Summary
A limited ultrasound (US) confined to the popliteal and femoral veins is usually performed
to detect deep vein thrombosis (DVT) in patients with clinically suspected acute pulmonary
embolism (PE). Our objective was to assess the diagnostic accuracy of complete lower
limb US examining both the proximal and distal veins in this setting. In this prospective
study, 210 consecutive patients were included. Complete US was performed by independent
operators and compared blindly with a reference strategy combining clinical probability,
ventilation perfusion scan and pulmonary angiography to a three-month clinical follow-up.
Simultaneously,VIDAS D-dimer (DD) assay and helical computed tomography (HCT) of the
lungs were assessed independently and blindly. PE was present in 74 patients (35%).
Complete US detected DVT in 91 patients (43%), proximal in 51 and distal in 40. Sensitivity
and specificity with a 0.95 confidence interval were respectively 0.93 [0.85 – 0.97]
and 0.84 [0.77 – 0.89]. Limited US detected DVT in only 46 patients (22%). Sensitivity
and specificity were respectively 0.55 [0.44 – 0.66] and 0.96 [0.92 – 0.98]. For DD
they were 0.92 [0.83 – 0.96] and 0.24 [0.17 – 0.32] and for HCT 0.84 [0.73 – 0.90]
and 0.87 [0.80 – 0.92]. Complete lower limb US has higher sensitivity and capacity
to exclude PE than limited US, but a slightly lower specificity. Complete US results
also compared favourably with those of HCT and DD.The utility of including this method
in diagnostic strategies for PE needs to be assessed in cost-effectiveness analysis
and in outcome studies.
Keywords
Pulmonary embolism - deep vein thrombosis - ultrasound/diagnosis