Duplex Doppler sonography: is there clinical relevance to elevated renal vein velocity in kidney transplants?
OBJECTIVE
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.
Department of Radiology, University of Southern California Keck School of Medicine. Electronic address: mittul.gulati@med.usc.edu.
Mittul
M
Gulati
Department of Radiology, University of Southern California Keck School of Medicine.
Suzanne L
SL
Palmer
Department of Radiology, University of Southern California Keck School of Medicine.
Michael Y
MY
Im
Department of Radiology, University of Southern California Keck School of Medicine.
Hossein
H
Jadvar
Division of Nephrology, Department of Internal Medicine, University of Southern California Keck School of Medicine.
Yasir A
YA
Qazi
Division of Nephrology, Department of Internal Medicine, University of Southern California Keck School of Medicine.
Umer
U
Fazli
Department of Radiology, University of Southern California Keck School of Medicine.
Edward G
EG
Grant
D000328:Adult; D001706:Biopsy; D001783:Blood Flow Velocity; D003404:Creatinine / Q000097:blood; D005260:Female; D006085:Graft Survival; D006801:Humans; D007668:Kidney / Q000473:pathology; D016030:Kidney Transplantation / Q000401:mortality; D008297:Male; D008875:Middle Aged; D011183:Postoperative Complications / Q000503:physiopathology*; D012082:Renal Veins / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D012189:Retrospective Studies; D013997:Time Factors; D014463:Ultrasonography
D003404:Creatinine
Doppler sonography; Renal transplantation; Renal vein; Renal vein obstruction