Renal artery stents are treatment options when the blood vessels that feed the kidney are narrowed or have a clot. This reduces the ability of the kidneys to clear the blood stream of waste products and toxins. Renal artery stenosis or renal vein thrombosis may require the placement of a device that keeps the vein open to allow adequate blood flow. The doctor will discuss the risks and benefits of placement and what type of stent to use. Patients who are unable to use platelet inhibitors because of other medical conditions are not good candidates.
Angioplasty and Stents
Prior to the stent being placed in the renal artery, the surgeon may choose to perform a balloon angioplasty. The physician will insert a catheter into the femoral artery and guide it through the blood vessel to the renal artery, according to physicians at Case Western Reserve University. This catheter has a small balloon on the end that the doctor can inflate when it reaches the area of the renal artery that is blocked by plaque. This flattens the plaque against the wall of the artery. To keep the plaque from closing the artery again, a stent is put in place.
Bare Metal
Radiology Information, a joint project between the American College of Radiology and the Radiological Society of North America, describes the bare metal stent as a wire mesh product that is placed within the renal artery. The objective of the stent is to hold the renal artery open and allow blood flow. This type of stent is usually used after an angioplasty procedure and with anticoagulant therapy to reduce the possibility of clotting in the artery.
Drug Eluting
According to physicians at Mayo Clinic, drug eluting stents, which slowly release medication, should theoretically prevent the growth of scar tissue in the artery. This should help keep the artery open and smooth. They were originally developed when bare metal stents caused tissue regrowth in some patients. According to a study published in the Journal of Endovascular Therapy in August 2007, however, researchers found that there was no difference in long-term outcome between patients who had a bare metal or a Serolimus eluting stent. Serolimus is an immunosuppressant drug popularly used in kidney transplants. Drug eluting stents used in the heart can increase the risk of heart attack unless anticoagulant therapy is used appropriately.
References
- Case Western Reserve University: Renal Artery Angioplasty and Stenting
- RadiologyInfo: Vascular Angioplasty and Stenting
- Mayo Clinic: Drug Eluting Stents: Do They Increase Heart Attack
- Journal of Endovascular Therapy; “Sirolimus-eluting versus bare-metal low-profile stent for renal artery treatment (GREAT Trial): angiographic follow-up after 6 months and clinical outcome up to 2 years”; M. Zahringer; August 2007
