Endosonography guided management of pancreatic fluid collections

Abstract

The revised Atlanta classification of acute pancreatitis was adopted by international consensus, and is based on actual local and systemic determinants of disease severity. The local determinant is pancreatic necrosis (sterile or infected), and the systemic determinant is organ failure. Local complications of pancreatitis can include acute peri-pancreatic fluid collection, acute necrotic collection, pseudocyst formation, and walled-off necrosis. Interventional endoscopic ultrasound (EUS) has been increasing utilized in managing these local complications. After performing a PubMed search, the authors manually applied pre-defined inclusion criteria or a filter to identify publications relevant to EUS and pancreatic collections (PFCs). The authors then reviewed the utility, efficacy, and risks associated with using therapeutic EUS and involved EUS devices in treating PFCs. Due to the development and regulatory approval of improved and novel endoscopic devices specifically designed for transmural drainage of fluid and necrotic debris (access and patency devices), the authors predict continuing evolution in the management of PFCs. We believe that EUS will become an indispensable part of procedures used to diagnose PFCs and perform image-guided interventions. After draining a PFC, the amount of tissue necrosis is the most important predictor of a successful outcome. Hence, it seems logical to classify these collections based on their percentage of necrotic component or debris present when viewed by imaging methods or EUS. Finally, the authors propose an algorithm for managing fluid collections based on their size, location, associated symptoms, internal echogenic patterns, and content.

Keywords: Abscess; Drainage; Endoscopic ultrasound; Pancreas; Pancreatic fluid collection; Patency device; Pseudocyst; Walled of necrosis.

Figure 1

On November 15, 2014, the authors performed a PubMed search using following key word sets: endoscopic ultrasound in combination with terminologies related to pancreatic fluid collections such as pseudocyst, fluid collection, abscess, and walled off necrosis. Each published paper was simultaneously reviewed by two authors who extracted important information related to this review. EUS: Endoscopic ultrasound; WON: Walled off necrosis.

Figure 2

Selected magnetic resonance imaging frame showing a large peri-pancreatic pseudocyst extending from the pancreatic tail to the anterior abdominal wall in a patient with pancreatitis and splenic vein thrombosis.

Figure 3

In the same patient, endoscopic ultrasound permits visualization of the pancreatic pseudocyst, assessment of wall maturity, determination of distance between the collection and the luminal wall, identification of intervening vessels or collaterals (arrow) (A), and selection of the optimal puncture site (B). PP: Pancreatic pseudocyst.

Figure 4

Fluoroscopic image showing transpapillary drainage of a pancreatic pseudocyst that is shared with the main pancreatic duct.

Figure 5

Endoscopic ultrasound image of a 5 cm chronic pseudocyst with a thin wall (A) or a 7.8 cm irregular pseudocyst with walled off necrosis (B).

Figure 6

Endoscopic image of a self-expandable metal stent immediately after endoscopic ultrasound guided drainage (AXIOSTM system, Xlumina, Mountain View, CA, United States). Note the fluid floating through the stent opening. A guidewire extending through the stent lumen is still visible.

Figure 7

Corresponding endoscopic ultrasound image of a collapsed pancreatic pseudocyst immediately after drainage. Note reflexions from the stent mesh inside the collapsed cyst.

Figure 8

Authors' proposed endoscopic ultrasound-guided management algorithm based on the amount of internal debris inside a pancreatic fluid collection.