Clinical utility of the Revised Atlanta Classification of acute pancreatitis in a prospective cohort: Have all loose ends been tied?

Background and aim Revision of the Atlanta classification for acute pancreatitis (AP) was long awaited. The Revised Atlanta Classification has been recently proposed. In this study, we aim to prospectively evaluate and validate the clinical utility of the new definitions. Patient and methods 163 consecutive patients with AP were followed till death/6 mths after discharge. AP was categorized as mild (MAP) (no local complication[LC] and organ failure[OF]), moderate (MSAP)(transient OF and/or local/systemic complication but no persistent OF) and severe (SAP) AP (persistent OF). LC included acute peripancreatic fluid collections, pseudocyst, acute necrotic collection, walled-off necrosis, gastric outlet dysfunction, splenic/portal vein thrombosis, and colonic necrosis. Baseline characteristics (age/gender/hematocrit/BUN/SIRS/ BISAP) and outcomes (total hospital stay/need for ICU care/ICU days/primary infected (peri)pancreatic necrosis[IN]/in-hospital death) were compared. Results 43 (26.4%) patients had ANP, 87 (53.4%) patients had MAP, 58 (35.6%) MSAP and 18 (11.04%) SAP. Among the baseline characteristics, BISAP score was significantly higher in MSAP compared to MAP [1.6 (1.5-2.01) vs 1.2 (1.9-2.4); p = 0.002]; and BUN was significantly higher in SAP compared to MSAP[64.9 (50.7-79.1) vs 24.9 (20.7-29.1); p < 0.0001]. All outcomes except mortality were significantly higher in MSAP compared to MAP. Need for ICU care (83.3%vs43.1%; p = 0.01), total ICU days[7.9 (4.8-10.9) vs 3.5 (2.7-5.1); p = 0.04] and mortality (38.9%vs1.7%; p = 0.0002) was significantly more in SAP compared to MSAP. 8/18 (44.4%) patients had POF within seven days of disease onset (early OF). This was associated with 37.5% of total in-hospital mortality. Patients with MSAP who had primary IN (n = 10) had similar outcomes as SAP. Conclusions This study prospectively validates the clinical utility of the Revised Atlanta definitions of AP. However, MSAP patients with primary infected necrosis may behave as SAP. Furthermore, patients with early severe acute pancreatitis (early OF) could represent a subgroup that needs to be dealt with separately in classification systems.