The purpose of this study is to investigate local activation of the coagulation system in the kidney graft during organ preservation and during early reperfusion in adult kidney transplantation. Generation of thrombin and fibrin as well as activation and inhibition of fibrinolysis will be investigated. Influence of these events on delayed graft function (DGF) and acute cell-mediated rejection will be evaluated.
Background In clinical kidney transplantation organ retrieval, cold-preservation of the graft as well as restoration of the blood flow to the transplant cause tissue damage (ischemia/reperfusion injury). Clinically these events can manifest themselves as delayed graft function (DGF), which is usually defined as the need for dialysis during first week after transplantation. DGF increases the risk of developing chronic rejection and subsequently loss of the transplant. Ischaemia/reperfusion injury is biologically characterized by local profound inflammatory response, activation of the coagulation system and endothelial dysfunction in the transplanted organ. After reperfusion activated neutrophils cause tissue damage in the graft by production of reactive oxygen species (ROS) and release of proteolytic enzymes, which lead to plugging of the capillaries by accumulation of thrombocytes and fibrin. Blood flow is further diminished by increased blood viscosity and local vasoconstriction and swelling of the endothelial cells. Disorders of the microcirculation lead to "no-reflow" phenomenon whereby locally tissues remain ischemic, despite of good blood flow in the organ artery and vein. Coagulation is activated in the renal transplant during reperfusion, when circulating factor VIIa (FVIIa) comes into contact with the tissue factor (TF), which is expressed on the endothelium due to ischaemia. FVII-TF complex activates factor X (FX) and activated FX (FXa) cleaves thrombin (FII) from prothrombin. Thrombin activates thrombocytes, cleaves fibrin from fibrinogen and activates factor XIII( FXIII), which stabilizes fibrin clot. Fibrin has been demonstrated to accumulate in the kidney graft during reperfusion. Fibrin accumulation is aggravated by inhibition of fibrinolysis due to reperfusion. Furthermore, the investigators conducting this current research project, have previously gained indirect evidence in a small cohort study, that accumulation of fibrin occurs even before reperfusion, during donor care and organ retrieval. Most importantly, specifically this pre-reperfusion fibrin deposition was related to DGF. Patients and sample size There were several limitations in investigators previous study concerning intra-graft coagulation events in DGF. It was conducted as a part of a larger trial in renal transplantation and included only 30 patients in two study arms with different immunosuppressant regimens (peri-operative basiliximab and conventional triple therapy). Therefore, a new study, with larger sample size and standardized immunosuppression is warranted. Therefore, in this current prospective observational study surgical technique, anaesthesia and hemodynamic management, immunosuppressive medications are strictly standardized. Sample size is increased to 100. The investigators prospectively screen all adult patients receiving their first kidney transplant from cadaveric donor. Only patients scheduled to receive local standard triple immunosuppressant therapy with cyclosporine A, mycophenolate mofetil and methylprednisolone are included. Blood samples and prospective data collection Blood samples for assessment of intra-graft coagulation events (generation of thrombin and fibrin, activation and inhibition of fibrinolysis) are drawn peri-operatively. Predefined clinical and demographical data are collected preoperatively and prospectively during 3 months after kidney transplantation to assess the influence of these coagulation events on delayed graft function according to Halloran criteria (8) (primary outcome) and acute cell mediated graft rejection (primary outcome).
Study Type
OBSERVATIONAL
Enrollment
100
Helsinki University and Helsinki University Hospital
Helsinki, Finland
Trans-renal difference/ratio of plasma concentrations of coagulation measurements
Trans-transplant difference/ratio is determined in order to correlate intra-graft coagulation events to the incidences of other primary outcomes.
Time frame: Two minutes after reperfusion of the kidney transplant
Delayed Graft Function
Delayed graft function is assessed by Halloran criteria: oliguria \< 1000ml/24h for more than 2 days after transplantation or plasma creatinine \>500 micromol/l during the first week after transplantation or more than one dialysis during the first week after transplantation (Halloran et al, Transplantation 1988;46:223-8.)
Time frame: During 1 week after kidney transplantation
Acute cell mediated graft rejection
Time frame: During 3 months after kidney transplantation
Plasma creatinine value (micromol/L)
Time frame: At admission to the hospital, during the first week after transplantation and at 1 and 3 months after renal transplantation
Plasma urea value (mmol/L)
Time frame: At admission to the hospital, during the first week after transplantation and at 1 and 3 months after renal transplantation
Estimated glomerular filtration rate (ml/min/1.73 m2)
Estimated glomerular filtration rate is calculated according to the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) formula
Time frame: At admission to the hospital, during the first week after transplantation and at 1 and 3 months after renal transplantation
Urine output (ml/24h)
Urine output (ml/24h) before the surgery and during the first week after transplantation will be recorded
Time frame: Pre-operative urine output (ml/24h) and daily urine output (ml/24h) during the first week after transplantation
Renal artery and renal vein blood flow (ml/min)
Renal artery and renal vein blood flow (ml/min) are measured intra-operatively immediately after blood sample retrieval using a specific probe
Time frame: Immediately after blood sample retrieval during reperfusion
Fluid balance during surgery and post-anesthesia care unit stay (ml)
All fluids infused from the start of the kidney transplantation surgery until discharge from the post-anaesthesia care unit (until discharge to the ward) are recorded. All fluids losses (blood loss, urine output) during this period are recorded.
Time frame: From the start of the kidney transplantation surgery until the discharge from post-anesthesia care unit (up to 24 hours from the start of the surgery)
Transfusion
All blood products used during this time frame are recorded and reported
Time frame: From the start of the kidney transplantation surgery until the discharge from post-anesthesia care unit (up to 24 hours from the start of the surgery)
Prothrombin fragment 1+2 (F1+2)
Preoperative value and the trans-transplant difference and/or ratio is determined in order to assess thrombin generation.
Time frame: Blood samples are taken at two timepoints: 1) immediately before the start of the surgery; 2) 2 minutes after reperfusion of the kidney transplant
Fibrinopeptide A
Preoperative value and the trans-transplant difference and/or ratio is determined in order to assess fibrin generation.
Time frame: Blood samples are taken at two timepoints: 1) immediately before the start of the surgery; 2) 2 minutes after reperfusion of the kidney transplant
D-dimers
Preoperative value and the trans-transplant difference and/or ratio is determined in order to assess fibrin degradation
Time frame: Blood samples are taken at two timepoints: 1) immediately before the start of the surgery; 2) 2 minutes after reperfusion of the kidney transplant
Tissue type plasminogen activator
Preoperative value and the trans-transplant difference and/or ratio is determined in order to assess activation of fibrinolysis.
Time frame: Blood samples are taken at two timepoints: 1) immediately before the start of the surgery; 2) 2 minutes after reperfusion of the kidney transplant
Plasminogen activator inhibitor
Preoperative value and the trans-transplant difference and/or ratio is determined in order to assess inhibition of fibrinolysis.
Time frame: Blood samples are taken at two timepoints: 1) immediately before the start of the surgery; 2) 2 minutes after reperfusion of the kidney transplant
Syndecan-1
Preoperative value and the trans-transplant difference and/or ratio is determined in order to assess degradation of endothelial glycocalyx
Time frame: Blood samples are taken at two timepoints: 1) immediately before the start of the surgery; 2) 2 minutes after reperfusion of the kidney transplant
Myeloperoxidase and/or lactoferrin
Preoperative value and the trans-transplant difference and/or ratio is determined in order to assess activation of neutrophiles
Time frame: Blood samples are taken at two timepoints: 1) immediately before the start of the surgery; 2) 2 minutes after reperfusion of the kidney transplant
Interleukin 6, interleukin 8, interleukin 10
Preoperative value and the trans-transplant difference and/or ratio is determined in order to assess activation/inhibition of inflammation
Time frame: Blood samples are taken at two timepoints: 1) immediately before the start of the surgery; 2) 2 minutes after reperfusion of the kidney transplant
Number of hemodialyses and their indication after surgery
All dialysis sessions will be recorded during first post-operative week. Indication for dialysis (oliguria, hyperkalemia, hypervolemia, acidosis) will be recorded during first post-operative week. At 1 and 3 months after surgery only number of dialyses/week will be recorded
Time frame: From the start of the surgery until 3 months after surgery
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