VExUS (Venous Excess Ultrasound) Scan
The VExUS scan is a point-of-care ultrasound protocol specifically designed to assess systemic venous congestion by evaluating hemodynamic patterns in the hepatic vein, portal vein, and intrarenal veins, fundamentally different from standard venous ultrasound which focuses on detecting thrombosis through compression techniques. 1
Primary Indications
The VExUS examination is indicated for:
- Assessment of hemodynamic congestion resulting from elevated right atrial pressure and functional right ventricular failure 1
- Volume status evaluation in critically ill patients, particularly those at risk for fluid overload 2
- Perioperative fluid management in cardiac surgery patients where risks of fluid overload are substantial 3
- Detection and grading of central venous pressure elevation in intensive care settings 4
The exam has proven feasible across diverse patient populations, including critically ill children, with 100% successful acquisition rates in pediatric ICU studies 4.
Technical Components
The VExUS protocol integrates analysis of multiple venous beds 2:
- Inferior vena cava (IVC) diameter assessment - IVC dilation is strongly associated with elevated CVP (P < .001) 4
- Hepatic vein Doppler waveform - severe patterns correlate with elevated CVP (P = .026) 4
- Portal vein Doppler waveform - evaluated for pulsatility patterns 5
- Intrarenal vein Doppler waveform - the most independently associated component with high CVP, with both mild (P = .005) and severe (P = .025) patterns showing significance 4
The intrarenal vein Doppler pattern remains the only independent variable associated with elevated CVP after adjustment for confounding factors, making it the most critical component 4.
Grading System and Reliability
The VExUS score demonstrates substantial inter-rater reliability with a Kappa statistic of 0.71 and Intraclass Correlation Coefficient of 0.83 (p < 0.001) 6. Inter-user reproducibility is also substantial with a Kappa of 0.63 and ICC of 0.8 6.
Concurrent ECG tracing significantly improves agreement among interpreters, and ECG-augmented VExUS should be considered standard practice 6. The score is interpretable by clinicians with diverse backgrounds, not requiring subspecialty expertise 6.
The severity of the VExUS score is strongly associated with CVP levels (P < .001) 4.
Acquisition Techniques
Standard acquisition uses a phased-array probe during transthoracic examination 3. For cardiac surgery patients, transesophageal echocardiography (TEE)-supported VExUS examination is feasible and may optimize perioperative care 3.
Key Limitations
VExUS does not detect venous thrombosis - it evaluates hemodynamic congestion patterns, not anatomic obstruction 1. Standard compression ultrasound remains necessary for DVT evaluation 7.
The exam requires adequate acoustic windows and may be limited by:
- Patient body habitus affecting image quality
- Operator experience with Doppler waveform interpretation
- Need for concurrent ECG for optimal interpretation 6
Clinical Pitfalls to Avoid
Do not confuse VExUS with standard venous ultrasound for DVT - these are fundamentally different examinations with different diagnostic targets 1. Standard venous ultrasound uses compression techniques to detect thrombosis 7, while VExUS uses Doppler waveform analysis to assess congestion 5.
Always obtain concurrent ECG tracing when performing VExUS to maximize inter-rater reliability 6.
Do not rely solely on IVC diameter or single venous bed assessment - the integrated multi-vessel approach is what provides diagnostic value 2, 4.