Factors Impacting Treatment Outcomes in the Endoscopic Management of Walled-off Pancreatic Necrosis

Ji Young Bang; C Mel Wilcox; Jessica Trevino; Jayapal Ramesh; Shajan Peter; Muhammad Hasan; Robert H. Hawes; Shyam Varadarajulu

Disclosures

J Gastroenterol Hepatol. 2013;28(11):1725-1732. 

In This Article

Methods

Patients

This is a retrospective study of all patients with WOPN who underwent endoscopic transmural drainage over a 10-year period at the University of Alabama at Birmingham from 2003 to 2011 and at Florida Hospital in Orlando from January to December 2012. Included in the study were (i) patients aged more than 19 years with symptomatic WOPN measuring > 6 cm in size and located adjacent to the stomach or duodenum with (ii) evidence of ongoing infection (fever, leukocytosis) despite administration of intravenous antibiotics, (iii) continued clinical deterioration despite ongoing supportive measures, and (iv) gastric outlet or biliary obstruction secondary to mass effect by the WOPN. Excluded from the study were patients with WOPN located > 1.5 cm from the gastrointestinal lumen, patients with coagulopathy, patients who underwent only an endoscopic retrograde cholangiopancreatogram (ERCP) for pancreatic duct stent placement, and patients with follow-up of less than 90 days. Informed procedural consents were obtained from all patients. This study received approval from the Institutional Review Board of the University of Alabama at Birmingham and from Florida Hospital.

Procedural Protocol

Prior to endoscopic drainage, a contrast-enhanced computed tomogram (CT) was obtained at our hospital unless a CT of suitable diagnostic quality that was performed recently at an outside institution was available for review. Intravenous ciprofloxacin (400 mg) was administered in all patients prior to the procedure and was continued for 48 h or until discharge. An ERCP was performed prior to transmural drainage to define the communication between the main pancreatic duct and the WOPN. In patients with partial duct disruption, a bridging stent was placed as long as the proximal duct could be accessed with a guidewire. ERCP was not performed in patients with DPDS diagnosed by magnetic retrograde cholangiopancreatography or if they had gastric outlet obstruction.

Standard Technique (Fig. 1)

Figure 1.

Illustration demonstrating the standard technique for endoscopic drainage of a walled-off pancreatic necrosis.

Following ERCP, in patients with a luminal compression, transmural drainage was undertaken using a standard duodenoscope. The luminal compression was punctured using a needle knife catheter, and after the fistula was dilated to 12–15 mm, two to three 10Fr double pigtail stents were deployed. A 7Fr nasocystic catheter was placed adjacent to the stents to facilitate irrigation of the necrotic cavity with 200 mL of normal saline every four hours. However, the treatment protocol evolved over time to achieve better evacuation of the necrotic material, and during the latter phase of the study, the WOPN was irrigated with 500 mL of normal saline mixed with 120 mg gentamicin every 4 h. In patients without an obvious luminal compression, transmural drainage was undertaken using a therapeutic echoendoscope. At endoscopic ultrasound (EUS), the WOPN was accessed using a 19-gauge fine needle aspiration needle. After a 0.035-inch guidewire was coiled and the transmural tract was sequentially dilated to 12–15 mm using a radial expansion balloon, two to three 7Fr double pigtail stents were deployed. Additionally, a 7Fr nasocystic catheter was deployed as described earlier.

Multiple Transluminal Gateway Technique (Fig. 2)

Figure 2.

Illustration demonstrating the multiple transluminal gateway technique for endoscopic drainage of a walled-off pancreatic necrosis.

Our procedural protocol evolved over time, leading to the development of a multiple transluminal gateway technique (MTGT) for drainage of WOPNs. In this technique, the caudal part of the WOPN was first accessed using EUS guidance, usually from the duodenum or the distal stomach. After dilation of the gut wall and placement of two 7Fr stents, multiple sites were created in the WOPN for placement of additional transmural stents. In general, when the WOPN was 6–12 cm in size, only one transmural tract was created for transmural drainage; for WOPNs between 12 and 15 cm in size, at least two transmural tracts were created, and three to six transmural tracts were created for WOPNs greater than 15 cm. An 18Fr nasogastric tube was then advanced over a guidewire into the gateway that drained the cranial part of the WOPN (or into the single transmural tract created for WOPNs 6–12 cm in size), which was usually at the level of the proximal stomach. As with the standard technique, the nasogastric tube was irrigated every 4 h so as to flush out the necrotic debris through the multiple gateways in the stomach.

Postprocedure Protocol

A repeat CT scan of the abdomen was obtained in all patients at 72 h to assess treatment response. If there was a decrease in the size of the necrotic collection by > 50% in association with improvement in symptoms, and there was no return of necrotic fluid on aspiration of the drainage tube, the drain was continued. If patients remained symptomatic, additional stent placement, endoscopic necrosectomy, or surgery was undertaken following interdepartmental consultation with pancreatic surgeons. A CT scan of the abdomen was obtained in all patients at 8 weeks following patient discharge from the hospital. Patients with persistent symptoms and residual necrosis on CT underwent surgery.

Stent Management

At 8-week follow-up, the transpapillary pancreatic duct stents were removed if follow-up pancreatogram revealed an intact main pancreatic duct. In patients with persistent leak or strictures, stent exchange was undertaken until the leak resolved. Our practice pattern for the management of transmural stents in patients with DPDS evolved over time. While we routinely removed all transmural stents following resolution of the WOPN during the initial years, of late, we have been leaving at least two stents in place permanently to decrease the risk of PFC recurrence.[15]

By protocol, telephone calls were made to all patients at 6-month intervals, during which they were queried about the need for further interventions for any pancreatitis-related complaints.

Definitions

Treatment success was defined as complete resolution or decrease in size of the WOPN to ≤2 cm on follow-up CT at 8 weeks in association with symptom resolution.

Treatment failure was defined as persistence or worsening of symptoms in association with a residual WOPN measuring >2 cm on follow-up CT scan at 8 weeks.

PFC recurrence was defined as symptomatic peripancreatic fluid collection diagnosed on CT imaging following initial treatment success.

The primary outcome measures were improved treatment success and decreased rate of PFC recurrence.

Statistical Analysis

Patient characteristics, features of WOPNs, and procedure details were compared according to endoscopic drainage success in order to anticipate which variables may be associated with treatment success in logistic regression. Continuous variables were summarized as means (with standard deviations) and medians (with interquartile range and range) and compared using the Wilcoxon rank sum test. Categorical variables were expressed as frequencies and proportions and compared using the χ2-test or Fisher's exact test as indicated. Multiple logistic regression and reverse stepwise multivariate logistic regression analyses were then performed to identify the predictor variables associated with treatment success. Statistical significance was determined as P-value < 0.05. Datasets were compiled using Microsoft Excel (Microsoft Corporation, Redmond, WA, USA), and all statistical analyses were performed using Stata 10 (StataCorp LP, College Station, TX, USA).

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