Renal embolization is a specialized, minimally invasive procedure performed by interventional radiologists to manage various conditions affecting the kidney. The technique involves accessing the body’s vascular system and delivering small materials to purposefully block blood flow (embolization) to a targeted vessel or area within the kidney. The primary goal is to treat a localized issue while preserving as much healthy kidney function as possible.
Indications for the Procedure
Patients undergo renal embolization for specific medical needs, primarily to control bleeding or reduce the size of abnormal tissue. Acute hemorrhage is a frequent reason, especially when bleeding results from trauma, a kidney biopsy complication, or the rupture of vascular lesions. This technique stops severe blood loss without requiring open surgery.
The procedure treats specific kidney tumors, such as renal cell carcinoma. Used before surgical removal (pre-nephrectomy embolization), it decreases the tumor’s blood supply, reducing blood loss during the operation. It can also be a palliative option for non-surgical candidates, alleviating symptoms like pain or severe bleeding (hematuria) caused by the tumor.
Benign vascular tumors, like renal angiomyolipomas (AMLs), are another indication, particularly when they exceed four centimeters and carry a high risk of spontaneous rupture. Cutting off the blood supply causes the AML to shrink, reducing the risk of hemorrhage. Embolization also treats acquired vascular abnormalities, such as arteriovenous malformations (AVMs) or fistulas, and can address severe hypertension linked to specific renal issues.
How Renal Embolization Is Performed
The procedure is conducted in an angiography suite and typically begins with the patient receiving local anesthesia at the access site, usually the common femoral artery in the groin, along with moderate sedation. A tiny incision is made, and a flexible catheter is inserted into the artery. The interventional radiologist uses real-time X-ray imaging (fluoroscopy) to guide the catheter through the aorta and into the main renal artery.
To ensure precision, the radiologist steers a smaller microcatheter further into the kidney’s vascular network. This advanced targeting, called superselective catheterization, navigates specifically to the arterial branches supplying the target area, minimizing the risk of blocking healthy kidney tissue. Once positioned, the embolization material is injected through the tube.
The choice of embolic agent depends on the condition being treated and the size of the vessels needing to be blocked. Options include metallic microcoils, which permanently block the vessel, or particulate agents like microscopic spheres or polyvinyl alcohol (PVA) particles. Liquid agents, such as specialized glues or alcohol, may also be used for widespread, permanent blockage. A final angiogram, an X-ray with contrast dye, confirms that blood flow to the targeted area has been successfully stopped.
Recovery, Risks, and Follow-Up
Following the procedure, patients are monitored closely in the recovery area to ensure the access site in the groin is stable. Most individuals require an overnight hospital stay for observation and pain control. The required rest period involves lying flat for several hours to prevent bleeding or bruising at the puncture site. Access site care usually involves applying pressure and monitoring for signs of hematoma.
A common and expected consequence is Post-Embolization Syndrome (PES), which occurs as a reaction to the sudden death of the treated tissue. PES is a temporary side effect, not a complication, often presenting with flu-like symptoms, including flank pain, fever, and nausea. These symptoms usually begin within the first day or two and are managed with supportive care, typically resolving within three to ten days.
While generally safe, potential risks include non-target embolization, where the blocking material inadvertently travels to a healthy part of the kidney or other organ. There is also a small risk of kidney failure, especially in patients with compromised kidney function, or an allergic reaction to the contrast dye. Patients should seek urgent medical attention if they experience a high fever, chills, persistent worsening of pain, or symptoms lasting longer than two weeks after discharge. Long-term monitoring involves follow-up imaging, such as a CT scan or MRI, to confirm the treated area remains blocked and to assess therapeutic effects like tumor shrinkage.