ASSESSMENT OF PRESERVATION INDUCED REPERFUSION INJURY VIA INTRAOPERATIVE RENAL-TRANSPLANT BLOOD-FLOW AND ENDOTHELIN CONCENTRATION STUDIES

Purpose: We investigated a possible relationship between levels of the vasoconstrictive peptide endothelin and renal transplant reperfusion injury, and modified a technique for measuring renal blood flow with a n ultrasonic perivascular transit time now probe. Materials and Method s: Renal grafts in a swine transplant model were cold flushed with eit her Collins-2 or University of Wisconsin solution. Renal blood flow an d renal vein endothelin levels after reperfusion of transplanted graft s, as well as histological parameters within the transplanted kidney w ere measured. The 5-minute post-reperfusion renal blood flow was used as the baseline allograft flow. The definition of reperfusion injury w as a decrease in flow from baseline with no recovery within 1 hour of reperfusion. In 9 human recipients reperfusion injury was further veri fied by monitoring subsequent serum creatinine, urine output, graft su rvival and rejection episodes. Results: In the swine model and human t ransplant recipients no evidence of post-reperfusion ischemia was note d by histological examination, supporting that moderate to mild reperf usion injury or ischemic injury cannot be clinically determined with t his method. In the swine model the decrease flow from baseline in allo graft post-reperfusion renal blood flow was significantly greater in k idneys preserved in Collins'-2 than in University of Wisconsin solutio n (41.75 +/- 5.69 versus 11.18 +/- 13.99 ml. per minute, p = 0.005), s upporting that this technique can assess mild to moderate reperfusion injury. The increase in serum endothelin in the allografts from the sw ine model and in humans was not significantly different from baseline. Clinically, post-reperfusion renal blood flow changes correlated well with subsequent function. The 4 patients with renal transplant reperf usion injury had significantly higher serum creatinine values and lowe r urine output 1 Reek postoperatively than 5 patients with no evidence of injury (serum creatinine: 6.75 +/- 3.03 versus 2.08 +/- 1.28 mg./d l., p = 0.015). Reperfusion injury patients had more rejections (2 ver sus 1) and less graft survival (75% versus 100%) at 1-year followup co mpared to the nonreperfusion injury patients. Conclusions: Vasoactive factors other than endothelin most likely contribute to reperfusion in jury. Furthermore, the ultrasonic transit time flow probe accurately m easures post-reperfusion renal blood flow and offers a practical metho d for assessing acute reperfusion injury, which may help to optimize i mmunosuppressive strategies to decrease allograft loss associated with delayed graft function.