壊死性膵炎に対する様々な介入の最適時期は?

Pancreatic fluid collections (PFCs) typically develop as local complications of acute pancreatitis and complicate the clinical course of patients with acute pancreatitis and potentially fatal clinical outcomes. Interventions are required in cases of symptomatic walled-off necrosis (WON) (matured PFCs with necrosis) and pancreatic pseudocysts (matured PFCs without necrosis). In the management of necrotizing pancreatitis and WON, endoscopic ultrasound-guided transluminal drainage combined with ondemand endoscopic necrosectomy (i.e. the step-up approach) is increasingly used as a less invasive treatment modality compared with a surgical or percutaneous approach. Through the substantial research efforts and development of specific devices and stents (e.g. lumen-apposing metal stents), endoscopic techniques of PFC management have been standardized to some extent. However, there has been no consensus about timing of carrying out each treatment step; for instance, it is uncertain when direct endoscopic necrosectomy should be initiated and finished and when a plastic or metal stent should be removed following clinical treatment success. Despite emerging evidence for the effectiveness of noninterventional supportive treatment (e.g. antibiotics, nutritional support, irrigation of the cavity), there has been only limited data on the timing of starting and stopping the treatment. Large studies are required to optimize the timing of those treatment options and improve clinical outcomes of patients with PFCs. In this review, we summarize the current available evidence on the indications and timing of interventional and supportive treatment modalities for this patient population and discussed clinical unmet needs that should be addressed in future research.