Distribution of Lower Extremity Deep Vein Thrombosis and Implications for Limited Compression Ultrasound Examinations.

BACKGROUND: Limited compression bedside ultrasonography (LCUS) including two-point, three-point, and extended compression examinations have become increasingly popular among emergency physicians to assess for lower extremity deep venous thrombosis (DVT). OBJECTIVE: Our objective in this study was to determine the prevalence and distribution of lower extremity DVT in sites identified by complete duplex ultrasonography (CDUS) that may potentially be missed using limited compression ultrasonography techniques. METHODS: This was a retrospective, multicenter study conducted at 12 hospitals within the Northwell Health system over a span of 4 years. Study participants (emergency department patients) underwent CDUS to assess for possible DVT. Images were reviewed and interpreted by radiologists and vascular surgeons at each of the participating institutions. RESULTS: A total of 42,487 CDUS examinations were performed, of which 3383 were positive for DVT. DVTs were deemed to be acute in 2664 (79%) and chronic in the remaining 21% on the basis of comparison with previous studies and appearance of the vein. Of the acute DVTs, 136 (5.1%) were confined to the common femoral vein, 116 (4.4%) to the femoral vein, 8 (0.3%) to deep femoral vein, 213 (8.0%) to popliteal vein, and 934 (35.1) to calf veins alone. CONCLUSIONS: In our study, a significant number of DVTs were identified in sites that may have been potentially missed on LCUS examinations, thereby supporting the use of complete duplex ultrasonography when available.