Ureteral Stent May Not Be Associated With The Development of Significant BK Viruria and/or Viremia.

Abstract

Background: In recent years, the incidence of Polyoma BK virus infection has increased in renal transplant recipients. Several risk factors have been proposed including intensity of immunosuppression, higher HLA mismatch, pediatric status, BK virus mismatch between donor and recipient, immunosuppressant drugs, and most recently ureteral stent placement. Some studies have suggested a potential role of ureteral trauma in the pathogenesis of BK virus infection. No studies have found an association of ureteral stent duration with significant BK viruria (BKU), BK viremia (BKV), or BK nephropathy (BKN). Objective: We aimed to determine if ureteral stent placement is an independent risk factor for BK virus infection and to evaluate different risk factors for BKU and BKV adjusted for presence or absence and duration of stent placement. Methods: 93 consecutive kidney transplant recipients treated by 2 surgeons during Sep 2010 to July 2012 followed for more than 1 year were included in this analysis. Multiple variables including blood type, donor type, race, gender, induction regimen, DM status, and presence of ureteral stent were evaluated. All patients had documented negative BK virus in urine and blood before transplantation. Maintenance immunosuppression consisting of tacrolimus, mycophenolate sodium and corticosteroids were used in all patients. Results: Surgeon A who does not place an ureteral stent performed 48 (52%) cases and Surgeon B who routinely places an ureteral stent performed 45 (48%) cases. Basiliximab induction was used in 66 patients (71%) and rabbit anti-thymocyte globulin in 27 patients (29%). The stent was removed at a median (minimum-maximum) time of 94 (9-964) days from the transplant. The overall incidence of BKU and BKV was 42.2% and 26.8% of tested patients respectively. A significant difference was detected between those with and without BKU in race distribution, with more Hispanics (p=0.041) in the positive BKU group. There was also a significant association with male gender and BKV (p=0.03). There was no significant difference between subjects with and without ureteral stent placement in BKU (p= 0.72) or BKV (p= 0.97), or for duration of stent in BKU (p= 0.56) or BKV (p= 0.85). Conclusions: Our study would suggest that placement of ureteral stent in and of itself would not confer additional risk for BK virus infection.