Aspirin and Compression Devices for VTE Prophylaxis in Orthopaedic Oncology

This is a research study to compare the efficacy of aspirin (acetylsalicylic acid) and pneumatic compression devices versus enoxaparin (also known as Lovenox) and pneumatic compression devices in preventing deep vein thrombosis in patients with pelvic and lower extremity malignant tumors and undergoing surgery. Pneumatic compression devices are also known as sequential compression devices and are inflatable compression sleeves that are placed around patient's legs to reduce the risk of clot formation deep vein thrombosis. Pneumatic compression devices are made of a soft material that wraps around the lower leg and periodically squeeze the calf. A deep vein thrombosis is a blood clot. Most hospitalized patients wear these as a preventive measure. Pneumatic compression devices alone are not sufficient to prevent deep vein thrombosis formation. Therefore, medicines, such as aspirin and enoxaparin are utilized. Both drugs are used for prevention, but there are no studies in patients with musculoskeletal tumors which have determined whether one drug is better than another. The knowledge gained from this study will determine whether aspirin and pneumatic compression devices is the same or better than enoxaparin and pneumatic compression devices in preventing deep vein thrombosis in this patient population and may result in fewer wound and bleeding complications

PRIMARY OBJECTIVES: I. To perform a randomized prospective study to determine efficacy of acetylsalicylic acid (ASA)+pneumatic compression device (PCD) prophylaxis compared to low-molecular weight heparin (LMWH)+PCD in patients undergoing orthopaedic procedures for musculoskeletal neoplasms (MSN) of the pelvis and lower extremity. II. To prove that ASA+PCD is clinically equivalent to or better than LMWH+PCD in providing deep vein thrombosis (DVT) prophylaxis in this patient population and results in fewer major bleeding complications. III. To measure rates of postoperative DVT and pulmonary embolism (PE) as primary outcomes. SECONDARY OBJECTIVES: I. To measure secondary outcomes including rates of readmission, reoperation, bleeding complications (including hematoma formation and prolonged wound drainage), and death. OUTLINE: Patients are randomized to 1 of 2 treatment arms. ARM I: Patients receive acetylsalicylic acid orally (PO) twice daily (BID) and wear PCD on days 1-28 after surgery. ARM II: Patients receive enoxaparin subcutaneously (SC) once daily (QD) and wear PCD on days 1-28 after surgery. After completion of study treatment, patients are followed up at 2 weeks, 6 weeks, and 3 months.

Wear PCD (Flowtron calf compression). Patients will continue to use PCDs for the duration of their hospitalization. If patients refuse to wear the PCDs, they will be withdrawn from the study.

This study will test if the ASA+PCD treatment group has a DVT rate (P1) not more than the DVT rate of the LMWH+PCD treatment group (P0) using a one sided test for these two proportions. Statistical significance will be defined as p < 0.05.

Inclusion Criteria: -Scheduled or to be scheduled for surgery performed on neoplasms of the pelvis or lower limbs, including both primary musculoskeletal lesions as well as metastatic lesions; these neoplasms may include major tumor resections, metastatic and pathologic fractures of the hip and lower extremities (LE), open biopsies, and primary malignant tumors; an active malignant neoplasm must be present at the time of surgery Exclusion Criteria: Prior history of DVT or PE Previously placed vena cava filter No detectable malignant disease at the time of operation Previous arterial thrombosis (myocardial infarction [MI], cerebral vascular accident [CVA]) Severe platelet dysfunction (uremia, medications, dysplastic hematopoiesis); excluded if platelets < 50,000 Preoperative anticoagulation or active/serious bleeding in past 2 weeks (prothrombin time [PT] & partial thromboplastin time [PTT] > 1.6 & > 35) Hypersensitivity or allergy to aspirin or heparin (including those diagnosed with heparin-induced thrombocytopenia) Conditions associated with bleeding (active ulcer disease, recent neurosurgery, bleeding disorders) Patients with renal insufficiency (creatinine [Cr] > 1.5) Pregnant patients Epidural anesthesia