Background:There is insufficient evidence regarding the optimal treatment method for distal deep vein thrombosis (DVT), including indications for anticoagulation therapy. Treatment results of patients with distal DVT were evaluated to clarify the risk factors that result in extension of distal DVT to the proximal vein and indications for anticoagulation therapy.

Methods and Results:Among 430 patients with DVT between January 2018 and December 2019, 253 were diagnosed with distal DVT; 41 patients who had already started anticoagulation therapy were excluded, and the remaining 212 were included as study subjects. Anticoagulation therapy was not started immediately; conservative treatment with compression stockings was performed. Ultrasonography after 2 weeks revealed thrombus disappearance in 39 patients (21%), and thrombus reduction in 38 patients (20%). In contrast, extension of thrombus to the proximal vein was noted in 12 patients (6.3%) and anticoagulation therapy was commenced. After 3 months, the thrombus had disappeared in 75 patients (52%). No patient developed pulmonary thromboembolism during follow-up. With respect to the risk factors for extension to proximal vein during conservative treatment, active cancer (P=0.03), prolonged bed rest (P<0.01), and D-dimer level >8µg/mL (P=0.01) were identified.

Conclusions:It is reasonable to consider anticoagulation therapy in distal DVT patients with active cancer, prolonged bed rest or high D-dimer level.

背景：关于远端深静脉血栓形成 (DVT) 的最佳治疗方法的证据不足，包括抗凝治疗的适应症。对远端 DVT 患者的治疗结果进行评估，以明确导致远端 DVT 扩展至近端静脉的危险因素和抗凝治疗的指征。

方法和结果：2018 年 1 月至 2019 年 12 月的 430 例 DVT 患者中，253 例被诊断为远端 DVT；41 名已经开始抗凝治疗的患者被排除在外，其余 212 名被纳入研究对象。未立即开始抗凝治疗；进行了压力袜保守治疗。2 周后超声检查显示 39 名患者（21%）血栓消失，38 名患者（20%）血栓减少。相比之下，12 名患者 (6.3%) 发现血栓延伸至近端静脉并开始抗凝治疗。3 个月后，75 名患者（52%）的血栓消失。随访期间没有患者发生肺血栓栓塞。关于保守治疗期间延伸至近端静脉的危险因素，活动性癌症（P=0.

结论：对于活动期癌症、长期卧床或高 D-二聚体水平的远端 DVT 患者，考虑抗凝治疗是合理的。