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Evaluation of a Modified Duodenoscope Facilitating Guidewire Fixation for ERCP
*T1459 Biliary Stent Clogging Solved by Nanotechnology? An in-vitro Study Uwe Seitz, Andreas Block, Tina Schaefer, Uwe Wienhold, Sabine Bohnacker, Klaus Siebert, Stefan Seewald, Frank Thonke, Boris Brand, Peter Schaefer, Nib Soehendra
*T1461 Evaluation of a Modified Duodenoscope Facilitating Guidewire Fixation for ERCP Michelle C. Beilstein, Nuzhat A. Ahmad, Michael L. Kochman, William B. Long, Janak N. Shah, Gregory G. Ginsberg
Background: The major drawback of plastic stents for bililary drainage is the occlusion by sludge. Aim of this study is to examine sludge accumulation in relation to plastic surface characteristics designed by nanotechnology. Methods: A variety of anorganic-organic sol-gel coated stents was incubated in sterilized bile and enzyme active E.coli for 35 days. The incubation containers were pivoted up and down at an angle of 408 10 times a minute simulating bile flow. Materials were uncoated Teflon, Teflon coated with hydrophobic ClearcoatTM, Teflon coated with high and low molecular epoxy resin hydrophobized by 3 different aminofluoro-silanes. Scanning electron microscopy (SEM) was performed by an investigator (S.T.) who was blinded to the type of coating. The amount of sludge accumulated on the surface was determined by semiquantitative method. Results: Partially hydrophilic-hydrophobic surfaces accumulated less sludge than hydrophobic surfaces. High-molecular (500 mol) epoxy resin performed better than lowmolecular (190 mol) epoxy resin. The lowest sludge accumulation was found on 25% hydrophobic surface on ‘‘hydrophobic modification type VI’’ epoxy resin. Discussion: Nanometer thin sol-gel coating is inexpensive. The coating with the lowest sludge accumulation has been shown to have a superior soil-release character on other surfaces (e.g. cars). This is the first published data comparing systematically modified surfaces. Conclusion: Optimized soil release may be the key to prevent biliary plastic stents from clogging. Studies to determine the most optimal surface are warranted.
Background: Catheter/guidewire exchange during ERCP requires coordinated effort of endoscopist and endoscopy assistant. Mishaps during catheter/guidewire exchanges are common and result in loss of access and/or need for repositioning of the guidewire. New prototype duodenoscopes (V-scope) were developed to improve catheter/guidewire exchange by enabling fixation of guidewires at the elevator lever. The modification constituted the addition of a V-shaped groove to the elevator lever and an increased angle of articulation. We evaluated the prototypes in comparison to standard duodenoscopes. Methods: The initial Olympus XTJF-140VF and further modified Olympus XTJF-140V2F prototype duodenoscopes were compared to the standard Olympus TJF-160 duodenoscope. Data was obtained prospectively from a single center. The Wilcoxon rank sum test was used to compare case length and fluoroscopy time. A linear regression model was used to compare exchange time. The chi-square model was used to compare guidewire repositioning and loss of wire access. Results: The average case length, analyzed as a function of total number of exchanges, was 12.1 min for the standard scope and 12.7 min for the V-scopes (p=0.989). The average fluoroscopy time analyzed as a function of total number of exchanges per case was 2.69 min for the standard scope and 2.87 min for the V-scopes (p=0.774). The mean exchange time for the standard scope was 62.7 sec vs. 58.8 sec for the V-scopes (p=0.251). Comparing the V2F to the TJF-160 endoscope the average exchange time was 55.2 sec vs. 62.7 sec, respectively (p=0.170). The guidewire required repositioning in 15 of 51 exchanges (29.4%) with the standard scope and 7 of 58 exchanges with the Vscopes (12.1%) (p=0.024). The guidewire was lost during 4 of 51 exchanges with the standard scope vs. none of the 58 exchanges with the V-scopes. (p=0.045). Conclusions: The V-scopes were associated with decreased need for guidewire repositioning and loss of guidewire access during a guidwire/catheter exchange. Shorter exchange times for the V-scopes vs. the standard duodenoscope, did not reach statistical significance. A multi-center trial is underway to substantiate these findings.
*T1460 Surface Modification with Anti-adhesion Peptide: A Novel Approach to Prevent Bacterial Attachment and Biliary Stent Blockage Joseph W. Leung, Yan-Lei Liu III, Xiao-Bing Wang, Rajendra Ramsamooj, Kit S. Lam Background: Bacterial biofilm is a known cause of medical implants failure, resulting in their removal due to chronic refractory infections. Cholangitis secondary to biliary stent blockage is a typical example. Aim: In vitro studies to determine the benefits of surface modification with an anti-adhesion peptide grafted stent. Method: Using the (one-bead one-compound) combinatorial library method, we synthesized a linear penta-peptide library on TentaGel beads. Peptidebeads were evaluated concurrently for their ability to resist bacterial attachment using a mixed (E. coli and Enterococci) bacterial culture and screened under fluorescent microscopy. Peptide-beads that remained free of bacterial attachment despite prolonged (4 weeks) exposure were harvested. The amino acids sequence was determined by automatic microsequencing. Significance of individual amino acid in resisting bacterial attachment was determined using the (alanine walk) method by substituting each amino acid with D-alanine and repeating the in vitro cultures. A selected resistant peptide was sequenced and re-synthesized in large quantity and grafted onto functionalized polypropylene sheet. The anti-adhesion and possible anti-microbial effects were tested using a mixed culture and zonal inhibition method. Results: Bacteria attached to the random peptide beads within 30 minutes, but a small proportion of peptide beads resisted bacterial attachment up to 4 weeks. Alanine walk testing was performed on the best bacterial attachment resistant peptide (BAR-1). Replacing the amino acid in position 3 of BAR-1 with D-alanine completely abolished the anti-adhesion property. Substituting other amino acids also reduced slightly the anti-adhesion property. Compared to controls, BAR-1 peptide grafted polypropylene sheet demonstrated no bacterial attachment at 24 hours and with minimal attachment at 7 days, whereas the control ungrafted polypropylene has significant bacterial attachment at 24 hours, and obvious biofilm formation at 7 days. No peptide inhibition of bacterial growth was observed on BAR-1 using the zonal inhibition test. Conclusion: Anti-adhesion peptide grafted stent can resist bacterial attachment and offers an alternative to prevent bacterial biofilm and biliary stent blockage.
VOLUME 59, NO. 5, 2004
*T1462 Covered Metallic Stents for the Management of Distal Malignant Biliary Obstruction -Risk Factors for the Specific Complications Hiroyuki Isayama, Yousuke Nakai, Yutaka Komatsu, Takeshi Tsujino, Nobuo Toda, Naoki Sasahira, Natsuyo Yamamoto, Kenji Hirano, Minoru Tada, Haruhiko Yoshida, Takao Kawabe, Masao Omata Background & Aim: We had previously reported efficacy of 2 types of covered metallic stent (CMS), polyurethane-covered Wallstent (PCW) (Gastrointest Endosc 2002; 55: 366-70) and polyurethane-covered Diamond stents (PCD) (Gut in-press). CMS was useful for the patient with malignant biliary obstruction but complications were increased such as cholecystitis and pancreatitis. We evaluated 3 types of CMS and analyzed the cause of these complications. Patients & Methods: From August 1997 to October 2003, we placed 256 metallic stents for the patients with unresectable distal malignant biliary obstruction. Causative diseases were as follows: pancreatic cancer 151, bile duct cancer 45, Gallbladder cancer 20, papillary cancer 6 and metastatic nodes 34. CMS were placed in 147 and uncovered metallic stents (UMS) in 109. We placed PCW in 21, PCD in 57 and silicone-covered Wallstent (SCW) in 69. Results: There was no significant difference in survival between these two groups. The cumulative patency of the CMS was significantly longer (p<0.01) than that of the UMS. In subgroup analysis, the cumulative patency of CMS was significantly higher (p<0.05) in the patients with pancreatic cancer, gallbladder cancer, and metastatic nodes. Stent occlusion occurred in 19 patients (13%) after a mean of 236 days in the CMS group, and in 52 patients (48%) after a mean of 166 days in the UMS group. Complications of CMS were 8 (5%) in acute cholecystitis, 10 (7%) in acute pancreatitis and 12 (8%) in migration. In 127 cases with overlapping the orifice of the cystic duct (CD), there were 8 cholecystitis, 7 cases had tumor invasion to the CD and other case had gallbladder stone. The incidence of cholecystitis was 33% (7/27) with invaded CD and 1% (1/100) with intact CD (p<0.001). All pancreatitis were mild and 9 cases improved conservatively and 3 cases needed stent removal. The incidence of pancreatitis with patent main pancreatic duct (MPD) (14%; 7/42) was significantly higher (p<0.001) than that with obstructed MPD (6%; 5/87) in 129 cases of overlapping the orifice of MPD. Previously EST showed significantly lower (p<0.05) incidence of pancreatitis in the patients with patent MPD (EST0%, EPBD27%, none 33%). Conclusions: CMS showed significantly superior to UMS. Pancreatic cancer, gallbladder cancer and metastatic nodes were good indications for the CMS. Risk factors of complications in the CMS placement such as cholecystitis or pancreatitis might be define and can be avoided.
GASTROINTESTINAL ENDOSCOPY
P187
*T1461 Evaluation of a Modified Duodenoscope Facilitating Guidewire Fixation for ERCP Michelle C. Beilstein, Nuzhat A. Ahmad, Michael L. Kochman, William B. Long, Janak N. Shah, Gregory G. Ginsberg
Background: The major drawback of plastic stents for bililary drainage is the occlusion by sludge. Aim of this study is to examine sludge accumulation in relation to plastic surface characteristics designed by nanotechnology. Methods: A variety of anorganic-organic sol-gel coated stents was incubated in sterilized bile and enzyme active E.coli for 35 days. The incubation containers were pivoted up and down at an angle of 408 10 times a minute simulating bile flow. Materials were uncoated Teflon, Teflon coated with hydrophobic ClearcoatTM, Teflon coated with high and low molecular epoxy resin hydrophobized by 3 different aminofluoro-silanes. Scanning electron microscopy (SEM) was performed by an investigator (S.T.) who was blinded to the type of coating. The amount of sludge accumulated on the surface was determined by semiquantitative method. Results: Partially hydrophilic-hydrophobic surfaces accumulated less sludge than hydrophobic surfaces. High-molecular (500 mol) epoxy resin performed better than lowmolecular (190 mol) epoxy resin. The lowest sludge accumulation was found on 25% hydrophobic surface on ‘‘hydrophobic modification type VI’’ epoxy resin. Discussion: Nanometer thin sol-gel coating is inexpensive. The coating with the lowest sludge accumulation has been shown to have a superior soil-release character on other surfaces (e.g. cars). This is the first published data comparing systematically modified surfaces. Conclusion: Optimized soil release may be the key to prevent biliary plastic stents from clogging. Studies to determine the most optimal surface are warranted.
Background: Catheter/guidewire exchange during ERCP requires coordinated effort of endoscopist and endoscopy assistant. Mishaps during catheter/guidewire exchanges are common and result in loss of access and/or need for repositioning of the guidewire. New prototype duodenoscopes (V-scope) were developed to improve catheter/guidewire exchange by enabling fixation of guidewires at the elevator lever. The modification constituted the addition of a V-shaped groove to the elevator lever and an increased angle of articulation. We evaluated the prototypes in comparison to standard duodenoscopes. Methods: The initial Olympus XTJF-140VF and further modified Olympus XTJF-140V2F prototype duodenoscopes were compared to the standard Olympus TJF-160 duodenoscope. Data was obtained prospectively from a single center. The Wilcoxon rank sum test was used to compare case length and fluoroscopy time. A linear regression model was used to compare exchange time. The chi-square model was used to compare guidewire repositioning and loss of wire access. Results: The average case length, analyzed as a function of total number of exchanges, was 12.1 min for the standard scope and 12.7 min for the V-scopes (p=0.989). The average fluoroscopy time analyzed as a function of total number of exchanges per case was 2.69 min for the standard scope and 2.87 min for the V-scopes (p=0.774). The mean exchange time for the standard scope was 62.7 sec vs. 58.8 sec for the V-scopes (p=0.251). Comparing the V2F to the TJF-160 endoscope the average exchange time was 55.2 sec vs. 62.7 sec, respectively (p=0.170). The guidewire required repositioning in 15 of 51 exchanges (29.4%) with the standard scope and 7 of 58 exchanges with the Vscopes (12.1%) (p=0.024). The guidewire was lost during 4 of 51 exchanges with the standard scope vs. none of the 58 exchanges with the V-scopes. (p=0.045). Conclusions: The V-scopes were associated with decreased need for guidewire repositioning and loss of guidewire access during a guidwire/catheter exchange. Shorter exchange times for the V-scopes vs. the standard duodenoscope, did not reach statistical significance. A multi-center trial is underway to substantiate these findings.
*T1460 Surface Modification with Anti-adhesion Peptide: A Novel Approach to Prevent Bacterial Attachment and Biliary Stent Blockage Joseph W. Leung, Yan-Lei Liu III, Xiao-Bing Wang, Rajendra Ramsamooj, Kit S. Lam Background: Bacterial biofilm is a known cause of medical implants failure, resulting in their removal due to chronic refractory infections. Cholangitis secondary to biliary stent blockage is a typical example. Aim: In vitro studies to determine the benefits of surface modification with an anti-adhesion peptide grafted stent. Method: Using the (one-bead one-compound) combinatorial library method, we synthesized a linear penta-peptide library on TentaGel beads. Peptidebeads were evaluated concurrently for their ability to resist bacterial attachment using a mixed (E. coli and Enterococci) bacterial culture and screened under fluorescent microscopy. Peptide-beads that remained free of bacterial attachment despite prolonged (4 weeks) exposure were harvested. The amino acids sequence was determined by automatic microsequencing. Significance of individual amino acid in resisting bacterial attachment was determined using the (alanine walk) method by substituting each amino acid with D-alanine and repeating the in vitro cultures. A selected resistant peptide was sequenced and re-synthesized in large quantity and grafted onto functionalized polypropylene sheet. The anti-adhesion and possible anti-microbial effects were tested using a mixed culture and zonal inhibition method. Results: Bacteria attached to the random peptide beads within 30 minutes, but a small proportion of peptide beads resisted bacterial attachment up to 4 weeks. Alanine walk testing was performed on the best bacterial attachment resistant peptide (BAR-1). Replacing the amino acid in position 3 of BAR-1 with D-alanine completely abolished the anti-adhesion property. Substituting other amino acids also reduced slightly the anti-adhesion property. Compared to controls, BAR-1 peptide grafted polypropylene sheet demonstrated no bacterial attachment at 24 hours and with minimal attachment at 7 days, whereas the control ungrafted polypropylene has significant bacterial attachment at 24 hours, and obvious biofilm formation at 7 days. No peptide inhibition of bacterial growth was observed on BAR-1 using the zonal inhibition test. Conclusion: Anti-adhesion peptide grafted stent can resist bacterial attachment and offers an alternative to prevent bacterial biofilm and biliary stent blockage.
VOLUME 59, NO. 5, 2004
*T1462 Covered Metallic Stents for the Management of Distal Malignant Biliary Obstruction -Risk Factors for the Specific Complications Hiroyuki Isayama, Yousuke Nakai, Yutaka Komatsu, Takeshi Tsujino, Nobuo Toda, Naoki Sasahira, Natsuyo Yamamoto, Kenji Hirano, Minoru Tada, Haruhiko Yoshida, Takao Kawabe, Masao Omata Background & Aim: We had previously reported efficacy of 2 types of covered metallic stent (CMS), polyurethane-covered Wallstent (PCW) (Gastrointest Endosc 2002; 55: 366-70) and polyurethane-covered Diamond stents (PCD) (Gut in-press). CMS was useful for the patient with malignant biliary obstruction but complications were increased such as cholecystitis and pancreatitis. We evaluated 3 types of CMS and analyzed the cause of these complications. Patients & Methods: From August 1997 to October 2003, we placed 256 metallic stents for the patients with unresectable distal malignant biliary obstruction. Causative diseases were as follows: pancreatic cancer 151, bile duct cancer 45, Gallbladder cancer 20, papillary cancer 6 and metastatic nodes 34. CMS were placed in 147 and uncovered metallic stents (UMS) in 109. We placed PCW in 21, PCD in 57 and silicone-covered Wallstent (SCW) in 69. Results: There was no significant difference in survival between these two groups. The cumulative patency of the CMS was significantly longer (p<0.01) than that of the UMS. In subgroup analysis, the cumulative patency of CMS was significantly higher (p<0.05) in the patients with pancreatic cancer, gallbladder cancer, and metastatic nodes. Stent occlusion occurred in 19 patients (13%) after a mean of 236 days in the CMS group, and in 52 patients (48%) after a mean of 166 days in the UMS group. Complications of CMS were 8 (5%) in acute cholecystitis, 10 (7%) in acute pancreatitis and 12 (8%) in migration. In 127 cases with overlapping the orifice of the cystic duct (CD), there were 8 cholecystitis, 7 cases had tumor invasion to the CD and other case had gallbladder stone. The incidence of cholecystitis was 33% (7/27) with invaded CD and 1% (1/100) with intact CD (p<0.001). All pancreatitis were mild and 9 cases improved conservatively and 3 cases needed stent removal. The incidence of pancreatitis with patent main pancreatic duct (MPD) (14%; 7/42) was significantly higher (p<0.001) than that with obstructed MPD (6%; 5/87) in 129 cases of overlapping the orifice of MPD. Previously EST showed significantly lower (p<0.05) incidence of pancreatitis in the patients with patent MPD (EST0%, EPBD27%, none 33%). Conclusions: CMS showed significantly superior to UMS. Pancreatic cancer, gallbladder cancer and metastatic nodes were good indications for the CMS. Risk factors of complications in the CMS placement such as cholecystitis or pancreatitis might be define and can be avoided.
GASTROINTESTINAL ENDOSCOPY
P187