Please select the eligibility criteria that correspond to the clinical trial below.
Title: Laparoscopic Bariatric Surgery: Two Regimens of Venous Thromboprophylaxis: Prospective Randomized Study
Brief Summary: Obese patients undergoing bariatric surgery warrant VTE prophylaxis because they are at high risk for developing a fatal pulmonary embolism or postthrombotic syndrome. However, a consensus does not exist on the most effective prophylactic approach.


Options:
A: Inclusion Criteria:

* Patients with confirmed diagnosis of COVID-19 admitted to hospital;
* Duration of symptoms related to hospitalization ≤ 14 days;
* Patients ≥ 18 year old;
* D-dimer above the upper limit of normal (collected until 72 hours before the randomization);
* Agreement to participate by providing the informed consent form (ICF).

Exclusion Criteria:

* Patients with indication for full anticoagulation during inclusion (for example, diagnosis of venous thromboembolism, atrial fibrillation, mechanical valve prosthesis);
* Platelets \< 50,000 /mm3
* Need for ASA therapy \> 100 mg;
* Need for P2Y12 inhibitor therapy (clopidogrel, ticagrelor or prasugrel);
* Chronic use of non-hormonal anti-inflammatory drugs;
* Sustained uncontrolled systolic blood pressure (BP) of ≥180 mmHg or diastolic BP of ≥100 mmHg;
* INR \> 1,5;
* Patients contraindicated to full anticoagulation (active bleeding, liver failure, blood dyscrasia or prohibitive hemorrhage risk as evaluated by the investigator);
* Criteria for disseminated intravascular coagulation (DIC);
* A history of hemorrhagic stroke or any intracranial bleeding at any time in the past or current intracranial neoplasm (benign or malignant), cerebral metastases, arteriovenous (AV) malformation, or aneurysm;
* Active cancer (excluding non-melanoma skin cancer) defined as cancer not in remission or requiring active chemotherapy or adjunctive therapies such as immunotherapy or radiotherapy;
* Hypersensitivity to rivaroxaban;
* Use of strong inhibitors of cytochrome P450 (CYP) 3A4 and/or P-glycoprotein (P-gp) (e.g. protease inhibitors, ketoconazole, Itraconazole) and/or use of P-gp and strong CYP3A4 inducers (such as but not limited to rifampin/rifampicin, rifabutin, rifapentine, phenytoin, phenobarbital, carbamazepine, or St. John's Wort);
* Known HIV infection;
* Creatinine clearance \< 30 ml/min according to the Cockcroft-Gault Formula;
* Pregnancy or breastfeeding.
B: Inclusion Criteria:

* BMI \>40 OR \>35 with comorbidities

Exclusion Criteria:

* No
C: Inclusion Criteria:

1. Birth to \<18 years of age; AND
2. Positive nucleic acid test for SARS-CoV-2 within the past 7 days; AND
3. Hospitalized, \<72 hours post-admission; AND
4. One or more signs and/or symptoms of COVID-19 illness within the past 72 hours, as follows:

   1. Cough; OR
   2. Fever (oral temperature \>100.4°F/38°C); OR
   3. Chest pain; OR
   4. Shortness of breath; OR
   5. Myalgia; OR
   6. Acute unexplained loss of smell or taste; OR
   7. New/increased supplemental oxygen requirement; OR
   8. Acute respiratory failure requiring non-invasive or invasive ventilation; OR
   9. Encephalitis.

Exclusion Criteria:

An individual who meets any of the following criteria will be excluded from participation in this study:

1. Receiving therapeutic anticoagulation for treatment of a thromboembolic event diagnosed within the past 12 weeks; OR
2. Clinical-relevant bleeding (see criteria under Primary Outcome, below) within the past 72 hours; OR
3. Platelet count \<50,000/µL within the past 24 hours; OR
4. Prothrombin time (PT) ≥2 seconds above the upper limit of age-appropriate local reference range within the past 24 hours; OR
5. Activated partial thromboplastin time (aPTT) ≥4 seconds above the upper limit of age-appropriate local reference range within the past 24 hours; OR
6. Fibrinogen level \<75 mg/dL; OR
7. Severe renal impairment, as defined by estimated glomerular filtration rate (eGFR) \<31 mL/min/ 1.73 m2, as calculated by the Schwartz formula; OR
8. Parent or legally authorized representative unwilling to provide informed consent for patient participation.
D: Inclusion Criteria for Anticoagulation Hypothesis

1. Adult patients (≥18 years), with polymerase chain reaction (PCR)-confirmed COVID-19 admitted to ICU within 7 days of initial hospitalization , who do not have another firm indication for anticoagulation (such as mechanical valve, high-risk atrial fibrillation (AF), VTE, or left ventricle (LV) thrombus),who are not enrolled in another blinded randomized trial, and are willing to participate in the study and provide informed consent .
2. Estimated survival of at least 24 hours at the discretion of enrolling physician

Exclusion Criteria for Anticoagulation Hypothesis

1. Weight \<40 Kilogram (kg)
2. Overt bleeding at the day of enrollment
3. Known major bleeding within 30 days (according to the Bleeding Academic Research Consortium (BARC) definition, Appendix A)
4. Platelet count \<50,000/Fl
5. Pregnancy (as confirmed by Beta human chorionic gonadotropin (HCG) testing among female patients \<50 years)
6. Patients on Extracorporeal Membrane Oxygenation (ECMO)
7. History of heparin induced thrombocytopenia or immune thrombocytopenia
8. Ischemic stroke within the past 2 weeks
9. Craniotomy/major neurosurgery within the past 3 months
10. Major head or spinal trauma in the past 30 days
11. Known brain metastases or vascular malformations (aneurysm)
12. Presence of an epidural, spinal or pericardial catheter
13. Major surgery other than neurosurgery within 14 days prior to enrollment
14. Coexistence of severe obesity (weight \>120 kg or BMI\>35 kg/m2 along with severe renal insufficiency defined as creatinine clearance (CrCl) \<30 mL/sec)
15. Allergic reaction to study medications
16. Lack or withdrawal of informed consent

Inclusion Criteria for the Statin Randomization

1. Patients enrolled for the anticoagulation randomization
2. Willingness to participation in the study and providing informed consent

Exclusions Criteria for the Statin Randomization

1. Baseline liver function tests\> 3 times upper normal limits (ULN) or creatine kinase (CK) \>500 U/L
2. Active liver disease (LFT\>3 ULN plus histologic finding including cirrhosis or inflammation or necrosis)
3. Routine use of statins prior to the index hospitalization
4. Previous documented statin intolerance

Answer: B