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

• Applicant: Professor Dr. Bernd Pötzsch
• Subject Area: Hematology, Oncology
• Term: from 2007 to 2011
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 34774826

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.

• DFG Programme: Clinical Trials
• Participating Persons: Professor Dr. Christian Hamm; Dr. Katharina Madlener