Diagnosis of pulmonary embolism by multidetector CT alone or combined with venous ultrasonography of the leg: a randomised non-inferiority trial.
BACKGROUND
Multislice CT (MSCT) combined with D-dimer measurement can safely exclude pulmonary embolism in patients with a low or intermediate clinical probability of this disease. We compared this combination with a strategy in which both a negative venous ultrasonography of the leg and MSCT were needed to exclude pulmonary embolism.


METHODS
We included 1819 consecutive outpatients with clinically suspected pulmonary embolism in a multicentre non-inferiority randomised controlled trial comparing two strategies: clinical probability assessment and either D-dimer measurement and MSCT (DD-CT strategy [n=903]) or D-dimer measurement, venous compression ultrasonography of the leg, and MSCT (DD-US-CT strategy [n=916]). Randomisation was by computer-generated blocks with stratification according to centre. Patients with a high clinical probability according to the revised Geneva score and a negative work-up for pulmonary embolism were further investigated in both groups. The primary outcome was the 3-month thromboembolic risk in patients who were left untreated on the basis of the exclusion of pulmonary embolism by diagnostic strategy. Clinicians assessing outcome were blinded to group assignment. Analysis was per protocol. This study is registered with ClinicalTrials.gov, number NCT00117169.


RESULTS
The prevalence of pulmonary embolism was 20.6% in both groups (189 cases in DD-US-CT group and 186 in DD-CT group). We analysed 855 patients in the DD-US-CT group and 838 in the DD-CT group per protocol. The 3-month thromboembolic risk was 0.3% (95% CI 0.1-1.1) in the DD-US-CT group and 0.3% (0.1-1.2) in the DD-CT group (difference 0.0% [-0.9 to 0.8]). In the DD-US-CT group, ultrasonography showed a deep-venous thrombosis in 53 (9% [7-12]) of 574 patients, and thus MSCT was not undertaken.


CONCLUSIONS
The strategy combining D-dimer and MSCT is as safe as the strategy using D-dimer followed by venous compression ultrasonography of the leg and MSCT for exclusion of pulmonary embolism. An ultrasound could be of use in patients with a contraindication to CT.
Righini
Marc
M
Division of Angiology and Hemostasis, Geneva University Hospital and Faculty of Medicine, Geneva, Switzerland. Marc.Righini@hcuge.ch
Le Gal
Grégoire
G
Aujesky
Drahomir
D
Roy
Pierre-Marie
PM
Sanchez
Olivier
O
Verschuren
Franck
F
Rutschmann
Olivier
O
Nonent
Michel
M
Cornuz
Jacques
J
Thys
Frédéric
F
Le Manach
Cédric Petit
CP
Revel
Marie-Pierre
MP
Poletti
Pierre-Alexandre
PA
Meyer
Guy
G
Mottier
Dominique
D
Perneger
Thomas
T
Bounameaux
Henri
H
Perrier
Arnaud
A
D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D005338:Fibrin Fibrinogen Degradation Products / Q000378:metabolism*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011336:Probability; D011655:Pulmonary Embolism / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000209:etiology; D012307:Risk Factors; D014057:Tomography, X-Ray Computed; D014463:Ultrasonography; D020246:Venous Thrombosis / Q000150:complications
D005338:Fibrin Fibrinogen Degradation Products; C036309:fibrin fragment D