Saudi Journal of Kidney Diseases and Transplantation

: 2014  |  Volume : 25  |  Issue : 3  |  Page : 653--654

Author's reply

Behzad Einollahi 
 Nephrology and Urology Research Center, Baqiyatallah University of Medical Sciences, Tehran, I.R. Iran

Correspondence Address:
Dr. Behzad Einollahi
Nephrology and Urology Research Center, Baqiyatallah University of Medical Sciences, Tehran
I.R. Iran

How to cite this article:
Einollahi B. Author's reply.Saudi J Kidney Dis Transpl 2014;25:653-654

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Einollahi B. Author's reply. Saudi J Kidney Dis Transpl [serial online] 2014 [cited 2021 Apr 20 ];25:653-654
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Full Text

To the Editor,

I have read with interest the comments by Khan et al to my Letter to the Editor published in the recent issue of the Saudi Journal of Kidney Diseases and Transplantation.[1] They noted that a higher incidence of delayed graft function (DGF) and increased warm ischemia time (WIT) due to the expected increase in the vascular anastomoses time in recipients with multiple renal arteries (MRAs) may be associated with higher rates of acute rejection and poor renal allograft outcomes.

"Warm ischemia" is a term used to describe ischemia of cells and tissues under normothermic conditions. In the kidney transplant setting, WIT is used to describe two physiologically distinct periods of ischemia: (a) Ischemia during implantation, from removal of the kidney from ice until reperfusion and (b) ischemia during kidney retrieval, from the time of cross-clamping until cold perfusion is initiated. These periods of WIT differ in their nature and the magnitude of their pathophysiologic consequences. The majority of researchers prefer the terms "WIT in donor" and "WIT in recipient" to distinguish the two periods. I agree with Khan et al that WIT in the recipients will increase in kidney transplant patients with MRAs. I reviewed the collected data in our previous study again and the WIT mentioned was warm ischemia in the donor. [3] Thus, it is obvious that the reported WIT was in seconds and not minutes.

I agree that we had a higher rate of acute rejection in recipients of grafts with MRAs when compared with recipients with single renal artery in the first three months after kidney transplantation (P = 0.002); [2] however, the impact of early acute rejection episodes on graft survival is debated. Acute rejection has an adverse impact on graft survival, particularly if it occurs after three months. [3] However, not all acute rejection episodes lead to an adverse outcome, and the type, severity, timing and clinical course of acute rejection individually influence the impact of a rejection episode; if renal function recovers fully, there appears to be no survival disadvantage. [4] Acute rejection episodes should therefore be divided into early, defined as those occurring within three months, and late, defined as those occurring after three months. [3] It has also been shown that an episode of early acute rejection was not associated with long-term graft survival or chronic allograft nephropathy. [5]

In addition, there are many confounding factors for patient and graft outcomes. We did not look at most of the risk factors such as Cytomegalovirus infection, delayed graft function, mismatch of human leukocyte antigen (HLA), etc. in our study. [2] For example, a lower number of HLA-DR mismatches sum to reduce the occurrence of acute rejection. [5]

Furthermore, the number of patients receiving kidneys with three arteries was too small (n = 7), but the number of cases with two arteries was high (n = 83). [2] Thus, using grafts with two arteries is safer and the conclusion of the study was applicable more to patients receiving graft with two arteries. We thought that poorer outcome for grafts with three arteries may be due to the higher rate of acute rejection episodes, infection and other post-transplant complications, which was consistent with other reports. [2]


1Einollahi B, Nourbala MH, Fatahi MR. Favorable outcomes of living donor kidney transplantation following use of grafts with multiple renal arteries. Saudi J Kidney Dis Transpl 2013;24:578-9.
2Abbaszadeh S, Nourbala MH, Alghasi M, et al. Does renal artery multiplicity have impact on patient and allograft survival rates? Nephrol Urol Mon 2009;1:45-50.
3Joseph JT, Kingsmore DB, Junor BJ, et al. The impact of late acute rejection after cadaveric kidney transplantation. Clin Transplant 2001; 15:221-7.
4Nashan B. Is acute rejection the key predictor for long-term outcomes after renal transplantation when comparing calcineurin inhibitors? Transplant Rev (Orlando) 2009;23:47-52.
5He X, Johnston A. Early acute rejection does not affect chronic allograft nephropathy and death censored graft failure. Transplant Proc 2004;36:2993-6.