MACHINE PERFUSION PRESERVATION DOES NOT INCREASE THE RISK OF KIDNEY GRAFT REJECTION

Abstract

221 Continuous hypothermic pulsatile perfusion (CHPP) is recently more widely used for preservation of kidneys harvested from "marginal donors". CHPP proved to be effective, allowing longer preservation time with no increase in ATN rate. It has been suggested that perfusion can damage vascular endothelium, therefore accelerating rejection. The aim of our study was to assess correlation of preservation method and frequency of rejection episodes. Material. From Jun '94 to Jan '97 seventy-six ESRD pts received kidneys harvested from 38 cadaveric donors (13 in UNOS group B and 25 group C). One kidney from each donor was stored in ViaSpan in simple hypothermia (CS), while the other was machine perfused (CHPP) with Belzer's UW Gluconate) using MOX 100 system (Waters Instr.). Standard perfusion parameters were used. Kidneys were transplanted using typical surgical technique. Two pts in CHPP group and five in CS received second or third kidney graft. Recipients factors (age, gender, cause of ESRD, pretransplant dialysis time, number of blood transfusion and maximum PRA) did not differ between the groups. Cold ischemia times were longer for kidneys stored using CHPP than in CS (30 h 32′ vs. 26h 31′; p<0.0001). The time of vascular anastomosis was similar (NS). Recipients received tripple immunosuppressive treatment. Mean mismatch number was 2.94 vs. 3.0 in CHPP vs CS (NS). Patients in CS group were slightly better matched for DR antigens: 0.67 vs. 0.76 mismatch in CHPP group (p<0.001). Graft function (serum creatinine and diuresis), incidence of ATN (with number of dialysis required), CMV infection and frequency of rejection (biopsy, duplex-scan Doppler or clinical signs) were monitored. Ethical Committee of Warsaw Medical School permission for this study was obtained. Results. No hyperacute rejection was observed in any case. Eleven pts from CHPP group had ATN requiring 1,54 ±2,84 hemodialysis procedures, in one case primary non-function occur and one patient died of myocardial infarction. Among controls, there were seventeen patients with ATN (p<0.05) requiring 2,8 ± 3,22 hemodialyses (p<0.05) and one graft never regain function. Significantly lower number of acute rejection episodes in CHPP group (0.57±0.88 rejections/patient) than in CS group (1.06±1.15) was observed (p=0.04). CS group patients required slightly higher doses of methylprednisolone for the treatment of rejection episodes (1.96 vs 1.32 g;), as well as more doses of ATG/OKT3 (0.86 vs. 0.45 doses/patient,) for steroid resistant rejection treatment. Chronic rejection affected graft function in 9.4% of recipients in CHPP group and 18.8% in the study group (p=0.04). After 24 months follow-up patients from CS group had significantly higher serum creatinine level: 1,68 mg% vs. 1,32 mg% (p<0,03). No kidney in the study group was lost due to rejection. Multivariate analysis shown no correlation between preservation method and acute rejection (F=1,67 beta=0,216 p<0,2). Acute rejection precedes accelerated chronic rejection (beta=0,47). Conclusions. Method of preservation has been found the risk factor for the allograft rejection. Patients who received kidneys stored using CHPP had less episodes of acute rejection. Therefore the suggestion that endothelial damage could induct rejection process has not been supported by our study. Moreover, the benefit of machine perfusion can be due to more efficient preservation of endothelium and/or better maintenance of whole organ integrity reflected by better postoperative function.