## 4 Discussion  
Given their proven applications as criteria for the definition of sepsis and sepsis-related organ dysfunctions, both SIRS and qSOFA could be useful markers in predicting the severity of post-ERCP AEs, especially of PEP. However, to date, only few prospective studies have investigated such an extended use of these criteria in order to identify possible alternative severity and prognostic markers of PEP. Regarding PEP, large clinical trials have aimed to refine its definition and severity scaling but with no clear consensus, mainly due to the variability of hospital stay and discharge criteria [19], the exact timing for the measurement of pancreatic enzymes, and their diagnostic value [1, 4, 16, 20]. Pre-existing pain, organ dysfunction, or sepsis due to acute biliary pancreatitis or cholangitis further influence the definition and prediction of PEP severity [4, 16, 20]. The Atlanta definition has not been embraced so far, probably because it requires pancreas imaging [10]. Hence, identification of predictive tools for PEP severity seems mandatory. Figure 2: Receiver operating characteristic curves analyzing predictive effect of systemic inflammatory response syndrome criteria and the quick Sequential Organ Failure Assessment score on survival rates, organ dysfunction, and length of stay in post-endoscopic retrograde cholangiocarcinomareatography pancreatitis patients. ERCP: endoscopic retrograde cholangiocarcinomareatography; PEP: post-ERCP pancreatitis; ROC: receiver operating characteristic; qSOFA: quick Sequential Organ Failure Assessment; SIRS: systemic inflammatory response syndrome. Incidence of PEP in our prospective cohort is similar to that reported in most of the previous trials and meta-analyses [1; 4; 21]. For the PEP severity assessment, practice guidelines of ASGE suggest grading severity after the length of hospital stay and the presence of local complications [1], while the ESGE recommends staging severity mainly after the presence and length of organ dysfunction [4]. Thus, we designed our research so that it could evaluate prediction of both length of stay and organ dysfunction. The cumulative 60-day mortality of PEP patients in our prospective cohort reached 17%, which is similar to figures presented in a recently published systematic review of PEP cases [3]. However, such a mortality rate is also within the mortality range of patients with all-cause acute pancreatitis [22; 23]. The only reason that could explain such high mortality is the complexity of cases--our center is a tertiary one with an emergency setting of admittance. To date, there is no complexity scoring system in patients with bile duct obstructions--as such conditions refer to a relatively large number of diseases: benign and malignant strictures, regular and difficult bile duct stones, and post-operative bile duct injuries--all these being either associated or not with acute cholangitis. The only tool to demonstrate the complexity of cases would be the ASA scaling--more than a half of patients were classified as ASA 2-4. Moreover, ASA class is significantly associated with the incidence of post-ERCP adverse events. Notwithstanding, although less reproducible, the overall complexity of cases is also sustained by the relatively high length of stay especially when referring to an emergency hospital. Both SIRS and qSOFA were tested within our prospective cohort to predict organ dysfunction and mortality in PEP patients. Persistent SIRS criteria have previously been shown to predict a poor prognosis in post-ERCP cholangitis patients [24]. Furthermore, persistent SIRS has been linked to post-ERCP perforations but with no additional value on the prediction of organic dysfunction or mortality in such cases [25]. Despite lack of similar results within our cohort, a recent previous study suggests that SIRS may predict overall length of stay in PEP patients [26]. Organ dysfunctions should be screened for before and after digestive interventional procedures, irrespective of the type of procedure [27].