**4. Key controversies in the result of multiorgan procurement**

We have many unresolved issues about multiorgan procurement surgery that needs more time to answer by the researchers. As the same with other works which are done by a team, expertise of each of the team member and their coordination with other members have a great effect on the final result of the operation. Undoubtedly, multiorgan retrieval may compromise the function of each organ and will be associated with a higher incidence of delicate anatomical structures damage. It may be better to perform all the dissections without any compromise in the circulation of any other organs. Many researchers show that this concern is not completely definite. Even some authors in their prospective and retrospective studies show that multiorgan harvesting may improve each separate organ function [10]. The main factor that affects the final result is the stability of the patient during the operation and the expertise of who is in charge of the whole operation [15]. One study shows that renal anatomical damage is more common when the operation is done by renal team only and if the operation is done by the liver team with experience of more than 50 procurement per year, the final anatomical (artery, vein ureter or capsular) damage will be significantly reduced [16]. In unstable patients, it is the duty of the team leader to determine which organ is more important and is the first priority. Usually in urgent situations, this is the "liver", because liver transplantation has the only way to cure the hepatic failure without any other treatment option in these patients with an acceptable success rate.

Another concern is that should dissection be done in warm or cold condition and en-bloc or separate organ retrieval is different? In fact, although theoretically the anatomical damage may be reduced if all the delicate dissections are performed in the donor before clamping of the aorta and all the organs retrieved separately, but most studies show that en-bloc retrieval and continuing the dissections after whole body cooling and whole blood evacuation have better results [10]. The rationale for this concept is that complete dissection especially in inexperienced hands is extremely time consuming and may result in end organ ischemia by inducing vasospasm. Using rapid technique is more acceptable for operating room personnel and

other members of the team, and this technique that one was used only for unstable donors is now the routine in most transplant centers [10].

Although most centers are reluctant to change their previous successful policies and it is a routine to perform double cannulation (aortic and portal) for dual perfusion of the liver, but nowadays with increased use of the pancreas and small bowel for transplantation, double perfusion may be replaced by the single aortic perfusion as a rule for most deceased donors [10]. With the advent of machine perfusion which used only one system for ex situ perfusion, there is increasingly more doubt about need for double perfusion and most studies shows that arterial perfusion is more important in saving the organ function especially the biliary system [17].
