PROLONG
Trial question
What is the role of D-dimer testing in determining the duration of anticoagulation therapy in patients who had a first idiopathic episode of VTE?
Study design
Multi-center
Open label
RCT
Population
Characteristics of study participants
53.0% female
47.0% male
N = 223
223 patients (118 female, 105 male)
Inclusion criteria: patients with a first unprovoked proximal DVT or PE who had received a VKA for at least 3 months and underwent D-dimer testing
Key exclusion criteria: serious liver disease, renal insufficiency, other indications or contraindications for anticoagulation, or a limited life expectancy
Interventions
N=120 abnormal D-dimer level with discontinuation of anticoagulation (discontinuation of VKA therapy)
N=103 abnormal D-dimer level with resumption of anticoagulation (resumption of VKA therapy)
Primary outcome
Recurrence of thromboembolism
15
2.9
15.0 %
11.3 %
7.5 %
3.8 %
0.0 %
Abnormal D-dimer level with discontinuation of
anticoagulation
Abnormal D-dimer level with resumption of
anticoagulation
Significant
increase ▲
NNH = 8
Significant increase in recurrence of thromboembolism (15% vs. 2.9%; aHR 4.26, 95% CI 1.23 to 14.6)
Safety outcomes
No significant difference in deaths.
Conclusion
In patients with a first unprovoked proximal DVT or PE who had received a VKA for at least 3 months and underwent D-dimer testing, abnormal D-dimer level with discontinuation of anticoagulation was inferior to abnormal D-dimer level with resumption of anticoagulation with respect to recurrence of thromboembolism.
Reference
Palareti G, Cosmi B, Legnani C et al. D-dimer testing to determine the duration of anticoagulation therapy. N Engl J Med. 2006 Oct 26;355(17):1780-9.
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