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Re: The Prognostic Value of Renal Resistance During Hypothermic Machine Perfusion of Deceased Donor Kidneys
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RENAL TRANSPLANTATION AND RENOVASCULAR HYPERTENSION
Re: The Prognostic Value of Renal Resistance During Hypothermic Machine Perfusion of Deceased Donor Kidneys I. Jochmans, C. Moers, J. M. Smits, H. G. Leuvenink, J. Treckmann, A. Paul, A. Rahmel, J. P. Squifflet, E. van Heurn, D. Monbaliu, R. J. Ploeg and J. Pirenne Department of Abdominal Transplant Surgery, University Hospital Leuven, Leuven, Belgium Am J Transplant 2011; 11: 2214 –2220.
Vascular renal resistance (RR) during hypothermic machine perfusion (HMP) is frequently used in kidney graft quality assessment. However, the association between RR and outcome has never been prospectively validated. Prospectively collected RR values of 302 machine-perfused deceased donor kidneys of all types (standard and extended criteria donor kidneys and kidneys donated after cardiac death), transplanted without prior knowledge of these RR values, were studied. In this cohort, we determined the association between RR and delayed graft function (DGF) and 1-year graft survival. The RR (mmHg/mL/min) at the end of HMP was an independent risk factor for DGF (odds ratio 21.12 [1.03– 435.0]; p ⫽ 0.048) but the predictive value of RR was low, reflected by a c-statistic of the receiver operator characteristic curve of 0.58. The RR was also found to be an independent risk factor for 1-year graft failure (hazard ratio 12.33 [1.11–136.85]; p ⫽ 0.004). Determinants of transplant outcome are multifactorial in nature and this study identifies RR as an additional parameter to take into account when evaluating graft quality and estimating the likelihood of successful outcome. However, RR as a stand-alone quality assessment tool cannot be used to predict outcome with sufficient precision. Editorial Comment: This study used data from a large multicenter European trial of pulsatile perfusion (PP) vs cold storage preservation. Kidneys from the same donor were randomized to either PP or cold storage. The authors used a variety of deceased donor kidneys, including standard criteria donors, expanded criteria donors and donation by cardiac death donors. Centers were blinded to the hemodynamic performance of kidneys, which is the strength of the study design. Decisions on use for the PP group were not based on PP parameters such as flow, pressure or renal resistance. Organs were used independent of PP parameters. In the United States PP parameters have been used to assess the usability of organs. Those with poor flow or high terminal renal resistance are often turned down due to concern over poor recovery of function and possible primary nonfunction. This group found that the terminal renal resistance was independently associated with DGF, although this was an insufficient predictor (receiver operator characteristic curve C-index of 0.58) of events. It was also noted that low terminal renal resistance was associated with lower 1-year graft failure. While PP parameters may be useful as part of many factors in determining the usability of an organ, they are insufficient as a stand-alone predictor of DGF or graft failure. David A. Goldfarb, M.D.
RENAL TRANSPLANTATION AND RENOVASCULAR HYPERTENSION
Re: The Prognostic Value of Renal Resistance During Hypothermic Machine Perfusion of Deceased Donor Kidneys I. Jochmans, C. Moers, J. M. Smits, H. G. Leuvenink, J. Treckmann, A. Paul, A. Rahmel, J. P. Squifflet, E. van Heurn, D. Monbaliu, R. J. Ploeg and J. Pirenne Department of Abdominal Transplant Surgery, University Hospital Leuven, Leuven, Belgium Am J Transplant 2011; 11: 2214 –2220.
Vascular renal resistance (RR) during hypothermic machine perfusion (HMP) is frequently used in kidney graft quality assessment. However, the association between RR and outcome has never been prospectively validated. Prospectively collected RR values of 302 machine-perfused deceased donor kidneys of all types (standard and extended criteria donor kidneys and kidneys donated after cardiac death), transplanted without prior knowledge of these RR values, were studied. In this cohort, we determined the association between RR and delayed graft function (DGF) and 1-year graft survival. The RR (mmHg/mL/min) at the end of HMP was an independent risk factor for DGF (odds ratio 21.12 [1.03– 435.0]; p ⫽ 0.048) but the predictive value of RR was low, reflected by a c-statistic of the receiver operator characteristic curve of 0.58. The RR was also found to be an independent risk factor for 1-year graft failure (hazard ratio 12.33 [1.11–136.85]; p ⫽ 0.004). Determinants of transplant outcome are multifactorial in nature and this study identifies RR as an additional parameter to take into account when evaluating graft quality and estimating the likelihood of successful outcome. However, RR as a stand-alone quality assessment tool cannot be used to predict outcome with sufficient precision. Editorial Comment: This study used data from a large multicenter European trial of pulsatile perfusion (PP) vs cold storage preservation. Kidneys from the same donor were randomized to either PP or cold storage. The authors used a variety of deceased donor kidneys, including standard criteria donors, expanded criteria donors and donation by cardiac death donors. Centers were blinded to the hemodynamic performance of kidneys, which is the strength of the study design. Decisions on use for the PP group were not based on PP parameters such as flow, pressure or renal resistance. Organs were used independent of PP parameters. In the United States PP parameters have been used to assess the usability of organs. Those with poor flow or high terminal renal resistance are often turned down due to concern over poor recovery of function and possible primary nonfunction. This group found that the terminal renal resistance was independently associated with DGF, although this was an insufficient predictor (receiver operator characteristic curve C-index of 0.58) of events. It was also noted that low terminal renal resistance was associated with lower 1-year graft failure. While PP parameters may be useful as part of many factors in determining the usability of an organ, they are insufficient as a stand-alone predictor of DGF or graft failure. David A. Goldfarb, M.D.