Prediction of morbidity and mortality after early cholecystectomy for acute calculous cholecystitis: results of the S.P.Ri.M.A.C.C. study

Abstract Background: Less invasive alternatives than Early Cholecystectomy (EC) for Acute Calculous Cholecystitis (ACC) treatment have been spreading in recent years. We still lack a reliable tool to select high-risk patients who could benefit from these alternatives. Our study aimed to prospectively validate the Chole-Risk score in predicting postoperative complications in patients undergoing EC for ACC compared with other pre-operative risk prediction models. Method: The S.P.Ri.M.A.C.C. study is a World Society of Emergency Surgery (WSES) prospective multicenter observational study. From 1st September 2021 to 1st September 2022, 1253 consecutive patients admitted in 79 centers were included. The inclusion criteria were a diagnosis of ACC and to be a candidate for EC. A Cochran-Armitage test of the trend was run to determine whether a linear correlation existed between the Chole-risk score and a complicated postoperative course. To assess the accuracy of the analyzed prediction models - POSSUM Physiological Score (PS), modified Frailty Index, Charlson Comorbidity Index, American Society of Anesthesiologist score (ASA), APACHE II score, ACC severity grade - receiver operating characteristic (ROC) curves were generated. The area under the ROC curve (AUC) was used to compare the diagnostic abilities. Results: A 30-day major morbidity of 6.6% and 30-day-mortality of 1.1% were found. Chole-risk was validated, but POSSUM PS was the best risk prediction model for a complicated course after EC for ACC (in-hospital mortality: AUC 0.94, p < 0,001; 30day-mortality: AUC 0.94, p < 0.001; in-hospital major morbidity: AUC 0.73, p < 0.001; 30day-major morbidity: AUC 0.70, p < 0.001). POSSUM PS with a cut-off of 25 (defined in our study as a ‘Chole-POSSUM’ score) was then validated in a separate cohort of patients. It showed a 100% sensitivity and a 100% negative predictive value for mortality and a 96–97% negative predictive value for major complications. Conclusions: The Chole-risk score was externally validated, but the CHOLE-POSSUM stands as a more accurate prediction model. CHOLE-POSSUM is a reliable tool to stratify patients with ACC into a low-risk group, that may represent a safe EC candidate, and a high-risk group, where new minimally invasive endoscopic techniques may find the most useful field of action. Trial Registration: ClinicalTrial.gov NCT04995380