Post written by Hideyuki Shiomi, MD, PhD, from the Division of Hepatobiliary and Pancreatic Diseases, Department of Gastroenterology, Hyogo Medical University, Hyogo, and Tomotaka Saito, MD, PhD, from the Department of Gastroenterology, Graduate School of Medicine, University of Tokyo, Tokyo, Japan, for the WONDERFUL study group.

Our study externally validated the quadrant (an abdominal quadrant distribution), necrosis, and infection (QNI) classification system for risk stratification in patients with walled-off necrosis (WON) undergoing EUS-guided peripancreatic fluid drainage. This novel classification evaluates WON severity based on 3 key parameters: anatomical distribution across abdominal quadrants, degree of necrosis within the collection, and presence of infection. The system categorizes patients into high- and low-risk groups to predict treatment complexity and outcomes.

WON management remains one of the most challenging aspects of pancreatitis care, with substantial variations in clinical outcomes and persistently high morbidity and mortality rates despite advances in endoscopic techniques. The QNI classification was developed at Mayo Clinic and showed promise in internal validation but lacked external validation across different populations and healthcare systems. To our knowledge, this represents the first multi-institutional external validation of this promising risk stratification tool, which is essential before widespread clinical adoption and integration into treatment guidelines.

Our comprehensive analysis of 212 patients from 10 high-volume centers in Japan successfully validated the QNI classification’s predictive capabilities. QNI-high patients demonstrated significantly longer time to clinical success (median, 68 vs 46 days; P = .0016), required substantially more endoscopic interventions (median, 5 vs 2; P < .001), and experienced higher rates of grade III adverse events (18.8% vs 6.3%; P = .008) and mortality (12.0% vs 3.8%; P = .031).

Importantly, the QNI classification was independently associated with time to clinical success and risk of severe adverse events in multivariable analyses. These findings add robust external evidence supporting the clinical use of QNI-based risk stratification for treatment planning and patient counseling.

This validation study opens the door for developing QNI-based treatment algorithms and clinical pathways. QNI-high patients may benefit from early referral to high-volume centers with multidisciplinary expertise, more aggressive initial management strategies, and enhanced monitoring protocols. Conversely, QNI-low patients might be safely managed with more conservative step-up approaches, potentially reducing unnecessary interventions and healthcare costs while maintaining excellent outcomes. Future research should focus on developing specific treatment protocols tailored to QNI risk levels.

Graphical abstract

Read the full article online.

The information presented in Endoscopedia reflects the opinions of the authors and does not represent the position of the American Society for Gastrointestinal Endoscopy (ASGE). ASGE expressly disclaims any warranties or guarantees, expressed or implied, and is not liable for damages of any kind in connection with the material, information, or procedures set forth.