Keywords: بیا; VTE; Venous thromboembolism; CVCs; Central venous catheters; aPTT; Activated partial thromboplastin time; CT; Computed tomography; CI; Confidence interval; (F1.2); Prothrombin fragment 1.2; (TAT); Thrombin-antithrombin; FVIII: C; FVIII coagulant activity;