To the Editor: In their randomized controlled trial, Dr Bernardi and colleagues1 found equivalent safety for 2 ultrasound-based diagnostic strategies for managing outpatients with suspected deep vein thrombosis (DVT). The results of the study deserve some comments.
First, for the 2-point strategy the prevalence of proximal DVT detection on the second ultrasound test was 5.5% (14/256). This is much higher than has been previously reported. For example, in the study by Cogo et al,2 which included more than 1700 patients with suspected DVT, this rate was less than 1%.2 It has been suggested that the second ultrasound test is of limited added value, and strategies have been proposed using a single proximal venous examination, which proved to have an acceptable 3-month thromboembolic rate.3 However, the use of a single proximal vein ultrasonography might be criticized if the prevalence of proximal DVT detected at the second ultrasound test is as high as 5.5%. The high prevalence of cancer in this study (30%) may account for the high rate of proximal extension, indicating a need for particular care when choosing a diagnostic strategy for cancer patients.