In Reply: In response to Drs Quere and Righini, we believe that a second ultrasonography is warranted only if the first ultrasonography was limited to the proximal veins and the D-dimer test was abnormal. Our study demonstrated that a second ultrasonography can be safely spared in patients with a normal 2-point ultrasonography and a normal D-dimer at baseline. Our findings confirm data from 2 cohort studies investigating the role of D-dimer in the management of patients with suspected DVT.1,2 In both studies the prevalence of DVT at the second ultrasonography test was comparable with that reported in our trial (3.7%; 95% confidence interval [CI], 2.2%-5.6%1; and 5.7%; 95% CI, 1.9-12.8%,2 respectively). The comparison with the study by Cogo et al3 may not be applicable because in that study all patients with a normal baseline ultrasonography underwent repeat testing at 1 week.
Bernardi E, Camporese G, Noventa F. Ultrasound-Based Diagnostic Strategies for Deep Vein Thrombosis—Reply. JAMA. 2009;301(9):933-935. doi:10.1001/jama.2009.186