Excluding Suspected DVT with a Single Whole-Leg Compression Ultrasound is Sound Practice: Study
According to researchers in Utah and Ontario, withholding anticoagulation in patients with suspected deep vein thrombosis (DVT) based on a single whole-leg compression ultrasound (CUS) is associated with a low risk of venous thromboembolism (VTE). They presented their data at the 51st Annual Meeting and Exposition of the American Society of Hematology in New Orleans.
Compression ultrasonography is typically used as the initial test to confirm or exclude suspected lower extremity DVT. Patients with a negative CUS and either a moderate-to-high probability and/or a positive D-dimer usually are subject to repeat CUS after five to seven days to exclude proximal propagation of distal DVT, reducing diagnostic efficiency. Whole-leg compression ultrasound may safely exclude proximal and distal DVT in a single evaluation, the researchers believed.
To assess the safety of withholding anticoagulation in patients presenting with suspected lower extremity DVT following a single, negative whole-leg CUS, they performed a meta-analysis of randomized controlled trials and prospective cohort studies published between January 1970 and April 2009 without language restrictions. Two authors independently reviewed articles and extracted data. The search was supplemented by reviewing appropriate online sources, meeting abstracts, conference proceedings, reference lists, and by contacting experts.
Six studies were included with 4229 patients with negative whole-leg CUS exams not receiving anticoagulation. Death by VTE or suspected VTE-related death occurred within the 90-day follow-up period in 24 (0.6%) patients. Of these 24 events, nine (37.5%) were distal DVT, seven (29.2%) were proximal DVT, six (25.0%) included non-fatal pulmonary embolism, and two (8.3%) were deaths possibly related to VTE. The combined VTE event rate at three months was 0.46% (95% confidence interval, 0.22 to 0.70). One limitation of the research is that pretest probability assessment was not available for all analyzed patients.
As noted, withholding anticoagulation in patients with suspected DVT based on a single whole-leg CUS is associated with a low risk of VTE (0.46%) during three months of follow-up. The researchers concluded that the strategy is a safe and efficient alternative to serial CUS testing in patients with suspected DVT.