Vascular Ultrasound for Dialysis Patients

What is Dialysis?

Dialysis is a treatment for kidney failure. When the kidneys work correctly, they filter toxins and waste from the blood. Dialysis is a process in which blood is removed from the body and filtered using a machine before being delivered back into the body.

Kidney failure occurs most often due to chronic kidney disease. Chronic kidney disease is a disease in which kidney function deteriorates over time. The five stages of chronic kidney disease correlate to how well the kidneys are functioning according to the glomerular filtration rate, or GFR. Stage 5 chronic kidney disease indicates kidney failure. 

Early-stage kidney disease may have few symptoms, but they become more apparent as time goes on. Symptoms include, but are not limited to: 

• Blood in the urine 
• Darkening of the skin 
• Fatigue 
• Frequent urination
• High blood pressure 
• Loss of appetite 
• Muscle cramps 
• Nausea 
• Shortness of breath
• Swelling of the feet, ankles, and hands 

Ultrasound for Dialysis

Patients with kidney failure will often undergo dialysis treatment. In some cases, this process is assisted by connecting an artery and vein in the arm to help remove the blood and deliver it back to the body. This process is called an arteriovenous (AV) fistula. Vein mapping determines which veins and arteries to use in the procedure.

Vein mapping is done via a vascular ultrasound exam. A vascular ultrasound exam uses Doppler technology to create images and videos of what is going on inside the vascular, or circulatory system. Doppler technology uses harmless, high-frequency soundwaves to create these images and videos. This process will often also include a duplex ultrasound, which shows images of the tissues surrounding the veins and arteries.

Vascular ultrasound exams can be used for vein mapping (determining the location and layout of the veins) and determining the speed and direction of blood flow and whether there are blockages or narrowing of the veins.

In addition to initial vein mapping, vascular ultrasound for dialysis can help to monitor an AV fistula post-procedure. Vascular ultrasound exams are also used for AV bypass graft surgery, an alternative to the AV fistula procedure in cases where the veins are not large enough for an AV fistula.

Vascular Ultrasound Process

Vascular ultrasound exams are efficient and painless with no known health risks. These exams are typically performed by Registered Vascular Technologists or RVTs. RVTs are specifically trained to conduct vascular ultrasound exams. Below is an example of a typical examination process: 

• The ultrasound machine consists of a video monitor, a console, and a handheld device called a transducer. The transducer emits harmless, high-frequency soundwaves that help create images of what is happening inside the body.
• The RVT will apply gel to the transducer, which minimizes air pockets and allows the soundwaves to travel better. Then, the RVT will press the transducer against the skin of the imaged area. Through gentle compressions, the RVT can find specific veins and arteries of interest and determine if any anomalies, such as stiff veins or a blockage that reduces blood flow, may be present.
• The images and videos are sent to a trained physician for interpretation, and then to the referring doctor for final review and diagnosis.

Overall, vascular ultrasound exams can be a crucial precursor to dialysis treatment. Dialysis is often necessary for late-stage chronic kidney disease, during which kidney failure occurs. In the case where an AV fistula or AV bypass graft is necessary to begin dialysis, a vascular ultrasound exam can be used for vein mapping. Vascular ultrasound exams are ideal for vein mapping and post-procedure monitoring because they are noninvasive, painless, and pose no known health risks. 

Guest Contributor: Jordan Galerkin

Sources:

1. Types of Ultrasound. Ultrasound Quotes. https://www.ultrasoundquotes.com/blog/doppler-vs-duplex/
2. Dialysis. Cleveland Clinic. https://my.clevelandclinic.org/health/treatments/14618-dialysis
3. Kidney Disease. Cleveland Clinic. https://my.clevelandclinic.org/health/diseases/15096-kidney-disease-chronic-kidney-disease
4. Vein Mapping. Cleveland Clinic. https://my.clevelandclinic.org/health/diagnostics/17607-arterial–venous-mapping
5. Preparing for Dialysis. Yale Medicine. https://www.yalemedicine.org/conditions/preparing-dialysis-av-fistulaPage Break