Please select the eligibility criteria that correspond to the clinical trial below.
Title: Aspirin After Six Months or One Year of Oral Anticoagulants for the Prevention of Recurrent Venous Thromboembolism in Patients With Idiopathic Venous Thromboembolism. The WARFASA Study.
Brief Summary: To determine whether aspirin is more effective than placebo for the prevention of recurrent symptomatic venous thromboembolism when given for at least two years after the initial 6-12 month of oral anticoagulant therapy in patients with idiopathic venous thromboembolism


Options:
A: Inclusion Criteria:

* Symptomatic proximal DVT involving the iliac and/or common femoral vein, confirmed by Duplex Sonography, Angio-CT, Angio-MRI or Phlebography
* Written informed consent

Exclusion Criteria

* Age less than 18 years or greater than 75 years
* Symptom duration \> 14 days for the DVT episode in the index leg (i.e., non-acute DVT).
* In the index leg: established post-thrombotic syndrome (PTS) or previous symptomatic DVT within the last 2 years.
* Limb-threatening circulatory compromise.
* PE with hemodynamic compromise (i.e., hypotension).
* Inability to tolerate catheter procedure due to severe dyspnea or acute systemic illness.
* Allergy, hypersensitivity, or thrombocytopenia from heparin, r-tPA, or iodinated contrast, except for mild-moderate contrast allergies for which steroid pre-medication can be used.
* Known significant bleeding risk, or known coagulation disorder (including vitamin K antagonists with INR \> 2.0 and platelet count \< 100 000/mm3)
* Severe renal impairment (estimated GFR \< 30 ml/min).
* Active bleeding, recent (\< 3 mo) GI bleeding, severe liver dysfunction, bleeding diathesis.
* Recent (\< 3 mo) internal eye surgery or hemorrhagic retinopathy; recent (\< 10 days) major surgery, cataract surgery, trauma, CPR, obstetrical delivery, or other invasive procedure.
* History of stroke or intracranial/intraspinal bleed, tumor, vascular malformation, aneurysm.
* Severe hypertension on repeated readings (systolic \> 180 mmHg or diastolic \> 105 mmHg).
* Pregnant, lactation or parturition within the previous 30 days (positive pregnancy test, women of childbearing age must be tested or use a medically accepted method of birth control).
* Recently (\< 1 mo) had thrombolysis.
* Life expectancy \< 6 months or chronic non-ambulatory status.
* Participating in any other investigational drug or device study or previous enrollment in this study
* Inability to provide informed consent or to comply with study assessments (e.g. due to cognitive impairment or geographic distance).
* Any other condition that the investigator feels would place the patient at increased risk if the investigational therapy is initiated
B: Inclusion Criteria:

* first episode of symptomatic, objectively confirmed idiopathic proximal deep vein thrombosis and/or pulmonary embolism;
* initial treatment with unfractionated heparin or low-molecular-weight heparin (or effective alternative) followed by a vitamin K antagonist (target INR 2.0-3.0). All patients will receive 6 or 12 months of oral anticoagulant treatment. Patients initially treated with thrombolytic therapy who received warfarin therapy are eligible for inclusion.

Exclusion Criteria:

* permanent risk factors for venous thromboembolism: patients known to have antiphospholipid antibodies or lupus anticoagulant (based on local laboratory criteria) or to have homozygous factor V Leiden or homozygous prothrombin G21210A or heterozygous factor V Leiden plus heterozygous prothrombin G21210A or antithrombin III deficiency; patients with active malignancy
* temporary risk factors for venous thromboembolism
* any recurrence of venous thromboembolism or bleeding episode during the established 6-month period of oral anticoagulant treatment
* allergy or intolerance of aspirin
* clear indication for aspirin or other anti-platelet therapy (e.g. clopidogrel, ticlopidine)
* clear indication for long-term anticoagulant therapy (e.g. recurrent idiopathic venous thromboembolism, prosthetic heart valve)
* treatment with non-selective COX-1/2 non-steroidal anti-inflammatory drugs
* life expectancy less than 6 months
* active bleeding or at high risk of bleeding (gastrointestinal bleeding within the past 12 months; endoscopic diagnosis of peptic ulcer disease or ulcerative esophagitis within the past 6 months unless there is documented endoscopic evidence of healing; intracranial bleeding within the past year; known bleeding diathesis)
* anticipated non-adherence to study medications
* inability to attend follow up because of geographic inaccessibility
* failure to provide informed consent
C: Inclusion Criteria:

* proved SARS-COVID-2 infection

Exclusion Criteria:

* none
D: Inclusion Criteria:

* Signed Informed consent
* Confirmed COVID-19 (i.e. symptoms + positive test for SARS-CoV-2)
* Male or female, age ≥ 55 years
* At least two of the following additional risk factors:

Age ≥ 70 years Body mass index \> 25 kg/m2 Chronic obstructive pulmonary disease (COPD)\* Diabetes\* Cardiovascular disease\* Corticosteroid use

\*Defined as any disease requiring medical intervention or treatment.

Exclusion Criteria:

* Contraindications to unfractionated heparin or LMWH
* Recent (\<48 hours) or planned spinal or epidural anesthesia or puncture, PCI or thrombolytic therapy within the preceding 24 hours
* Increased risk for bleeding complications
* Pregnant women
* Severe renal impairment (GFR \< 30 mL/min)
* Receiving any antiplatelet therapy (with the exception of low dose (≤100mg) aspirin) or anticoagulant therapy (e.g. VKA, DOAC)
* Patients participating in an interventional study that is outside the purview of TRI sponsored studies.

Answer: B