What is a dialysis shunt?
A dialysis shunt is a surgically created connection between an artery and a vein. Sufficient blood flows through this connection to allow hemodialysis to be performed. There are two types of surgically created dialysis shunts: a direct connection between an artery and a vein (native shunt) and a connection via a plastic prosthesis (see figure).
A newly created AV fistula takes time to mature, usually at least 4–6 weeks; a prosthetic shunt must first heal in place (at least 14 days). Depending on the type of access and the individual situation, the surgery should therefore be planned well in advance and, if possible, performed several months before the expected start of dialysis . The treatment team determines the appropriate timing for surgery based on the type of approach, the vascular conditions, and the individual patient’s situation.
AV fistula (native shunt): Dialysis shunt created from the patient’s own blood vessels
An AV fistula (arteriovenous fistula) is a surgically created shunt between an artery and a vein. No artificial vascular material is used in this procedure. After surgery, the vein adapts to the increased blood flow and pressure: it becomes wider, and its vessel wall
Prosthetic shunt: Dialysis shunt with a plastic prosthesis
If the veins are in poor condition or unsuitable, a synthetic graft is inserted to connect the artery and the vein. It forms an artificial blood vessel under the skin that can be punctured during hemodialysis. A prosthetic shunt can usually be used sooner than an AV fistula, often after about two weeks. The exact timing depends on the type of prosthesis used, the healing of the wound, and the doctor’s assessment.
Dialysis shunt or dialysis catheter: What’s the difference?
A dialysis shunt is a surgically created vascular access intended for long-term hemodialysis. A dialysis catheter, on the other hand, is inserted into a large vein, usually in the neck, and can generally be used right away. It is used in particular when dialysis must begin immediately, the dialysis shunt is not yet fully developed, or there are no suitable vessels available for shunt creation. Because dialysis catheters carry a higher risk of infection and thrombosis, a dialysis shunt is preferred whenever possible for long-term treatment.
Creating a Dialysis Shunt: The Surgical Procedure
Preparing for Shunt Surgery
If your nephrologist has determined that hemodialysis may be necessary, your blood vessels will be carefully examined during an initial outpatient consultation. In addition to a clinical examination, an ultrasound examination is typically performed to assess the arteries and veins. We will then work with you to determine which dialysis access is best suited to your individual situation.
Once the vessels for the planned shunt have been identified, no further blood draws or venous access procedures should be performed on that arm. This prevents damage to the vessel walls and protects the vessels during surgery.
Dialysis shunt training should begin approximately twelve weeks before the surgery, following the treatment team’s instructions. For example, repeatedly squeezing a soft ball helps exercise the blood vessels and improve blood circulation in the arm. After surgery, exercise can help the dialysis shunt mature. The treatment team determines on a case-by-case basis when and how the exercises should be performed.
The exercises:
Shunt training should generally be performed twice a day (in the morning and in the evening); the total duration of the exercises is approximately 10 Minutes:
- Squeeze the rubber or foam ball in your hand 10 times and then release it (1 to 2 seconds per squeeze),
- 1-minute break (leave the congestion in place),
- 10 fist clenches with a rubber ball or foam ball,
- 1-minute break (leave the congestion in place),
- 10 fist clenches with a rubber ball or foam ball,
- 2-minute break (leave the congestion in place),
- Repeat the exercise set one more time.
Dialysis Shunt Surgery
In this procedure, the vascular surgeon connects an artery directly to a vein or, if the patient’s own vessels are unsuitable, inserts a synthetic graft to serve as a connection. Afterward, clinical and ultrasound examinations are performed to verify that the dialysis shunt has adequate blood flow.
Depending on the type and location of the dialysis shunt, the complexity of the procedure, and your overall health, the surgery may be performed on an outpatient basis or require a short hospital stay. In most cases, a local or regional anesthetic is sufficient, such as brachial plexus anesthesia. Whether another form of anesthesia is necessary is determined on a case-by-case basis. The duration of the surgery also depends on the type and location of the planned dialysis access.
Follow-up Care and Maintenance of the Dialysis Shunt
The surgery is followed by follow-up appointments. During this process, wound healing, blood flow to the hand, and the function of the dialysis shunt are monitored. If necessary, an ultrasound examination will also be performed. Your nephrologist and the treatment team will support you as you continue your dialysis shunt training and show you how to protect and monitor your dialysis access in your daily life.
A properly functioning dialysis shunt can usually be identified by a palpable pulsation under the skin. You should check this so-called shunt hum every day. If it becomes significantly weaker or can no longer be felt, you should contact the treatment team immediately. This also applies if you experience increasing pain, redness, warmth, swelling, or fever, as well as if your hand feels cold, pale, bluish, or numb.
No blood draws, infusions, or blood pressure measurements should be performed on the shunt arm. Keep the shunt arm clean and protect it from bumps, cuts, and other injuries. Also, avoid tight clothing, jewelry, and prolonged pressure on the dialysis shunt. Once the wound has healed, the arm can usually be moved normally during everyday activities. You should consult with your treatment team before engaging in strenuous physical activity or strength training.
After removing the dialysis needles, apply pressure to the puncture site with a clean gauze pad until the bleeding stops. If you experience heavy or prolonged bleeding, seek medical attention immediately. The treatment team determines when the dialysis shunt can be used for hemodialysis for the first time, based on the shunt’s maturation and the patient’s individual healing process.
When should I seek medical help for shunt problems?
If the buzzing sound is absent or has changed significantly, or if there is increasing pain, redness, warmth, swelling, or fever, the treatment team should be contacted promptly. A cold, pale, or bluish hand; sensory disturbances; loss of strength; or uncontrollable bleeding must be evaluated by a doctor immediately.
Additional Services Related to Dialysis Access
- Placement of Dialysis Catheters
- Checking Dialysis Shunts When Problems Arise
- Surgical Corrections for Malfunctions
- Vascular imaging usingCO2 as a contrast agent, meaning without conventional contrast agents that place a strain on the kidneys
When is shunt revision necessary?
Shunt revision may be necessary if the dialysis shunt does not mature sufficiently, blood flow decreases, or the access is partially or completely blocked by a narrowing or a blood clot. Other possible causes include dilation of the shunt vein, an infection, or reduced blood flow to the hand. Depending on the cause, the dialysis shunt is treated using a catheter-based procedure—such as balloon dilation or the removal of a blood clot—or through surgical correction. If the existing access cannot be preserved, it may be necessary to create a new dialysis shunt.
Risks and Possible Complications of Shunt Surgery
In most cases, shunt surgery proceeds without serious complications. However, as with any surgical procedure, there are certain risks involved. These depend, among other things, on the type of dialysis shunt, the vascular conditions, and the patient’s overall health. Possible complications include:
- Bleeding and Bruising: After the procedure, you may experience some bleeding or swelling in the surgical area.
- Wound-healing complications and infections: The surgical wound or dialysis access site may become inflamed. In the case of a prosthetic shunt, the plastic prosthesis may also be affected by an infection.
- Shunt thrombosis (blockage of the shunt by a blood clot): A blood clot can partially or completely block the dialysis shunt.
- Inadequate shunt maturation: An AV fistula may not develop sufficiently and may therefore not be usable for hemodialysis as planned.
- Shunt stenosis (narrowing of the shunt vein): A narrowing of the vessel can reduce blood flow in the dialysis shunt.
- Reduced blood flow to the hand: In rare cases, too much blood flows through the dialysis shunt. This condition, known as “steal syndrome,” can manifest as pain, a sensation of cold, paleness, numbness, or weakness in the hand.
- Enlargement of the shunt vein: Over time, bulges in the vessel wall—known as aneurysms—can form.
- Nerve irritation: Temporary numbness or pain may occur in the operated arm.
- Strain on the Heart: A very high blood flow through the dialysis shunt can put additional strain on the heart. This complication is rare.
- Follow-up Procedure: If the dialysis shunt is not functioning properly or changes over time, a correction, reopening, or creation of a new shunt may be necessary.
Before the surgery, the treatment team will discuss the risks specific to your situation with you in detail.
Dialysis Access Surgery at the USZ—Your Benefits
At the USZ, specialists in vascular surgery and nephrology—as well as, when necessary, angiology and interventional radiology—work closely together. This allows the dialysis access to be planned on an individual basis and tailored to the patient’s vascular conditions, health status, and planned dialysis treatment. Even in cases of difficult vascular conditions or dialysis access sites that have already undergone multiple treatments, suitable solutions are evaluated through an interdisciplinary approach.
Open-surgery and—when medically appropriate—endovascular procedures are available for the placement and management of dialysis access sites. Close coordination among the participating departments enables coordinated care, from initial evaluation and shunt placement through follow-up care to the treatment of potential functional disorders and complications.
