Diagnosis of pulmonary embolism in patients with proximal deep vein thrombosis - Specificity of symptoms and perfusion defects at baseline and duringanticoagulant therapy

To determine the specificity of pulmonary embolism (PE) symptoms and lung s can perfusion defects in patients with deep vein thrombosis (DVT), we analy zed data on 400 patients with phlebography-proven proximal DVT included in a prospective trial. As the incidence of PE during anticoagulant therapy wa s the main outcome measure of the trial, all patients underwent lung scanni ng and/or pulmonary angiography within 48 h of inclusion, and then whenever PE was suspected. Angiography was recommended in patients with nondiagnost ic lung scan. At baseline, the presence or absence of PE could be ascertain ed in 350 patients (87.5%), and 197 (56%) had PE. Sensitivity and specifici ty of symptoms for PE were 74 and 67%, respectively. Among 37 patients with symptoms and nondiagnostic lung scan, only 8 (22%) had PE at angiography. During anticoagulant therapy (3 mo), there were 29 events suspicious for PE , mostly (53%) within 2 wk of inclusion. Repeated perfusion studies with co mparison to baseline tests excluded PE in 21 cases. Cumulated 3-mo risks of suspected and confirmed on-treatment PE were 6.8% (95% CI, 5.4-8.2%) and 2 .0% (95% CI, 0.6-3.4%) respectively. even in patients with known proximal D VT, PE symptoms are unspecific and careful imaging studies are needed for d iagnosis, both at baseline and during anticoagulant therapy.