lower-extremity venous access technically infeasible or unsafe.
3. Pregnant or breastfeeding at the time of enrollment.
4. High-risk for pulmonary embolism (PE), defined as those presenting with:
* Hemodynamic instability (e.g., sustained hypotension, shock, or cardiac arrest)
* Requirement for thrombolytic therapy or surgical embolectomy
* Any condition that, in the investigator's judgment, would pose an unacceptable risk for participation in the study
5. Presents with cardiogenic shock or is hemodynamically unstable.
6. Any prior or current cancer diagnosis that, in the investigator's judgment, would pose an unacceptable risk or confound study outcomes including but not limited to:
* Tumor-associated venous thrombosis, defined as: venous thrombosis occurring in the context of active malignancy or cancer-related hypercoagulability
* Presence of metastatic disease or ongoing chemotherapy
7. Known antiphospholipid syndrome or other high-risk coagulation disorders, including:
* Confirmed diagnosis of antiphospholipid antibody syndrome
* Severe inherited or acquired thrombophilia (e.g., protein C or S deficiency, antithrombin deficiency)
* Any coagulation disorder that, in the investigator's judgment, would pose an unacceptable risk for thrombectomy or confound study outcomes
8. Estimated life expectancy of less than 12 months, based on the investigator's clinical judgement, available medical history, and prognostic indicators.
9. Chronic non-ambulatory status, defined as:
* Persistent inability to walk or perform basic mobility activities due to underlying medical conditions
* Conditions such as advanced neurological disease, severe musculoskeletal impairment, or long-term paralysis
10. Contraindicated for intravascular therapy including:
* Active bleeding
* Severe anemia with hemoglobin (Hb) \< 8 g/dL
* High risk of bleeding
* History of heparin allergy/hypersensitivity or heparin-induced thrombocytopenia
* Hypersensitivity to contrast agents
* Contraindication to oral/intravenous anticoagulation
* Hypercoagulable risk
* Any other condition that cannot be effectively managed
11. Renal dysfunction (eGFR \< 30 mL/min/1.73m2, not yet on dialysis).
12. Cerebral or myocardial infarction in the last 3 months.
13. Any condition that, in the investigator's judgment, would pose unacceptable risk or interfere with study participation, including:
* Severe allergy to contrast media
* Active systemic infection
* Uncontrolled coagulopathy
* Phlegmasia
