The role compression ultrasound in hospitalized patients with suspected pulmonary embolism.

In emergency departments, suspected pulmonary embolism (PE) can be safely ruled out by a normal multi-slice CT angiography (CTPA) [1–4] without the need for additional leg compression ultrasonography (CUS). This diagnostic approach for those who develop symptoms of PE during hospitalization has been validated by only a limited number of studies. [2,5]. In this study we aim to estimate prevalence of both proximal and distal deep vein thrombosis (DVT) in hospitalizedpatientswith suspected pulmonary embolism (PE) and estimate the clinical utility of a bilateral whole leg CUS in patientswith suspected PE.We conducted a prospective single center cohort study approved by the ethics board at the Hospital Italiano de Buenos Aires; a 500 hundred bed academic hospital. The original plan was to conduct the study at two centers and recruit 210 subjects however, one of the research teamswere unable to recruit subjects due to financial constraints. As the study had already enrolled more than 30% of the expected sample size, an analysiswas done in order to rule out futility. Patients evaluated for suspected PE were eligible to participate in the study if: 1-They were able to provide consent; 2-Presented with symptoms suggestive of PE (acute onset of new or worsening shortness of breath, chest pain, hemoptysis, presyncope, or syncope); 3-Symptoms developed N48 hours after admission in medically ill patients; or N24hs of admission after a major surgical procedure (defined as an anaesthesia time N90 minutes); and were evaluated with CTPA. All patients were evaluated with a 64multi-slice CT scanner (Aquilion, Toshiba). Patients were excluded if they had symptoms compatible with PE prior to admission. Within 24 hours of providing written consent, all patients had a bilateral whole leg CUS. Proximal DVT was defined as non-compressible segment above the trifurcation of the popliteal vein. PEwas considered diagnosedwhen the CTPA showed a filling defect in a segmental or larger pulmonary artery and was present in at least two consecutive images (single sub-segmental embolus was considered as a PE only if the CUSwas positive for a proximal DVT). Between November 2011 to December 2013, 95 patients were originally enrolled in the study. Fourteen patients (16.8%) had a CTPA performed (one had a sub-segmental PE) but did not complete any further testing as decided by the treating physician andwere therefore, excluded. Six patients were evaluated with V/Q scans and were also excluded. Seventy five hospitalized patients with suspected PE (baseline characteristics