Practical Step 7: From Imaging to Action – Sustaining Long-Term Patency of AVG
In the care of hemodialysis access, artificial blood vessels serve as a vital alternative. Compared with autologous arteriovenous fistulas (AVF), arteriovenous grafts (AVG) involve more complex puncture procedures with higher requirements. Additionally, due to their shorter service life and greater susceptibility to adverse factors such as improper puncture techniques, hypotension, and inadequate disinfection, AVGs are prone to dysfunctional complications including graft occlusion and infection.
Since the service life of AVGs in dialysis patients is affected by multiple factors, ultrasound assessment has become an indispensable monitoring tool.
Key Points of Ultrasound Assessment
1. Ultrasound Manifestations of Normal AVG
Grayscale Ultrasound: Parallel hyperechoic vessel walls with anechoic lumens.
Color Doppler: Complete and uniform filling of blood flow signals.
Spectral Doppler: Low-resistance blood flow at the arterial end and arterialized spectrum at the venous end.
2. Key Assessment Sites and Standards
Arterial Anastomosis
Ultrasound Scanning: Multi-angle scanning with the angle between the sound beam and the vessel ≤ 60°.
Normal Indicators: PSV < 300 cm/s; no significant abnormalities in spectral morphology.
Artificial Graft Body
Ultrasound Scanning: Full-length scanning along the graft course, with attention to compressibility.
Normal Indicators: Uniform lumen diameter; no abnormal echoes.
Venous Anastomosis
Ultrasound Scanning: Focus on observing the 5–8 cm range of the outflow tract.
Normal Indicators: PSV < 250 cm/s; no mosaic blood flow signals.
3. Diagnostic Criteria for Stenosis
Morphological Standard: Luminal diameter reduction > 50%.
Hemodynamic Standards:
Local PSV ratio ≥ 2 (compared with the adjacent normal segment);
Outflow tract PSV < 50 cm/s;
Blood flow volume < 600 mL/min.
4. Ultrasound Features of Thrombosis
Acute Phase: Hypoechoic lesions; non-compressible lumens.
Chronic Phase: Hyperechoic lesions, possibly accompanied by organization and recanalization.
Color Doppler: Blood flow signal filling defects.
Puncture Planning: Balancing Safety and Efficiency
1.Optimal Puncture Segment:
Prioritize the middle segment, avoid areas near anastomoses, and ensure a 15–30° angle with the blood flow direction to minimize vascular injury.
2.How to Locate the Best Puncture Site Using Ultrasound?
Prioritize regions with a lumen diameter ≥ 6 mm, avoid areas with thickened vessel walls, perivascular edema, or calcification. Real-time visualization of the needle tip echo ensures accurate puncture angle and depth. Aseptic
3.Technique + Imaging Guidance = Higher Success
Rate For newly implanted artificial grafts, ultrasound-guided puncture can significantly reduce complications such as hematoma, oozing, and fistula infection.
Handheld Ultrasound: Anytime, Anywhere Assessment
With the application of portable devices such as the SonoMaxx handheld ultrasound, AVG management has become safer and more efficient, further advancing hemodialysis departments into a new era of “Imaging-as-a-Service.”
The SonoMaxx handheld ultrasound enables immediate bedside assessment in dialysis centers, featuring:
Compact size, fast boot-up, and suitability for multiple scenarios;
Real-time imaging, allowing novices to quickly master puncture angles;
Equipped with an intelligent measurement package to support standardized management.
The maintenance of arteriovenous graft (AVG) access requires the perfect integration of ultrasound assessment and puncture planning. Through standardized evaluation processes, personalized puncture protocols, and continuous monitoring and management, the service life of AVGs can be significantly prolonged, providing reliable lifelines for hemodialysis patients.
☛ Next Episode Preview | The Ultimate Test of Safeguarding the “Lifeline”
When the thrill weakens and the bruit fades—your fistula is sending a distress signal! In the next episode, we will confront one of the most intractable clinical challenges: Ultrasound Diagnosis and Management Strategies for Common Fistula Complications, helping you establish a comprehensive system for the prevention and treatment of complications