Please select the eligibility criteria that correspond to the clinical trial below.
Title: Comparing the Efficacy of Two Frequently Used Doses of Enoxaparin for VTE Prophylaxis After Bariatric Surgery
Brief Summary: Approximately two thirds of the adult population in developed countries is categorized as over-weight or obese (BMI\>30). In spite of worldwide increasing awareness, obesity is a major health concern. In the presence of numerous diets, medical therapies, and robust research, bariatric surgery remains the most effective means of weight reduction in morbidly obese patients (BMI\>40, or BMI\>35 with co-morbidities). However, bariatric surgery harbors a relatively high risk for postoperative complications; of them, venous thromboembolic events (VTE) are not common, but potentially lethal. Taken together with the propensity of morbidly obese patients to develop VTE, perioperative thromboprophylaxis is mandatory.

To date, low molecular weight heparins (LMWH) are most commonly used for VTE prophylaxis in the aforementioned population. Due to the pharmacologic properties of LMWH and the characteristics of surgically treated obese patients, the optimal dose that is to be utilized for VTE prophylaxis in this population remains unclear. Assessment of anti-FXa levels in the patients' plasma can be used in order to monitor LMWH activity. Levels of 0.2-0.5 U/ml have been proposed by some authors for VTE prophylaxis.

Few studies have compared different dosing regimens of enoxaparin (between 30mg-60mg q/12h) for VTE prophylaxis in the population undergoing bariatric surgery; nevertheless, these were small non- randomized trials, containing numerous methodological weaknesses. Hence, the optimal regimen of enoxaparin to be used for the prevention of VTE in the discussed population remains unclear.

The aim of the present study is to evaluate plasma levels of anti-FXa activity, comparing two most commonly used enoxaparin prophylactic regimens (40mg vs 60mg q/24h) in a large and homogenous cohort of sleeve gastrectomy patients. Although universally used by bariatric surgeons, the pharmacologic efficacy of these regimens has not been evaluated in patients undergoing bariatric surgery.


Options:
A: Inclusion Criteria:

* Adult patient (≥ 18 years of age)
* Positive COVID-test
* Under mechanical ventilation
* D-Dimers\>1.2 mg/L

Exclusion Criteria:

* Pregnancy
* Allergy to the drug (bivalirudin)
* Inherited coagulation abnormalities
* No informed consent
B: Inclusion criteria:

* Positive Sinerem®-enhanced MRI of carotid plaque confirmed by a consultant neuroradiologist
* Must either be statin naive or have been on a stable dose of a statin(Permitted statins and total daily dose are as follows: atorvastatin =10mg, simvastatin =40mg, pravastatin =40mg, fluvastatin =80mg, rosuvastatin =10mg for =4 weeks prior to screening, with no evidence of statin intolerability.)

Exclusion criteria:

* Require continued use of non-statin lipid modifying therapies or therapy with any other lipid regulating medications
* History of statin intolerance
* History of chronic viral hepatitis or other liver dysfunction
* Renal impairment with serum creatinine \>2.5 mg/dl (\>221 mol/L)
* History of myopathy or inflammatory muscle disease, or 3 times more than the upper limit of normal levels of total creatinine kinase in serum
* Doppler assessment of less than 40% stenosis during screening assessment
* Allergy to dextran and iron salts
* Contraindication to MRI scanning
* Planned carotid surgery or endovascular intervention earlier than 10 weeks within the study period
C: Inclusion Criteria:

* Adult patient undergoing laparoscopic sleeve gastrectomy.
* The patient undergoes the surgery in the surgical wing of the Tel-Aviv Sourasky Medical Center.
* The patient has received full information regarding the studies nature, has agreed to participate and has given informed consent (documented by a signed informed consent form).

Exclusion Criteria:

* Patients with a previous Venous Thromboembolic Event.
* Patients requiring an IVC filter.
* Patients with known thrombophilia due to coagulation factor disorders (i.e factor V leiden).
* Patients with a bleeding disorder
* Patients with renal failure.
D: Inclusion Criteria:

* Subject must be willing, understanding and able to provide written informed consent
* Subject must be a man or a woman with age \> 18 years at screening
* Subject must have an active moderate to severe COVID-19 confirmed by

  o A positive SARS-CoV-2 PCR test in the last 14 days
* At least one of the following features should be present

  * D-Dimer elevation \> 1.5 ULN (age adjusted cut-offs) AND/OR
  * Cardiac injury reflected by an elevation in hs-cTnT \> 2.0 upper limit of normal (ULN) AND at least one of the following conditions:

    * Known coronary artery disease (CAD)
    * Known diabetes mellitus
    * Active smoking
* A woman of childbearing potential must have a negative serum or urine pregnancy test before randomization occurs. Before randomization, a woman must be either:

  * Postmenopausal, defined as \>45 years of age with amenorrhea for at least 18 months,
  * If menstruating:

    * If heterosexually active, practicing a highly effective method of birth control, including hormonal prescription oral contraceptives, contraceptive injections, contraceptive patch, intrauterine device, double-barrier method \[(e.g., condoms, diaphragm, or cervical cap, with spermicidal foam, cream, or gel)\], or male partner sterilization, consistent with local regulations regarding use of birth control methods for subjects participating in clinical studies, for the duration of their participation in the study, or
    * Surgically sterile (have had a hysterectomy or bilateral oophorectomy, tubal ligation, or otherwise be incapable of pregnancy), or
    * Not heterosexually active

Exclusion Criteria:

* Subject has a very high bleeding risk: Any condition that, in the opinion of the investigator, contraindicates anticoagulant therapy or would have an unacceptable risk of bleeding, such as, but not limited to, the following:

  * Any bleeding (defined as bleeding requiring hospitalization, transfusion, surgical intervention, invasive procedures, occurring in a critical anatomical site, or causing disability) within 1 months prior to randomization or occurring during index hospitalization.
  * Major surgery, biopsy of a parenchymal organ, ophthalmic surgery (excluding cataract surgery), or serious trauma (including head trauma) within 4 weeks before randomization.
  * A history of hemorrhagic stroke or any intracranial bleeding at any time in the past, evidence of primary intracranial hemorrhage on CT or magnetic resonance imaging scan of the brain, or clinical presentation consistent with intracranial hemorrhage. This applies as well to subjects hospitalized for ischemic stroke upon randomization.
  * Subject has a history of or current intracranial neoplasm (benign or malignant), cerebral metastases, arteriovenous (AV) malformation, or aneurysm.
  * Active gastroduodenal ulcer, defined as diagnosed within 1 months or currently symptomatic or known AV malformations of the gastrointestinal tract.
  * Platelet count \<90,000/μl at screening.
  * Patients with the diagnosis of bronchiectasis, that due to the investigator judgement are at an increased bleeding risk.
* Subject has any of the following diseases in the medical history:

  * 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. Chronic hormonal therapy (e.g. tamoxifen, anastrozole, leuprolide acetate) for cancer in remission is allowed.
  * Any medical condition (e.g. atrial fibrillation) that requires use of any therapeutic parenteral or oral anticoagulant(s) (e.g. warfarin sodium or other vitamin K antagonists, Factor IIa or FXa inhibitors, fibrinolytics) concomitantly with study medication.
  * Subject has known allergies, hypersensitivity, or intolerance to rivaroxaban or any of its excipients.
  * Baseline eGFR \<30 mL/min/1.73m2 calculated using CKD-EPI formula
  * Known significant liver disease (e.g. acute hepatitis, chronic active hepatitis, cirrhosis) which is associated with coagulopathy or moderate or severe hepatic impairment.
  * Known HIV infection.
* Subject has undergone any of the following procedures or received any of the following drugs:

  * Received fibrinolysis during index hospitalization.
  * Use of antiplatelet therapy with prasugrel or ticagrelor up to 7 days prior to randomization. Other P2Y12 antagonists can be given. However, the use of concomitant antiplatelet therapy should be carefully considered. ASS \> 100 mg/d and continuous NSAIDs should be avoided.
  * Use of dual antiplatelet therapy, such as aspirin plus clopidogrel during the study.
* Subject is a woman who is pregnant or breast-feeding.
* Known intolerance or history of hypersensitivity to the active substance or to any of the excipients of the Investigational Medicinal Product (IMP)
* Subjects who are legally detained in an official institution.
* Subjects who may be dependent on the sponsor, the investigator or the trial sites, are not eligible to enter the trial.

Answer: C