Patients with acute venous thromboembolism (VTE) in the setting of transient provoking factors are typically treated with short-term anticoagulation. However, the risk of recurrence may be increased in the presence of enduring risk factors. In such patients, the optimal duration of treatment remains uncertain. HI-PRO is a single-center, double-blind randomized trial. Patients with deep vein thrombosis (DVT) or pulmonary embolism (PE) following a major provoking factor, including major surgery or major trauma, who completed at least 3 months of standard-dose therapeutic anticoagulation and have at least one enduring risk factor (such as obesity or heart failure), will be considered for inclusion. Patients will be randomized to apixaban 2.5 mg twice daily or placebo for 12 months. The primary efficacy outcome will be symptomatic recurrent VTE –a composite of DVT and/or PE at 12 months after randomization. Secondary efficacy outcomes include a composite of death due to cardiovascular causes, nonfatal myocardial infarction, stroke or systemic embolism, major adverse limb events, or coronary or peripheral ischemia requiring revascularization at 12 months, and individual components of these outcomes. The primary safety outcome is major bleeding according to the International Society on Thrombosis and Haemostasis definition. The study plans to enroll 600 patients (300 per arm) to have 80% power for detecting a 75% relative risk reduction in the primary outcome. Active recruitment began in March 2021. HI-PRO will provide clinically meaningful data on whether patients with provoked VTE and enduring risk factors have fewer adverse clinical outcomes if prescribed low-intensity extended duration anticoagulation.

中文翻译：

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延长持续时间低强度阿哌沙班预防诱发静脉血栓栓塞患者复发：HI-PRO 试验设计

急性静脉血栓栓塞 (VTE) 患者在短暂诱发因素的情况下通常接受短期抗凝治疗。然而，在存在持久风险因素的情况下，复发的风险可能会增加。在此类患者中，最佳治疗持续时间仍不确定。HI-PRO 是一项单中心、双盲随机试验。发生深静脉血栓形成 (DVT) 或肺栓塞 (PE) 的患者在主要诱发因素（包括大手术或重大创伤）后完成了至少 3 个月的标准剂量治疗性抗凝治疗并具有至少一个持久的风险因素（例如肥胖或心力衰竭），将被考虑纳入。患者将被随机分配至阿哌沙班 2.5 mg 每日两次或安慰剂治疗 12 个月。主要疗效结果将是有症状的复发性 VTE——随机分组后 12 个月时 DVT 和/或 PE 的复合。次要疗效结局包括心血管原因导致的死亡、非致死性心肌梗死、中风或全身性栓塞、主要不良肢体事件或需要在 12 个月时进行血运重建的冠状动脉或外周缺血，以及这些结局的各个组成部分。根据国际血栓和止血协会的定义，主要安全性结局是大出血。该研究计划招募 600 名患者（每组 300 名），以有 80% 的功效来检测主要结果的 75% 相对风险降低。积极招聘于 2021 年 3 月开始。