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:

* Diagnosis of COVID-19 and hospitalization on ICU, or
* Diagnosis of COVID-19 and hospitalization on normal ward, or
* Diagnosis of COVID-19 (within 10 days) and troponin ≥ ULN and/or D-dimer ≥0.5 mg/L

Exclusion Criteria:

* Age below 18
* Life expectancy less than 3 months before COVID-19
* Resuscitation \> 30 minutes
* Hypersensitivity to the active substance, to Edoxaban or any of its excipients
* Significantly increased bleeding risk
* Other indication for anticoagulation beyond COVID-19
* GFR \< 15 ml/min
* Planned transfer of the patient to another clinic within the next 42 days
B: Inclusion Criteria:

1. Patients aged 50 years or older with a positive test for SARS-CoV2 in the past 5 days and eligible for ambulatory treatment.
2. Presence of respiratory symptoms (i.e. cough, sore throat, or shortness of breath) or body temperature \>37.5° C.
3. Ability of the patient to travel to the study center by private transportation, performed either by accompanying person from same household or by the patient him/herself
4. Ability to comply with standard hygiene requirements at the time of in-hospital visit, including a face mask and hand disinfectant.
5. Ability to walk from car to study center or reach it using a wheel chair transport with the help of an accompanying person from the same household also complying with standard hygiene requirements.
6. Ability to self-administer prefilled enoxaparin injections after instructions received at the study center or availability of a person living with the patient to administer enoxaparin.

Exclusion Criteria:

1. Any acute or chronic condition posing an indication for anticoagulant treatment, e.g. atrial fibrillation, prior VTE, acute confirmed symptomatic VTE, acute coronary syndrome.
2. Anticoagulant thromboprophylaxis deemed necessary in view of the patient's history, comorbidity or predisposing strong risk factors for thrombosis:

   1. Any of the following events occurring in the prior 30 days: fracture of lower limb, hospitalization for heart failure, hip/knee replacement, major trauma, spinal cord injury, stroke,
   2. previous VTE,
   3. histologically confirmed malignancy, which was diagnosed or treated (surgery, chemotherapy, radiotherapy) in the past 6 months, or recurrent, or metastatic, or inoperable.
3. Any clinically relevant bleeding (defined as bleeding requiring hospitalization, transfusion, surgical intervention, invasive procedures, occurring in a critical anatomical site, or causing disability) within 30 days prior to randomization or sign of acute bleeding.
4. Intracerebral bleeding at any time in the past or signs/symptoms consistent with acute intracranial hemorrhage.
5. Hemoglobin \<8 g/dL and platelet count \<50 x 109 cells/L confirmed by recent laboratory test (\<90 days).
6. Subjects with any known coagulopathy or bleeding diathesis, including known significant liver disease associated with coagulopathy.
7. Severe renal insufficiency (baseline creatinine clearance \<30 mL/min calculated using the Cockcroft-Gault formula) confirmed by recent laboratory test (\<90 days).
8. Contraindications to enoxaparin therapy, including prior heparin-induced thrombocytopenia and known hypersensitivity.
9. Current use of dual antiplatelet therapy.
10. Participation in other interventional studies over the past 30 days.
11. Non-compliance or inability to adhere to treatment or lack of a family environment or support system for home treatment.
C: Inclusion Criteria:

1. Men or women 18 years or older.
2. Body mass index (BMI) of 35kg/m2 or greater.
3. Undergoing laparoscopic bariatric surgery, i.e., laparoscopic sleeve gastrectomy, laparoscopic Roux-en Y gastric bypass or laparoscopic duodenal switch.

Exclusion Criteria:

1. History of previous deep vein thrombosis.
2. History of previous pulmonary emboli.
3. History of documented clotting/coagulation disorder.
4. History of cancer.
5. Weight \< 50 kg or \> 200 kg or unable to fit in MRI scanner.
6. Presence of metallic foreign bodies
7. Recent history of smoking (within the last year).
8. History of venous stasis disease.
9. History of obesity hypoventilation syndrome.
10. Patients who are unable to lay flat for extended periods of time or are claustrophobic.
11. Patients who have a pacemaker, an implanted defibrillator or certain other implanted or electronic or metallic devices (implanted medical or metallic devices, shrapnel, or metal).
12. History of hypersensitivity reaction to anticoagulation products.
13. History of HIT (Heparin Induced Thrombocytopenia.
14. History of Renal Insufficiency (Creatinine Clearance \< 50).
15. Active clinically significant bleeding.
16. Acute bacterial endocarditis.
17. BMI \> 60.
18. Patients with metallic foreign body or implant (unable to have an MRV study).
D: 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

Answer: D