Please select the eligibility criteria that correspond to the clinical trial below.
Title: Reduced-dosed Rivaroxaban and Standard-dosed Rivaroxaban Versus ASA in the Long-term Prevention of Recurrent Symptomatic Venous Thromboembolism in Patients With Symptomatic Deep-vein Thrombosis and/or Pulmonary Embolism
Brief Summary: This is a multicenter, randomized, double-blind, 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 of anticoagulation are eligible for this trial


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:

* Confirmed acute symptomatic proximal PE with or without symptomatic DVT

Exclusion Criteria:

* Legal lower age limitations (country specific)
* Thrombectomy, insertion of a caval filter, or use of a fibrinolytic agent to treat the current episode of DVT and/or PE
* Other indication for VKA than DVT and/or PE
* The pre-randomization anti-coagulant treatment (Criteria # 4) has been prolonged from 36 hours to a maximum of 48 hours.
C: 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
D: Inclusion Criteria:

* Confirmed acute symptomatic DVT, i.e. proximal or extensive calf-vein thrombosis involving at least the upper third part of the calf veins, without concomitant symptomatic PE
* Written informed consent

Exclusion Criteria:

* Legal lower age limitations (country specific)
* Thrombectomy, insertion of a caval filter, or use of a fibrinolytic agent to treat the current episode of DVT
* Other indication for VKA than PE/DVT
* More than 36 hours pre-randomization treatment with therapeutic dosages of (LMW) heparin or more than a single dose of VKA prior to randomization
* Participation in another pharmacotherapeutic study within the prior 30 days
* Creatinine clearance \< 30 mL/min, impaired liver function (transaminases \> 2 x ULN), or bacterial endocarditis
* Life expectancy \< 3 months
* Active bleeding or high risk for bleeding contraindicating treatment with (LMW) heparin
* Uncontrolled hypertension: systolic blood pressure \> 200 mmHg and diastolic blood pressure \> 110 mmHg
* Pregnancy or childbearing potential without proper contraceptive measures
* Any other contraindication listed in the labeling of warfarin, acenocoumarol, phenprocoumon, fluindione, UFH, enoxaparin, or tinzaparin
* Systemic treatment with azole compounds or other strong CYP3A4 inhibitors (e.g. ketoconazole, fluconazol, itraconazole, HIV protease inhibitors) within 4 days prior to randomization and during the study

Answer: A