Safety of a strategy combining D-dimer testing and whole-leg ultrasonography to rule out deep vein thrombosis

Abstract

Guidelines for the diagnostic workup of deep vein thrombosis (DVT) recommend assessing the clinical pretest probability before proceeding to D-dimer testing and/or compression ultrasonography (CUS) if the patient has high pretest probability or positive D-dimer. Referring only patients with positive D-dimer for whole-leg CUS irrespective of pretest probability may simplify the workup of DVT. In this prospective management outcome study, we assessed the safety of such a strategy. We included consecutive outpatients referred to the Emergency Department at Østfold Hospital, Norway, with suspected DVT between February 2015 and November 2018. STA-Liatest D-Di Plus D-dimer was analyzed for all patients, and only patients with levels ≥0.5 µg/mL were referred for CUS. All patients with negative D-dimer or negative CUS were followed for 3 months to assess the venous thromboembolic rate. One thousand three hundred ninety-seven patients were included. Median age was 64 years (interquartile range, 52-73 years), and 770 patients (55%) were female. D-dimer was negative in 415 patients (29.7%) and positive in 982 patients (70.3%). DVT was diagnosed in 277 patients (19.8%). Six patients in whom DVT was ruled out at baseline were diagnosed with DVT within 3 months of follow-up for a thromboembolic rate of 0.5% (95% confidence interval, 0.2-1.2). A simple diagnostic approach with initial stand-alone D-dimer followed by a single whole-leg CUS in patients with positive D-dimer safely ruled out DVT. We consider this strategy to be a valuable alternative to the conventional workup of DVT in outpatients. This trial was registered at www.clinicaltrials.gov as #NCT02486445.

Conflict of interest statement

Conflict-of-interest disclosure: S.G.F. and C.T.J. report grants from Bayer, the South-Eastern Norway Regional Health Authority, and the Østfold Hospital Trust to the conduct of the study (no personal fees). A.E.A.D. reports grants and personal fees from Pfizer AS and personal fees from Bristol-Myers Squibb and Novartis Norway AS, outside of the submitted work. F.A.K. reports research grants from Bayer, Bristol-Myers Squibb, Boehringer Ingelheim, Daiichi-Sankyo, MSD, Actelion, the Dutch Heart Foundation, and the Dutch Thrombosis Association, outside of the submitted work. W.G. reports grants from Bayer, the South-Eastern Norway Regional Health Authority and Østfold Hospital Trust for the conduct of this study; grants from Bayer, Bristol-Myers Squibb, and Novartis, outside of the submitted work; and participation on an advisory board for Amgen and Novartis. The remaining authors declare no competing financial interests.

© 2020 by The American Society of Hematology.

Figures

Graphical abstract

Figure 1.

Inclusion of patients.1Ninety-three due to superficial thrombophlebitis.

Figure 2.

Study flow and outcomes.