The Combination of Low D-Dimer Concentration and Non-High Clinical Probability Score is a Safe Strategy to Exclude Deep Venous Thrombosis

Reviewer: Walter F. Sall, MD
The Abramson Cancer Center of the University of Pennsylvania
Last Modified: December 10, 2001

Presenter: Roger E.G. Schutgens
Presenter's Affiliation: St. Antonius Hospital, the Netherlands
Type of Session: Scientific

Background

Compression Ultrasonography (CUS) is considered the gold standard for the diagnosis of deep venous thrombosis (DVT). Though it is highly sensitive, it is expensive and inefficient, given that serial CUS examinations are required to reliably excude DVT.

It has been shown that it is safe to withold anti-coagulation in patients with a low pre-test clinical probability score (PCP) and an initial negative CUS.

It has also been shown it is safe to withold anti-coagulation in patients with normal D-Dimer (DD) and an initial negative CUS.

The goal of this trial was to determine if the combination of PCP and DD could reliably exclude DVT, reducing the need for CUS.

Materials and Methods

This is a prospective, multi-center cohort study of 902 outpatients with symptoms suspicious for DVT.

PCP score was assigned: "Non-high" was <3, while high was >3. DD was tested using quantitative latex assay: normal was < 500ug/L.

Three cohorts were created. Normal DD and non-high PCP received follow up only. 175 patients were in this group. Normal DD and high PCP proceeded to undergo a single CUS. This group included 38 patients. High DD patients proceeded to serial CUS irrespective of PCP status. This group included 595 patients.

Outcome measures were documented DVT or PE in the follow-up period

Results

In the normal DD, non-high PCP group, one DVT in 175 patients occurred.

In the normal DD, high PCP group, one PE in 38 patients occurred.

In the high DD group, 291 of 595 had an initial abnormal CUS. Of those with a normal CUS, 15 proceeded to develop DVT during F/U.

The overall failure of this strategy for DVT diagnosis was less than 3%, which is comparable to that seen in most studies of serial CUS.

The need for CUS was reduced by 29% over a strategy using CUS alone.

Author's Conclusions

Non-high PCP and normal DD is a safe and effective method to rule out DVT in the outpatient setting without the use of CUS.

The need for CUS can be reduced by 29% with the use of this method

Clinical/Scientific Implications
PCP and DD assays have been shown here to adequately replace CUS in the disgnosis of DVT without the occurrence of excess PE or subsequent DVT. As PCP and DD testing methods may vary from one institution to another, it remains to be seen whether the success of this method will stand up to testing. While this method is very promising, CUS remains the standard of care.

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