Duplex Doppler sonography: is there clinical relevance to elevated renal vein velocity in kidney transplants?

PURPOSE: This study aims to determine a velocity threshold in the main renal vein (MRV) of renal transplants and evaluate the cause and clinical significance of elevated velocity. METHODS: Maximum MRV velocity from 331 consecutive renal transplant Doppler ultrasounds in 170 patients was recorded. A priori, twice the median MRV velocity was selected as the threshold for elevation. Ultrasounds were divided into "early" and "late" periods based on time after transplantation. Charts were reviewed for outcomes associated with elevated MRV velocity. Endpoints included graft failure or death. Serum creatinine (Cr) levels among groups were compared, and temporal changes in MRV velocity were plotted. RESULTS: A ≥70 cm/s was chosen as the threshold for elevated MRV velocity. Graft failure and complication/intervention rates were higher only in the "late" group with elevated MRV velocity. There was no association between elevated MRV velocity and death, no predilection for a particular biopsy result, and no difference in Cr levels among groups. The majority of elevated velocities occurred during the immediate postoperative period and resolved without intervention. CONCLUSIONS: Elevated MRV velocity in the early postoperative period is a transient phenomenon not correlating with outcome or requiring intervention. In the late period, elevated MRV velocity is associated with entities including hydronephrosis, perinephric collections, and arteriovenous fistulae.

Costimulation targeting therapies in organ transplantation.

PURPOSE OF REVIEW: Long-term side effects of posttransplant immunosuppressive agents contribute to graft loss and death. This article reviews recent publications on the potential role of costimulation targeting therapies, especially belatacept, in solid organ transplantation. RECENT FINDINGS: Belatacept, currently undergoing phase III clinical trials in renal transplantation, has shown promise as a safe and effective alternative immunosuppression regimen to calcineurin inhibitor and steroid-based therapies. Phase II trials demonstrated similar efficacy to cyclosporine, with greatly improved renal function. Although its side effects are not yet well characterized, belatacept has shown a decrease of the renal, cardiovascular, and metabolic side effects associated with calcineurin inhibitors. SUMMARY: Belatacept appears to be a safe and effective alternative to calcineurin inhibitor and steroid-based immunosuppressive strategies. Using belatacept in combination with another agent that blocks a different costimulatory pathway has proved especially effective. The results of ongoing and future phase III trials will be needed to validate current findings and determine the most effective belatacept-based regimen for patient populations.