Clinico-radiological comparison and short-term prognosis of single acute pancreatitis and recurrent acute pancreatitis including pancreatic volumetry

Purpose The necrosis-fibrosis hypothesis describes a continuum between single attacks of acute pancreatitis (SAP), recurrent acute pancreatitis (RAP) and chronic pancreatitis (CP) with endocrine and exocrine pancreatic insufficiency. For prevention purposes we evaluated clinico-radiological parameters and pancreatic volumetry to compare SAP and RAP and provide prognostic relevance on short-term mortality, need for intervention and the hospitalization duration. Materials and methods We retrospectively investigated 225 consecutive patients (150 males, range 19-97years) with acute pancreatitis (74%SAP, 26%RAP) according to the revised Atlanta classification. All patients received an intravenous contrast-enhanced CT after a median time of 5 (IQR 5-7) days after onset of symptoms. Two experienced observers rated the severity of AP by 3 CT scores (CTSI, mCTSI, EPIC). Moreover, total pancreatic volumes and additional parenchymal necrosis volumes were assessed, when appropriate. Clinical parameters were etiology of AP, lipase on admission, CRP 48 hours after admission (CRP48), and the presence of organ dysfunction, assessed by the modified Marshall score. The modified Marshall score included systolic blood pressure, serum creatinine, and the ratio of arterial oxygen partial pressure to fractional inspired oxygen (PaO2/FiO(2) ratio) and was assessed on admission and 48 hours after admission to find patients with persistent organ failure. Outcome parameters were total hospitalization duration, short-term mortality and need for intervention. Results Lipase, CRP48, etiology of AP, EPIC, PaO2/FiO(2) ratio, and the presence of a pleural effusion differed significantly in both groups (p<0.05). In 109 patients with interstitial edematous AP, the total pancreatic volume was significantly smaller in patients with RAP compared to those with SAP (69 +/- 35cm(3) ; (RAP) vs 106 +/- 45cm(3); (SAP), p<0.001). All outcome parameters including the mortality rates (SAP vs. RAP: 15% vs. 7%) were comparable in both groups (p>0.05). In the necrotizing RAP group, only the necrotic volume correlated significantly with total hospitalization time (r = 0.72, p<0.001), whereas the systolic blood pressure was the only, but weak predictor for short-term mortality beta-coefficient: -0.05, p = 0.03) and the need for intervention (beta-coefficient: -0.02, p = 0.048) in the total RAP group. In patients with SAP, the modified Marshall score was the strongest predictor of short-term mortality, followed by the mCTSI on multivariate logistic regression (Marshall score: beta-coefficient: 1.79, p<0.001; mCTSI: beta-coefficient: 0.40, p<0.001). CTSI was the best predictor for required intervention in necrotizing SAP (beta-coefficient: 0.46, p<0.001), followed by the volume of intrapancreatic necrosis beta-coefficient: 0.17, p = 0.03). Conclusion Total pancreatic volume differed significantly between interstitial RAP and SAP and intrapancreatic necrosis volume revealed prognostic value for the total hospitalization duration in necrotizing RAP. Although all outcome parameters were comparable between SAP and RAP, only systolic blood pressure and pancreatic volumetry were prognostic in RAP. In SAP, only the modified Marshall score and mCTSI revealed prognostic value for short-term mortality, whereas CTSI was predictive for the need for intervention.