Serial pulsatility index measurements in renal grafts before, during, and after episodes of urinary obstruction

The usefulness of pulsatility index determinations for the diagnosis of obs tructive collecting system dilatation was investigated in 10 renal transpla nt patients whose grafts developed urinary obstruction from different cause s. For this purpose we compared pulsatility index values obtained (1) befor e the ultrasonographic detection of obstruction or baseline study, (2) 1 da y before surgical repair, and (3) within 2 weeks after surgery. In 7 of 10 obstructed grafts, the pulsatility index values were increased only mildly to moderately preoperatively. In the remaining three grafts, a mild decreas e in pulsatility index was observed in spite of severe collecting system di latation. Changes in pulsatility index were not statistically significant. Impedance measurements appeared not to be useful for diagnosing obstructive collecting system dilatation.