Onyinye Okorji | DO EM/IM PGY3

The Article

Isolated Deep Venous Thrombosis: Implications for 2-Point Compression Ultrasonography of the Lower Extremity Srikar Adhikari, MD, MS; Wes Zeger, DO; Christopher Thom, MD; J. Matthew Fields, MD

The Idea

Should emergency physicians use an extended proximal compression ultrasonographic technique to assess for isolated thrombi in locations beyond the common femoral and popliteal veins? The objective of this study is to determine the prevalence and distribution of deep venous thrombi isolated to lower-extremity veins other than the common femoral and popliteal veins in emergency department (ED) patients with clinically suspected deep venous thrombosis.

The Study

This was a retrospective study of all patients who received a lower-extremity venous duplex ultrasonographic examination in the ED during a 6-year period.

Inclusion criteria: all adult patients (> 19 years) who received a comprehensive lower extremity venous duplex ultrasonographic examination in the ED for evaluation of deep venous thrombosis were included in this study. Total of 2,451 patients (women 1,595; men 856). The ultrasonographic examinations were performed by vascular surgery division sonographers.

The Findings

Superficial vein thrombosis was detected in 96 cases (3.9%; 95% CI 3.1% to 4.7%). Deep venous thrombosis was detected in 362 patients (14.7%; 95% CI 13.3% to 16.1%). Thrombus confined to the common femoral vein alone was found in 5 of 362 cases (1.4%; 95% CI 0.2% to 2.6%). Isolated femoral vein thrombus was identified in 20 of 362 patients (5.5%; 95% CI 3.2% to 7.9%). Isolated deep femoral vein thrombus was found in 3 of 362 cases (0.8%; 95% CI –0.1% to 1.8%). Thrombus in the popliteal vein alone was identified in 53 of 362 cases (14.6%; 95% CI 11% to 18.2%).

The Takeaway

In this study, 6.3% of ED patients with suspected deep venous thrombosis had isolated thrombi in proximal veins other than common femoral and popliteal vein. Exclusion of the femoral vein imaging with 2-point compression ultrasonography would have resulted in missing a significant number of isolated lower-extremity thrombi. The results of this study support the use of extended point-of-care compression ultrasonographic technique evaluating the common femoral vein, femoral vein, proximal deep femoral vein, and popliteal vein. It was recommended to perform compression of the proximal deep femoral vein because there is a small incidence (<1%) of isolated thrombus in this region. It requires only translation of the probe down from the common femoral vein over the femoral and proximal deep femoral veins to assess for compressibility. The use of extended point-of-care compression ultrasonographic technique may decrease D-dimer testing and therefore decrease the incidence of false-positive D-dimer test results that would require whole-leg, color-coded, duplex, lower extremity ultrasonography.