Extrapancreatic necrosis volume: A new tool in acute pancreatitis severity assessment?

ARTICLE HIGHLIGHTS

Research background

Acute pancreatitis has increased in frequency over the past two decades and poses serious health threats. Mild and moderate forms have a benign evolution with rapid resolution of symptoms. Severe forms are a major therapeutic challenge and have a high mortality because of life-threatening complications. Rapid identification of patients with acute pancreatitis and a severe prognosis could lead to timely and more effective treatment and reduced morbidity and mortality.

Research motivation

Many scores derived from clinical, biological, and imaging markers have been proposed to assess the severity of pancreatitis at onset, including the Ranson score, APACHE II, and the Glasgow criteria. The computed tomography severity index (CTSI) and the modified CTSI (mCTSI) are the most widely used imaging scores for assessing the severity of pancreatitis. Since their development, there have been several attempts to design predictive imaging scores, but none has proven better. A recently studied indicator, the extrapancreatic necrosis volume, has shown promise.

Research objectives

The study aimed to: (1) Evaluate the discriminatory power of the extrapancreatic necrosis volume to identify severe acute pancreatitis; (2) Demonstrate a correlation between the extrapancreatic necrosis volume and the severity of acute pancreatitis; and (3) Improve the existing level of evidence regarding the performance of the extrapancreatic necrosis volume to detect severe acute pancreatitis and to pave the way for better and safer management of patients at risk.

Research methods

We conducted a retrospective study of 123 patients, hospitalized at the Institute of Gastroenterology and Hepatology, Iaşi, Romania between January 1, 2017 and December 31, 2019. The pancreatitis was diagnosed by the revised Atlanta protocol in patients with two of the three following criteria: A clinically significant picture, a significant increase of pancreatic enzymes to at least three times the normal level, and significant radiological findings. The patient characteristics included age, sex, and C-reactive protein on hospital admission (normal value is < 0.5 mg/dL). Radiological scores (CTSI, mCTSI, and extrapancreatic necrosis volume) were calculated following computed tomography examination and within 48-72 h after the onset of symptoms.

Research results

Highly significant correlations were noticed between the imaging scores (CTSI, mCTSI, and extrapancreatic necrosis volume) and the severity of pancreatitis estimated by the rAC (r = 0.926, P < 0.001; r = 0.950, P < 0.001; and r = 0.784, P < 0.001, respectively). The correlation between CRP and severity was positive but did not reach significance (r = 0.133, P = 0.154). Differences between the mean volumes of extrapancreatic necrosis observed at each level of rAC-defined severity were significant. The best predictor of severe pancreatitis was the volume of necrosis [area under the curve (AUC) = 0.993; 95% confidence interval (CI): 0.981-1.005], with a 99.5% sensitivity, 99.0% specificity, and cutoff value of 167 mL, followed by the mCTSI (2007) score (AUC = 0.972; 95%CI: 0.946-0.999), with a 98.0% sensitivity and 96.5% specificity, and the CTSI (1990) score (AUC = 0.969; 95%CI: 0.941-0.998), with a 97.0% sensitivity and 95.0% specificity.

Research conclusions

To conclude, the correlations of radiological severity scores with disease activity were positive and significant. The best correlation was seen for the CTSI score (r = 0.926, P < 0.001). The extrapancreatic necrosis volume had the highest diagnostic accuracy for severe pancreatitis, with a 99.5% sensitivity and 99.0% specificity for a cutoff value of 167 mL. The study increases the overall quality of evidence in support of the inclusion of this score in current practice, as it was more useful in predicting severe forms of pancreatitis compared with widely used imaging scores.

Research perspectives

The results have significant impact and value. The relationship of severity with mortality has been documented in numerous evidence-based studies. Disease severity is the single most important indicator of a negative prognosis. Early recognition of severe disease and intervention could be lifesaving. Extensive study is required to validate the superiority of extrapancreatic necrosis volume to assess the severity of acute pancreatitis.