Peripancreatic fluid collections (PFC), including pseudocysts and walled-off pancreatic necrosis (WOPN), are increasingly managed through endoscopic ultrasound (EUS)-guided drainage. However, there is no widely adopted, post-inflammatory, imaging-based score to stratify risk and predict outcomes after endoscopic drainage, especially in resource-limited settings where plastic stents are mainly used. The recently proposed Quadrant–Necrosis–Infection (QNI) classification, derived from cross-sectional imaging, showed promise in a US cohort treated exclusively with lumen-apposing metal stents (LAMS), but has not been validated externally. We aimed to evaluate the clinical utility of QNI in predicting outcomes of EUS-guided drainage of PFCs in an Indian public-sector cohort predominantly treated with double-pigtail plastic stents. 

We retrospectively reviewed prospectively maintained records of consecutive patients who underwent EUS-guided drainage of PFCs between January 2022 and February 2025 at a tertiary-care centre. Baseline CT/MRI/EUS were used to assign a QNI score based on (i) the number of retroperitoneal quadrants involved, (ii) the extent of necrosis, and (iii) the presence of infection. Patients were classified as Low QNI (Group 1: ≤2 quadrants, <30% necrosis, no infection) or High QNI (Group 2: ≥3 quadrants, ≥30% necrosis in ≥2 quadrants or >60% in any quadrant, and infection). The primary outcomes were technical success (successful stent placement) and clinical success (symptom resolution with a greater than 50% reduction in PFC size at 4 weeks). Secondary outcomes included need for endoscopic necrosectomy, additional drainage (nasocystic drain [NCD] or percutaneous catheter drain [PCD]), complications, length of hospital stay, stent migration, and mortality. The study was approved by the Institutional Ethics Committee.  

Of 53 screened patients, 48 met the inclusion criteria (5 were excluded due to incomplete records or inadequate follow-up). Thirty-one patients were classified as Low QNI and 17 as High QNI. Group 1 underwent drainage with either single or dual double-pigtail plastic stents, while Group 2 received dual plastic stents or LAMS, depending on collection complexity and feasibility. Baseline demographics were similar, although High QNI patients had a higher burden of infected and extensive necrosis. Technical success was 100% in both groups. Clinical success was achieved in 100% (31/31) of Low QNI and 88% (15/17) of High QNI patients. Additional drainage procedures (NCD/PCD or extra stent) were needed in 2 (6%) vs 4 (23%) patients in Groups 1 and 2, respectively (p = 0.17). Endoscopic necrosectomy was required in 4 (23%) High QNI patients but in none of the Low QNI group (p = 0.014). Minor bleeding occurred in 6% vs 23% (p = 0.17), all managed conservatively. The median hospital stay was significantly longer in the High QNI group (16 vs 5 days, p < 0.001). At 3 months, all patients had residual collections less than 3 cm; spontaneous stent migration occurred in 5 Low QNI and 3 High QNI cases, and two LAMS were electively removed at 6–8 weeks. One death (6%) occurred in the High QNI group; there were no deaths in the Low QNI group.  

In this real-world, resource-limited cohort, the QNI classification emerged as a simple, preprocedural, imaging-based tool that stratifies clinical trajectory after EUS-guided drainage of PFCs. High QNI status was associated with a greater need for necrosectomy and adjunct drainage, more complications, and prolonged hospitalisation, despite high overall technical and clinical success rates. Our findings extend prior LAMS-based data to a predominantly plastic-stent practice, supporting QNI as a pragmatic framework to guide upfront therapeutic strategy and selection of more aggressive interventions in high-risk collections. Prospective multicentre validation, with systematic capture of organ failure and nutritional status, is warranted before routine adoption in ESGE-affiliated centres and broader clinical practice.