Eligibility Criteria:
Inclusion Criteria:
* Men and women
* Age \> 18 years
* Current or prior diagnosis of symptomatic MM based on International Myeloma Working Group (IMWG) guidelines (http://imwg.myeloma.org/category/guidelines-2/) and will be starting or already receiving IMiD therapy with thalidomide \[Thalomid\], lenalinomide \[Revlimid\], or pomalidomide \[Pomalyst\]
* IMiD therapy given in the setting of newly diagnosed MM, relapsed MM, progressive MM, maintenance therapy or consolidation therapy as per IMWG criteria
* Willing to provide written informed consent
* Eastern Cooperative Oncology Group (ECOG) functional status ≤ 2
* Providers must plan to treat the patient with IMiD therapy for a minimum of 6 cycles
Exclusion Criteria:
* Pregnancy
* Breastfeeding
* Women of child-bearing potential who are unwilling or unable to use an acceptable method of birth control (such as oral contraceptives, other hormonal contraceptives \[vaginal products, skin patches, or implanted or injectable products\], or mechanical products such as an intrauterine device or barrier methods \[diaphragm, condoms, spermicides\]) to avoid pregnancy for the entire study
* Any prior venous thromboembolism
* Contraindication to anticoagulant therapy
* Conditions for which serious bleeding may occur including:
1. Current or within last 6 months: intracranial bleeding, intraocular bleeding, gastrointestinal bleeding, endoscopically documented ulcer disease
2. Current or within last month: head trauma or other major trauma, major surgery
3. Current or within last 2 weeks: stroke, neurosurgical procedure
4. Current: gross hematuria, major unhealed wound, major surgery planned during the trial period, intracranial mass, vascular malformation, or aneurysm, overt bleeding, blood dyscrasia
5. CNS involvement of MM or other history of CNS malignancy
* Active and clinically significant liver disease
* Uncontrolled hypertension: systolic blood pressure \>180 mm Hg or diastolic blood pressure \>100 mm Hg
* Current endocarditis
* Requirement for ongoing anticoagulant therapy, including mechanical heart valve replacement and atrial fibrillation
* Severe valvular heart disease, including rheumatic heart disease and mitral stenosis
* Bioprosthetic heart valve replacement
* Requirement for dual antiplatelet therapy or single agent antiplatelet therapy with clopidogrel, prasugrel, or ticagrelor
* Requirement for aspirin at a dose higher than 165 mg daily.
* Hemoglobin \< 9 mg/dL at time of screening
* Platelet count \< 100,000/mm3 at time of screening
* Serum calculated creatinine clearance (CrCl) \< 25 ml/m at time of screening
* Alanine aminotransferase or aspartate aminotransferase level \> 2 times the upper limit of the normal at time of screening
* Total bilirubin level \> 1.5 times the upper limit of the normal at time of screening
* Life expectancy \< 12 months or hospice care
* Prisoners or subjects who are involuntarily incarcerated
* Subjects who are compulsorily detained for treatment of either a psychiatric or physical (e.g., infectious disease) illness
* Receiving concurrent non-FDA-approved or investigational agents or has received an investigational agent within the past 30 days prior to the first dose of study treatment (with the exception of approved medications being used for an approved indication, e.g., investigating a new dosing regimen for an approved indication).
* Any condition, which in the opinion of the investigator, would put the subject at an unacceptable risk from participating in the study
* Any other medical, social, logistical, or psychological reason, which in the opinion of the investigator, would preclude compliance with, or successful completion of, the study protocol