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A simple decision rule including D-dimer to reduce the need for computed tomography-scanning in patients with suspected pulmonary embolism.
J Thromb Haemost. 2015 May 20;
Authors: van Es J, Beenen LF, Douma RA, den Exter PL, Mos IC, Kaasjager K, Huisman MV, Kamphuisen PW, Middeldorp S, Bossuyt PM
Abstract
INTRODUCTION: An 'unlikely' clinical decision rule with a negative D-dimer result safely excludes pulmonary embolism (PE) in 30% of presenting patients. We aimed to simplify this diagnostic approach and to increase its efficiency.
METHODS: Data of 723 consecutive patients with suspected PE were analysed (22% PE prevalence). After constructing a logistic regression model with the D-dimer test result and items from Wells' score, we identified the most prevalent combinations of influential items and selected new D-dimer positivity thresholds. The performance was separately validated in data from 2,785 consecutive patients with suspected PE.
RESULTS: Three Wells items significantly added incremental value to the D-dimer test: haemoptysis, signs of deep vein thrombosis and 'PE most likely'. Based on the most frequent combinations of these three items, we identified two groups: (1) none of these three items positive (41%), (2) one or more of these items positive (59%). When applying a 1000 μg/L D-dimer threshold in group 1 and 500 μg/L in group 2, PE could be excluded without CT-scanning in 36%, at a false-negative rate of 1.2% (95%: 0.04-3.3%). In the validation set, these proportions were 46% and 1.9% (95% CI 1.2-2.7%), respectively. Using the conventional Wells score with a normal D-dimer result, these rates were respectively 22% and 0.6% (95% CI 0.10-2.4%).
CONCLUSION: Combining Wells items with the D-dimer test resulted in a simplified decision rule, which reduces the need for CT-scanning in patients with suspected PE. A prospective validation is required before it can be implemented in clinical practice. This article is protected by copyright. All rights reserved.
PMID: 25990714 [PubMed - as supplied by publisher]