The optimal ischemia time varies greatly for the individual organs.
- Kidney:
- cold ischemia time < 20 h ( suboptimal up to > 36 h)
- liver:
- cold ischemia time < 10 h (suboptimal to > 10 h)
- heart:
- cold ischemia time < 4 h (suboptimal > 4 h)
- lung:
- cold ischemia time < 8 h (suboptimal > 8 h) (Krukemeyer 2008)
The functional assessment of the transplant depends - in addition to donor factors, such as the functional status of the kidneys, the age of the donor, etc. - (Angstwurm 2013), whereby the warm ischemic period plays a greater role.
A warm ischemia time of e.g. 30 min. causes greater tissue damage to the organ and also delayed organ function than a cold ischemia time of > 24 h (Wüthrich 2013).
However, the ischemia time is also of crucial importance for the long-term success of a transplantation.
This is taken into account in the allocation of a donor organ by Eurotransplant in the form of additional points (Bundesärztekammer 2013):
- 200 points if the removal of the donation and the implantation can take place in the same region
- 100 points if the collection of the donation and the implantation can take place in the same country
- 0 points if the collection of the donation and the implantation took place in different countries
In the case of a kidney transplant, for example, acute tubular necrosis can occur, among other things, as a result of a long cold ischemia period of > 30 h or a long warm ischemia period (more precise details are not available). This occurs in 19 % of all postmortem transplantations (Hoffmann 2014).
In order to keep the cold ischemia period as short as possible, a selective angiography of the renal vessels should be performed preoperatively on the potential donor in order to be informed about any anomalies (Kasper 2015).