Please select the eligibility criteria that correspond to the clinical trial below.
Title: Once-daily Oral Direct Factor Xa Inhibitor Rivaroxaban in the Long-term Prevention of Recurrent Symptomatic Venous Thromboembolism in Patients With Symptomatic Deep-vein Thrombosis or Pulmonary Embolism. The Einstein-Extension Study
Brief Summary: This is a multicenter, randomized, double-blind, placebo-controlled, event-driven, superiority study for efficacy. Patients with confirmed symptomatic DVT (deep vein thrombosis) or PE (pulmonary embolism) who completed 6 or 12 months of treatment with rivaroxaban or VKA (vitamin K antagonist) are eligible for this trial (Einstein-Extension study).


Options:
A: Inclusion Criteria:

* Patients with confirmed symptomatic PE and/or DVT who have been treated for 6 to 12 months and did not interrupt anticoagulation for longer than 1 week

Exclusion Criteria:

* Legal lower age limitations (country specific) Indication for therapeutic-dosed anticoagulants Indication for antiplatelet therapy or a conventional non-steroid anti-inflammatory drug (NSAID) Hepatic disease which is associated with coagulopathy leading to a clinically relevant bleeding risk Calculated creatinine clearance \< 30 mL/min
B: Inclusion Criteria:

* Patients with confirmed symptomatic PE or DVT who have been treated for 6 or 12 months with VKA or rivaroxaban

Exclusion Criteria:

* Legal lower age limitations (country specific)
* Indication for VKA other than DVT and/or PE
* Patients in whom anticoagulant treatment for their index PE or DVT should be continued
* Childbearing potential without proper contraceptive measures, pregnancy or breast feeding. Proper contraceptive measures are defined as a method of contraception with a failure rate \< 1 % during the course of the study (including the observational period). These methods of contraception according to the note for guidance on non-clinical safety studies for the conduct of human trials for pharmaceuticals (CPMP \[Committee for Proprietary Medicinal Products\]/ICH \[International Conference on Harmonization\]/286/95, modification) include consistent and correct use of hormone containing implants and injectables, combined oral contraceptives, hormone containing intrauterine devices, surgical sterilization, sexual abstinence and vasectomy
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

1. Acute deep vein thrombosis (DVT) of the leg involving proximal veins, and/or pulmonary embolism (PE) iin patients for whom at least 6 months of anticoagulant therapy is considered appropriate
2. Male or female, being 18 years of age or older
3. Written informed consent for study participation

Exclusion criteria

1. Overt symptoms of VTE for longer than 2 weeks prior to enrolment
2. PE satisfying at least one of the following criteria: Haemodynamic instability, embolectomy is indicated or performed, thrombolytic therapy is indicated or performed, or suspected source of PE is other than the legs
3. Actual or anticipated use of vena cava filter
4. Contraindications to anticoagulant therapy
5. Patients who in the investigators opinion should not be treated with warfarin
6. Allergy to heparins or other alternate approved therapy used for initial treatment, warfarin or dabigatran, or to one of the excipients included in these medications
7. Patients who in the investigators judgement are perceived as having an excessive risk of bleeding
8. Known anaemia
9. Need of anticoagulant treatment for disorders other than VTE
10. Recent unstable cardiovascular disease
11. Elevated AST or ALT \> 2x ULN
12. Liver disease expected to have any potential impact on survival
13. Patients who have developed transaminase elevations upon exposure to ximelagatran
14. Severe renal impairment
15. Women who are pregnant, nursing, or of childbearing potential who refuse to use a medically acceptable form of contraception
16. Participation in another clinical trial with an investigational drug during the last 30 days or previous participation in this study
17. Patients considered unsuitable for inclusion by the investigator

Answer: B