No abstract

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.

The incidence of asymptomatic DVT is still significant despite prophylaxis but most DVTs remain distal and occur in the first 2 weeks. Extended US could replace phlebography for systematic screening in clinical trials using surrogate endpoints in view of its high accuracy and reliability.

No abstract

The objective of the study was to assess the clinical validity of a non-invasive diagnostic strategy for acute pulmonary embolism using clinical assessment combined with both ELISA D-dimer and complete lower limb ultrasound (US) examination of proximal and distal veins, before single-detector helical computed tomography (CT) of pulmonary arteries. We expected the strategy to have a high diagnostic exclusion power and to safely decrease the number of CT scans. This prospective, multicenter outcome study included 274 consecutive outpatients. All underwent a priori clinical probability, D-dimer and bilateral complete lower limb US assessments. Only patients with a high clinical probability and both tests negative, or positive D-dimer and negative US assessments, underwent CT. This was deemed necessary in 114 patients (42%). At baseline, venous thromboembolism (VTE) was detected in 110 patients (40%), either by US showing proximal (n=65) or distal (n=36) thrombosis, or by CT (n=9). Anticoagulant was withheld in the remaining patients with negative results in both D-dimer and US but a non-high clinical probability (n=59), or in both US and CT (n=90), or with negative US (n=6) and inadequate CT (n=9). All patients underwent a three-month clinical follow-up. VTE occurred in one patient with inadequate CT, yielding an incidence of 0.6% [95% confidence interval: 0.1-3.4]. No patient died from VTE or had major bleeding. Using clinical probability, ELISA D-dimer and complete US before helical CT is a safe strategy resulting in a substantial reduction in CT scans.