Yukiko Ito

Measurement of radial and axial forces of biliary self-expandable metallic stents

BACKGROUND Efforts to understand the properties of self-expandable metallic stents (SEMSs) through their mechanical properties have progressed. Among them, radial force (RF) is well known as an expanding force, but axial force (AF) has not been measured before. Correlations of these properties to clinical results are not well known. OBJECTIVE We measured RF and AF of 14 different SEMSs and discussed the results in terms of clinical implications. DESIGN Experimental study. SUBJECTS Measurement of RF and AF of 14 different covered and uncovered SEMSs. METHODS RF was measured with an RF measurement machine manufactured by Machine Solution, and AF was measured with in-house equipment. RESULTS Measurements of RF in the process of expansion showed characteristic patterns closely related to the structures and materials of SEMSs. Results of AF measurement can be classified into 3 groups: high, medium, and low AF, depending on the type of SEMS. AF decreased with an increase of the length of stents. A plot of RF against AF revealed 3 distinguished RF/AF combinations and indicated the importance of understanding the properties by not only RF or AF individually but also by RF/AF combination. LIMITATIONS In vitro study using measurement equipment. CONCLUSION It was demonstrated that a combination of RF and AF is more effective than RF or AF individually in understanding the clinical implications of SEMSs. More work is needed to correlate mechanical properties with clinical results by designing model experiments.

Ulinastatin for pancreatitis after endoscopic retrograde cholangiopancreatography: A randomized, controlled trial

BACKGROUND & AIMS Pancreatitis remains the major complication of endoscopic retrograde cholangiopancreatography (ERCP), and hyperenzymemia after ERCP is common. Because ulinastatin, a protease inhibitor, has proved effective in the treatment of acute pancreatitis, the aim of this study was to assess the efficacy of ulinastatin for the prevention of post-ERCP pancreatitis and hyperenzymemia. METHODS In a multicenter, randomized, double-blind, placebo-controlled trial, patients undergoing a first ERCP were randomized to receive ulinastatin (150,000 U) or placebo by intravenous infusion for 10 minutes starting immediately before ERCP. All patients were hospitalized at least 24 hours after ERCP for evaluation of clinical symptoms. Serum pancreatic enzyme levels were measured before and at 4 and 18 hours after ERCP. The primary end point was the incidence of post-ERCP pancreatitis and the secondary objective was the occurrence of hyperenzymemia. RESULTS A total of 406 patients were enrolled (204 in the ulinastatin group and 202 in the placebo group). There were no differences between the 2 groups regarding baseline characteristics, details of fluoroscopic findings, or endoscopic procedure. The incidence of hyperenzymemia was significantly lower in the ulinastatin group than in the placebo group (amylase, P = .011; lipase, P = .008). Six patients in the ulinastatin group and 15 patients in the placebo group developed pancreatitis (2.9% vs. 7.4%, P = .041). There was no case of severe pancreatitis in either group. Patients who received ulinastatin did not present any side effects related to the medication. CONCLUSIONS Prophylactic short-term administration of ulinastatin decreases the incidence of pancreatitis and hyperenzymemia after ERCP.

Preliminary report on a new, fully covered, metal stent designed for the treatment of pancreatic fluid collections

BACKGROUND Endoscopic transluminal treatment of pancreatic fluid collections (PFC) has been reported as an effective alternative approach to surgical treatment. A wide, short stent with an anti-migration system has been developed. OBJECTIVE To evaluate a newly developed, fully covered, self-expandable metal stent (FCSEMS) customized for cystogastrostomy. DESIGN Retrospective case series. SETTING Tertiary-care academic medical centers and affiliated hospitals. PATIENTS Nine patients who underwent endoscopic treatment of PFCs (5 with pseudocysts and 4 with walled-off pancreatic necrosis). INTERVENTION Stent deployment after endoscopic US-guided puncture. Irrigation and necrosectomy were performed at the discretion of the endoscopist. MAIN OUTCOME MEASUREMENTS Technical and clinical success rate, complications, and removability. RESULTS The FCSEMS was inserted successfully in all cases (9/9, 100%). Clinical success was achieved in 7 of 9 cases (77.8%). No early complications associated with the procedure were observed. Late complications were observed in 2 cases (bleeding and asymptomatic migration). The FCSEMS was removed without any complications in all 6 cases where it was attempted after the procedure had been completed (100%). LIMITATIONS This was a retrospective evaluation of a small number of cases. The FCSEMS was always inserted via the transgastric route. Follow-up duration was short. CONCLUSION The endoscopic approach that uses this new FCSEMS is feasible for the treatment of PFCs. However, further evaluation is required.

A multicentre randomised phase II trial of gemcitabine alone vs gemcitabine and S-1 combination therapy in advanced pancreatic cancer: GEMSAP study.

Background:This randomised phase II trial compared gemcitabine alone vs gemcitabine and S-1 combination therapy in advanced pancreatic cancer.Methods:Patients were randomly assigned to 4-week treatment with gemcitabine alone (1000, mg m−2 gemcitabine by 30-min infusion on days 1, 8, and 15) or gemcitabine and S-1 combination therapy (1000, mg m−2 gemcitabine by 30-min infusion on days 1 and 15 and 40 mg m−2 S-1 orally twice daily on days 1–15). The primary end point was progression-free survival (PFS).Results:Between July 2006 and February 2009, 106 patients were enrolled. The PFS in gemcitabine and S-1 combination arm was significantly longer than in gemcitabine arm (5.4 vs 3.6 months), with a hazard ratio of 0.64 (P=0.036). Overall survival (OS) for gemcitabine and S-1 combination was longer than that for gemcitabine monotherapy (13.5 vs 8.8 months), with a hazard ratio of 0.72 (P=0.104). Overall, grade 3 or 4 adverse events were similar in both arms.Conclusion:Gemcitabine and S-1 combination therapy demonstrated longer PFS in advanced pancreatic cancer. Improved OS duration of 4.7 months was found for gemcitabine and S-1 combination therapy, though this was not statistically significant.

Risk factors for pancreatitis in patients with common bile duct stones managed by endoscopic papillary balloon dilation.

OBJECTIVES:Endoscopic papillary balloon dilation has been accepted as a possible alternative to endoscopic sphincterotomy, especially in patients with impaired hemostasis. However, pancreatitis associated with endoscopic papillary balloon dilation has remained a controversial, serious issue. The aim of the study was to investigate the risk factors for postendoscopic papillary balloon dilation pancreatitis in a single-center study.METHODS:A total of 304 patients who underwent endoscopic papillary balloon dilation for the management of common bile duct stones were enrolled. The risk of postendoscopic papillary balloon dilation pancreatitis was evaluated and the risk factors were analyzed by univariate and multivariate analysis. Definition and grade of the severity of postendoscopic papillary balloon dilation pancreatitis were based on the 1991 consensus guidelines.RESULTS:Common bile duct was cleared in 292 of 304 patients (96%). Procedure-related pancreatitis occurred in 15 patients (5.0%). The grade was mild in 8 and moderate in 7. Two risk factors, stone diameter and contrast medium injection to the pancreas, were identified by univariate analysis. Finally, only the contrast medium injection to the pancreas was statistically significant by multivariate analysis. Prior history of pancreatitis was identified as a risk factor for postendoscopic papillary balloon dilation pancreatitis in previous studies, but this factor was not identified as a risk factor in our series.CONCLUSIONS:Although the pathogenesis of pancreatitis after endoscopic papillary balloon dilation remains unresolved, the unnecessary injection of contrast medium to the pancreas can certainly be considered to be associated with the increased risk of pancreatitis.

Management of occluded uncovered metallic stents in patients with malignant distal biliary obstructions using covered metallic stents.

Background Self-expandable metallic stents (EMSs) have been widely used for the palliative treatment of unresectable malignant biliary obstructions, but EMSs are often occluded owing to tumor ingrowth via the wire mesh. Currently, there is no consensus on the management of occluded EMSs. We evaluated the efficacy of a covered EMS as a second endoprosthesis in patients with an occluded EMS. Methods Forty patients with an occluded uncovered EMS (14 men, 26 women; mean age 72 y, range 41 to 89 y) were studied. The patients suffered from the following: pancreatic cancer in 18, bile duct cancer in 11, gallbladder cancer in 5, lymph node metastasis in 4, and papillary cancer in 2. Of these, 26, 7, and 7 were treated with a covered EMS, an uncovered EMS, and a plastic stent (PS), respectively. The second stent was inserted as a stent-in-stent. Results The mean patent period for the covered EMS was 220 days, whereas the mean patent periods for the uncovered EMS and plastic stent were 141 and 58 days, respectively. The cumulative patency of the covered EMS group was significantly higher (P=0.0404) than that of the uncovered EMS group. No significant differences in survival were observed between the covered and uncovered groups. No serious complications occurred. Conclusion Insertion of a covered EMS is an effective and safe treatment for an occluded uncovered EMS.

Management of malignant gastric outlet obstruction with a modified triple-layer covered metal stent

BACKGROUND A high incidence of migration with covered metal stents has been reported in malignant gastric outlet obstruction (GOO). A newly modified, partially covered, triple-layer nitinol stent was developed that has a longer uncovered portion (5-15 mm) to prevent stent migration. OBJECTIVE To estimate the efficacy and safety of the modified covered, triple-layer metal stent. DESIGN Multicenter, prospective cohort study. SETTING Three tertiary referral centers. PATIENTS Fifty consecutive patients (26 with pancreatic carcinoma, 14 with gastric carcinoma, 9 with cholangiocarcinoma, 1 with a metastatic node) who presented with symptomatic unresectable malignant GOO between April 2007 and March 2010. INTERVENTIONS Endoscopic placement of the modified covered, triple-layer metal stent. MAIN OUTCOME MEASUREMENTS The primary endpoint was to improve the GOO scoring system (GOOSS) score. Secondary endpoints were success rate, patency, and complications. RESULTS The median GOOSS score improved significantly (P < .0001) after stenting (from 0 to 3). The technical and clinical success rates were 100% and 90%, respectively. Stent occlusion by tumor overgrowth or ingrowth at the uncovered portion developed in 5 patients (10%). Asymptomatic stent migration occurred in 3 patients (6%) receiving chemotherapy at 95, 230, and 553 days after stent placement, but these patients tolerated solid food 68, 260, and 142 days after stent migration, respectively. Other complications occurred in 1 patient with insufficient expansion, cholangitis, and pancreatitis. No procedure-related deaths occurred. LIMITATIONS A single-arm study in tertiary-care centers. CONCLUSIONS The modified covered, triple-layer metal stent was effective and safe for managing malignant GOO and can prevent tumor ingrowth and stent migration. ( CLINICAL TRIAL REGISTRATION NUMBER UMIN000004566.).

Japanese multicenter estimation of wallflex duodenal stent for unresectable malignant gastric outlet obstruction

This retrospective study estimated the efficacy and safety of the WallFlex duodenal stent for malignant gastric outlet obstruction (GOO) in Japan.

Duodenal invasion is a risk factor for the early dysfunction of biliary metal stents in unresectable pancreatic cancer.

BACKGROUND Although the placement of self-expandable metal stents (SEMSs) has been widely accepted as palliation for distal malignant biliary obstruction, the risk factors for their early dysfunction remain unclear. OBJECTIVE To identify risk factors for early (<3 months) SEMS dysfunction in unresectable pancreatic cancer. DESIGN A multicenter retrospective study. SETTING Five tertiary referral centers. PATIENTS Patients were included who underwent first-time SEMS placement for distal malignant biliary obstruction caused by pancreatic cancer between April 1994 and August 2010. MAIN OUTCOME MEASUREMENTS Rates and causes of early dysfunction were evaluated, and risk factors were analyzed. RESULTS In all, 317 eligible patients were identified. Covered SEMSs were placed in 82% of patients. Duodenal invasion was observed endoscopically in 37%. The median time to dysfunction was 170 days. The rates of all and early SEMS dysfunction were 55% and 31%, respectively. The major causes of SEMS dysfunction were food impaction and nonocclusion cholangitis (21% each) in early dysfunction and sludge (29%) in nonearly dysfunction. The rate of early dysfunction was 42% with duodenal invasion and 24% without duodenal invasion (P = .001). Early dysfunction caused by food impaction was more frequent in patients with duodenal invasion (10% and 4%, P = .053). Duodenal invasion was a risk factor (odds ratio 2.35; 95% CI, 1.43-3.90; P = .001) in a multiple logistic regression model. LIMITATIONS A retrospective design. CONCLUSIONS Duodenal invasion is a risk factor for early SEMS dysfunction in patients with pancreatic cancer.

Predictive factors of solid food intake in patients with malignant gastric outlet obstruction receiving self‐expandable metallic stents for palliation

Aim:  As for self‐expandable metallic stents (SEMS) for malignant gastric outlet obstruction (GOO), some predictive factors of stent patency have been reported, although re‐canalization of GOO by SEMS does not necessarily lead to favorable food intake. Therefore, we analyzed the predictive factors of oral food intake following SEMS placement.