A stent is small tube made of a metal or fabric mesh that is inserted into the body to improve the flow of fluids---usually blood through a blood vessel. Doctors place kidney stents in the renal arteries, the blood vessels that carry blood to the kidneys, or in the ureters, small tubes that carry urine from the kidneys to the bladder. Stents are often used to treat blood vessels that have become too narrow, a condition known as stenosis. Complications from kidney stents are usually rare, although some side effects may occur.
Urinary Tract Infections
Kidney stents in the ureters increase the risk of urinary tract infections, according to the Stillwater Medical Group. The presence of a foreign object in the ureter promotes the growth of bacteria, resulting in infection. In some cases, the stent may become encrusted with crystals made of minerals found in urine, which can cause severe pain when urinating, the Stillwater Medical Group reports.
Stent Displacement
On rare occasions, a kidney stent may become dislodged from its location and move away from the kidney. If a stent in an artery moves into the opening of another artery, it can block blood flow, a condition known as occlusion, explains Radiology Info.
Kidney Damage
Kidney damage is a complication of stent placement in the renal artery. Stents in this artery carry the risk of temporarily decreasing kidney function in 1 to 13 percent of patients, according to a study published by the Agency for Healthcare Research and Quality. In 1.5 percent of patients, a severe decrease in kidney function was observed, the study reports. Some of the kidney damage results from the contrast dye that physicians use during the procedure to place the stent, explains the National Heart Lung and Blood Institute.
Artery Damage
Another complication of kidney stents is artery damage. Insertion of a stent into blood vessels carries the risk of damaging the blood vessels, states Radiology Info. The blood vessels may become torn or bruised by the stent, and in rare cases, vessels may rupture.
Blood Clots
Blood clots can occur related to the placement of kidney stents. Approximately 1 to 2 percent of people receiving stents develop a blood clot where the stent is inserted, reports the National Heart Lung and Blood Institute. If a blood clot breaks away from the blood vessel where it formed, it can travel to the heart, brain or lungs, causing a heart attack, stroke or pulmonary embolism. The risk of blood clot increases with the length of time the stent is in place, explains the National Heart Lung and Blood Institute. Doctors often prescribe blood thinners to reduce this risk in people receiving stents.
Severe Bleeding
Severe bleeding, also called a hemorrhage, results in roughly 1 percent of people receiving kidney stents, reports a study published by the Agency for Healthcare Research and Quality. In some cases, the bleeding may be so severe that patients may require a blood transfusion, explains Radiology Info.
References
- Stillwater Medical Group: Frequently Asked Questions about Ureteral Stents
- Radiology Info: Angioplasty and Vascular Stenting
- Agency for Healthcare Research and Quality: Comparative Effectiveness of Management Strategies for Renal Artery Stenosis: 2007 Update.
- National Heart Lung and Blood Institute: Stents
