Endoscopic Bilateral Stent-in-Stent Versus Stent-by-Stent Deployment in Advanced Malignant Hilar Obstruction: A Meta-Analysis and Systematic Review.

BACKGROUND AND AIM: There is no clear data to compare the effectiveness and safety of bilateral stent-in-stent (SIS) or stent-by-stent (SBS) deployment for advanced malignant hilar obstruction (MHO). This meta-analysis was done to investigate clinical outcomes of these deployment methods. METHODS: We did a literature search to identify studies that reported the clinical outcomes of bilateral metal stents in patients with advanced MHO. Weighed pooled rates (WPR) along with 95% confidence interval (95% CI) were calculated in order to compare outcomes including technical and clinical success, adverse events, and stent occlusion between the two groups. We conducted a meta-analysis using a random-effects model. RESULTS: Five comparative studies with 250 patients, and 20 single-arm studies for the SIS or SBS method were eligible for the meta-analysis and systematic review. The bilateral SIS deployment had a significantly higher technical success rate than did SBS deployment (OR 6.43; 95% CI 1.08-38.09). There was no difference in the clinical success (OR 1.23; 95% CI 0.45-3.38), overall adverse events rates (OR 0.42; 95% CI 0.15-1.18), or overall occlusion rate (OR 1.55; 95% CI 0.89-2.70). As a single-armed group, WPR of technical success of the SIS and SBS groups was 96.4% and 89.6%, respectively. Clinical success was 97.5% and 98.3%. Overall, adverse events were 35.9% and 22.6%. Occlusion rates were 27.7% and 37.7%. CONCLUSIONS: Although there was a lack of quality data and heterogeneity, bilateral SIS deployment had a higher technical feasibility than did the SBS method in patients with advanced MHO, without differences in terms of clinical success, adverse events, or occlusion rates.

Comparison of endoscopic bilateral metal stent drainage with plastic stents in the palliation of unresectable hilar biliary malignant strictures: Large multicenter study.

BACKGROUND: Endoscopic stenting to manage malignant hilar biliary obstruction has no consensus regarding the optimal stenting strategy. In this multicenter study, we compared transpapillary parallel-style bilateral metal stenting with bilateral plastic stenting, and evaluated short- and long-term outcomes. METHODS: We recruited 262 consecutive patients (Bismuth classification types II-IV) who underwent either bilateral metal or plastic stenting as primary therapy at four tertiary centers. To overcome selection bias, we performed 1:1 propensity score matching. Our primary outcome was overall survival. RESULTS: After propensity score matching, each group comprised 96 patients, with no significant differences in any baseline characteristics. The median survival was significantly longer in the metal stenting group than in the plastic stenting group (7.2 months [95% CI 6.0-8.5] vs. 4.1 months [95% CI 2.9-5.3]; P = 0.015). The clinical success rates were significantly higher in the metal stenting group than in the plastic stenting group (99.0% vs. 71.9%, respectively; P < 0.001), and lower post-procedure cholangitis incidence (7.3% vs. 26.0%; P < 0.001), longer median symptom-free stent patency (9.2 months [95% CI 7.6-10.6] vs. 4.8 months [95% CI 4.2-5.3]; P < 0.001), and fewer total interventions (1.3 ± 0.6 vs. 2.0 ± 1.4; P < 0.001). In multivariate Cox analysis of the overall survival, metal stenting (HR 0.589, P = 0.002), hilar cholangiocarcinoma (HR 0.419, P = 0.009), and adjuvant treatment (HR 0.596, P = 0.006) were independent predictors of death. CONCLUSIONS: Endoscopic therapy using bilateral metal stenting is superior to bilateral plastic stenting, with prolonged overall survival, higher clinical success, and longer stent patency in patients with advanced hilar biliary malignancies.

Current Endoscopic Management of Malignant Biliary Stricture.

Biliary and pancreatic cancers occur silently in the initial stage and become unresectable within a short time. When these diseases become symptomatic, biliary obstruction, either with or without infection, occurs frequently due to the anatomy associated with these cancers. The endoscopic management of these patients has changed, both with time and with improvements in medical devices. In this review, we present updated and integrated concepts for the endoscopic management of malignant biliary stricture. Endoscopic biliary drainage had been indicated in malignant biliary obstruction, but the concept of endoscopic management has changed with time. Although routine endoscopic stenting should not be performed in resectable malignant distal biliary obstruction (MDBO) patients, endoscopic biliary drainage is the treatment of choice for palliation in unresectable MDBO patients. Self-expanding metal stents (SEMS) have better stent patency and lower costs compared with plastic stents (PS). For malignant hilum obstruction, PS and uncovered SEMS yield similar short-term outcomes, while a covered stent is not usually used due to a potential unintentional obstruction of contralateral ducts.

Intrahepatic Cholangiocarcinoma Associated Paradoxical Peripheral Embolism and a Submassive Pulmonary Embolism.

Paradoxical peripheral embolism and submassive pulmonary embolism (PE), secondary to cancer-associated thrombosis, are yet to be reported in the literature. Here we describe a case presenting with an acute peripheral arterial embolism. Subsequent testing revealed a PE and an intrahepatic cholangiocarcinoma as the likely risk factors for thrombus, with arterial spread likely achieved through a patent foramen ovale. The patient's symptoms almost relieved upon catheter-directed thrombus fragmentation and aspiration, catheter-directed thrombolysis, and combined anticoagulation. Embolism and major bleeding did not occur during 6 months of follow-up under systemic anticoagulation with rivaroxaban. This case documents that catheter-directed thrombolysis and anticoagulation could be likely effective and safe in the treatment and prevention of recurrence of paradoxical embolism and PE secondary to cancer-associated thrombosis.

[A Case Report of an Elderly Patient's Intrahepatic Cholangiocellular Carcinoma with Cholangitis].

We report a case of an elderly patient diagnosed with intrahepatic cholangiocellular carcinoma with cholangitis.An 88- year-old woman presented with fever.Computed tomography examination showed a hepatic tumor and dilation of the peripheral bile duct.Cholangiocarcinoma was diagnosed.Biliary tract drainage and palliative care were suggested because of her age.However, her family asked for a second opinion about operative management and consulted our hospital.Radical operations for intrahepatic cholangiocellular carcinoma that has spread to the left lobe are usually accompanied by widespread lymph node dissection and extensive hepatectomy with biliary tract reconstruction.However, in this case, the patient was very elderly and was able to safely undergo an operation by reduction of the excision range and by omitting lymph node dissection.We conclude that appropriate surgery and postoperative care to prevent complications are necessary when performing very invasive surgery in elderly patients.

[A Case of Intrahepatic Cholangiocarcinoma with Invasion to the Transverse Colon and Gallbladder, Forming an Intra-Tumor Abscess].

An 81-year-old man was referred to our institution for evaluation of high fever and a liver tumor that had been detected by ultrasonography. Computed tomography revealed a low-density mass with peripheral ring-like enhancement in S5 of the liver. The liver mass was in contact with the gallbladder, and the boundary between the mass and the gallbladder was unclear. On the suspicion of liver abscess, percutaneous transhepatic drainage was performed. The cavity of the abscess communicated with the gallbladder. Because the cavity had no tendency to reduce in size, we performed surgical resection under a preoperative diagnosis of liver abscess or primary liver carcinoma invading to the gallbladder. Intraoperative findings revealed a liver tumor invading the transverse colon and gallbladder. Subsegmentectomy of S4a and S5 of the liver combined with gallbladder and transverse colon resection was performed. Histopathological findings indicated the growth of a mass forming type intrahepatic cholangiocarcinoma with invasion to the transverse colon and gallbladder, and the pathological stage of the tumor was pT3N0M0, fStage Ⅲ. Thus far, the patient is alive without recurrence 9 months after surgery. Here, we report an extremely rare case of intrahepatic cholangiocarcinoma that invaded other organs and was associated with an intra-tumor abscess.

Infusion of 50% glucose solution to occlude an intrahepatic portosystemic venous shunt before percutaneous transhepatic portal embolization: report of a case.

A 68-year-old man with cholangiocarcinoma underwent percutaneous transhepatic portal embolization to expand the indication for hepatic resection. Selective right posterior portography revealed an intrahepatic portosystemic venous shunt (IPSVS) connecting the segment VII branch to the right hepatic venous branch. An infusion of 50 % glucose solution was given to occlude the shunt. This is novel management for IPSVSs when they are numerous, small, or torturous, and makes the subsequent procedures simpler, shorter, and less expensive.

Association of Cholangiocarcinoma among People with Periductal Fibrosis.

BACKGROUND: Cholangiocarcinoma (CCA) is a highly fatal tumor, and the most favorable chance for long-term survival lies in curative resection. Periductal fibrosis (PDF), a precancerous condition associated with chronic inflammation of the bile ducts, can serve as a screening marker for CCA using hepatobiliary ultrasonography (US). However, limited studies have explored the relationship between PDF and CCA. This study aimed to investigate the association between PDF and CCA in a population at risk in Northeast Thailand. METHODS: The study included participants enrolled in the Cholangiocarcinoma Screening and Care Program (CASCAP) between 2013 and 2021 who underwent US. Histological evaluations were conducted following the standard protocol of the tertiary hospital at Khon Kaen University, Thailand. PDF was defined as the presence of fibrosis in the peripheral (PDF1), segmental (PDF2), or main bile duct (PDF3), diagnosed by well-trained general practitioners or radiologists. The association between PDF and CCA was assessed using multiple logistic regression, calculating adjusted odds ratios (AORs) and 95% confidence intervals (CIs). RESULTS: Out of 751,061 participants, the overall prevalence of PDF was 115,267 (15.35%), with an overall CCA rate of 0.11%. The rates of CCA were 0.1%, 0.15%, and 0.27% in participants with PDF1, PDF2, and PDF3, respectively. After adjusting for gender, age at enrollment, education levels, history of O. viverrini infection, smoking, and alcohol consumption, the AORs for CCA were 0.94 (95% CI: 0.74 - 1.20), 1.4 (95% CI: 1.03 - 1.91), and 2.52 (95% CI: 1.38 - 4.58) for participants with PDF1, PDF2, and PDF3, respectively. CONCLUSION: Our findings demonstrate a significant association between fibrosis of the segmental and main bile ducts (PDF2 and PDF3) and CCA, with the strongest association observed in participants with PDF3. Hepatobiliary US screening could serve as a valuable tool for early detection of CCA, enabling timely curative treatment.

Percutaneous transhepatic self-expanding metal stents for palliation of malignant biliary obstruction.

BACKGROUND: Malignant biliary obstruction is often inoperable at presentation and has a poor prognosis. Percutaneously placed self-expanding metal stents (SEMS) have been widely used for palliation of malignant biliary obstruction as an alternative to major bypass surgery or when endoscopic drainage is not technically feasible. The success rate, procedural complications and outcomes in patients who underwent placement of SEMS in a tertiary referral centre are presented. METHODS: All patients who had percutaneous transhepatic cholangiography (PTC) and SEMS for palliation of malignant biliary obstruction between May 2008 and July 2010 at Groote Schuur Hospital, Cape Town, were reviewed. A retrospective chart review was undertaken using multidisciplinary case notes of all patients. The data analysed included demographic information, diagnosis, level of biliary obstruction, number and type of procedures, efficacy and complications of SEMS insertion. Boston Scientific 69 mm by 10 mm Wallstent SEMS were used in all patients. RESULTS; Fifty patients (28 men, 22 women, mean age 61 years, range 48 - 80 years) underwent percutaneous SEMS placement. Twenty-one patients had biliary obstruction at the level of the hilum involving the hepatic duct bifurcation, 5 in the mid-common bile duct and 24 in the low common bile duct. In 20 patients (40%) SEMS were placed at the time of initial biliary drainage (one-stage procedure), while the remaining 30 patients underwent stent placement within 2 - 23 days of biliary drainage as a two-stage procedure because of difficult access through the lesion during the initial procedure. Five patients (10%) required bilateral SEMS insertion. Stent placement was successful in all patients and biliary obstruction was relieved in all. The mean serum bilirubin level decreased by a mean of 56% from 294 µmol/l to 129 µmol/l measured 5 days after stent insertion. Mean hospital stay after stent insertion was 4.1 days. The average length of hospital stay for patients who underwent a one-stage procedure was 3.2 days (range 1 - 11 days), and for patients who underwent a two-stage procedure 7.6 days (range 3 - 23 days). Nine patients (18%) developed a procedure-related complication, which included cholangitis after stent insertion (n=4), cholangitic liver abscesses (n=1), subphrenic liver collection (n=1), bile leakage (n=1) and cholecystitis (n=2). Three patients (6%) developed complications unrelated to SEMS insertion, which included myocardial ischaemia (n=2) and pneumonia (n=1). Stent occlusion occurred in 4 patients (8%) within a week as result of stent migration (n=3) or presumed biliary sludge (n=1); 2 (4%) stents occluded between 7 days and 1 month. Four patients (8%) died during hospital admission due to pre-existing biliary sepsis (n=3) and pneumonia (n=1). Nine patients developed duodenal obstruction due to disease progression and required endoscopic duodenal stenting. Four patients (8%) survived less than 1 month, 12 (24%) between 1 month and 3 months, 11 (22%) between 3 and 6 months, and 10 (20%) beyond 6 months. Follow-up was not possible for 9 patients (18%) from distant referral sites. CONCLUSION: These results demonstrate that percutaneously placed SEMS achieved satisfactory palliation with a low complication rate in a high-risk patient group with advanced malignant biliary obstruction.

An unusual complication of pyloric ring obstruction caused by flange of lumen apposing metal stent in endoscopic ultrasound-guided gallbladder drainage: A case report.

INTRODUCTION: Endoscopic ultrasound-guided gallbladder drainage (EUS-GBD) is an alternative treatment option for patients with acute cholecystitis, especially for those who are unsuitable for cholecystectomy. Recently used luminal apposing metal stents (LAMS) in EUS-GBD has several advantages over standard metal stents. However, there is no current guideline on where to locate the LAMS when transgastric approach is required. This study reports a case of gastric outlet obstruction (GOO) by placing LAMS too close to the pyloric ring. PATIENT CONCERNS: A 79-year-old female patient was referred to our department for evaluation of a large hepatic mass on abdominal ultrasound. Abdominal pain on right upper quadrant and spiking fever up to 38 °C appeared after liver biopsy. Abdominal ultrasound showed thickened GB wall and positive sonographic Murphy sign. DIAGNOSES: Intrahepatic cholangiocarcinoma with multiple lung and intrahepatic metastasis, acute cholecystitis, and pyloric ring obstruction caused by flange of LAMS in EUS-GBD. INTERVENTIONS: EUS-GBD via transgastric approach was performed with LAMS. After complete deployment of stent, esophagogastroduodenoscopy showed complete GOO by flange of LAMS. A gastroduodenal metal stent was inserted to relieve the GOO. OUTCOMES: The patient recovered well. She did not complain about obstruction induced symptom such as vomiting or abdominal fullness after gastroduodenal stent insertion. CONCLUSION: To the best of our knowledge, this is the first case report of EUS-GBD induced GOO. If physicians use LAMS as a transgastric approach in EUS-GBD, the puncture site should be carefully selected considering the size of the flange.

Transhepatic portal stent placement and jejunal varix embolization for management of treatment-limiting gastrointestinal bleeding in a patient with unresectable recurrent intrahepatic cholangiocarcinoma.

Recurrent cholangiocarcinoma carries a dismal prognosis, with surgery providing the only potential cure. In those with unresectable disease, chemotherapy is the typical therapeutic mainstay but, given the myelosuppressive effects of this regimen, a pre-existing cytopenia may necessitate dose delay or reduction and contribute to poorer patient outcomes. We present a case of unresectable recurrent cholangiocarcinoma in which chronic gastrointestinal bleeding precluded chemotherapy administration, and which was successfully managed by portal vein stenting and ectopic variceal embolization.

Comparison of long-term efficacy between endoscopic and percutaneous biliary drainage for resectable extrahepatic cholangiocarcinoma with biliary obstruction: A systematic review and meta-analysis.

BACKGROUND/AIM: For resectable extrahepatic cholangiocarcinoma with biliary obstruction, it remains a controversy whether to choose percutaneous transhepatic biliary drainage (PTBD) or endoscopic biliary drainage (EBD). A systematic review was conducted to compare the long-term efficacy between the two techniques. MATERIALS AND METHODS: Eligible studies were searched from January 1990 to May 2018, comparing the long-term efficacy between EBD and PTBD for extrahepatic cholangiocarcinoma. Primary end point was overall survival (OS) rate, and secondary end points included postoperative severe complications and seeding metastasis. Effect size on outcomes was calculated using a fixed- or random-effect model, accompanied with hazard ratio (HR) and 95% confidence interval (CI). RESULT: Six studies were included in this meta-analysis. Meta-analysis showed that EBD was superior to PTBD in OS (HR = 0.70, 95% CI 0.59-0.84,P= 0.0002). But subgroup results showed that the superiority disappeared in distal cholangiocarcinoma (HR = 0.76, 95% CI 0.56-1.01,P= 0.06). Other prognostic factors such as intraoperative blood transfusion, lymphatic metastasis and seeding metastasis, were inconsistent between groups. In addition, regional disparity was obviously apparent between Japanese and non-Japanese studies. CONCLUSION: The conclusion that EBD was superior to PTBD in OS for resectable extrahepatic cholangiocarcinoma with biliary obstruction is less convincing, and more trials need to be conducted in future.

External lymphatic fistula after intra-abdominal lymphadenectomy for cancer. Treatment with total parenteral nutrition and somatostatin.

OBJECTIVE: External lymphatic fistula or chyloperitoneum after intra-abdominal lymphadenectomy may present challenging problems. In the absence of definite guidelines the choice of treatment is often empirical, with unpredictable effectiveness, and the reporting of new cases may broaden the available experience. METHODS: We describe two cases. One patient had high-output external fistula (1300 mL/d) after para-aortic lymphadenectomy for metastatic lymph nodes. The fistula became fully evident at postoperative day 4, with resumption of an oral diet, on the basis of a 1300-mL/d output of white milky fluid from an abdominal drainage. Oral feeding was interrupted and total parenteral nutrition was started; this was transiently associated with octreotide administration, subsequently replaced by somatostatin. The second patient had a low-output fistula (350 mL/d) after liver resection and lymphadenectomy for cholangiocarcinoma and underwent treatment with total parenteral nutrition and somatostatin. RESULTS: In the first case the lymphatic fistula healed in just less than 3 wk, with the patient constantly remaining in very good condition, without secondary complications. In the second case the low-output fistula healed more rapidly. CONCLUSION: Interruption of oral feeding with total parenteral nutrition and continuous somatostatin infusion was an effective treatment in both patients with an intra-abdominal lymphatic leak.

Diagnosis and initial management of cholangiocarcinoma with obstructive jaundice.

Cholangiocarcinoma is the second most common primary hepatic cancer. Despite advances in diagnostic techniques during the past decade, cholangiocarcinoma is usually encountered at an advanced stage. In this review, we describe the classification, diagnosis, and initial management of cholangiocarcinoma with obstructive jaundice.

Percutaneous transhepatic biliary metal stent for malignant hilar obstruction: results and predictive factors for efficacy in 159 patients from a single center.

AIM: To investigate and compare the efficacy and safety of percutaneous transhepatic biliary stenting (PTBS) using a one- or two-stage procedure and determine the predictive factors for the efficacious treatment of malignant hilar obstruction (MHO). METHODS: 159 consecutive patients with MHO who underwent PTBS were enrolled between January 2010 and June 2013. Patients were classified into one- or two-stage groups. Independent predictors of therapeutic success were evaluated using a logistic regression model. RESULTS: 108 patients were treated with one-stage PTBS and 51 patients were treated with two-stage PTBS. The stents were technically successful in all patients. Successful drainage was achieved in 114 patients (71.4 %). A total of 42 early major complications were observed. Re-interventions were attempted in 23 patients during follow-up. The cumulative primary patency rates at 3, 6, and 12 months were 88, 71, and 48 %, respectively. Stent placement using a one- or two-stage procedure did not significantly affect therapeutic success, early major complications, median stent patency, or survival. A stent placed across the duodenal papilla was an independent predictor of therapeutic success (odds ratio = 0.262, 95 % confidence interval [0.107-0.642]). Patients with stents across papilla had a lower rate of cholangitis compared with patients who had a stent above papilla (7.1 vs. 20.3 %, respectively, p = 0.03). CONCLUSIONS: The majority of patients with MHO who underwent one-stage PTBS showed similar efficacy and safety outcomes compared with those who underwent two-stage PTBS. Stent placement across the duodenal papilla was associated with a higher therapeutic success rate.

Icteric type hepatocellular carcinoma: revisited 20 years later.

Icteric type hepatocellular carcinoma is rare, and a poor prognosis has been demonstrated in the past. We performed this study to re-evaluate prognosis since the availability of modern diagnostic modalities. Of 3921 patients with hepatocellular carcinoma in our hospital, 9 patients who presented with tumor fragments in common bile duct and had a patent portal vein were submitted for analysis. Cholangiocarcinoma was suspected in 7 patients before the study was completed, and icteric type hepatocellular carcinoma was diagnosed in all 9 patients after serial studies that included serum alpha-fetoprotein levels, computed tomography, angiography, and histology. The prognosis was better in the 4 resectable patients (survival time 16, 31, 33, and 63 months, respectively), and was extremely poor for the 5 patients who received palliative treatment only (mean survival time, 4.5 months). Because of the apparently discrepant outcomes, this specific type of hepatocellular carcinoma should be kept in mind in areas where hepatocellular carcinomas are prevalent, and the suspected cases should be thoroughly investigated, because prognosis may be improved when resection is done at an earlier stage.

Intrahepatic cholangiocarcinoma masked as fever of unknown origin.

Intrahepatic cholangiocarcinoma is a rare malignancy that often presents in an advanced stage. For many patients, early diagnosis is often delayed, secondary to vague symptoms and a lack of physical findings. Herein, we report an unusual case of fever of unknown origin secondary to intrahepatic cholangiocarcinoma.

The influence of Enteral Nutrition in postoperative patients with poor liver function.

AIM: To investigate the safety, rationality and the practicality of enteral nutritional (EN) support in the postoperative patients with damaged liver function and the protective effect of EN on the gut barrier. METHODS: 135 patients with liver function of Child B or C grade were randomly allocated to enteral nutrition group (EN, 65 cases), total parenteral nutrition group (TPN, 40 cases) and control group (CON, 30 cases). Nutritional parameters, hepatic and kidney function indexes were measured at the day before operation, 5th and 10th day after the operation respectively. Comparison was made to evaluate the efficacy of different nutritional support. Urinary concentrations of lactulose(L) and mannitol(M) were measured by pulsed electrochemical detection(HPLC-PED) and the L/M ratio calculated to evaluate their effectiveness on protection of gut barrier. RESULTS: No significant damages in hepatic and kidney function were observed in both EN and TPN groups between pre- and postoperatively. EN group was the earliest one reaching the positive nitrogen balance after operation and with the lowest loss of body weight and there was no change in L/M ratio after the operation (0.026+/-0.004) at the day 1 before operation, 0.030+/-0.004 at the day 5 postoperative and 0.027+/-0.005 at the day 10 postoperative), but the change in TPN group was significant at the day 5 postoperative (0.027+/-0.003 vs 0.038+/-0.009,P<0.01). CONCLUSION: EN is a rational and effective method in patients with hepatic dysfunction after operation and has significant protection effect on the gut barrier.

Comparison of treatment outcomes between biliary plastic stent placements with and without endoscopic sphincterotomy for inoperable malignant common bile duct obstruction.

AIM: Considerable controversy surrounds the adoption of endoscopic sphincterotomy (ES) to facilitate the placement of 10F plastic stents (PS) and to reduce the risk of pancreatitis The aim of the study was to assess the possible advantages of ES before PS placement. METHODS: From 3/1996 to 6/2001, 172 consecutive patients, who underwent placement of a single 10F- polyethylene stent for inoperable malignant strictures of the common bile duct, were randomly assigned to 2 groups. In group A (96 patients), a ES was performed before PS placement In Group B, 96 patients had PS directly. Early complications (within 30 d) and late effects (from 30 d to stent replacement) were assessed. Patency interval was defined as the period between PS placement and obstruction or death. The success of stent replacement in the 2 groups was evaluated. RESULTS: Stent insertion was successful in 95.8%(92/96) of the pts in group A and in 93.7%(90/96) of the patients in group B (P>0.05). Early complications were more frequent in patients who underwent ES (6.5% vs 4.4%) but the data were not significant (P>0.05). In group A pancreatitis developed in two patients and bleeding in three; whereas pancreatitis occurred in 2 patients in group B. Complications were managed conservatively. No procedure related mortality occurred. All late complications were acute cholangitis due to stent occlusion. We performed a stent replacement in 87 patients that was successful in 84 cases without differences between groups. CONCLUSION: Sphincterotomy does not seem to be necessary for placement of 10F-PS in patients with malignant common bile duct obstruction.