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D-Dimer for suspected DVT

Evaluation of D-Dimer in the Diagnosis of Suspected Deep-Vein Thrombosis.
Wells PS, Anderson DR, Rodger M, Forgie M, Kearon C, Dreyer J, Kovacs G, Mitchell M, Lewandowski B, Kovacs MJ
N Engl J Med 2003 Sep 25;349(13):1227-1235.
abstract (from PubMed)

This study looked at the ability of a D-dimer assay used together with clinical probability to safely reduce the number of outpatients with suspected DVT requiring duplex ultrasound examination. Patients were randomized to either a "no D-dimer, all ultrasound" strategy, or to a "D-dimer, selective ultrasound strategy". Using a clinical scoring system, patients were first assigned a low or a high probability of having a DVT.

In the group of patients with a clinically low probability of DVT, those randomized to the all-ultrasound strategy underwent a single ultrasound examination. Patients randomized to the selective ultrasound strategy underwent an ultrasound examination only if the D-dimer was positive.

In the group of patients with a clinically high probability of DVT, those randomized to the all-ultrasound strategy underwent an ultrasound examination, with a second examination a week later if the first was negative. Those randomized to the selective strategy also all underwent a first duplex ultrasound, but underwent the second examination only if the D-dimer was positive.


The authors conclude that this approach, combining D-dimer assay with a clinical assessment is safe, and allows a reduction in the number of ultrasound examinations required.


Using a clinical scoring system

September 25, 2003

The applicability of this study depends on classifying patients into low-risk and high-risk groups the same way the authors did. They use a scoring system which takes into account a number of risk factors, including prior DVT, edema, pain along the trajectory of a vein, active cancer. If this particular scoring system is not used when applying these results to the "real world", they may not be valid.

Studies with clinical scoring systems always make me wonder how many practicing physicians actually remember and apply them. Maybe with the increasing use of handhelds this will become easier?
posted on 2003-09-25 13:05:44 by
Michael Jacobson, MD, MPH

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