Background: It remains unclear whether a single complete ultrasound examination, which detects calf vein thrombosis, is as safe as a baseline rapid ultrasound examination, repeated after 1 week when negative, which examines the veins in the groin and the knee. Therefore, we compared the safety and feasibility of two diagnostic ultrasound strategies, involving rapid and complete compression ultrasound (CUS) examination.
Methods: Consecutive patients with suspected deep vein thrombosis (DVT) underwent clinical probability assessment. In patients with an unlikely clinical probability and a normal D-dimer finding, DVT was considered to be excluded. All others were randomized to undergo a rapid or a single complete CUS examination. Patients in whom DVT was excluded were followed for 3 months to assess the incidence of venous thromboembolism (VTE).
Results: A total of 1002 patients were included. A clinical decision rule indicating DVT to be unlikely and a normal D-dimer finding occurred in 481 patients (48%), with a VTE incidence of 0.4% [95% confidence interval (CI) 0.05-1.5%] during follow-up. DVT was confirmed in 59 of the 257 patients (23%) who underwent rapid CUS examination, and in 99 of the 264 patients (38%) who underwent complete CUS examination. VTE during follow-up occurred in four patients (2.0%; 95% CI 0.6-5.1%) in the rapid CUS arm, and in two patients (1.2%; 95% CI 0.2-4.3%) in the complete CUS arm.
Conclusions: A diagnostic strategy with a clinical decision rule, a D-dimer test and a CUS examination is safe and efficient. Both the rapid and the complete CUS test are comparable and efficient strategies, with differing advantages and disadvantages.