Diagnosing pulmonary embolism in outpatients with clinical assessment, D-dimer measurement, venous ultrasound, and helical computed tomography: a multicenter management study.
OBJECTIVE
To evaluate a diagnostic strategy for pulmonary embolism that combined clinical assessment, plasma D-dimer measurement, lower limb venous ultrasonography, and helical computed tomography (CT).


METHODS
A cohort of 965 consecutive patients presenting to the emergency departments of three general and teaching hospitals with clinically suspected pulmonary embolism underwent sequential noninvasive testing. Clinical probability was assessed by a prediction rule combined with implicit judgment. All patients were followed for 3 months.


RESULTS
A normal D-dimer level (<500 microg/L by a rapid enzyme-linked immunosorbent assay) ruled out venous thromboembolism in 280 patients (29%), and finding a deep vein thrombosis by ultrasonography established the diagnosis in 92 patients (9.5%). Helical CT was required in only 593 patients (61%) and showed pulmonary embolism in 124 patients (12.8%). Pulmonary embolism was considered ruled out in the 450 patients (46.6%) with a negative ultrasound and CT scan and a low-to-intermediate clinical probability. The 8 patients with a negative ultrasound and CT scan despite a high clinical probability proceeded to pulmonary angiography (positive: 2; negative: 6). Helical CT was inconclusive in 11 patients (pulmonary embolism: 4; no pulmonary embolism: 7). The overall prevalence of pulmonary embolism was 23%. Patients classified as not having pulmonary embolism were not anticoagulated during follow-up and had a 3-month thromboembolic risk of 1.0% (95% confidence interval: 0.5% to 2.1%).


CONCLUSIONS
A noninvasive diagnostic strategy combining clinical assessment, D-dimer measurement, ultrasonography, and helical CT yielded a diagnosis in 99% of outpatients suspected of pulmonary embolism, and appeared to be safe, provided that CT was combined with ultrasonography to rule out the disease.
Perrier
Arnaud
A
Medical Clinic 1, Geneva University Hospital, Switzerland. Arnaud.Perrier@hcuge.ch
Roy
Pierre-Marie
PM
Aujesky
Drahomir
D
Chagnon
Isabelle
I
Howarth
Nigel
N
Gourdier
Anne-Laurence
AL
Leftheriotis
Georges
G
Barghouth
Ghassan
G
Cornuz
Jacques
J
Hayoz
Daniel
D
Bounameaux
Henri
H
D004636:Emergency Service, Hospital; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D005338:Fibrin Fibrinogen Degradation Products / Q000032:analysis*; D006801:Humans; D007866:Leg / Q000098:blood supply; D008297:Male; D008875:Middle Aged; D017063:Outcome Assessment, Health Care; D011336:Probability; D011446:Prospective Studies; D011651:Pulmonary Artery / Q000000981:diagnostic imaging; D011655:Pulmonary Embolism / Q000150:complications / Q000175:diagnosis* / Q000000981:diagnostic imaging; D012680:Sensitivity and Specificity; D036542:Tomography, Spiral Computed; D014463:Ultrasonography; D020246:Venous Thrombosis / Q000150:complications / Q000000981:diagnostic imaging*
D005338:Fibrin Fibrinogen Degradation Products; C036309:fibrin fragment D