Incidence of Venous Thromboembolism in Patients Undergoing Major Esophageal Resection

Inclusion Criteria: 1. Patients must be at least 18 years of age. 2. Patients may be of either gender. 3. Patients must be diagnosed with resectable esophageal cancer. 4. Patients must be undergoing an esophagectomy as either the first-line treatment or after completion of neoadjuvant therapies. 5. Patients must receive VTE prophylaxis as per local institutional guidelines 6. Patients must be competent to understand and sign consent documents. Exclusion Criteria: 1. All patients with known allergic or anaphylactic reaction to contrast dye, heparin, or low molecular weight heparin (LMWH). 2. Patients must not be under current anticoagulation for venous thromboembolism or other medical conditions. 3. Patients must not have known renal impairment, defined as creatinine clearance value of less than 55ml/min/m2 as calculated by the Cockcroft-Gault method. 4. Patients with a history of, or ongoing liver disease, manifested as ascites or previous peritoneal tapping for ascites. 5. Patients with known hepatic insufficiency, defined as international normalized ratio (INR) \>1.5. 6. Patients must not be pregnant or planning to become pregnant. 7. Patients must not have been diagnosed or treated for VTE in the past 3 months prior to surgery. 8. Patients must not have a present or previous increased risk of haemorrhage. 9. Patients must not have known, objectively confirmed bleeding and clotting disorders such as thrombophilia, von Willebrand's disease, hemophilia or otherwise active bleeding. 10. Patients must not have a history of previous heparin-induced thrombocytopenia (HIT). 11. Platelet count must be above 75,000, but transient, recovered thrombocytopenia associated with chemotherapy will not be a basis for exclusion. 12. Patients must not have previously inserted inferior vena cava (IVC) filter.