Asymptomatic Walled-Off Pancreatic Necrosis: A Prospective Study of Natural Course and Risk Factors for Intervention

Walled-off pancreatic necrosis (WOPN), a complication of acute necrotizing pancreatitis, presents management challenges, especially when asymptomatic. While current guidelines advocate conservative management for asymptomatic WOPN, the natural history of these collections remains unclear. This study aimed to investigate the natural history of asymptomatic WOPN and identify predictors of symptom development or complications necessitating intervention.

This prospective observational study included consecutive adult patients with asymptomatic WOPN (those tolerating oral nutrition with minimal or no abdominal pain, without infection, pressure symptoms, or GI bleeding) diagnosed via contrast-enhanced CT or MRI from September 2021 to October 2023. Data on demographics, etiology, imaging findings, and clinical outcomes were collected. Patients were followed for 12 months with monthly assessments for the first 6 months and then every 3 months. MRI abdomen was performed at 6 and 12 months. The primary outcome was the proportion of patients developing symptoms/complications during follow-up requiring intervention.

Of the 54 patients, 32 (59.2%) developed complications requiring intervention [infection (n = 12), refractory pain (n = 10), obstructive jaundice (n = 2), intracystic hemorrhage (n = 2) and spontaneous rupture (n = 6)]. There was one death (1.9%) secondary to hemorrhage from a splenic artery pseudoaneurysm. Twenty-two patients (40.7%) remained asymptomatic. Interventions included endoscopic ultrasound-guided drainage (n = 22), percutaneous drainage (n = 8), and surgical necrosectomy (n = 2). The mean size of WOPN at baseline was significantly higher in patients requiring intervention (9.28 vs. 6.01 cm, p = 0.003). A WOPN size greater than 5.6 cm predicted the need for intervention with 88.5% sensitivity and 54% specificity. Multivariable logistic regression identified WOPN size as an independent predictor of intervention (OR 1.2, p = 0.011).

A significant proportion of patients with asymptomatic WOPN require interventions within 12 months. WOPN size is a key predictor of symptom development and intervention.