Abstract:Objective To compare the clinical characteristics of the upper extremity veinous thrombosis (UEVT) and to explore the influencing factors of thrombosis in different stages after peripherally inserted central catheter (PICC) placement in patients with tumor undergoing chemotherapy. Methods We prospectively followed up 3142 patients with tumor undergoing chemotherapy treated with PICC and analyzed relevant clinical data. Patients developing PICC-related UEVT 1 to 30 days or 31 to 210 days after PICC placement were included in shortterm thrombosis group (n = 86) or long-term thrombosis group (n = 68). Results The overall incidence of PICC-related UEVT was 4.90% with a total number of 154 patients. The incidence of asymptomatic thrombosis was higher in the short-term thrombosis group, while that of symptomatic thrombosis was higher in long-term thrombosis group (P < 0.05). The clinical symptoms and other complications associated with PICC were different between the two groups (P < 0.05), but there was no difference in the vein with thrombosis, the degree of thrombosis, history of PICC, site of puncture, the vein selected for puncture, catheter diameter to vein diameter ratio, length of catheter, the number of puncture, the number of catheter placement and the position of catheter tip between the two groups (P > 0.05). The time to PICC-related UEVT from the last chemotherapy was short in short-term thrombosis group but long in long-term thrombosis group. The history of surgery and platelet-stimulating agent use were different between the two groups (P < 0.05), whereas the history of radiotherapy, total parenteral nutrition, blood transfusion, erythropoietin and chemotherapy drug use were not different between the two groups (P > 0.05). After anticoagulant and thrombolytic treatments, the venous thrombosis in short-term thrombosis group was milder than that in longterm thrombosis group (P < 0.05). Conclusions The incidence of PICC-related UEVT in patients with tumor undergoing chemotherapy shows a dynamic trend - being first high, then low and slowly on the rise - with the change of catheter placement time. The characteristics and related factors of thrombosis in distinct stages after catheter placement are different. Thus, corresponding intervention measures should be taken to reduce the incidence of PICCrelated UEVT.