J Hepatobiliary Pancreat Sci (2015) 22:396–401 DOI: 10.1002/jhbp.219
ORIGINAL ARTICLE
8-mm versus 10-mm diameter self-expandable metallic stent in bilateral endoscopic stent-in-stent deployment for malignant hilar biliary obstruction Itaru Naitoh · Takahiro Nakazawa · Tesshin Ban · Fumihiro Okumura · Atsuyuki Hirano · Hiroki Takada · Shozo Togawa · Kazuki Hayashi · Katsuyuki Miyabe · Shuya Shimizu · Hiromu Kondo · Yuji Nishi · Michihiro Yoshida · Hiroaki Yamashita · Shuichiro Umemura · Yasuki Hori · Akihisa Kato · Hitoshi Sano · Takashi Joh Published online: 22 January 2015 © 2015 Japanese Society of Hepato-Biliary-Pancreatic Surgery
Abstract Background We aimed to clarify the clinical benefits of using 8-mm versus 10-mm diameter self-expandable metallic stent (SEMS) in bilateral endoscopic stent-in-stent (SIS) deployment for malignant hilar biliary obstruction (MHBO). Methods A total of 72 consecutive patients with MHBO treated by endoscopic bilateral SIS deployment were enrolled. The 8-mm and 10-mm diameter SEMSs were used in 37 patients (8-mm group) and 35 patients (10-mm group), I. Naitoh (✉) · T. Nakazawa · K. Hayashi · K. Miyabe · S. Shimizu · H. Kondo · Y. Nishi · M. Yoshida · H. Yamashita · S. Umemura · Y. Hori · A. Kato · T. Joh Department of Gastroenterology and Metabolism, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan e-mail: [email protected] T. Ban Department of Gastroenterology, Nagoya Daini Red Cross Hospital, Nagoya, Japan F. Okumura · H. Sano Department of Gastroenterology, Gifu Prefectural Tajimi Hospital, Tajimi, Japan A. Hirano Department of Gastroenterology, Nagoya City West Medical Center, Nagoya, Japan H. Takada Department of Gastroenterology, Kasugai Municipal Hospital, Kasugai, Japan S. Togawa Department of Gastroenterology, Japan Community Healthcare Organization Chukyo Hospital, Nagoya, Japan
respectively. We retrospectively compared technical success, functional success, complications, successful re-intervention, time to recurrent biliary obstruction (RBO) and survival time between two groups. Results There were no significant inter-group differences in terms of technical success (8-mm vs. 10-mm group, both 100%), functional success (96% vs. 100%), early (5% vs. 9%) and late (19% vs. 14%) complications other than RBO, and successful endoscopic re-intervention (94% vs. 100%), respectively. Time to RBO (median: 198 days vs. 222 days; log-rank, P = 0.440) and survival time (median: 186 days vs. 235 days; log-rank, P = 0.883) did not differ significantly between the two groups. However, the success rate of endoscopic bilateral revisionary stent insertion for RBO was significantly higher in the 10-mm compared to the 8-mm group (68% vs. 31%; P = 0.044). Conclusions The 10-mm diameter SEMS is more suitable with regard to endoscopic re-intervention. Keywords Bilateral stent · Hilar malignant biliary obstruction · Re-intervention · Self-expandable metallic stent · Stent-in-stent
Introduction Endoscopic biliary drainage is accepted as a palliative therapy for malignant hilar biliary obstruction (MHBO) because of its limited invasiveness. A self-expandable metallic stent (SEMS) is a superior option over plastic stent for patients with a predicted survival of >3 months, with regards to both long-term
J Hepatobiliary Pancreat Sci (2015) 22:396–401
patency and cost-effectiveness [1–3]. However, despite several reports that have compared the two methods [4–9], there exists no definitive consensus on whether unilateral or bilateral stenting is the most suitable method for MHBO [10]. Furthermore, there are two deployment options available for bilateral metal stenting: side-by-side (SBS) deployment and stent-instent (SIS) deployment. Previously we compared SBS and SIS deployment with regards to stent patency and complications and discovered that stent patency is significantly longer in SBS compared to SIS deployment [11]. Conversely, the incidence of complications was greater for SBS compared to SIS deployment. These observations make deciding upon which deployment is most suitable for MHBO challenging. The other study reported no differences between the two deployments with regards to stent patency, complication rates and overall survival [12]. Stent-in-stent deployment is technically challenging as endoscopists often encounter difficulty when inserting the second SEMS through the mesh of the first SEMS. Endoscopic re-intervention for stent occlusion is also difficult because of challenges associated with the insertion of the revisionary stent. However, the success rate of SIS can be significantly improved by using a laser-cutting stent, opencell-type stent, or the newly developed “Y” stent [13–15]. Such technical improvements have allowed for a more common usage of SIS and improved success rate. For distal malignant biliary obstruction, the use of a 10-mm diameter SEMS is popular, although an 8-mm option is also available. However, the optimal diameter of SEMS for use in MHBO has not been determined. The diameter of SEMS used may influence the success rate, stent patency or complication rate of the procedure, yet no studies that compare the 8-mm and 10-mm diameter SEMS in SIS deployment have been published to date. Therefore, the purpose of this present study is to retrospectively compare 8-mm and 10-mm diameter SEMS in SIS deployment for MHBO and to clarify any differences in clinical features. Methods Patients Between 2006 and 2014 a total of 72 consecutive patients with MHBO treated by endoscopic bilateral SIS deployment using SEMS were enrolled at the Nagoya City University Graduate School of Medical Sciences and from five tertiarycare referral centers. Inclusion criteria were patients with unresectable MHBO with Bismuth type II or higher, age ≥ 20 years old, and performance status ≤ 3. Exclusion criteria were severe liver atrophy and severe comorbidities. The diagnosis of MHBO was based on imaging and/or pathological findings. Unresectability was judged according to advanced
397
tumor extension or other factors pertaining to the condition of patients. Some patients received chemotherapy after SEMS placement. Laboratory data were evaluated every month after SEMS placement. Radiological examinations were performed at fixed intervals or when stent dysfunction was suspected. All patients were followed from stent insertion until death or the end of the present study. Written informed consent was obtained from all patients in accordance with the Helsinki declaration. This study was approved by the Review Board of Nagoya City University Graduate School of Medical Sciences (approval no. 1047).
Technique Participating endoscopists had at least 5 years of experience and 200 cases per year of therapeutic endoscopic retrograde cholangiopancreatography. Trainees who had less experience were allowed to carry out endoscopic procedures under the supervision of experienced endoscopists. Endoscopic bilateral SEMS insertion was performed under conscious sedation, and prophylactic treatment with broad-spectrum antibiotics was initiated after the procedure. After biliary cannulation and completion of the cholangiogram, two 0.035-inch-diameter guide wires were passed through the stricture and inserted into the left hepatic duct (LHD) and right hepatic duct (RHD). Endoscopic sphincterotomy with middle incision was performed before SEMS placement in principle. The location and length of the stricture was evaluated by the cholangiogram. Two SEMSs were inserted in SIS deployment. The first SEMS was an uncovered Niti-S Y-type stent or a Large-cell D-type stent (Taewoong Medical, Seoul, Korea), and the second SEMS was an uncovered Niti-S Y-type stent, a D-type stent or a Large-cell D-type stent (Teawoong Medical). Where a Large-cell D-type stent was available, we used Large-cell D-type stent for all patients. The length of the SEMS was chosen on the basis of the maximum size necessary to span the stenotic area, and all SEMSs were placed above the papilla. There was no criteria to select 8-mm diameter or 10-mm diameter SEMS. The diameter of SEMS was determined at the discretion of the endoscopist and institution. The same diameter SEMSs were selected for both the first and second SEMSs. When recurrent biliary obstruction (RBO) was identified, re-intervention was performed according to the following strategy. Firstly, endoscopic reintervention was performed by inserting a plastic stent or SEMS through the initial SEMS. For endoscopic reintervention, we first attempted bilateral drainage. When endoscopic bilateral drainage proved difficult we performed endoscopic unilateral drainage. Secondly, percutaneous reintervention was conducted using percutaneous transhepatic biliary drainage following failure of endoscopic re-
398
intervention. The final drainage area (unilateral or bilateral) and stent type (plastic or SEMS) was determined at the discretion of each endoscopist at the time of endoscopic re-intervention. The following outcomes were assessed in both the 8-mm and 10-mm groups: (1) technical success; (2) functional success (first session and final); (3) RBO; (4) complications other than RBO (early and late); and (5) re-intervention. Time to RBO and survival time were also compared between the two groups. Technical success was defined as passage of the stent across the stenosis, together with flow of contrast through the stent. Functional success was defined as a decrease in the level of bilirubin to normal level or less than 75% of the pretreatment value in the first month. Recurrent biliary obstruction was defined as recurrence of jaundice, cholangitis, and migration requiring biliary intervention [16]. Recurrent biliary obstruction was classified into four causes: tumor ingrowth, tumor overgrowth, sludge occlusion and stent migration. Early and late complications other than RBO were defined as those occurring within 30 days of stent placement, and 30 days or beyond, respectively. Time to RBO was calculated as the time interval between SEMS insertion and RBO, or patient death without RBO. Transient cholangitis that did not require re-intervention was not defined as RBO. With regards to re-intervention, the drainage route (endoscopic or percutaneous) and drainage area (unilateral or bilateral) were evaluated.
J Hepatobiliary Pancreat Sci (2015) 22:396–401
Biliary diameter was defined as the diameter of the common bile duct distal to the biliary stricture. The median follow-up periods were 5.9 and 6.8 months in the 8-mm and 10-mm groups, respectively. Outcomes
Results
Clinical outcomes of the 8-mm and 10-mm groups are shown in Table 2. Technical success at the first session was achieved in 36 of the 37 cases (97%) in the 8-mm group and 33 of the 35 (94%) in the 10-mm group. In all three cases the cause of unsuccessful stent insertion was a failure to pass the second stent delivery system through the mesh of the first SEMS. The second SEMS was successfully inserted 5–7 days after first session following the expansion of the first SEMS, in each of the three cases. Final technical success was 100% for both groups. Functional success was achieved in 36 of the 37 cases (97%) in the 8-mm group and 34 of the 35 cases (97%) in the 10-mm group. The median bilirubin level was reduced to 0.72 mg/dL and 0.78 mg/dL in the 8-mm and 10-mm group, respectively. Recurrent biliary obstruction occurred in 17 (46%) of the patients in the 8-mm group and 19 (54%) in the 10-mm group. There was no significant difference in the incidence of complications between the 8-mm and 10-mm groups (P = 0.637). Complications other than RBO occurred in nine (24%) of the patients in the 8-mm group and eight (23%) of the patients in the 10-mm group. There was no significant difference in the incidence of complications between the 8-mm and 10-mm groups (P = 0.896). There was also no significant difference in the incidence of early (5% vs. 9%; P = 0.949) and late (19% vs. 14%; P = 0.754) complications other than RBO between the 8-mm and 10-mm groups. There was no procedure-related mortality. There was no difference in the time to RBO between the 8mm and 10-mm groups (log-rank, P = 0.440) (Fig. 1). The median times to RBO were 198 and 222 days in the 8-mm and 10-mm groups, respectively. There was no difference in the survival time curve between the 8-mm and 10-mm groups (log-rank, P = 0.883). The median survival times for the 8-mm and 10-mm groups were 186 and 235 days, respectively.
Patient characteristics
Re-intervention for recurrent biliary obstruction
The 8-mm group comprised 37 patients (19 male and 18 median age, 75 years) and the 10-mm group comprised 35 (21 male and 14 female; median age, 78 years). The clinical characteristics of the two groups are summarized in Table 1. There were no significant inter-group differences in gender, age, performance status, diagnosis, Bismuth classification, administration of chemotherapy, total bilirubin level, biliary diameter and follow-up period.
Re-intervention for RBO was attempted in 16 of 17 patients in the 8-mm group and all 19 patients in the 10-mm group. Re-intervention was not attempted in one patient in the 8-mm group due to their poor condition. Endoscopic re-intervention was successful in 15 (94%) of 16 patients in the 8-mm group and all 16 patients (100%) in the 10-mm group (P = 0.457). We could not insert a revisionary plastic stent through the occluded SEMS in one
Statistical analysis The Mann–Whitney U-test was used for comparison of continuous variables, and the χ 2 test or the Fisher’s exact test for categorical variables. Time to RBO and survival time were estimated by Kaplan–Meier analysis, and curves were compared by the log-rank test. Statistical tests were two-sided and significance was defined as P < 0.05. All statistical analyses were performed using the IBM SPSS Statistics software, version 21.
J Hepatobiliary Pancreat Sci (2015) 22:396–401
399
Table 1 Clinical characteristics between the 8-mm and 10-mm groups 8-mm group Number Gender (Male/Female) Age (years), median (range) Performance status (0–1/≥2) Diagnosis Cholangiocarcinoma Gallbladder carcinoma Others Bismuth classification Type II Type III Type IV Chemotherapy Total bilirubin (mg/dL), median (range) Biliary diameter (mm), median (range) Follow-up period (month), median (range)
37 19/18 75 (58-93) 32/5
10-mm group 35 21/14 78 (55-92) 28/7
16 16 5
22 10 3
6 7 24 20 8.3 (0.6–25.7) 9.5 (6–13) 5.9 (0.7–34.1)
15 4 16 18 10.2 (0.8–33.4) 9 (5–15) 6.8 (0.4–22.4)
P-value
0.617 0.099 0.537 0.418
0.098
0.810 0.171 0.942 0.521
Biliary diameter: the diameter of the common bile duct distal to the biliary stricture Table 2 Outcomes between the 8-mm and 10-mm groups
Technical success at the first session Final technical success Functional success Complication Recurrent biliary obstruction Ingrowth Overgrowth Sludge Complications other than recurrent biliary obstruction Early Cholecystitis Pancreatitis Late Cholecystitis Cholangitis Liver abscess Median survival time (days)
patient in the 8-mm group, and this patient was subsequently treated by PTBD. Endoscopic bilateral revisionary stent insertion for RBO was successful in five (31%) of 16 patients in the 8-mm group and 13 (68%) of 19 patients in the 10-mm group. The success rate of endoscopic bilateral revisionary stent insertion was significantly greater in the 10-mm group compared to the 8-mm group (68% vs. 31%; P = 0.044). Re-intervention for RBO in both the 8-mm and 10-mm groups is presented in Table 3.
8-mm group
10-mm group
P value
36/37 (97%) 37/37 (100%) 36/37 (97%)
33/35 (94%) 35/35 (100%) 34/35 (97%)
0.609 1 1
17/37 (46%) 15 1 1 9/37 (24%) 2/37 (5%) 1 1 7/37 (19%) 1 4 2 198
19/35 (54%) 17 1 1 8/35 (23%) 3/35 (9%) 1 2 5/35 (14%) 1 1 3 222
0.637
0.896 0.949
0.754
0.883
Discussion The present study revealed clinical differences between use of an 8-mm and a 10-mm diameter SEMS in bilateral endoscopic SIS deployment for MHBO. The success rate of endoscopic bilateral revisionary stent insertion for RBO was significantly greater using a 10-mm compared to an 8-mm diameter SEMS (68% vs. 31%; P = 0.044). However, there were no significant differences between the 8-mm and 10-mm diameter SEMS in
400
J Hepatobiliary Pancreat Sci (2015) 22:396–401
Fig. 1 There was no difference in the time to recurrent biliary obstruction between the 8-mm and 10-mm groups by Kaplan–Meier analysis (log-rank, P = 0.440)
terms of technical success, functional success, complication, time to RBO and survival time. The success rate of SIS deployment has been reported to range from 85% to 100% [8, 11, 12]. Kogure et al. [13] (Niti-S Large-cell D-type; Taewoong Medical), and Lee et al. [14] and Hwang et al. [15] (Niti-S Biliary Y-stent; Taewoong Medical) reported high technical success rates with large-cell stents in SIS deployment. The failure of insertion of second SEMS though the mesh is caused by insufficient expansion due to low radial force. Kogure et al. [17] developed modified large-cell stent with stronger radial force and a slimmer delivery system to achieve high technical success rate. Table 3 Re-intervention for recurrent biliary obstruction
Successful re-intervention Successful endoscopic re-intervention Successful endoscopic bilateral re-intervention Method of re-intervention Percutaneous Unilateral PTBD Endoscopic Bilateral stenting PS SEMS Unilateral stenting PS SEMS
8-mm group
10-mm group
P-value
16/16 (100%)
19/19 (100%)
1
15/16 (94%)
19/19 (100%)
0.457
5/16 (31%)
13/19 (68%)
0.044*
1/16 (6%) 1 15/16 (94%) 5/16 (31%) 5 0 10/16 (63%) 7 3
0 0 19/19 (100%) 13/19 (68%) 11 2 6/19 (32%) 4 2
* P
ORIGINAL ARTICLE
8-mm versus 10-mm diameter self-expandable metallic stent in bilateral endoscopic stent-in-stent deployment for malignant hilar biliary obstruction Itaru Naitoh · Takahiro Nakazawa · Tesshin Ban · Fumihiro Okumura · Atsuyuki Hirano · Hiroki Takada · Shozo Togawa · Kazuki Hayashi · Katsuyuki Miyabe · Shuya Shimizu · Hiromu Kondo · Yuji Nishi · Michihiro Yoshida · Hiroaki Yamashita · Shuichiro Umemura · Yasuki Hori · Akihisa Kato · Hitoshi Sano · Takashi Joh Published online: 22 January 2015 © 2015 Japanese Society of Hepato-Biliary-Pancreatic Surgery
Abstract Background We aimed to clarify the clinical benefits of using 8-mm versus 10-mm diameter self-expandable metallic stent (SEMS) in bilateral endoscopic stent-in-stent (SIS) deployment for malignant hilar biliary obstruction (MHBO). Methods A total of 72 consecutive patients with MHBO treated by endoscopic bilateral SIS deployment were enrolled. The 8-mm and 10-mm diameter SEMSs were used in 37 patients (8-mm group) and 35 patients (10-mm group), I. Naitoh (✉) · T. Nakazawa · K. Hayashi · K. Miyabe · S. Shimizu · H. Kondo · Y. Nishi · M. Yoshida · H. Yamashita · S. Umemura · Y. Hori · A. Kato · T. Joh Department of Gastroenterology and Metabolism, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan e-mail: [email protected] T. Ban Department of Gastroenterology, Nagoya Daini Red Cross Hospital, Nagoya, Japan F. Okumura · H. Sano Department of Gastroenterology, Gifu Prefectural Tajimi Hospital, Tajimi, Japan A. Hirano Department of Gastroenterology, Nagoya City West Medical Center, Nagoya, Japan H. Takada Department of Gastroenterology, Kasugai Municipal Hospital, Kasugai, Japan S. Togawa Department of Gastroenterology, Japan Community Healthcare Organization Chukyo Hospital, Nagoya, Japan
respectively. We retrospectively compared technical success, functional success, complications, successful re-intervention, time to recurrent biliary obstruction (RBO) and survival time between two groups. Results There were no significant inter-group differences in terms of technical success (8-mm vs. 10-mm group, both 100%), functional success (96% vs. 100%), early (5% vs. 9%) and late (19% vs. 14%) complications other than RBO, and successful endoscopic re-intervention (94% vs. 100%), respectively. Time to RBO (median: 198 days vs. 222 days; log-rank, P = 0.440) and survival time (median: 186 days vs. 235 days; log-rank, P = 0.883) did not differ significantly between the two groups. However, the success rate of endoscopic bilateral revisionary stent insertion for RBO was significantly higher in the 10-mm compared to the 8-mm group (68% vs. 31%; P = 0.044). Conclusions The 10-mm diameter SEMS is more suitable with regard to endoscopic re-intervention. Keywords Bilateral stent · Hilar malignant biliary obstruction · Re-intervention · Self-expandable metallic stent · Stent-in-stent
Introduction Endoscopic biliary drainage is accepted as a palliative therapy for malignant hilar biliary obstruction (MHBO) because of its limited invasiveness. A self-expandable metallic stent (SEMS) is a superior option over plastic stent for patients with a predicted survival of >3 months, with regards to both long-term
J Hepatobiliary Pancreat Sci (2015) 22:396–401
patency and cost-effectiveness [1–3]. However, despite several reports that have compared the two methods [4–9], there exists no definitive consensus on whether unilateral or bilateral stenting is the most suitable method for MHBO [10]. Furthermore, there are two deployment options available for bilateral metal stenting: side-by-side (SBS) deployment and stent-instent (SIS) deployment. Previously we compared SBS and SIS deployment with regards to stent patency and complications and discovered that stent patency is significantly longer in SBS compared to SIS deployment [11]. Conversely, the incidence of complications was greater for SBS compared to SIS deployment. These observations make deciding upon which deployment is most suitable for MHBO challenging. The other study reported no differences between the two deployments with regards to stent patency, complication rates and overall survival [12]. Stent-in-stent deployment is technically challenging as endoscopists often encounter difficulty when inserting the second SEMS through the mesh of the first SEMS. Endoscopic re-intervention for stent occlusion is also difficult because of challenges associated with the insertion of the revisionary stent. However, the success rate of SIS can be significantly improved by using a laser-cutting stent, opencell-type stent, or the newly developed “Y” stent [13–15]. Such technical improvements have allowed for a more common usage of SIS and improved success rate. For distal malignant biliary obstruction, the use of a 10-mm diameter SEMS is popular, although an 8-mm option is also available. However, the optimal diameter of SEMS for use in MHBO has not been determined. The diameter of SEMS used may influence the success rate, stent patency or complication rate of the procedure, yet no studies that compare the 8-mm and 10-mm diameter SEMS in SIS deployment have been published to date. Therefore, the purpose of this present study is to retrospectively compare 8-mm and 10-mm diameter SEMS in SIS deployment for MHBO and to clarify any differences in clinical features. Methods Patients Between 2006 and 2014 a total of 72 consecutive patients with MHBO treated by endoscopic bilateral SIS deployment using SEMS were enrolled at the Nagoya City University Graduate School of Medical Sciences and from five tertiarycare referral centers. Inclusion criteria were patients with unresectable MHBO with Bismuth type II or higher, age ≥ 20 years old, and performance status ≤ 3. Exclusion criteria were severe liver atrophy and severe comorbidities. The diagnosis of MHBO was based on imaging and/or pathological findings. Unresectability was judged according to advanced
397
tumor extension or other factors pertaining to the condition of patients. Some patients received chemotherapy after SEMS placement. Laboratory data were evaluated every month after SEMS placement. Radiological examinations were performed at fixed intervals or when stent dysfunction was suspected. All patients were followed from stent insertion until death or the end of the present study. Written informed consent was obtained from all patients in accordance with the Helsinki declaration. This study was approved by the Review Board of Nagoya City University Graduate School of Medical Sciences (approval no. 1047).
Technique Participating endoscopists had at least 5 years of experience and 200 cases per year of therapeutic endoscopic retrograde cholangiopancreatography. Trainees who had less experience were allowed to carry out endoscopic procedures under the supervision of experienced endoscopists. Endoscopic bilateral SEMS insertion was performed under conscious sedation, and prophylactic treatment with broad-spectrum antibiotics was initiated after the procedure. After biliary cannulation and completion of the cholangiogram, two 0.035-inch-diameter guide wires were passed through the stricture and inserted into the left hepatic duct (LHD) and right hepatic duct (RHD). Endoscopic sphincterotomy with middle incision was performed before SEMS placement in principle. The location and length of the stricture was evaluated by the cholangiogram. Two SEMSs were inserted in SIS deployment. The first SEMS was an uncovered Niti-S Y-type stent or a Large-cell D-type stent (Taewoong Medical, Seoul, Korea), and the second SEMS was an uncovered Niti-S Y-type stent, a D-type stent or a Large-cell D-type stent (Teawoong Medical). Where a Large-cell D-type stent was available, we used Large-cell D-type stent for all patients. The length of the SEMS was chosen on the basis of the maximum size necessary to span the stenotic area, and all SEMSs were placed above the papilla. There was no criteria to select 8-mm diameter or 10-mm diameter SEMS. The diameter of SEMS was determined at the discretion of the endoscopist and institution. The same diameter SEMSs were selected for both the first and second SEMSs. When recurrent biliary obstruction (RBO) was identified, re-intervention was performed according to the following strategy. Firstly, endoscopic reintervention was performed by inserting a plastic stent or SEMS through the initial SEMS. For endoscopic reintervention, we first attempted bilateral drainage. When endoscopic bilateral drainage proved difficult we performed endoscopic unilateral drainage. Secondly, percutaneous reintervention was conducted using percutaneous transhepatic biliary drainage following failure of endoscopic re-
398
intervention. The final drainage area (unilateral or bilateral) and stent type (plastic or SEMS) was determined at the discretion of each endoscopist at the time of endoscopic re-intervention. The following outcomes were assessed in both the 8-mm and 10-mm groups: (1) technical success; (2) functional success (first session and final); (3) RBO; (4) complications other than RBO (early and late); and (5) re-intervention. Time to RBO and survival time were also compared between the two groups. Technical success was defined as passage of the stent across the stenosis, together with flow of contrast through the stent. Functional success was defined as a decrease in the level of bilirubin to normal level or less than 75% of the pretreatment value in the first month. Recurrent biliary obstruction was defined as recurrence of jaundice, cholangitis, and migration requiring biliary intervention [16]. Recurrent biliary obstruction was classified into four causes: tumor ingrowth, tumor overgrowth, sludge occlusion and stent migration. Early and late complications other than RBO were defined as those occurring within 30 days of stent placement, and 30 days or beyond, respectively. Time to RBO was calculated as the time interval between SEMS insertion and RBO, or patient death without RBO. Transient cholangitis that did not require re-intervention was not defined as RBO. With regards to re-intervention, the drainage route (endoscopic or percutaneous) and drainage area (unilateral or bilateral) were evaluated.
J Hepatobiliary Pancreat Sci (2015) 22:396–401
Biliary diameter was defined as the diameter of the common bile duct distal to the biliary stricture. The median follow-up periods were 5.9 and 6.8 months in the 8-mm and 10-mm groups, respectively. Outcomes
Results
Clinical outcomes of the 8-mm and 10-mm groups are shown in Table 2. Technical success at the first session was achieved in 36 of the 37 cases (97%) in the 8-mm group and 33 of the 35 (94%) in the 10-mm group. In all three cases the cause of unsuccessful stent insertion was a failure to pass the second stent delivery system through the mesh of the first SEMS. The second SEMS was successfully inserted 5–7 days after first session following the expansion of the first SEMS, in each of the three cases. Final technical success was 100% for both groups. Functional success was achieved in 36 of the 37 cases (97%) in the 8-mm group and 34 of the 35 cases (97%) in the 10-mm group. The median bilirubin level was reduced to 0.72 mg/dL and 0.78 mg/dL in the 8-mm and 10-mm group, respectively. Recurrent biliary obstruction occurred in 17 (46%) of the patients in the 8-mm group and 19 (54%) in the 10-mm group. There was no significant difference in the incidence of complications between the 8-mm and 10-mm groups (P = 0.637). Complications other than RBO occurred in nine (24%) of the patients in the 8-mm group and eight (23%) of the patients in the 10-mm group. There was no significant difference in the incidence of complications between the 8-mm and 10-mm groups (P = 0.896). There was also no significant difference in the incidence of early (5% vs. 9%; P = 0.949) and late (19% vs. 14%; P = 0.754) complications other than RBO between the 8-mm and 10-mm groups. There was no procedure-related mortality. There was no difference in the time to RBO between the 8mm and 10-mm groups (log-rank, P = 0.440) (Fig. 1). The median times to RBO were 198 and 222 days in the 8-mm and 10-mm groups, respectively. There was no difference in the survival time curve between the 8-mm and 10-mm groups (log-rank, P = 0.883). The median survival times for the 8-mm and 10-mm groups were 186 and 235 days, respectively.
Patient characteristics
Re-intervention for recurrent biliary obstruction
The 8-mm group comprised 37 patients (19 male and 18 median age, 75 years) and the 10-mm group comprised 35 (21 male and 14 female; median age, 78 years). The clinical characteristics of the two groups are summarized in Table 1. There were no significant inter-group differences in gender, age, performance status, diagnosis, Bismuth classification, administration of chemotherapy, total bilirubin level, biliary diameter and follow-up period.
Re-intervention for RBO was attempted in 16 of 17 patients in the 8-mm group and all 19 patients in the 10-mm group. Re-intervention was not attempted in one patient in the 8-mm group due to their poor condition. Endoscopic re-intervention was successful in 15 (94%) of 16 patients in the 8-mm group and all 16 patients (100%) in the 10-mm group (P = 0.457). We could not insert a revisionary plastic stent through the occluded SEMS in one
Statistical analysis The Mann–Whitney U-test was used for comparison of continuous variables, and the χ 2 test or the Fisher’s exact test for categorical variables. Time to RBO and survival time were estimated by Kaplan–Meier analysis, and curves were compared by the log-rank test. Statistical tests were two-sided and significance was defined as P < 0.05. All statistical analyses were performed using the IBM SPSS Statistics software, version 21.
J Hepatobiliary Pancreat Sci (2015) 22:396–401
399
Table 1 Clinical characteristics between the 8-mm and 10-mm groups 8-mm group Number Gender (Male/Female) Age (years), median (range) Performance status (0–1/≥2) Diagnosis Cholangiocarcinoma Gallbladder carcinoma Others Bismuth classification Type II Type III Type IV Chemotherapy Total bilirubin (mg/dL), median (range) Biliary diameter (mm), median (range) Follow-up period (month), median (range)
37 19/18 75 (58-93) 32/5
10-mm group 35 21/14 78 (55-92) 28/7
16 16 5
22 10 3
6 7 24 20 8.3 (0.6–25.7) 9.5 (6–13) 5.9 (0.7–34.1)
15 4 16 18 10.2 (0.8–33.4) 9 (5–15) 6.8 (0.4–22.4)
P-value
0.617 0.099 0.537 0.418
0.098
0.810 0.171 0.942 0.521
Biliary diameter: the diameter of the common bile duct distal to the biliary stricture Table 2 Outcomes between the 8-mm and 10-mm groups
Technical success at the first session Final technical success Functional success Complication Recurrent biliary obstruction Ingrowth Overgrowth Sludge Complications other than recurrent biliary obstruction Early Cholecystitis Pancreatitis Late Cholecystitis Cholangitis Liver abscess Median survival time (days)
patient in the 8-mm group, and this patient was subsequently treated by PTBD. Endoscopic bilateral revisionary stent insertion for RBO was successful in five (31%) of 16 patients in the 8-mm group and 13 (68%) of 19 patients in the 10-mm group. The success rate of endoscopic bilateral revisionary stent insertion was significantly greater in the 10-mm group compared to the 8-mm group (68% vs. 31%; P = 0.044). Re-intervention for RBO in both the 8-mm and 10-mm groups is presented in Table 3.
8-mm group
10-mm group
P value
36/37 (97%) 37/37 (100%) 36/37 (97%)
33/35 (94%) 35/35 (100%) 34/35 (97%)
0.609 1 1
17/37 (46%) 15 1 1 9/37 (24%) 2/37 (5%) 1 1 7/37 (19%) 1 4 2 198
19/35 (54%) 17 1 1 8/35 (23%) 3/35 (9%) 1 2 5/35 (14%) 1 1 3 222
0.637
0.896 0.949
0.754
0.883
Discussion The present study revealed clinical differences between use of an 8-mm and a 10-mm diameter SEMS in bilateral endoscopic SIS deployment for MHBO. The success rate of endoscopic bilateral revisionary stent insertion for RBO was significantly greater using a 10-mm compared to an 8-mm diameter SEMS (68% vs. 31%; P = 0.044). However, there were no significant differences between the 8-mm and 10-mm diameter SEMS in
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J Hepatobiliary Pancreat Sci (2015) 22:396–401
Fig. 1 There was no difference in the time to recurrent biliary obstruction between the 8-mm and 10-mm groups by Kaplan–Meier analysis (log-rank, P = 0.440)
terms of technical success, functional success, complication, time to RBO and survival time. The success rate of SIS deployment has been reported to range from 85% to 100% [8, 11, 12]. Kogure et al. [13] (Niti-S Large-cell D-type; Taewoong Medical), and Lee et al. [14] and Hwang et al. [15] (Niti-S Biliary Y-stent; Taewoong Medical) reported high technical success rates with large-cell stents in SIS deployment. The failure of insertion of second SEMS though the mesh is caused by insufficient expansion due to low radial force. Kogure et al. [17] developed modified large-cell stent with stronger radial force and a slimmer delivery system to achieve high technical success rate. Table 3 Re-intervention for recurrent biliary obstruction
Successful re-intervention Successful endoscopic re-intervention Successful endoscopic bilateral re-intervention Method of re-intervention Percutaneous Unilateral PTBD Endoscopic Bilateral stenting PS SEMS Unilateral stenting PS SEMS
8-mm group
10-mm group
P-value
16/16 (100%)
19/19 (100%)
1
15/16 (94%)
19/19 (100%)
0.457
5/16 (31%)
13/19 (68%)
0.044*
1/16 (6%) 1 15/16 (94%) 5/16 (31%) 5 0 10/16 (63%) 7 3
0 0 19/19 (100%) 13/19 (68%) 11 2 6/19 (32%) 4 2
* P
