Pattern Analysis of Lower Extremity Venous Thrombosis: Implications for Point of Care Ultrasound (POCUS) Protocols

Abstract

Introduction

Emergency department point-of-care ultrasound (POCUS) can identify lower extremity venous thrombosis (LEVT) with a published accuracy is 85–90%. The aim of this study was to compare the patterns of LEVT with protocol results and determine the clinical impact of the study results.

Methods

Patterns of superficial venous thrombosis(SVT) and deep venous thrombosis (DVT) were collated from positive venous duplex ultrasound (VDU) studies. Each pattern was mapped to the potential findings by the described POCUS protocols. Analysis of the literature was used to identify the potential clinical impact of the findings and the functional efficacy of each strategy and a numerical result was developed.

Results

One hundred six studies were positive for DVT (42), SVT (44), or both (20) on VDU. Patterns for DVT (single or multiple levels and unilateral or bilateral) and SVT (great saphenous vein above and/or below knee or small saphenous vein in single, multiple or bilateral and juxta-junctional) were noted. The patterns covered by the “two-area” protocol showed DVT = 80% and SVT = 38%, and by “three-point compression” DVT = 74% and SVT = 0%. Particular areas not covered included proximal disease (iliac and vena cava) and calf DVT and SVT in all areas except juxta-junctional. The potential impact for DVT is high, whereas for SVT it is moderate to low. The functional efficacy of the “two-area” protocol (5.9) exceeds the “three-point compression” strategy (3.7) but falls short of the “gold standard” VDU (10).

Conclusion

Pattern analysis of venous thrombosis identifies weakness in POCUS strategies; the clinical implications allow for an assignment of the functional efficacy of each study. Knowledge of these findings should inform emergency room POCUS strategies.