**5. Donor selection**

Pancreas blood supply is performed under low-flux conditions. This low blood flow rate increases the risk of surgical complications, such as thrombosis and ischemia. In addition, exocrine pancreas produces a large amount of protein cleavage enzymes, making it very susceptible to ischemia-reperfusion injury during transplantation. Pancreas present the highest donor discard rate among abdominal solid organ transplantations, with up to 33% of all pancreas being discarded by surgical teams prior to pancreas extraction, and an additional 50% being discarded following the extraction due to macroscopic appearance.

In an attempt to standardize donor acceptance criteria and predict short-term pancreas graft function, several scoring systems have been developed. P-PASS was one of the first to be described and was used in the Eurotransplant area to increase sensitivity in allocation. It categorized donors in low (<17) or high (≥17) risk donors [12]. The initial enthusiasm was halted by the reports of its inability to predict short- and long-term graft survival [13].

In 2010, Axelrod et al. published a complex scoring system, including donor and recipient variables, which enabled to predict 1-year graft survival [14]. Despite the promising results, it lacked several key factors, which are thought to influence outcomes, such as previous cardiac arrest in donors after brain death and perfusion solution. In 2013, Finger et al. demonstrated that the presence of at least two factors such as BMI ≥30 kg/m<sup>2</sup> , donor creatinine ≥2.5 mg/dL, donor age > 50 years, and preservation time > 20 h were associated with technical failure [15].

Donors after brain death (DBD) have been the most widely used deceased donors since late 1980s; donors after cardiocirulatory death (DCD) were the first deceased donors used for organ transplantation in many countries until a brain death diagnosis and its acceptance for organ donation was legislated. Since the mid-2000s, DCDs regained protagonism as a potential source to increase donor pool, with an increasing number of transplanted organs ever since. DCDs should be evaluated carefully, since the definition includes donors with different backgrounds. According to the Maastricht classification, DCD donors can be classified from type I–V (**Table 4**) [16]. For pancreas transplantation, both type II (uncontrolled) and type III (controlled) have been used. Results from single center and registry analysis suggest


**Table 4.** Maastricht classification [16].

that DCD donors are a suitable source of organs for pancreas and islet transplantation in selected donors [17]. Age limit acceptance is usually lower for DBD donors (<45 years), and both warm and cold ischemia times should be strictly respected, at the risk of increased surgical complications.

**Table 5** describes the acceptance criteria for both DBD and DCD donors at our center. In summary, all donors under 45 years without other risk factors, with BMI ≤30 kg/m<sup>2</sup> , and transaminases and pancreatic enzymes <3× normal values are accepted for transplantation, regardless of being DBD or DCD. Beyond those criteria, individual evaluations are performed.


**Table 5.** Hospital clinic pancreas donor acceptance criteria.
