A graft thrombectomy is a medical procedure to remove a blood clot from a dialysis access graft. Its purpose is to restore blood flow for hemodialysis treatments in patients with kidney failure. The formation of a clot, known as thrombosis, obstructs the graft and renders it unusable. This intervention is an often urgent requirement for patients who rely on grafts for dialysis.
Indications for the Procedure
An arteriovenous (AV) graft is a surgically created access point for patients undergoing hemodialysis. It consists of a synthetic tube that links an artery to a vein, creating a durable site that can withstand repeated needle insertions. This setup allows for the high blood flow rates necessary during dialysis.
The primary indication for a thrombectomy is thrombosis, which is the formation of a blood clot inside the AV graft. This clot acts as a blockage, preventing the volume of blood needed from flowing through the graft. A healthy, functioning graft produces a distinct vibration, called a “thrill,” and a whooshing sound, a “bruit.” The sudden absence of this thrill and bruit is a clear sign that a clot has formed.
Other symptoms of a thrombosed graft include swelling, tenderness, or pain in the access arm due to blocked blood flow. During a hemodialysis session, a technician may be unable to place the needles or find the graft cannot sustain the required blood flow. A diagnosis is confirmed through a physical examination, often supplemented by a Doppler ultrasound to visualize the blockage and its location.
Surgical and Endovascular Techniques
Once a clot is confirmed, it can be removed via open surgical thrombectomy or percutaneous endovascular thrombectomy. The choice depends on the patient’s anatomy, the age of the clot, and available medical resources. Both approaches aim to clear the blockage and address underlying issues that caused the clot.
Open surgical thrombectomy is performed by a vascular surgeon. This procedure involves a small incision in the skin over the AV graft. The surgeon opens the graft to insert a Fogarty embolectomy catheter, which has a small balloon at its tip. The catheter is guided past the clot, the balloon is inflated, and it is pulled back to remove the clot. The surgeon also inspects the graft for any narrowing, or stenosis, that may have caused the clot and can repair it directly.
Percutaneous endovascular thrombectomy is a less invasive method performed by an interventional radiologist using real-time imaging. The physician makes needle punctures into the graft to insert catheters for clot removal. This is done with pharmacomechanical methods, combining clot-dissolving medications with mechanical devices. These devices can include rotating wires that break up the clot or aspiration systems that vacuum it out.
A part of the endovascular approach is treating the root cause, which is often a stenosis in the vein near the graft connection. After clearing the clot, the physician performs an angiogram by injecting contrast dye to visualize the blood vessels. Any identified narrowing is treated with balloon angioplasty, where a balloon widens the vessel. A stent may be placed to hold the vessel open and improve long-term graft function.
The Patient Experience Before and After
Before the procedure, patients are instructed to fast for several hours, particularly if sedation is used. The medical team will review current medications, and any blood thinners may need to be adjusted to reduce bleeding risks. Patients must also arrange for transportation home, as they cannot drive immediately after the procedure.
Following the thrombectomy, the patient is moved to a recovery area for monitoring. Staff will observe the access site for bleeding or swelling and confirm that blood flow has been restored. Pain at the incision or puncture sites is common and can be managed with medication. The arm with the graft may need to be elevated to reduce swelling.
Upon discharge, patients receive home care instructions. These include avoiding heavy lifting or pressure on the access arm to allow healing. Instructions are provided on caring for the incision to prevent infection. The medical team will advise when to resume using the graft for hemodialysis, which is often possible within a day.
Managing Graft Health Long-Term
Clearing a clot with a thrombectomy addresses the immediate blockage, but it does not eliminate the underlying conditions that lead to thrombosis. The most common cause is venous outflow stenosis, a narrowing of the vein connected to the graft. Therefore, long-term management is focused on surveillance and proactive care to maintain the graft’s function, or patency.
Regular monitoring by a patient’s dialysis care team is a foundation of long-term graft health. This involves periodic graft surveillance studies, such as Doppler ultrasound, to measure blood flow rates and detect new areas of stenosis. If a significant narrowing is found, a preventative procedure like an angioplasty may be recommended to keep the graft open.
Patients play an active role in this process through daily self-monitoring. This involves feeling the graft several times a day to check for a strong, consistent thrill. Any weakening or change in this vibration should be reported to the medical team promptly, as it can be an early warning sign. Following medical advice regarding medications, such as antiplatelet agents, can also help reduce the risk of future clots.