Background/Aims: von Willebrand factor antigen (vWF-Ag) is a noninvasive predictor of portal hypertension that serves as a negative prognostic marker in various malignancies. Increased portal hypertension is associated with higher postoperative morbidity and decreased survival after hepatectomy. The purpose of this study was to determine the correlation between vWF-Ag, postoperative morbidity and oncological outcome. Methods: This analysis includes 55 patients who underwent liver resection for hepatocellular carcinoma (HCC) between 2008 and 2015 with available preoperative vWF-Ag levels. The primary endpoints were postoperative complications and long-term outcome, including overall and diseasefree survival. Results: The median plasma level of vWF-Ag was 191% (range, 162.5% to 277%). There was a significant correlation between vWF-Ag levels and tumor size in the resected specimens (p=0.010, r=0.350). Patients who developed any grade of postoperative complication had significantly higher preoperative vWF-Ag levels (216% [range, 178% to 283.25%] vs 176% [range, 148% to 246%], p=0.041). Median overall survival was 39.8 months in patients withhigh vWF-Ag levels (≥191%) compared with 73.4 months in patients with low levels (<191%, p=0.007). Of note, there was a remarkable disparity in the number of patients who died of HCC with low versus high vWF-Ag levels (14.8% vs 28.6%, p=0.011). Conclusions vWF-Ag may serve as a prognostic marker for the outcome of patients undergoing liver resection for HCC that is closely connected to tumor size, postoperative complication rate and long-term outcome.

Background/Aims: Endosonography is associated with a long learning curve. We aimed to assess variables that may influence the diagnostic outcomes in endoscopic ultrasound-guided fine-needle aspiration/biopsy (EUS-FNA/B) of solid pancreatic tumors regarding the level of endoscopists' experience. Methods: Consecutive patients undergoing EUS-guided puncture of solid pancreatic tumors (eight endosonographers, including six trainees) were prospectively enrolled. An experienced endosonographer was defined as having performed at least 250 EUS examinations, including 75 FNA/Bs. The final diagnosis was determined by cytopathology, histopathology, or clinical followup. Results: In total, 283 EUS-FNA/Bs of solid pancreatic tumors (75.6% malignant) in 239 patients (median age 69 years, 57.6% males) were enrolled. Trainees performed 149/283 (52.7%) of the interventions. Accuracy and sensitivity for detecting malignancy were significantly higher in the expert group than in the trainee group (85.8% vs 73.2%, p=0.01 and 82.5% vs 68.4%, p=0.02). Solid lesions evaluated by an expert using FNB needles showed the best odds for a correct diagnosis (odds ratio, 3.07; 95% confidence interval, 1.15 to 8.23; p=0.02). More experienced endoscopists achieved better accuracy in sampling via the transduodenal approach (86.7% vs 68.5%, p<0.001), in the sampling of malignant lesions (82.5 vs 68.4, p=0.02), and in the sampling of lesions located in the pancreatic head (86.1 vs 69.1, p=0.02). In cases involving these factors, we observed a moderate improvement in the diagnostic accuracy after 40 attempts. Conclusions Transduodenal approach, pancreatic head lesions, and malignancy were recognized as the most important clinical factors affecting the learning curve in EUS-FNA/B of solid pancreatic lesions.