Case report/series
Pseudoaneurysm caused by a self-expandable metal stent: a report of three cases
Authors
Yasuko Nezu1, So Nakaji2, Hiroyuki Fujii2, Eiji Ishii2, Nobuto Hirata2
Institutions
1 2
Department of Gastroenterology, Tohoku Rosai Hospital, Sendai, Miyagi, Japan Department of Gastroenterology, Kameda Medical Center, Kamogawa, Chiba, Japan
submitted 8. November 2013 accepted after revision 27. November 2013
We present three cases of pseudoaneurysm caused by self-expandable metal stents that formed arteriobiliary fistulas and caused hemobilia. Diagnoses were made on the basis of dynamic
computed tomography or angiography. One patient died because of bleeding and cholangitis, whereas the others were successfully treated by transarterial embolization.
Bibliography DOI http://dx.doi.org/ 10.1055/s-0033-1359178 Endoscopy 2014; 46: 248–251 © Georg Thieme Verlag KG Stuttgart · New York ISSN 0013-726X
Introduction
lus in the main portal vein. He died because of bleeding and cholangitis 40 days after SEMS placement. The autopsy report concluded that the arteriobiliary fistula was formed by a right hepatic artery pseudoaneurysm near the edge of the " Fig. 1). SEMS, and its rupture caused hemobilia (●
Corresponding author Yasuko Nezu, MD Department of Gastroenterology Tohoku Rosai Hospital 4-3-21 Dainohara Aoba-ku, Sendai Miyagi 981-8563 Japan Fax: +81-2-22754431 [email protected]
!
Because of its long patency, a self-expandable metal stent (SEMS) is frequently used to treat malignant biliary obstruction. However, serious adverse events associated with SEMSs have been reported, including pancreatitis, cholangitis, cholecystitis, liver abscess, and migration of the stent. A considerably less frequent adverse event is the formation of a pseudoaneurysm leading to hemobilia. Because bleeding may be fatal, correctly diagnosing the condition is critically important.
Case report !
Case 1 A 72-year-old man diagnosed with unresectable pancreatic cancer was admitted to our hospital. He received gemcitabine and cisplatin chemotherapy combined with radiotherapy (40 Gy) following the placement of a plastic stent for the management of biliary obstruction. On arrival, he was diagnosed with cholangitis, presumably due to occlusion of the plastic stent. The plastic stent was therefore replaced with a 60-mm covered SEMS (Wallstent; Boston Scientific, Natick, Massachusetts, USA) by endoscopic retrograde cholangiopancreatography. The patient developed melena 5 days after placement of the SEMS. Abdominal computed tomography (CT) revealed a high attenuation value in the common bile duct (CBD). Esophagogastroduodenoscopy (EGD) revealed a clot in the SEMS, and angiography revealed a right hepatic artery pseudoaneurysm adjacent to the SEMS tip. Embolization was considered but not performed because of a tumor embo-
Nezu Yasuko et al. Pseudoaneurysm caused by an SEMS … Endoscopy 2014; 46: 248–251
Case 2 An 82-year-old woman with hematemesis was admitted to our hospital. She had been diagnosed 20 days earlier with malignant biliary obstruction caused by pancreatic carcinoma. A 60-mm uncovered SEMS (Wallflex; Boston Scientific) was placed endoscopically. Dynamic CT revealed a small aneurysm near the lower part of the SEMS, and EGD revealed numerous clots in the SEMS. Angiography was performed, and a pseudoaneurysm was observed at the posterior superior pancreaticoduodenal artery (PSPD). The artery was successfully embolized, and the patient gradually " Fig. 2). recovered from anemia (●
Case 3 An 80-year-old man with gallbladder carcinoma was admitted for chemotherapy. However, treatment was suspended because he presented with hematemesis and melena the next day. Six months earlier, he had undergone endoscopic placement of a 60-mm uncovered SEMS (Wallflex) for treatment of a malignant biliary obstruction. Angiography suggested the presence of a right hepatic artery pseudoaneurysm near the SEMS edge. The artery was successfully embo" Fig. 3). lized (●
This document was downloaded for personal use only. Unauthorized distribution is strictly prohibited.
248
Fig. 1 Pseudoaneurysm in a 72-year-old man (Case 1). a Esophagogastroduodenoscopy (EGD) revealed a clot (arrows) in the self-expandable metal stent (SEMS) 5 days after placement. b Angiography revealed a pseudoaneurysm (arrow) of the right hepatic artery. The SEMS tip was adjacent to the
Fig. 2 Angiography revealed a pseudoaneurysm (arrow) at the posterior superior pancreaticoduodenal artery (Case 2).
artery. c The arteriobiliary fistula (arrow) formed by the right hepatic artery pseudoaneurysm near the SEMS edge. d Histopathological examination confirmed the presence of an arteriobiliary fistula (arrow).
Fig. 3 Angiography revealed a pseudoaneurysm at the right hepatic artery (arrow) (Case 3).
Nezu Yasuko et al. Pseudoaneurysm caused by an SEMS … Endoscopy 2014; 46: 248–251
249
This document was downloaded for personal use only. Unauthorized distribution is strictly prohibited.
Case report/series
Case report/series
Table 1
Type of stent, length, and diameter.
Authors, year [ref]
Age, years
Sex
Stent
Length of stent, mm
Diameter of stent, mm 10
Monroe et al., 1993 [1]
67
M
Uncoverd Wallstent
68
Murayama et al., 1997 [2]
54
M
Uncoverd Wallstent
N/A
N/A
Rai et al., 2003 [3]
47
F
N/A
N/A
N/A
Uncovered Wallflex
Watanabe et al., 2012 [4]
70
M
Hyun et al., 2013 [5]
61
M
80
10
50 to 100
10
65
F
51
M
10
79
M
65
M
72
M
Case 1
72
M
Covered Wallstent
60
10
Case 2
82
F
Uncovered Wallflex
60
10
Case 3
80
M
Uncovered Wallflex
60
10
ZA stent (n = 1) New Hanaro nitinol stent (n = 2) Niti-D stent (n = 1) BONASTENT (n = 2)*
10 10 10 10
n/a: not available. * Which stent was used for each patient ist not available in Hyun et al.
Table 2
Patient demographics, clinical manifestation, treatment, and prognosis.
Authors,
Age,
year [ref]
years
Monroe et al., 1993 [1])
67
Murayama et al., 1997 [2]
Sex
Antineoplastic
Duration from stent-
therapy
ing to bleeding
M
Chemotherapy
3 weeks
54
M
Chemotherapy
Rai et al., 2003 [3]
47
F
Watanabe et al., 2012 [4]
70
Hyun et al., 2013 [5]
Symptoms
Treatment for
Therapeutic
bleeding
effect
Prognosis
Melena
TAE
Success
No rebleeding, however died of colon cancer 9 weeks after stentitng
1 month
Hematemesis
TAE
Success
Discharged with no rebleeding
CRT
1 year
Melena
TAE
Success
Discharged with no rebleeding
M
Chemotherapy
9 months
Abdominal pain and jaundice
TAE
Success
Discharged with no rebleeding
61
M
N/A
152 days
Melena
TAE
Success
Discharged with no rebleeding
65
F
N/A
15 days
Melena
TAE
Success
No rebleeding; however, died of pulmonary edema 4 weeks after stenting
51
M
N/A
76 days
Melena
TAE
Success
No rebleeding
79
M
N/A
40 days
Melena
TAE
Success
Follow-up loss
65
M
N/A
15 days
Melena
TAE
Success
No rebleeding; however, died of sepsis
72
M
N/A
152 days
Hematemesis
Stent replacement and NBCA embolization
success
No rebleeding; however, died of cancer 6 months after stenting
Case 1
72
M
CRT
5 days
Hematemesis and melena
None
–
Died from bleeding and cholangitis 40 days after stenting
Case 2
82
F
None
20 days
Hematemesis
TAE
Success
Discharged with no rebleeding
Case 3
80
M
Chemotherapy
6 months
Hematemesis and melena
TAE
Success
Discharged with no rebleeding
CRT, chemoradiation therapy; N/A, not available; TAE, transarterial embolization.
Discussion !
Obstruction and migration are major adverse events of biliary stents. In contrast, formation of a pseudoaneurysm is a rare but serious adverse event [1 – 5]. The frequency of pseudoaneurysms caused by an SEMS is unclear. At our hospital, between April 2008 and March 2013, 248 patients received an SEMS for the management of malignant biliary obstruction and three (1.2 %) developed pseudoaneurysms.
CT and angiography of these patients revealed pseudoaneurysms at the right hepatic artery (Cases 1 and 3) and at the PSPD (Case 2). This anatomical difference may reflect different mechanisms responsible for causing pseudoaneurysms. In Cases 1 and 3, the right hepatic artery was near the SEMS edge, and was easily damaged by the stent that penetrated the wall of the CBD, causing a pseudoaneurysm and arteriobiliary fistula [2]. Even the looped wire ends of the Wallflex SEMS in Case 3 damaged the artery. Case 2 appeared to bleed from the PSPD adjacent to the middle of the SEMS and not at the edge. Therefore, the pressure exerted
Nezu Yasuko et al. Pseudoaneurysm caused by an SEMS … Endoscopy 2014; 46: 248–251
This document was downloaded for personal use only. Unauthorized distribution is strictly prohibited.
250
Case report/series
sible because the rupture can cause a severe hemorrhage that can be fatal. However, it is difficult to treat a right hepatic artery pseudoaneurysm if there is a tumor embolus in the main portal vein, as we had encountered in Case 1. Our experience indicates that it is important to consider that a pseudoaneurysm is an adverse event caused by an SEMS because timely diagnosis and treatment are required to prevent fatal hemorrhage. Competing interests: None
References 1 Monroe PS, Deeter WT, Rizk P. Delayed hemobilia secondary to expandable metal stent. Gastrointest Endosc 1993; 39: 190 – 191 2 Murayama M, Hase K, Watanabe C et al. [A case report of hemobilia and biliary obstruction caused by a pseudoaneurysm as a complication of percutaneous placement of Wallstent]. Article in Japanese. Nihon Shokakibyo Gakkai Zasshi 1997; 94: 139 – 142 3 Rai R, Rose J, Manas D. An unusual case of haemobilia. Eur J Gastroenterol Hepatol 2003; 15: 1357 – 1359 4 Watanabe M, Shiozawa K, Mimura T et al. Hepatic artery pseudoaneurysm after endoscopic biliary stenting for bile duct cancer. World J Radiol 2012; 4: 115 – 120 5 Hyun D, Park KB, Hwang JC et al. Delayed, life-threatening hemorrhage after self-expandable metallic biliary stent placement: clinical manifestations and endovascular treatment. Acta Radiol 2013; 54: 939 – 943 6 Carrasco CH, Wallace S, Charnsangavej C et al. Expandable biliary endoprosthesis: an experimental study. AJR Am J Roentgenol 1985; 145: 1279 – 1281 7 Tsuji Y, Yoshimura H, Uto F et al. Physical and histopathological assessment of the effects of metallic stents on radiation therapy. J Radiat Res 2007; 48: 477 – 483 8 Siersema PD, Hop WC, Dees J et al. Coated self-expanding metal stents versus latex prostheses for esophagogastric cancer with special reference to prior radiation and chemotherapy: a controlled, prospective study. Gastrointest Endosc 1998; 47: 113 – 120 9 Goodnight JEJr, Blaisdell FW. Hemobilia. Surg Clin North Am 1981; 61: 973 – 979
Nezu Yasuko et al. Pseudoaneurysm caused by an SEMS … Endoscopy 2014; 46: 248–251
This document was downloaded for personal use only. Unauthorized distribution is strictly prohibited.
on the tumor may have caused arterial wall necrosis, which subsequently led to bleeding [1]. Moreover, inflammation surrounding the bile duct and presence of adhesions between the metal stent and artery may have contributed to the formation of the pseudoaneurysm [3]. Our search of the literature uncovered only five reports of pseu" Table 1 and ● " Table 2). doaneurysms associated with SEMS (● Most of these reports state that bleeding occurred from 2 weeks to 1 year after the SEMS was placed. However, we report here that a pseudoaneurysm can occur after only 5 days. Carrasco et al. [6] examined five adult mongrel dogs to assess the tissue reactions induced by expandable stents placed in the bile ducts. The stents of round stainless-steel wire with eight zigzag bends were constructed. Upon microscopic examination, they observed sloughed, necrotic mucosa adjacent to the sites of compression in contact with the stent wire, and the severity of the injury was not related to the length of time that the stents were in place. They also reported that the submucosa showed chronic inflammatory infiltrates in all cases with varying degrees of fibrosis and were more pronounced in animals with stents that were in place the longest. Furthermore, Tsuji et al. reported infiltration of inflammatory cells and fibrosis in patients with an SEMS who underwent external irradiation [7]. These changes were marked in animals treated with external irradiation after SEMS placement, suggesting that radiotherapy administered to patients with SEMS may damage the bile duct. Prior radiation, chemotherapy, or both may increase the risk of device-related adverse events for the same reasons that Siersema et al. [8] reported for patients with esophagogastric cancer. What is the best approach for early detection? Goodnight et al. [9] recommended that CT followed by angiography can be diagnostic as well as therapeutic. At present, using the early arterialphase multidetector row CT system may be more effective. Embolization by angiography is the first treatment of choice to repair a ruptured pseudoaneurysm and is needed as soon as pos-
251
Copyright of Endoscopy is the property of Georg Thieme Verlag Stuttgart and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use.
Pseudoaneurysm caused by a self-expandable metal stent: a report of three cases
Authors
Yasuko Nezu1, So Nakaji2, Hiroyuki Fujii2, Eiji Ishii2, Nobuto Hirata2
Institutions
1 2
Department of Gastroenterology, Tohoku Rosai Hospital, Sendai, Miyagi, Japan Department of Gastroenterology, Kameda Medical Center, Kamogawa, Chiba, Japan
submitted 8. November 2013 accepted after revision 27. November 2013
We present three cases of pseudoaneurysm caused by self-expandable metal stents that formed arteriobiliary fistulas and caused hemobilia. Diagnoses were made on the basis of dynamic
computed tomography or angiography. One patient died because of bleeding and cholangitis, whereas the others were successfully treated by transarterial embolization.
Bibliography DOI http://dx.doi.org/ 10.1055/s-0033-1359178 Endoscopy 2014; 46: 248–251 © Georg Thieme Verlag KG Stuttgart · New York ISSN 0013-726X
Introduction
lus in the main portal vein. He died because of bleeding and cholangitis 40 days after SEMS placement. The autopsy report concluded that the arteriobiliary fistula was formed by a right hepatic artery pseudoaneurysm near the edge of the " Fig. 1). SEMS, and its rupture caused hemobilia (●
Corresponding author Yasuko Nezu, MD Department of Gastroenterology Tohoku Rosai Hospital 4-3-21 Dainohara Aoba-ku, Sendai Miyagi 981-8563 Japan Fax: +81-2-22754431 [email protected]
!
Because of its long patency, a self-expandable metal stent (SEMS) is frequently used to treat malignant biliary obstruction. However, serious adverse events associated with SEMSs have been reported, including pancreatitis, cholangitis, cholecystitis, liver abscess, and migration of the stent. A considerably less frequent adverse event is the formation of a pseudoaneurysm leading to hemobilia. Because bleeding may be fatal, correctly diagnosing the condition is critically important.
Case report !
Case 1 A 72-year-old man diagnosed with unresectable pancreatic cancer was admitted to our hospital. He received gemcitabine and cisplatin chemotherapy combined with radiotherapy (40 Gy) following the placement of a plastic stent for the management of biliary obstruction. On arrival, he was diagnosed with cholangitis, presumably due to occlusion of the plastic stent. The plastic stent was therefore replaced with a 60-mm covered SEMS (Wallstent; Boston Scientific, Natick, Massachusetts, USA) by endoscopic retrograde cholangiopancreatography. The patient developed melena 5 days after placement of the SEMS. Abdominal computed tomography (CT) revealed a high attenuation value in the common bile duct (CBD). Esophagogastroduodenoscopy (EGD) revealed a clot in the SEMS, and angiography revealed a right hepatic artery pseudoaneurysm adjacent to the SEMS tip. Embolization was considered but not performed because of a tumor embo-
Nezu Yasuko et al. Pseudoaneurysm caused by an SEMS … Endoscopy 2014; 46: 248–251
Case 2 An 82-year-old woman with hematemesis was admitted to our hospital. She had been diagnosed 20 days earlier with malignant biliary obstruction caused by pancreatic carcinoma. A 60-mm uncovered SEMS (Wallflex; Boston Scientific) was placed endoscopically. Dynamic CT revealed a small aneurysm near the lower part of the SEMS, and EGD revealed numerous clots in the SEMS. Angiography was performed, and a pseudoaneurysm was observed at the posterior superior pancreaticoduodenal artery (PSPD). The artery was successfully embolized, and the patient gradually " Fig. 2). recovered from anemia (●
Case 3 An 80-year-old man with gallbladder carcinoma was admitted for chemotherapy. However, treatment was suspended because he presented with hematemesis and melena the next day. Six months earlier, he had undergone endoscopic placement of a 60-mm uncovered SEMS (Wallflex) for treatment of a malignant biliary obstruction. Angiography suggested the presence of a right hepatic artery pseudoaneurysm near the SEMS edge. The artery was successfully embo" Fig. 3). lized (●
This document was downloaded for personal use only. Unauthorized distribution is strictly prohibited.
248
Fig. 1 Pseudoaneurysm in a 72-year-old man (Case 1). a Esophagogastroduodenoscopy (EGD) revealed a clot (arrows) in the self-expandable metal stent (SEMS) 5 days after placement. b Angiography revealed a pseudoaneurysm (arrow) of the right hepatic artery. The SEMS tip was adjacent to the
Fig. 2 Angiography revealed a pseudoaneurysm (arrow) at the posterior superior pancreaticoduodenal artery (Case 2).
artery. c The arteriobiliary fistula (arrow) formed by the right hepatic artery pseudoaneurysm near the SEMS edge. d Histopathological examination confirmed the presence of an arteriobiliary fistula (arrow).
Fig. 3 Angiography revealed a pseudoaneurysm at the right hepatic artery (arrow) (Case 3).
Nezu Yasuko et al. Pseudoaneurysm caused by an SEMS … Endoscopy 2014; 46: 248–251
249
This document was downloaded for personal use only. Unauthorized distribution is strictly prohibited.
Case report/series
Case report/series
Table 1
Type of stent, length, and diameter.
Authors, year [ref]
Age, years
Sex
Stent
Length of stent, mm
Diameter of stent, mm 10
Monroe et al., 1993 [1]
67
M
Uncoverd Wallstent
68
Murayama et al., 1997 [2]
54
M
Uncoverd Wallstent
N/A
N/A
Rai et al., 2003 [3]
47
F
N/A
N/A
N/A
Uncovered Wallflex
Watanabe et al., 2012 [4]
70
M
Hyun et al., 2013 [5]
61
M
80
10
50 to 100
10
65
F
51
M
10
79
M
65
M
72
M
Case 1
72
M
Covered Wallstent
60
10
Case 2
82
F
Uncovered Wallflex
60
10
Case 3
80
M
Uncovered Wallflex
60
10
ZA stent (n = 1) New Hanaro nitinol stent (n = 2) Niti-D stent (n = 1) BONASTENT (n = 2)*
10 10 10 10
n/a: not available. * Which stent was used for each patient ist not available in Hyun et al.
Table 2
Patient demographics, clinical manifestation, treatment, and prognosis.
Authors,
Age,
year [ref]
years
Monroe et al., 1993 [1])
67
Murayama et al., 1997 [2]
Sex
Antineoplastic
Duration from stent-
therapy
ing to bleeding
M
Chemotherapy
3 weeks
54
M
Chemotherapy
Rai et al., 2003 [3]
47
F
Watanabe et al., 2012 [4]
70
Hyun et al., 2013 [5]
Symptoms
Treatment for
Therapeutic
bleeding
effect
Prognosis
Melena
TAE
Success
No rebleeding, however died of colon cancer 9 weeks after stentitng
1 month
Hematemesis
TAE
Success
Discharged with no rebleeding
CRT
1 year
Melena
TAE
Success
Discharged with no rebleeding
M
Chemotherapy
9 months
Abdominal pain and jaundice
TAE
Success
Discharged with no rebleeding
61
M
N/A
152 days
Melena
TAE
Success
Discharged with no rebleeding
65
F
N/A
15 days
Melena
TAE
Success
No rebleeding; however, died of pulmonary edema 4 weeks after stenting
51
M
N/A
76 days
Melena
TAE
Success
No rebleeding
79
M
N/A
40 days
Melena
TAE
Success
Follow-up loss
65
M
N/A
15 days
Melena
TAE
Success
No rebleeding; however, died of sepsis
72
M
N/A
152 days
Hematemesis
Stent replacement and NBCA embolization
success
No rebleeding; however, died of cancer 6 months after stenting
Case 1
72
M
CRT
5 days
Hematemesis and melena
None
–
Died from bleeding and cholangitis 40 days after stenting
Case 2
82
F
None
20 days
Hematemesis
TAE
Success
Discharged with no rebleeding
Case 3
80
M
Chemotherapy
6 months
Hematemesis and melena
TAE
Success
Discharged with no rebleeding
CRT, chemoradiation therapy; N/A, not available; TAE, transarterial embolization.
Discussion !
Obstruction and migration are major adverse events of biliary stents. In contrast, formation of a pseudoaneurysm is a rare but serious adverse event [1 – 5]. The frequency of pseudoaneurysms caused by an SEMS is unclear. At our hospital, between April 2008 and March 2013, 248 patients received an SEMS for the management of malignant biliary obstruction and three (1.2 %) developed pseudoaneurysms.
CT and angiography of these patients revealed pseudoaneurysms at the right hepatic artery (Cases 1 and 3) and at the PSPD (Case 2). This anatomical difference may reflect different mechanisms responsible for causing pseudoaneurysms. In Cases 1 and 3, the right hepatic artery was near the SEMS edge, and was easily damaged by the stent that penetrated the wall of the CBD, causing a pseudoaneurysm and arteriobiliary fistula [2]. Even the looped wire ends of the Wallflex SEMS in Case 3 damaged the artery. Case 2 appeared to bleed from the PSPD adjacent to the middle of the SEMS and not at the edge. Therefore, the pressure exerted
Nezu Yasuko et al. Pseudoaneurysm caused by an SEMS … Endoscopy 2014; 46: 248–251
This document was downloaded for personal use only. Unauthorized distribution is strictly prohibited.
250
Case report/series
sible because the rupture can cause a severe hemorrhage that can be fatal. However, it is difficult to treat a right hepatic artery pseudoaneurysm if there is a tumor embolus in the main portal vein, as we had encountered in Case 1. Our experience indicates that it is important to consider that a pseudoaneurysm is an adverse event caused by an SEMS because timely diagnosis and treatment are required to prevent fatal hemorrhage. Competing interests: None
References 1 Monroe PS, Deeter WT, Rizk P. Delayed hemobilia secondary to expandable metal stent. Gastrointest Endosc 1993; 39: 190 – 191 2 Murayama M, Hase K, Watanabe C et al. [A case report of hemobilia and biliary obstruction caused by a pseudoaneurysm as a complication of percutaneous placement of Wallstent]. Article in Japanese. Nihon Shokakibyo Gakkai Zasshi 1997; 94: 139 – 142 3 Rai R, Rose J, Manas D. An unusual case of haemobilia. Eur J Gastroenterol Hepatol 2003; 15: 1357 – 1359 4 Watanabe M, Shiozawa K, Mimura T et al. Hepatic artery pseudoaneurysm after endoscopic biliary stenting for bile duct cancer. World J Radiol 2012; 4: 115 – 120 5 Hyun D, Park KB, Hwang JC et al. Delayed, life-threatening hemorrhage after self-expandable metallic biliary stent placement: clinical manifestations and endovascular treatment. Acta Radiol 2013; 54: 939 – 943 6 Carrasco CH, Wallace S, Charnsangavej C et al. Expandable biliary endoprosthesis: an experimental study. AJR Am J Roentgenol 1985; 145: 1279 – 1281 7 Tsuji Y, Yoshimura H, Uto F et al. Physical and histopathological assessment of the effects of metallic stents on radiation therapy. J Radiat Res 2007; 48: 477 – 483 8 Siersema PD, Hop WC, Dees J et al. Coated self-expanding metal stents versus latex prostheses for esophagogastric cancer with special reference to prior radiation and chemotherapy: a controlled, prospective study. Gastrointest Endosc 1998; 47: 113 – 120 9 Goodnight JEJr, Blaisdell FW. Hemobilia. Surg Clin North Am 1981; 61: 973 – 979
Nezu Yasuko et al. Pseudoaneurysm caused by an SEMS … Endoscopy 2014; 46: 248–251
This document was downloaded for personal use only. Unauthorized distribution is strictly prohibited.
on the tumor may have caused arterial wall necrosis, which subsequently led to bleeding [1]. Moreover, inflammation surrounding the bile duct and presence of adhesions between the metal stent and artery may have contributed to the formation of the pseudoaneurysm [3]. Our search of the literature uncovered only five reports of pseu" Table 1 and ● " Table 2). doaneurysms associated with SEMS (● Most of these reports state that bleeding occurred from 2 weeks to 1 year after the SEMS was placed. However, we report here that a pseudoaneurysm can occur after only 5 days. Carrasco et al. [6] examined five adult mongrel dogs to assess the tissue reactions induced by expandable stents placed in the bile ducts. The stents of round stainless-steel wire with eight zigzag bends were constructed. Upon microscopic examination, they observed sloughed, necrotic mucosa adjacent to the sites of compression in contact with the stent wire, and the severity of the injury was not related to the length of time that the stents were in place. They also reported that the submucosa showed chronic inflammatory infiltrates in all cases with varying degrees of fibrosis and were more pronounced in animals with stents that were in place the longest. Furthermore, Tsuji et al. reported infiltration of inflammatory cells and fibrosis in patients with an SEMS who underwent external irradiation [7]. These changes were marked in animals treated with external irradiation after SEMS placement, suggesting that radiotherapy administered to patients with SEMS may damage the bile duct. Prior radiation, chemotherapy, or both may increase the risk of device-related adverse events for the same reasons that Siersema et al. [8] reported for patients with esophagogastric cancer. What is the best approach for early detection? Goodnight et al. [9] recommended that CT followed by angiography can be diagnostic as well as therapeutic. At present, using the early arterialphase multidetector row CT system may be more effective. Embolization by angiography is the first treatment of choice to repair a ruptured pseudoaneurysm and is needed as soon as pos-
251
Copyright of Endoscopy is the property of Georg Thieme Verlag Stuttgart and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use.
