Using clinical evaluation and lung scan to rule out suspected pulmonary embolism: Is it a valid option in patients with normal results of lower-limb venous compression ultrasonography?
BACKGROUND
In patients with a low clinical probability of pulmonary embolism (PE) and a nondiagnostic lung scan, the prevalence of PE is theoretically very low. We assessed the safety and usefulness of this association for ruling out PE.


METHODS
We analyzed data from 2 consecutive cohort management studies performed in 2 university hospitals (Geneva University Hospital, Geneva, Switzerland, and Hospital Saint-Luc, Montreal, Quebec), which enrolled 1034 consecutive patients who came to the emergency department with clinically suspected PE. All patients were submitted to a sequential diagnostic protocol of lung scan, D-dimer testing, lower-limb venous compression ultrasonography (US), and pulmonary angiography in case of inconclusive results of noninvasive workup.


RESULTS
The prevalence of PE was 27.6%. Empirical assessment was accurate for identifying patients with a low likelihood of PE (8.2% prevalence of PE in the low clinical probability category). One hundred eighty patients had a low clinical probability of PE and a nondiagnostic lung scan. Among these patients, US showed deep vein thrombosis in 5. Hence, PE could be ruled out by a low clinical probability, a nondiagnostic lung scan, and a normal US in 175 patients (21.5%). The 3-month thromboembolic risk in these patients was low (1.7%; 95% confidence interval, 0.4%-4.9%).


CONCLUSIONS
Anticoagulant treatment could be safely withheld in patients with a low clinical probability of PE and a nondiagnostic lung scan, provided that the US is normal. This combination of findings avoided pulmonary angiography in 21.5% of patients with suspected PE in this series.
Perrier
A
A
Medical Clinic 1, Geneva University Hospital, Switzerland. Arnaud.Perrier@medecine.unige.ch
Miron
M J
MJ
Desmarais
S
S
de Moerloose
P
P
Slosman
D
D
Didier
D
D
Unger
P F
PF
Junod
A
A
Patenaude
J V
JV
Bounameaux
H
H
D000328:Adult; D000368:Aged; D000792:Angiography; D001784:Blood Gas Analysis; D015331:Cohort Studies; D003937:Diagnosis, Differential; D004562:Electrocardiography; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010808:Physical Examination; D011237:Predictive Value of Tests; D011655:Pulmonary Embolism / Q000097:blood / Q000175:diagnosis* / Q000000981:diagnostic imaging; D012306:Risk; D012307:Risk Factors; D013557:Switzerland; D014463:Ultrasonography