The impact of immunosuppression on postoperative graft function after graft-unrelated surgery: a retrospective controlled cohort study.

Background: Physicians are faced with a growing number of patients after renal transplantation undergoing graft-unrelated surgery. So far, little is known about the postoperative restitution of graft function and the risk factors for a poor outcome.

Methods: One hundred one kidney transplant recipients undergoing graft-unrelated surgery between 2005 and 2015 were reviewed retrospectively. A risk analysis was performed and differences in creatinine, GFR and immunosuppressive treatment were evaluated. Additional, a comparison with a case-matched non-transplanted control group were performed.

Results: Preoperative creatinine averaged 1.88 mg / dl [0.62-5.22 mg / dl] and increased to 2.49 mg / dl [0.69-8.30 mg / dl] postoperatively. Acute kidney failure occurred in 18 patients and 14 patients had a permanent renal failure. Significant risk factors for the development of postoperative renal dysfunction were female gender, a preoperative creatinine above 2.0 mg / dl as well as a GFR below 40 ml / min and emergency surgery. Patients with tacrolimus and mycophenolate mofetil treatment showed a significant lower risk of renal dysfunction than patients with other immunosuppressants postoperatively. Contrary to that, the risk of patients with cyclosporine treatment was significantly increased. Transplanted patients showed a significantly increased rate of postoperative renal dysfunction.

Conclusions: The choice of immunosuppressant might have an impact on graft function and survival of kidney transplant recipients after graft-unrelated surgery. Further investigations are needed.