Interobserver agreement for confocal imaging of ampullary lesions: a multicenter single-blinded study.

BACKGROUND: Malignant ampullary lesions can be difficult to classify by endoscopy alone. Probe-based confocal laser endomicroscopy (pCLE) permits in vivo assessment of mucosal structures in the gastrointestinal tracts in the real time. AIM: The objective of this pilot multicenter study was to assess the interobserver agreement and variance in interpretation of pCLE of ampullary lesions. METHODS: Twelve pCLE video clips of ampullary lesions were distributed to 6 gastrointestinal specialists at 5 medical centers, blinded to final pathologic results. Six variables were assessed for interobserver agreement using κ statistics. Variables included an epithelial outer border with irregular thickness, dark epithelium without discernable individual cells, heterogenously distributed elongated crypts, reduced number of goblet cells, neovascularization, and final diagnosis. RESULTS: The overall interobserver agreement for all observers was poor to slight for all variables (κ=0.02, 0.05, -0.01, 0.04, 0.018) except for the first variable with fair degree of agreement (κ=0.27). On the basis of experience, 3 observers were classified as less experienced, whereas 3 were classified as most experienced. Upon stratification, the less experienced observers had poor interobserver agreement for all variables, except 1. The most experienced observers had poor agreement for 2 variables, slight agreement for 3 variables, and fair agreement for the final diagnosis variable. CONCLUSIONS: The overall interpersonal agreement on pCLE for ampullary lesions was poor. The interobserver agreement was not substantially improved for experienced raters. Further standardization of pCLE image criteria is needed for ampullary lesions. Standardized training may improve interrater reliability to an acceptable level.

Interpretation of probe-based confocal laser endomicroscopy of indeterminate biliary strictures: is there any interobserver agreement?

BACKGROUND: Probe-based confocal laser endomicroscopy (pCLE) has enabled in vivo histopathology by obtaining high resolution images of the mucosal layers of the gastrointestinal tract. For indeterminate bile duct strictures, biopsy, cytologic brushing and needle aspiration have low levels of diagnostic accuracy. AIM: The objective of this multi-center pilot study was to assess the interobserver agreement in interpretation of pCLE imaging. METHODS: Twenty-five de-identified pCLE video clips of indeterminate biliary strictures were sent to 6 observers at 5 institutions. Miami Classification was used to standardize image interpretation. Seven variables were assessed for interobserver agreement using the Fleiss kappa statistic which included: presence of thick (>20 µm) or thin (<20 µm) dark or white bands, dark clumps, epithelium including glandular structures, interstitial fluorescein leakage, ease of interpretation, and final diagnosis. Based on operator experience, observers were categorized into 3 categories of experience (Category 1: 0-10; Category 2: 11-20; Category 3: >21 cases). RESULTS: Upon stratification, Category 1 interobserver agreement ranged from "Poor" to "Fair" (κ = 0.277, κ = -0.079, κ = -0.025, κ = -0.066, κ = 0.128, κ = 0.088), and for the final diagnosis variable, the agreement was slight (κ = 0.033). Category 2 and 3 interobserver agreement ranged from "Poor" to "Fair" (κ = 0.211, κ = 0.181, κ = 0.347, κ = 0.238, κ = -0.050, κ = 0.092), and for the final diagnosis variable, the agreement was slight (κ = 0.195). CONCLUSION: The overall interobserver agreement for pCLE image interpretation in indeterminate biliary strictures ranges from poor to fair. Interpretation criteria as well as training require further standardization toward improving inter-rater reliability.

Fully covered self-expanding metal stents placed temporarily in the bile duct: safety profile and histologic classification in a porcine model.

BACKGROUND: Fully covered Self-Expanding metal stents (FCSEMS) have been shown efficacious in palliating malignant biliary obstructions. There is little data analyzing mucosal response to their temporary placement in the bile duct. METHODS: Ten mini pigs underwent endoscopic placement of a FCSEMS (Wallflex, Boston Scientific). FCSEMS were kept in place for three months. At the end of the 3 months, FCSEMS were removed endoscopically. Five pigs were euthanized and their bile ducts harvested. The other five were kept alive for another month post removal. A single pathologist, created a scoring system (to determine degree of inflammation, fibrosis, and epithelial injury), examined all specimens in a blinded fashion. RESULTS: Four FCSEMS spontaneously migrated in the duodenum. On post mortem examination, mild mucosal thickness was noted in three bile duct specimens while superficial inflammation of the bile duct was noted in five animals. Histologic examination of the bile duct revealed focal acute inflammation in both groups. For the 5 animals euthanized immediately after stent removal, there was a tendency to have superficial mucosal erosion and fibrosis. In contrast, increased chronic inflammation was more commonly seen in the animals 1 month post stent removal, with all animals in this group showing moderate degrees of mononuclear inflammatory cell mucosal infiltrates. No severe inflammatory or fibrotic duct injury was observed in any of the study animals, with degree of injury graded as mild to moderate. CONCLUSION: FCSEMS appear to induce minimal tissue overgrowth or fibrosis post placement. Ease of removability and no significant histologic injury are advantages noted with FCSEMS., however, further studies are needed to evaluate treating benign biliary strictures with FCSEMS in humans.

Pretransplant predictors of recovery of renal function after liver transplantation.

The Model for End-Stage Liver Disease system has given priority on the liver transplant waiting list to candidates with renal failure. This study determined the predictors of spontaneous recovery of renal function after transplantation in 1041 liver transplant recipients on renal replacement therapy (RRT) at the time of transplant (from February 2002 to January 2007). Data from these patients were obtained from the US Organ Procurement and Transplantation Network and US Renal Data System databases. Univariate and multivariate survival models were constructed along with multivariate logistic regression models to find independent predictors of spontaneous renal recovery. Seven hundred seven recipients (67.9%) had spontaneous recovery of renal function after liver transplantation. Those recovering spontaneously had a significantly shorter course of RRT in the pretransplant time period (15.6 versus 36.6 days, P < 0.001). Recovery of renal function was observed in 70.8% and 11.5% of recipients on RRT for less than 30 days and more than 90 days, respectively. Other statistically significant pretransplant variables independently associated with recovery of renal function included recipient age, recipient pretransplant diabetes, and donor age. In conclusion, the duration of pretransplant RRT is highly predictive of spontaneous renal recovery post-transplant. Liver transplant candidates requiring less than 30 days of pretransplant RRT are likely to spontaneously recover renal function after liver transplantation, whereas those on RRT for more than 90 days are not.

Interpreting the CHARISMA study. What is the role of dual antiplatelet therapy with clopidogrel and aspirin?

The Clopidogrel for High Atherothrombotic Risk and Ischemic Stabilization, Management, and Avoidance (CHARISMA) study (N Engl J Med 2006; 354:1706-1717, J Am Coil Cardiol 2007; 49:1982-1988) assessed the effect of dual antiplatelet therapy with clopidogrel (Plavix) and aspirin in patients at risk of atherothrombotic events. At a median of 28 months, the rate of the primary efficacy end point (a composite of myocardial infarction, stroke, and death from cardiovascular causes) was not significantly lower in the group receiving clopidogrel plus aspirin than in the group receiving placebo plus aspirin. However, one subgroup may have derived some benefit from the combination: those at higher risk owing to a history of myocardial infarction, ischemic stroke, or symptomatic peripheral arterial disease.

Safety and efficacy of radiofrequency ablation in the management of unresectable bile duct and pancreatic cancer: a novel palliation technique.

UNLABELLED: Objectives. Radiofrequency ablation (RFA) has replaced photodynamic therapy for premalignant and malignant lesions of the esophagus. However, there is limited experience in the bile duct. The objective of this pilot study was to assess the safety and efficacy of RFA in malignant biliary strictures. METHODS: Twenty patients with unresectable malignant biliary strictures underwent RFA with stenting between June 2010 and July 2012. Diameters of the stricture before and after RFA, immediate and 30 day complications and stent patency were recorded prospectively. Results. A total of 25 strictures were treated. Mean stricture length treated was 15.2 mm (SD = 8.7 mm, Range = 3.5-33 mm). Mean stricture diameter before RFA was 1.7 mm (SD = 0.9 mm, Range = 0.5-3.4 mm) while the mean diameter after RFA was 5.2 mm (SD = 2 mm, Range = 2.6-9 mm). There was a significant increase of 3.5 mm (t = 10.8, DF = 24, P value = <.0001) in the bile duct diameter post RFA. Five patients presented with pain after the procedure, but only one developed mild post-ERCP pancreatitis and cholecystitis. CONCLUSIONS: Radiofrequency ablation can be a safe palliation option for unresectable malignant biliary strictures. A multicenter randomized controlled trial is required to confirm the long term benefits of RFA and stenting compared to stenting alone.

Expandable metal stents for benign biliary disease.

Benign biliary diseases include benign biliary strictures (BBS), choledocholithiasis, and leaks. BBS encompass postoperative injury, anastomotic stricture, chronic pancreatitis, primary sclerosing cholangitis, and gallstone-related stricture. Therapeutic options for benign biliary diseases include surgical, percutaneous, and endoscopic interventions. Endoscopic options include placement of plastic stents as well as self-expanding metal stents (SEMS). SEMS can be uncovered, partially covered, and fully covered, and have been used with some success in resolution of strictures and leaks; however, complications limit their use. This article reviews the currently published experience on SEMS and attempts to define their current role in the treatment of benign biliary diseases.