Pyelorenal backflow during retrograde pyelography after renal transplantation.

Retrograde pyelography in 140 transplanted kidneys within 3 days of the operation showed a high frequency (29%) of pyelorenal backflow. Pyelotubular backflow, ordinarily a rare form of backflow, was seen in one-third of the patients whose transplants were removed within 60 days because of rejection, but in only 4% of the patients with surviving grafts. Pyelosinus backflow was found in 61% of the patients with signs of urinary obstruction, but in only 9% of the other patients. No relationship was found between pyelosinus backflow and graft rejection, or between pyelotubular backflow and urinary obstruction. Pyelotubular backflow may be an early radiographic sign of impending and serious rejection.