Intraductal US in the assessment of tumor involvement to the orifice of the cystic duct by malignant biliary obstruction

Risk factors and treatment strategies for cholecystitis after metallic stent placement for malignant biliary obstruction: a multicenter retrospective study

BACKGROUND AND AIMS

Cholecystitis can occur after self-expandable metallic stent (SEMS) placement for malignant biliary obstruction (MBO), but the best treatment option for cholecystitis has not been determined. Here, we aimed to identify the risk factors of cholecystitis after SEMS placement and determine the best treatment option.

METHODS

Incidence, treatments, and predictive factors of cholecystitis were retrospectively evaluated in 1084 patients with distal MBO (DMBO) and 353 patients with hilar MBO (HMBO) who underwent SEMS placement at 12 institutions from January 2012 to March 2021.

RESULTS

Cholecystitis occurred in 7.5% of patients with DMBO and 5.9% of patients with HMBO. The recurrence rate was significantly lower (P = .043) and the recurrence-free period significantly longer (P = .039) in endoscopic procedures than in percutaneous procedures for cholecystitis treatment. EUS-guided gallbladder drainage (EUS-GBD) was better in terms of technical success, procedure time, and recurrence-free period than endoscopic transpapillary gallbladder drainage. Obstruction across the cystic duct orifice by tumor (P = .015) and by stent (P = .037) were independent risk factors for cholecystitis in DMBO. Cases with multiple SEMS placements (odds ratio [OR], 11; 95% confidence interval [CI], 0.68-190; P = .091) and with gallbladder stones (OR, 2.3; 95% CI ,0.92-5.6; P = .075) had a higher risk for cholecystitis in HMBO.

CONCLUSIONS

The incidences of cholecystitis after SEMS placement for DMBO and HMBO were similar. EUS-GBD is the optimal treatment option for patients with cholecystitis after SEMS placement for MBO.

Practice guidelines for managing extrahepatic biliary tract cancers

Backgrounds/Aims

Reported incidence of extrahepatic bile duct cancer is higher in Asians than in Western populations. Korea, in particular, is one of the countries with the highest incidence rates of extrahepatic bile duct cancer in the world. Although research and innovative therapeutic modalities for extrahepatic bile duct cancer are emerging, clinical guidelines are currently unavailable in Korea. The Korean Society of Hepato-Biliary-Pancreatic Surgery in collaboration with related societies (Korean Pancreatic and Biliary Surgery Society, Korean Society of Abdominal Radiology, Korean Society of Medical Oncology, Korean Society of Radiation Oncology, Korean Society of Pathologists, and Korean Society of Nuclear Medicine) decided to establish clinical guideline for extrahepatic bile duct cancer in June 2021.

Methods

Contents of the guidelines were developed through subgroup meetings for each key question and a preliminary draft was finalized through a Clinical Guidelines Committee workshop.

Results

In November 2021, the finalized draft was presented for public scrutiny during a formal hearing.

Conclusions

The extrahepatic guideline committee believed that this guideline could be helpful in the treatment of patients.

Efficacy and complications of inoperable malignant distal biliary obstruction treatment by metallic stents: fully covered or uncovered?

Obstructive jaundice caused by malignant distal biliary obstruction is a common clinical symptom in patients with inoperable biliary-pancreatic cancer. Endoscopic retrograde cholangiopancreatography (ERCP)-guided stent implantation is an effective treatment for obstructive jaundice. Internal stent drainage is more physiologic and associated with a better quality of life than external stent drainage methods such as percutaneous transhepatic gallbladder drainage or percutaneous transhepatic cholangiodrainage. Self-expanding metallic stents, which may be covered and uncovered, are commonly used. However, some uncertainties remain regarding the selection of metallic stents, including drainage patency time, clinical effect, stent migration, and post-operative complications such as pancreatitis, bleeding, and cholecystitis. This review aims to summarize the current progress and controversies surrounding the use of covered or uncovered metallic stents in inoperable common biliary obstruction via ERCP.

Retrospective Comparative Study of Side-by-Side and Stent-in-Stent Metal Stent Placement for Hilar Malignant Biliary Obstruction

BACKGROUND

In patients with unresectable hilar malignant biliary obstruction (MBO), bilateral metal stent placement is recommended. However, treatment selection between partially stent-in-stent (SIS) and side-by-side (SBS) methods is still controversial.

STUDY

Clinical outcomes of bilateral metal stent placement by SBS and SIS methods for hilar MBO were retrospectively studied in four Japanese centers. While large-cell-type uncovered metal stents were placed above the papilla in SIS, braided-type uncovered metal stents were placed across the papilla in SBS.

RESULTS

A total of 64 patients with hilar MBO (40 SIS and 24 SBS) were included in the analysis. Technical success rate was 100% in SIS and 96% in SBS. Functional success rate was 93% in SIS and 96% in SBS. Early adverse event rates were higher in SBS (46%) than in SIS (23%), though not statistically significant (P = 0.09). Post-procedure pancreatitis was exclusively observed in SBS group (29%). Recurrent biliary obstruction rates were 48% and 43%, and the median time to recurrent biliary obstruction was 169 and 205 days in SIS and SBS, respectively.

CONCLUSIONS

Other than a trend to higher adverse event rates including post-procedure pancreatitis in SBS, clinical outcomes of SIS and SBS methods were comparable in patients with unresectable hilar MBO.

Cholecystitis after Placement of Covered Self-Expandable Metallic Stents in Patients with Distal Malignant Biliary Obstructions

Background/Aims

Cholecystitis can occur after the placement of covered self-expandable metallic stents for distal malignant biliary obstructions. We aimed to identify risk factors for cholecystitis following covered self-expandable metallic stent placement.

Methods

We investigated risk factors related to cholecystitis following covered self-expandable metallic stent placement in 118 patients with distal malignant biliary obstructions between January 1, 2015 and April 30, 2019. Endoscopic assessments and tumor invasion to the arteries feeding the gallbladder were determined by a pancreaticobiliary endoscopist and a radiologist, respectively.

Results

The median patient age was 72 years (men, 61.0%). The flow of the contrast agent into the gallbladder and tumor involvement in the orifice of the cystic duct were observed in 35 (29.7%) and 35 (29.7%) patients, respectively. During the observation period (median, 179 days), cholecystitis occurred in 18 (15.3%) patients. Multivariate analysis revealed the flow of the contrast agent into the gallbladder (p=0.023) and tumor involvement in the orifice of the cystic duct (p=0.005) as significant independent risk factors associated with cholecystitis.

Conclusions

The flow of the contrast agent into the gallbladder and tumor involvement in the orifice of the cystic duct are potential independent risk factors for cholecystitis following the placement of covered self-expandable metallic stents. A follow-up prospective study is warranted to validate their influence.

A Prospective Multicenter Study of a Fully Covered Metal Stent in Patients with Distal Malignant Biliary Obstruction: WATCH-2 Study

BACKGROUND

Both fully covered (FC) and partially covered (PC) self-expandable metal stents (SEMSs) are now commercially available for distal malignant biliary obstruction (MBO). While FCSEMS can be easily removed at the time of re-interventions, it is theoretically prone to migration. However, few comparative data between FC and PC SEMSs have been reported.

AIMS

The aim of this study was to compare clinical outcomes of FCSEMS with those of PCSEMS.

METHODS

This was a multicenter, prospective study of FCSEMS for unresectable distal MBO with a historical control of PCSEMS, which was previously reported as the WATCH study. The primary outcome was recurrent biliary obstruction (RBO), and secondary outcomes were stent migration, stent removal, stent-related adverse events, and survival.

RESULTS

A total of 151 cases with unresectable distal MBO undergoing FCSEMS placement were enrolled and compared with a historical cohort of 141 cases undergoing PCSEMS placement. No significant differences were found in the rate of RBO (29 vs. 33%; P = 0.451), time to RBO (318 vs. 373 days; P = 0.382), and survival (229 vs. 196 days; P = 0.177) between FCSEMS and PCSEMS. The rate of stent migration also did not differ significantly between the two groups (14 vs. 8%; P = 0.113). The removal of FCSEMSs was successful in all 24 attempted cases (100%).

CONCLUSIONS

FCSEMSs appeared comparable to PCSEMSs in terms of RBO without a significant increase in stent migration rate in patients with unresectable distal MBO.

CLINICAL TRIAL REGISTRATION NUMBER

UMIN000007131.

Tumor invasion to the arteries feeding the gallbladder as a novel risk factor for cholecystitis after metallic stent placement in distal malignant biliary obstruction

BACKGROUND AND AIM

Cholecystitis is a major complication after self-expandable metallic stent (SEMS) placement for malignant biliary obstruction. Ischemia is one of the risk factors for cholecystitis, but little is known about the influence of tumor invasion to the feeding artery of the gallbladder on the onset of cholecystitis after SEMS placement. The aim of the present study was to identify risk factors for cholecystitis after SEMS placement.

METHODS

Incidence and nine predictive factors of cholecystitis were retrospectively evaluated in 107 patients who underwent SEMS placement for unresectable distal malignant biliary obstruction at Kyoto University Hospital and Otsu Red Cross Hospital between January 2012 and June 2016.

RESULTS

Cholecystitis occurred in 13 of 107 patients (12.1%) after SEMS placement during the median follow-up period of 262 days. Univariate analyses showed that tumor invasion to the feeding artery of the gallbladder and tumor involvement to the orifice of the cystic duct were significant predictors of cholecystitis (P = 0.001 and P < 0.001). Multivariate analysis confirmed that these two factors were significant and independent risks for cholecystitis with odds ratios of 22.13 (95% CI, 3.57-137.18; P = 0.001) and 25.26 (95% CI, 4.12-154.98; P < 0.001), respectively.

CONCLUSIONS

This study showed for the first time that tumor invasion to the feeding artery of the gallbladder as well as tumor involvement to the orifice of the cystic duct are independent risk factors for cholecystitis after SEMS placement.

Understanding the Mechanical forces of Self-Expandable Metal Stents in the Biliary Ducts

Self-expandable metallic stent (SEMS) was an effective biliary endoprosthesis. Mechanical properties of SEMS, radial and axial force (RF, AF), may play important roles in the bile duct after placement. RF was well known dilation force and influenced on the occurrence of migration. AF, newly proposed by this author, was defined as the recovery force when the SEMS vended. AF was related with the cause of bile duct kinking, pancreatitis, and cholecystitis due to the compression of the bile duct, orifice of the cystic duct, and pancreatic orifice. Ideal SEMS may show high RF and low AF.

Metallic stent with high axial force as a risk factor for cholecystitis in distal malignant biliary obstruction

BACKGROUND AND AIM

Tumor involvement to the orifice of cystic duct (OCD) is a risk factor for cholecystitis after self-expandable metallic stent (SEMS) placement, but its prevention is still difficult. We conducted this multicenter analysis to clarify a type of SEMS or a method to place SEMS which would decrease the incidence of cholecystitis after SEMS placement.

METHODS

The incidence of cholecystitis was studied in consecutive patients receiving SEMS for distal malignant biliary obstruction in five tertiary care centers. Multiple logistic regression analysis was performed to evaluate risk factors for cholecystitis.

RESULTS

A total of 376 patients who received SEMS placement for distal malignant biliary obstruction were analyzed. Tumor involvement to OCD was diagnosed in 25.3%. Overall incidence of cholecystitis was 6.9%. Cholecystitis was observed in 8.0% of 300 patients with covered SEMS, 16.8% of 95 patients with tumor involvement to OCD, 10.8% of 234 patients with SEMS of high axial force (AF), and 12.0% of 158 patients with SEMS length ≤ 60 mm. In the multivariate analysis, tumor involvement to OCD (odds ratio [OR] 5.40, P < 0.001), SEMSs with high AF (OR 5.33, P = 0.002), and SEMS length ≤ 60 mm (OR 3.19, P = 0.010) are risk factors. Among patients with tumor involvement to OCD, the incidence of cholecystitis in SEMS with high and low AF was 25.0% and 5.0%, respectively.

CONCLUSION

This study with an expanded cohort reconfirmed tumor involvement to OCD as a risk factor for cholecystitis after SEMS placement. SEMS with low AF might decrease cholecystitis.

ACR Appropriateness Criteria radiologic management of benign and malignant biliary obstruction

The optimal treatment for patients with biliary obstruction varies depending on the underlying cause of the obstruction, the clinical condition of the patient, and anticipated long-term effects of the procedure performed. Endoscopic and image-guided procedures are usually the initial procedures performed for biliary obstructions. Various options are available for both the radiologist and endoscopist, and each should be considered for any individual patient with biliary obstruction. This article provides an overview of the current status of radiologic procedures performed in the setting of biliary obstruction and describes multiple clinical scenarios that may be treated by radiologic or other methods. The ACR Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed every 2 years by a multidisciplinary expert panel. The guideline development and review include an extensive analysis of current medical literature from peer-reviewed journals and the application of a well-established consensus methodology (modified Delphi) to rate the appropriateness of imaging and treatment procedures by the panel. In those instances in which evidence is lacking or not definitive, expert opinion may be used to recommend imaging or treatment.

Predictive factors for pancreatitis and cholecystitis in endoscopic covered metal stenting for distal malignant biliary obstruction

BACKGROUND AND AIM

Pancreatitis and cholecystitis are major complications after self-expandable metal stent (SEMS) placement in distal malignant biliary obstruction. We aimed to clarify predictive factors for pancreatitis and cholecystitis after covered SEMS placement.

METHODS

We retrospectively reviewed 74 consecutive patients with distal malignant biliary obstruction who underwent initial endoscopic drainage using covered SEMS. Predictive factors for pancreatitis and cholecystitis were evaluated in the 74 patients described above and in 66 patients who had not undergone cholecystectomy.

RESULTS

The incidences of pancreatitis and cholecystitis were 10.8% (8/74) and 6.1% (4/66), respectively. Univariate analysis revealed that non-pancreatic cancer (P = 0.018) and contrast injection into the pancreatic duct (P = 0.030) were significant predictive factors for pancreatitis. Multivariate analysis revealed that non-pancreatic cancer (odds ratio [OR], 4.21; 95% confidence interval [CI], 1.63-14.18; P = 0.007) and contrast injection into the pancreatic duct (OR, 3.34; 95% CI, 1.33-9.60; P = 0.016) were significant independent predictive factors for pancreatitis. On the other hand, univariate and multivariate analyses revealed that tumor involvement to the orifice of the cystic duct (OCD) was a significant independent predictive factor for cholecystitis (OR, 5.85; 95% CI, 1.91-27.74; P = 0.005).

CONCLUSIONS

Non-pancreatic cancer and contrast injection into the pancreatic duct were predictive factors for pancreatitis, and tumor involvement to the OCD was a positive predictive factor for cholecystitis after endoscopic covered SEMS placement for distal malignant biliary obstruction.

Endoscopic retrograde cholangiopancreatography for distal malignant biliary stricture

Endoscopic biliary stent placement is widely accepted as palliation for malignant biliary obstruction or as a treatment of benign biliary stricture. Although various biliary stent designs have become available since self-expandable metallic stents were introduced, no single ideal stent has been developed. An ideal stent should be patent until death, or surgery, in patients with resectable malignant biliary obstruction. Fewer complications, maneuverability, cost-effectiveness, and removability are also important factors. Alternatively, should we develop a novel method for biliary drainage other than biliary stenting via endoscopic retrograde cholangiopancreatography? This article reviews the current status of biliary stenting for malignant biliary obstructions.

Comparison of partially covered nitinol stents with partially covered stainless stents as a historical control in a multicenter study of distal malignant biliary obstruction: the WATCH study

BACKGROUND

Covered self-expandable metal stents (CSEMSs) were developed to prevent tumor ingrowth, but stent migration is one of the problems with CSEMSs.

OBJECTIVE

To evaluate a new, commercially available CSEMS with flared ends and low axial force compared with a commercially available CSEMS without the anti-migration system and high axial force.

DESIGN

Multicenter, prospective study with a historical cohort.

SETTING

Twenty Japanese referral centers.

PATIENTS

This study involved patients with unresectable distal malignant biliary obstruction.

INTERVENTION

Placement of a new, commercially available, partially covered SEMS.

MAIN OUTCOME MEASUREMENTS

Recurrent biliary obstruction rate, time to recurrent biliary obstruction, stent-related complications, survival.

RESULTS

Between April 2009 and March 2010, 141 patients underwent partially covered nitinol stent placement, and between May 2001 and January 2007, 138 patients underwent placement of partially covered stainless stents as a historical control. The silicone cover of the partially covered nitinol stents prevented tumor ingrowth. There were no significant differences in survival (229 vs 219 days; P = .250) or the rate of recurrent biliary obstruction (33% vs 38%; P = .385) between partially covered nitinol stents and partially covered stainless stents. Stent migration was less frequent (8% vs 17%; P = .019), and time to recurrent biliary obstruction was significantly longer (373 vs 285 days; P = .007) with partially covered nitinol stents. Stent removal was successful in 26 of 27 patients (96%).

LIMITATIONS

Nonrandomized, controlled trial.

CONCLUSION

Partially covered nitinol stents with an anti-migration system and less axial force demonstrated longer time to recurrent biliary obstruction with no tumor ingrowth and less stent migration.

A multicenter prospective study of the short-term outcome of a newly developed partially covered self-expandable metallic biliary stent (WallFlex(®))

BACKGROUND

Self-expandable metallic stent (SEMS) placement is a widely used, effective therapy for unresectable malignant stricture of the lower bile duct.

AIMS

We evaluated the short-term outcome of the newly developed WallFlex(®) Biliary RX Partially Covered Stent in patients with malignant lower and middle biliary stricture in five tertiary referral centers.

METHODS

The subjects of this study were 52 patients in whom WallFlex(®) Biliary RX Stents were inserted into the bile duct for malignant stenosis of the middle and lower bile duct at five medical facilities between April 2009 and November 2009.

RESULTS

The stent placement success rate was 100%. Effective biliary decompression was achieved in all patients. The incidence of early complications was 7.7% (4/52). Stent occlusion occurred in two patients (3.8%) (one dislocation, one migration); cholecystitis occurred in two patients (3.8%). Neither acute pancreatitis nor stent kinking in the bile duct occurred.

CONCLUSIONS

The present results revealed that the new WallFlex(®) Biliary RX Partially Covered SEMSs were useful for the short-term relief of biliary obstruction due to unresectable distal biliary malignancies.

Endoscopic transpapillary gallbladder drainage with replacement of a covered self-expandable metal stent

Endoscopic self-expandable metal stent (SEMS) placement has become a standard palliative therapy for patients with malignant biliary obstruction. Acute cholecystitis after SEMS placement is a serious complication. We report a patient with an acute cholecystitis after covered SEMS placement, who was managed successfully with endoscopic transpapillary gallbladder drainage (ETGBD) and replacement of the covered SEMS. An 85-year-old man with pancreatic cancer suffered from acute cholecystitis after covered SEMS placement. It was impossible to perform percutaneous transhepatic gallbladder drainage. After removal of the covered SEMS with a snare, a 7Fr double pigtail stent was placed between the gallbladder and duodenum, subsequently followed by another covered SEMS insertion into the common bile duct beside the gallbladder stent. The cholecystitis improved immediately after ETGBD. ETGBD with replacement of the covered SEMS thus proved to be effective for treatment of patients with acute cholecystitis after covered SEMS placement.

New method of covered wallstents for distal malignant biliary obstruction to reduce early stent-related complications based on characteristics

AIM

We previously reported a low occlusion rate with covered Wallstents for malignant biliary obstruction, but stent-related complications other than occlusion posed a problem. A modified covered Wallstent insertion method based on stent characteristics was evaluated to reduce stent-related complications.

METHODS

A total of 138 patients with distal malignant biliary obstruction received covered Wallstent placement. From October 2001 to October 2003, 69 patients received covered Wallstent placement (Group 1). Thereafter, we modified our stent insertion method and 69 patients received stent placement using this modified method from November 2003 to January 2007 (Group 2). The modified insertion method consists of endoscopic sphincterotomy carried out in patients without pancreatic duct invasion and longer stent placement with the center of the stent located in the center of the biliary stricture to prevent pancreatitis, kinking of the bile duct, and stent dislocation. A comparative analysis was carried out using prospectively collected data in these two cohorts.

RESULTS

Tumor ingrowth was not observed, and stent occlusion rate was 18.8% in Group 1 and 23.2% in Group 2. The overall rates of stent-related complications did not differ (39.1% in Group 1 and 30.4% in Group 2), but stent-related complications within 3months decreased from 22 episodes in Group 1 to 13 episodes in Group 2. Median event-free survival was prolonged by modified stent insertion method (125days in Group 1 and 268days in Group 2, P=0.020), although cumulative survival and stent patency were not significantly different.

CONCLUSIONS

Our modified method of covered Wallstent placement showed improved event-free survival.

Newly designed large cell Niti-S stent for malignant hilar biliary obstruction: a pilot study

BACKGROUND

Whether uni- or bilateral drainage should be performed for malignant hilar biliary obstruction remains a matter of debate. Moreover, endoscopic placement of bilateral metallic stents has been considered difficult and complicated. Although the Y-stent with a central wide-open mesh facilitates bilateral stent placement, it has limitations. This study evaluated the feasibility and efficacy of the Niti-S large cell D-type biliary stent (LCD) with a uniform large cell for both uni- and bilateral drainage of malignant hilar biliary obstruction.

METHODS

From April 2008 to March 2009, a total of 12 consecutive patients with unresectable malignant hilar biliary obstruction of Bismuth type 2 or greater underwent placement of LCD. Before LCD placement, all the patients underwent endoscopic unilateral biliary drainage using a plastic stent or a nasobiliary drainage tube. If jaundice improved after the procedure, the plastic stent or nasobiliary drainage tube was replaced with the unilateral LCD. If jaundice did not resolve or contralateral cholangitis occurred, bilateral LCD placement was performed.

RESULTS

Seven patients had unilateral and five patients had bilateral LCD placement. Technical success was achieved for all 12 patients. An early complication occurred for one patient (8%), and stent occlusion occurred for six patients (50%) because of tumor ingrowth (n=4) or sludge (n=2). These patients were managed by insertion of plastic stents (n=4) or percutaneous transhepatic biliary drainage (n=2). The median stent patency period was 202 days.

CONCLUSIONS

The newly designed endoscopic metallic stent may be feasible and effective for malignant hilar biliary obstruction, and endoscopic reintervention is relatively simple.

Intraductal ultrasonography (IDUS) for the diagnosis of biliopancreatic diseases

Intraductal ultrasonography (IDUS) is an imaging modality having unique characteristics and suitable for imaging of a narrow ductal cavity, its wall and the neighbouring structures. As IDUS uses high-frequency ultrasound (12-30MHz), its image quality is very high within approximately 2-cm range of radius. The bile duct and the pancreatic duct, therefore, are good targets for the assessment by IDUS. Biliopancreatic IDUS is mainly performed through the papilla of Vater in the same session as endoscopic retrograde cholangiopancreatography (ERCP). Biliary IDUS is possible through the percutaneous transhepatic route as well. Not many comparative studies on biliopancreatic IDUS have been published. Gallbladder IDUS as well as most pancreatic IDUS are still at the level of clinical research. Constant delineation of Oddi's sphincter with the improvement of instruments will expand the use of IDUS for the assessment of the papilla of Vater lesions.

Covered metallic stents in the management of malignant and benign pancreatobiliary strictures

In the endoscopic management of unresectable malignant biliary obstructions by placement of a metallic stent (MS), longer patency and a lower incidence of stent occlusion are desirable goals. With its mesh structure, the uncovered MS (UMS) is occluded mainly by tumor or tissue ingrowth, making it impossible to remove. The covered MS (CMS) was developed to overcome these disadvantages, and was shown to maintain patency longer than the UMS in our randomized study. The most important characteristic of the CMS is that it is removable, allowing it to be used in patients with resectable malignancies and benign strictures. In addition, the drug-eluting CMS provides an additional approach to the treatment of biliary malignancies. The CMS may also change the treatment paradigm for biliary strictures and strictures due to chronic pancreatitis. The CMS is analogous to a large-bore, expandable plastic stent and is effective both as an endoprosthesis and a dilating or anti-cancer device. However, to better understand the utility of these devices, we need to first consider mechanical properties such as radial force (RF, expansion force) and axial force (AF, straightening force). AF is particularly important when developing CMSs because of related complications.

Management of distal malignant biliary obstruction with the ComVi stent, a new covered metallic stent

BACKGROUND

The covered metallic stent is effective for managing malignant distal biliary obstructions. The most popular covered metallic stent is the covered Wallstent (CWS). This study estimated the efficacy and safety of a new expanded polytetrafluoroethylene (e-PTFE)-covered nitinol metallic stent, the ComVi stent. This covered metallic stent consists of an e-PTFE membrane sandwiched between two uncovered metallic stents with weak axial (straightening) force. Wire is exposed on both the inner and outer surfaces.

METHODS

Between May 2005 and April 2007, ComVi stents were placed consecutively in 47 patients with unresectable malignant distal biliary obstruction. The cases involved 35 pancreatic cancers, 8 metastatic nodes, 2 gallbladder cancers, and 2 bile duct cancers. The patients were compared with 47 patients who received CWS placement between August 2001 and May 2005 matched for age, sex, and causative disease from 133 cases.

RESULTS

No significant differences in stent patency or patient survival were found. Stent occlusion was observed in 13 patients (27.7%) in the ComVi group and 10 patients (21.3%) in the CWS group. The cause of occlusion in both groups was tumor overgrowth (4.25% vs 4.2%), sludge (8.5% vs 6.3%), impaction of food scraps (14.9% vs 2.1%), and bile duct kinking (0% vs 8.4%). Other complications were migration (2.1% vs 17.0%; p = 0.0304) and cholecystitis (2.1% vs 6.3%), and there were significant differences in the incidence of complications except for occlusion (4.2% vs 24.6%; p = 0.0142).

CONCLUSION

The ComVi stent has a patency similar to that of the CWS and a lower incidence of migration. However, early occlusion by food impaction was increased and should be resolved.