double - j ( dj ) stents are used to drain urine from the kidney to the bladder and are effective in managing and preventing upper urinary tract ( ut ) obstruction in various urological conditions ( 1 ) .
the most common indication of stenting is to prevent and relieve upper ut obstruction ( 2 , 3 ) .
the known complications of dj stent include encrustation , fragmentation , proximal and distal migration , dysuria , and frequency ( 1 ) .
most of these complications are self - limited and can be managed with suitable urologic interventions and supportive medical management ( 2 - 4 ) .
we reported a rare and serious case of vascular migration of a stent to the pulmonary artery , with a long - time remained .
the patient was a 47-year - old man with a history of long - lasting renal colic from four months before his admission .
the surgeon had difficulty passing the ureteroscope through the intramural ureter and , with frequent manipulation , a 0.035 guidewire was passed through the intramural ureter , after which a dj stent of 4.8f-30 cm was inserted over the guidewire .
kub was performed after the procedure for control of the location of the dj , but the resident did not diagnose abnormal pathway of the stent .
he then developed gross hematuria for two days and , after passing a large clot in urine , the hematuria stopped , and he had no further urinary symptoms .
after two weeks , he came to the clinic , and the surgeon planned to remove the dj stent in the operating room by cystoscopy .
the cystoscope was passed into the bladder , but the stent could not be visualized there .
migration of the stent to another anatomical position , such as the ureter or retroperitoneal , or vascular migration was suggested .
the patient was referred to the radiology department , where kub and chest x - ray ( cxr ) was performed .
the stent had an abnormal pathway , probably entering into the inferior vena cava ( figure 1 ) .
cxr showed abnormal density that could have been the shadow of the stent ( figure 2 ) .
the x - ray revealed an abnormal pathway of the double - j stent that probably entered into the inferior vena cava .
the arrow shows the position of the ureteral stone , 8  6 mm in size , at the ureterovesical junction .
the patient was referred to the angiography department . in fluoroscopy , during pulmonary angiography , the dj stent was seen completely in the pulmonary artery .
the tip of the stent was fixed , which may have been due to wedging in the pulmonary artery branch , thrombus formation in this site , or other causes ( figure 3 ) .
other laboratory data including cbc , bun , esr , crp , and creatinine were normal .
blood culture was requested , and prophylactic antibiotic and anticoagulant therapies were performed for the patient .
there are two methods to remove endovascular foreign bodies : open surgery and intravascular retrieval ( 5 - 9 ) , and it was planned to remove the stent percutaneously .
10 french right femoral sheath was used , and pulmonary angiography was performed ( figure 4 ) . a multipurpose 7f catheter was used to try to release the fixed left tip of the stent , but frequent manipulation was not successful .
the right distal tip of the stent was captured by peripheral snare , and the stent was retrieved successfully without any complication .
when the peripheral snare was introduced percutaneously from the femoral sheath , and the tip of the stent was captured by it .
the common symptoms and probable complications following dj stent insertion include lower ut symptoms , loin pain , hematuria , ut infection , vesicoureteral reflux ( vur ) , stent malposition , luminal obstruction , ureteral erosion or necrosis , stone formation , encrustation , fracture , and migration proximally and distally in the urinary system ( 4 , 10 ) .
stent placements can be prone to vessel erosion , and in rare situations , intravascular migration of the dj stent has been reported ( 6 , 10 ) .
michalopoulos et al . reported pulmonary thromboembolism immediately after surgery from migration of a stent into the heart and left pulmonary arterial system after pyelolithotomy and antegrade insertion of a pigtail ureteral stent .
the stent was removed percutaneously by using the femoral vein as an access site ( 7 ) .
percutaneous removal of the migrated stent was performed under fluoroscopic guide ( 5 ) . however , in two other case reports , the stent was removed successfully via cardiopulmonary bypass ( 6 , 8) .
although placement of a ureteral stent is easy , serious complications may occur during or after such a procedure ( 5 - 9 ) . in this case , the surgeon blindly passed a 0.035 guidewire through the intramural ureter , when it probably passed into the submucosa and then the iliac vessel .
second , use of hydrophilic wire can prevent passing the wire into the submucosal layer .
moreover , dj stent insertion under fluoroscopic guide can reduce these complications . in the absence of fluoroscopy
if abnormal position of the stent is suspected , other diagnostic methods , such as ct with iv contrast , can confirm or disprove the diagnosis .
finally , clinicians should pay attention to warning symptoms of the patient , such as significant hematuria and severe abdominal pain . in this case , the stent was completely in the pulmonary arteries .
multiple treatment options can be used for this situation , such as percutaneous removal by snare catheter , when possible , and open surgery .
because of the good condition of the patient and available expertise for endovascular intervention , it was decided to remove the stent by the endovascular method with femoral access .
if expertise for endovascular intervention is not available , open surgical removal is an alternative , safe method .
intravascular migration of dj stents is a rare but serious complication . when there is doubt , complementary diagnostic procedures and early intervention are recommended .
percutaneous removal of a migrated stent under fluoroscopic guidance by snare catheter from femoral access is a safe and effective treatment .
 double - j ( dj ) stents are the main tools used in urological practice for prevention and treatment of obstruction . 
 stenting is also mandatory after complicated ureteroscopy or tul ( transureteral lithotripsy ) . 
 known complications are upper migration of dj stents into the kidney and lower migration to the bladder . in a man with an impacted right lower ureteral stone , a dj stent was placed because the ureteroscope was not passed from an intramural ureter . 
 we reported a very rare complication of dj ureteral stent placement with intravascular migration to the pulmonary arteries , which was removed percutaneously through the right femoral vein under fluoroscopic guidance . 
1. Introduction
2. Case Presentation
3. Discussion