Safety and efficacy of a D-Dimer-guided strategy for extension of secondary prophylaxis of venous thromboembolism - a prospective and randomized management trial

急性深静脉血栓形成(DVT)首次发作后，复发的风险相对较高，临床后果也很重要。因此，这些患者通常采用口服抗凝剂治疗(OAT)进行二级预防。这种治疗非常有效地降低了复发的风险，但会增加出血的风险。主要出血并发症可预计在2%的病人年内发生。因此，目前的建议将审裁处的期限限制在3至12个月。然而，停用燕麦片后，10%的首次出现无缘无故深静脉血栓的患者会在一年内复发。这组患者可能受益于长期的燕麦片疗法。两项独立观察性研究的结果显示，停用燕麦片后，D-二聚体水平升高的患者复发风险显著增加。D-二聚体是一种生物标志物，表明纤维蛋白形成后会发生纤溶。基于这些数据，我们假设D-二聚体检测可以成功地用于在无缘无故的DVT发作后定制患者的OAT持续时间。这项临床试验将使用前瞻性、随机化和对照设计来研究这一假设。停用燕麦片后，大约300名D-二聚体(&gt；500 ng/ml)升高的患者将被随机分为治疗组和非治疗组。在持续24个月的治疗期间，将记录客观记录的深静脉血栓/肺栓塞率(主要疗效终点)和出血率(主要安全终点)。持续12个月的跟踪期将显示停止延长的燕麦片后是否出现追赶现象。结果将表明，基于D-二聚体的治疗算法是否可以应用于临床实践。

After a first episode of acute deep venous thrombosis (DVT) the risk of recurrence is relatively high and clinical consequences are important. Therefore, secondary prophylaxis using oral anticoagulant treatment (OAT) is usually established in these patients. This treatment very effectively reduces the risk of recurrences but induces an increased risk of bleeding. Major bleeding complications can be expected in »2% patient-years. Therefore, current recommendations limit OAT to a period of 3 to 12 months. After stopping of OAT, however, »10 % of patients with an initial episode of unprovoked DVT will develop a recurrent event within 1 year. This group of patients may benefit from prolonged OAT. The results of 2 independent observational studies showed a significantly higher risk of recurrence in patients showing increased levels of D-Dimer after withdrawal of OAT. D-Dimer is a biomarker that indicates fibrin formation followed by fibrinolysis. Based on these data we hypothesize that D-Dimer testing can be successfully used to tailor the duration of OAT in patients after an unprovoked episode of DVT. This clinical trial will investigate this hypothesis using a prospective, randomized, and controlled design. Approximately 300 patients showing increased D-Dimer (> 500 ng/ml) after withdrawal of OAT will be randomly assigned to a treatment and a non-treatment group. During a 24-months lasting treatment period the rates of objectively documented DVT/pulmonary embolism (primary efficacy endpoint) and of hemorrhages (primary safety endpoint) will be documented. A 12-months lasting follow up period will show whether a catch-up phenomenon occurs after stopping of extended OAT. The results will show if D-Dimer-based treatment algorithms can be implemented into clinical practice.