Clinical Research Directory

Inclusion Criteria: * Age\>18 years old; Diagnosed with colorectal cancer and undergoing curative, palliative, or other limited surgeries (laparoscopic or open surgery), with an estimated surgery time of\>45 minutes; Expected postoperative survival\>6 months; Expected Caprini score of ≥ 5 on the first day after surgery; The patient agrees to the research plan and signs an informed consent form. Exclusion Criteria: * Renal dysfunction (CrCl\<30 mL/min) or liver dysfunction (ALT\>3 times the upper limit of normal); Known allergies to LMWH, anesthetics, or contrast agents; There is a systemic bleeding disorder or bleeding tendency, such as active peptic ulcer, uncontrolled hypertension, cerebral thrombosis within 6 months, cerebral hemorrhage, or a history of neurosurgical surgery; Known brain metastases, endocarditis, or previous heparin induced thrombocytopenia; VTE occurred within 3 months before surgery; Use heparin or oral anticoagulant therapy within 5 days before surgery; Pregnant or lactating women; Pregnant or lactating women; Any conditions that researcher determines the subject not suitable for anticoagulant therapy.