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:

* Men and women ≥ 18 years of age;
* Clinical diagnosis of Deep Vein Thrombosis (DVT) or Pulmonary Embolism (PE);
* Anticoagulant treatment completed
* No recurrence of Venous Thromboembolism (VTE)

Exclusion Criteria:

* Subjects with indications for long-term treatment with a vitamin K antagonist
* Active bleeding or high risk for serious bleeding
* Short life expectancy
* Uncontrolled high blood pressure
* Impaired kidney or liver function
B: Inclusion criteria:

1. Patients with confirmed symptomatic PE or proximal DVT of the leg(s) who have been treated for 6 to 18 months with therapeutic dosages (intended INR between 2-3) of an oral VKA (e.g. warfarin, acenocoumarol, phenprocoumon, or fluindione) or RE-COVER study medication up to the moment of screening for the current study.
2. Written informed consent

Exclusion criteria:

1. Younger then 18 years of age
2. Indication for VKA other than DVT and/or PE
3. Patients in whom anticoagulant treatment for their index PE or DVT should be continued
4. Active liver disease or liver disease decreasing survival (e.g. acute hepatitis, chronic active hepatitis, cirrhosis) or ALAT \> 3 x ULN
5. Creatinine clearance \< 30 ml/min
6. Acute bacterial endocarditis
7. Active bleeding or high risk for bleeding.
8. Uncontrolled hypertension (investigators judgement)
9. Intake of another experimental drug within the 30 days prior to randomization into the study
10. Life expectancy \<6 months
11. Childbearing potential without proper contraceptive measures\*, pregnancy or breast feeding
C: 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
D: Inclusion Criteria:

* Male or female subjects older than the minimum legal adult age (country specific);
* Acute symptomatic proximal DVT and/or symptomatic PE confirmed at the site by appropriate diagnostic imaging;
* Able to provide written informed consent

Exclusion Criteria:

* thrombectomy, insertion of a caval filter, or use of a fibrinolytic agent to treat the current episode of DVT and/or PE;
* More than 48 hours pre-treatment with anticoagulant therapy prior to randomization;
* Calculated Creatinine clearance (CrCL) \< 30 mL/min;
* significant liver disease (e.g., acute hepatitis, chronic active hepatitis, cirrhosis) or alanine transaminase (ALT) \>\\= 2 times the upper limit of normal (ULN), or total bilirubin (TBL) x 1.5 times the ULN;
* patients with active cancer for whom long term treatment with (LMW) heparin is anticipated;
* active bleeding or high risk for bleeding contraindicating treatment with (LMW) heparin or warfarin;
* chronic treatment with non-aspirin non-steroidal anti-inflammatory drugs (NSAIDs);
* treatment with aspirin in a dosage of more than 100 mg/per day or dual antiplatelet therapy;
* concurrent treatment with potent P-gp inhibitors;
* subjects with any condition that, as judged by the investigator, would place the subject at increased risk of harm if he/she participated in the study

Answer: C