Self-expandable metal stents for malignant gastric outlet obstruction: A pooled analysis of prospective literature

Table 1 Literature table

Ref.	Design, patients,indication	No. of stents1, biliary obstruction	Stent type	Technicalsuccess	ClinicalSuccess, definition	Adverse events	Stent dysfunction	Stent patency,median (range)	Survival, follow-up,median (range)
Maetani et al[15] 2014 Japan	RCT, n = 62 GC: n = 27 PC: n = 26 BDC: n = 7 OT: n = 2	No. of stents: 1: n = 58 2: n = 4 Biliary drainage: Yes: n = 24 No: n = 38	UCSEMS: -Niti-S PCSEMS: -Niti-S Comvi	100% (62/62)	90.3% (56/62) -UCSEMS: 93.5% (29/31) -PCSEMS: 87.1% (27/31) ≥ 1 grade of improvement in GOOSS at any visit compared to baseline	Perforation: 1.6% (1/62) -PCSEMS: 3.2% (1/31) Major bleeding: 1.6% (1/62) -UCSEMS: 3.2% (1/31)	Overall: 22.6% (14/62) -UCSEMS: 29.0% (9/31) -PCSEMS: 16.1% (5/31) Re-obstruction: 9.7% (6/62); -UCSEMS: 19.4% (6/31) -PCSEMS: 0% (0/31) Migration: 4.8% (3/62) -UCSEMS: 3.2% (1/31) -PCSEMS: 6.5% (2/31) Fracture: 4.8% (3/62) -UCSEMS: 6.5% (2/31) -PCSEMS: 3.2% (1/31) Insufficient expansion: 3.2% (2/62) -UCSEMS: 0% (0/31) -PCSEMS: 6.5% (2/31)	PCSEMS: 68 d UCSEMS: 88 d (P = 0.70)	PCSEMS: 73 d UCSEMS: 93 d (P = 0.34) FU: 83.5 d; until death
Shi et al[16] 2014 China	RCT, n = 65 GC: n = 65	No. of stents: 1: n = 65 Biliary obstruction: NR	UCSEMS: -Micro-Tech PCSEMS: -Micro-Tech (tailored cup- or funnel-shaped)	96.9% (63/65) -UCSEMS: 96.9% (31/32) -PCSEMS: 97.0% (32/33)	93.7% (59/63) -UCSEMS: 93.5% (29/31) -PCSEMS: 93.8% (30/32) Resolution of symptoms and the ability to restart a low residue diet after stent placement	Mild bleeding: 20% (13/65) -UCSEMS: 6.3% (2/32) -PCSEMS: 33.3% (11/33) Mild abdominal pain: 21.5% (14/65) -UCSEMS: 3.1% (1/32) -PCSEMS: 39.4% (13/33)	Overall: 18.5% (12/65) -UCSEMS: 25% (8/32) -PCSEMS: 12.1% (4/33) Re-obstruction: 12.3% (8/65) -UCSEMS: 21.9% (7/32) -PCSEMS: 3.0% (1/33) Migration: 3.1% (2/65) -UCSEMS: 0% -PCSEMS: 6.1% (2/33) Food impaction: 3.1% (2/65) -UCSEMS: 3.1% (1/32) -PCSEMS: 3.0% (1/33)	NR	Tailored PCSEMS: mean 231 (30-387) d Standard UCSEMS: mean 212 (43-267) d FU: until death
Tringali et al[1] 2014 Italy, Netherlands, Australia, Czech Republic, Canada, United States	Pros, n = 108 PC: n = 58 GC: n = 14 BDC: n = 7 GBC: n = 7 DC: n = 5 APC: n = 3 OT: n = 14	No. of stents: 1: n = 106 2: n = 2 Biliary obstruction: Yes: n = 56 No: n = 52	UCSEMS: -Evolution	99.1% (107/108)	84.5% (82/97) Relief of symptoms and/or improvement of oral intake at 14 d	Overall: 32.4% (35/108), including 19.4% (21/108) stent-related Perforation: 1.9% (2/108) Bleeding: 4.6% (5/108) No intervention required Abdominal pain: 1.9% (2/108) Other GI events: 15.7% (17/108)	Overall: 17.6% (19/108) Re-obstruction: 15.7% (17/108) Migration: 1.9% (2/108)	Estimated patency rates: -At 14 d: 94.6% (88/93) -At 60 d: 86.2% -At 180 d: 63.4%	Patients who completed 6 mo follow-up (11/108): 182 (178-195) d Patients who died before 6 mo follow-up: 52 (9-180) d FU: until 6 mo, death or re-intervention
Shi et al[17] 2013 China	Pros, n = 37 GC: n = 37	No. of stents: 1: n = 35 2: n = 2 Biliary obstruction: NR	PCSEMS: -Micro-Tech (cup- or funnel-shaped)	97.3% (36/37)	94.4% (34/36) Relief of obstructive symptoms	Mild bleeding: 40.5% (15/37) Major hemorrhage: 2.7% (1/37) Abdominal pain: 37.8% (14/37) Perforation: 0%	Overall: 5.4% (2/37) Food impaction: 5.4% (2/37) Migration: 0% Re-obstruction: 0%	NR	Mean 232 (28-387) d FU: until death
van den Berg et al[18] 2013 Netherlands	Pros, n = 46 PC: n = 25 GC: n = 5 BDC: n = 7 DC: n = 3 GBC: n = 1 OT: n = 5	No. of stents: 1: n = 43 2: n = 3 Biliary drainage: Yes: n = 34 No: n = 12	UCSEMS: -Evolution	89.1% (41/46)	71.7% (33/46) Improvement of GOOSS of ≥ 1 point and/or relief of symptoms after 1 wk	Overall: 56.5% (26/46) Procedure-related: -Perforation: 2.2% (1/46) -Pancreatitis: 2.2% (1/46) -Pain: 2.2% (1/46) -Cholangitis: 2.2% (1/46) Non procedure-related: -Acute abdomen: 2.2% (1/46) -Cholangitis: 13.0% (6/46) -Jaundice: 4.3% (2/46) -Anemia: 8.7% (4/46) -Pneumonia: 2.2% (1/46) -CVA: 6.5% (3/46) -Ascites: 4.3% (2/46) -Motility disorder: 10.9% (5/46)	Overall: 30.4% (14/46) Re-obstruction: 19.6% (9/46) Stent compression: 4.3% (2/46) Migration: 4.3% (2/46) Food impaction: 2.2% (1/46)	67% for up to 395 d, accounting for death unrelated to stent	87 (IQR 35-237) d FU: until death
Costamagna et al[2] 2012 Italy, Czech Republic, South Africa, Canada, Sweden, Brazil, France, Germany, Finland, Spain	Pros, n = 202 PC: n = 104 GC: n = 37 DC: n = 18 BDC: n = 12 GBC: n = 12 APC: n = 2 OT: n = 17	No. of stents: 1: n = 192 2: n = 10 Biliary drainage: Yes: n = 127 No: n = 75	UCSEMS: -WallFlex	98.0% (198/202)	91% (177/195) Relief of obstruction as measured by oral intake	Overall: 20.3% (41/202) Transient periprocedural symptoms: 3.5% (7/202) Bleeding: 3.0% (6/202) -Major: 2.0% (4/202) -Self-limiting: 1.0% (2/202) Perforation: 0.5% (1/202)	Re-obstruction: 12.4% (25/202) Migration: 1.5% (3/202) Food impaction: 0.5% (1/202)	Maintaining GOOS score of 2-3 (n = 149): 91 d (95%CI: 87-182)	Survival rate at 9 mo: 28.2% FU: until 9 mo
Isayama et al[19] 2012 Japan	Pros, n = 50 PC: n = 26 GC: n = 14 BDC: n = 9 OT: n = 1	No. of stents: NR Biliary obstruction: Yes: n = 30 No: n = 20	PCSEMS: -ComVi Niti-S (modified)	100% (50/50)	90% (45/50) Relief of symptoms or improvement in GOOSS after 3 d	Cholangitis: 2% (1/50) Mild pancreatitis: 2% (1/50) Minor perforation: 2% (1/50)	Overall: 18% (9/50) Re-obstruction: 10% (5/50) Stent migration: 6% (3/50) Insufficient expansion: 2% (1/50)	Mean ± SD: 149.8 ± 8.9 d	106 d FU: NR
Moura et al[20] 2012 Brazil	Pros, n = 15 PC: n = 9 GC: n = 3 BDC: n = 1 OT: n = 2	No. of stents: NR Biliary drainage: Yes: 8 No: 7	UCSEMS: -WallFlex	100% (15/15)	80% (12/15) Improvement of GOOSS at 15 d	Removal of foreign body: 7% (1/15)	Re-obstruction: 13% (2/15) Migration: 13% (2/15)	Mean time to first failure to maintain GOOS 2-3: 2.35 mo	NR FU: until 180 d
Dolz et al[21] 2011 Spain	Pros, n = 77 GC: n = 29 PC: n = 20 DC: n = 5 GBC: n = 4 BDC: n = 3 APC: n = 3 OT: n = 6 Unk: n = 7	No. of stents: NR Biliary obstruction: NR	UCSEMS: -WallFlex -Wallstent -Ultraflex	92.2% (71/77)	81.7% (58/71) GOOSS 2-3 post-stenting	Pneumonia: 1.4% (1/71) Central catheter infection: 1.4% (1/71) Self-limiting bleeding: 7.0% (5/71) Late perforation: 2.8% (2/71) Intense pain: 2.8% (2/71)	Re-obstruction: 14.1% (10/71) Insufficient expansion: 4.2% (3/71)	NR	91 (9-552) d FU: NR
Kim et al[22] 2011 South Korea	Pros, n = 50 GC: n = 31 PC: n = 11 BDC: n = 6 GBC: n = 2	No. of stents: NR Biliary drainage: Yes: n = 17 No: n = 33	PCSEMS: -Niti-S Comvi	100% (50/50)	88% (44/50) Ability to tolerate oral food intake without vomiting	Hyperamylasemia: 2% (1/50) Obstructive jaundice: 10% (5/50)	Re-intervention rate: 28% (14/50) Stent migration: 10% (5/50) Re-obstruction: 8% (4/50) Stent compression: 10% (5/50)	Mean 92 (4-238) d	Mean 110 (30-290) d FU: until death
van Hooft et al[23] 2011 Netherlands	Pros, n = 52 PC: n = 32 GC: n = 7 BDC: n = 10 APC: n = 1 DC: n = 1 OT: n = 1	No. of stents: 1: n = 45 2: n = 7 Biliary obstruction: NR	UCSEMS: -Niti-S D-Weave	96.2% (50/52)	76.9% (40/52) Relief of symptoms or improvement of GOOSS after 1 wk	Overall complications: 23.1% (12/52) Procedure-related: -Pain: 7.7% (4/52) -Cholangitis: 1.9% (1/52) Non procedure-related: -Anemia: 3.8% (2/52) -Pneumonia: 1.9% (1/52) -Ascites: 1.9% (1/52) -Gastroenteritis: 1.9% (1/52) -Peritonitis carcinomatosis: 1.9% (1/52) -Bacteremia: 1.9% (1/52)	Overall: 25% (13/52) Re-obstruction: 21.2% (11/52) Migration: 3.8% (2/52)	75% for up to 190 d, accounting for death unrelated to stent	82 (IQR 31-135) d FU: until death
Jeurnink et al[9], 2010 Netherlands	RCT, n = 21 PC: n = 15 GC: n = 2 DC: n = 3 OT: n = 1	No. of stents: 1: n = 17 2: n = 4 Biliary drainage: Yes: n = 12 No: n = 9	UCSEMS: -WallFlex	95.2% (20/21)	85.7% (18/21); persistent obstruction within 4 wk in 3/21	Bacterial infection: 4.8% (1/21) Delayed gastric emptying: 14.3% (3/21) Jaundice post stent: 19.0% (4/21) Cholangitis: 4.8% (1/21)	Overall: 19.0% (4/21) Re-obstruction: 9.5% (2/21) Migration: 4.8% (1/21) Food obstruction: 9.5% (2/21) Re-intervention rate: 33% (7/21)	NR	56 d FU: until death
Kim et al[24] 2010 South Korea	RCT, n = 80 GC: n = 80	No. of stents: NR Biliary obstruction: NR	PCSEMS: -Niti-S pyloric -Niti-S Comvi UCSEMS: -Wallstent -WallFlex	100% (80/80)	92.5% (74/80) -PCSEMS: 95% (38/40) -UCSEMS: 90% (36/40) Relief of symptoms or improvement of GOOSS at 3 d	Perforation by migrated stent: 1.5% (1/67) -PCSEMS: 3.2% (1/31) Intestinal obstruction by migrated stent fragment after fracture: 1.5% (1/67) -PCSEMS: 3.2% (1/31)	Re-obstruction: 25.4% (17/67) -PCSEMS: 3.2% (1/31) -UCSEMS: 44.4% (16/36) Migration: 19.4% (13/67) -PCSEMS: 32.3% (10/31) -UCSEMS: 8.3% (3/36) Fracture: 4.5% (3/67) -PCSEMS: 9.7% (3/31) Stent collapse: 1.5% (1/67) -PCSEMS: 3.2% (1/31)	PCSEMS: 14 wk (95%CI: 8.9-19.1) UCSEMS: 13 wk (95%CI: 9.5-16.5)	PCSEMS: 26 wk (95%CI: 11-41) UCSEMS: 19 wk (95%CI: 10-28) FU: until 8 wk
Maetani et al[25] 2010 Japan	Pros, n = 53 GC: n = 29 PC: n = 14 BDC: n = 5 OT: n = 5	No. of stents: 1: n = 44 2: n = 9 Biliary drainage: Yes: n = 17 No: n = 36	UCSEMS: -Niti-S	98.1% (52/53)	94.3% (50/53) Ability to tolerate oral intake without vomiting	Procedure-related perforation: 1.9% (1/53) Obstructive jaundice: 1.9% (1/53) Major bleeding: 1.9% (1/53)	Overall: 18.9% (10/53) Insufficient expansion: 3.8% (2/53) Re-obstruction: 13.2% (7/53) Food impaction: 1.9% (1/53) Fracture: 1.9% (1/53) Re-intervention rate: 20.8% (11/53)	NR	88 d FU: until death
Shaw et al[26], 2010 South Africa	Pros, n = 70 GC: n = 19 PC: n = 34 GBC: n = 5 DC: n = 2 BDC: n = 3 OT: n = 7	No. of stents: NR Biliary drainage: Yes: n = 35 No: n = 35	UCSEMS: -WallFlex	92.9% (65/70)	88.6% (62/70) Resumption of intake that enabled the patient to return home independent of nutritional support	Minor bleeding: 2.9% (2/70) Perforation: 0%	Overall: 7.1% (5/70) Re-obstruction: 4.3% (3/70) Insufficient expansion: 1.4% (1/70) Stent migration: 1.4% (1/70)	NR	1.8 (0.1-19) mo FU: 54 (range 1-570) d; until death
Havemann et al[27] 2009 Denmark	Pros, n = 45 PC: n = 30 GC: n = 5 OT: n = 10	No. of stents: NR Biliary drainage: Yes: n = 11 No: n = 34	UCSEMS: -Hanaro	91.1% (41/45)	63.4% (26/41) Improvement in GOOSS by ≥ 1 point	Procedure-related perforation: 4.4% (2/45) Biliary obstruction: 17.8% (8/45)	Re-obstruction: 8.9% (4/45) Migration: 6.7% (3/45) Re-intervention rate: 13.3% (6/45)	NR	Mean 121 (95%CI: 62-181) d FU: NR
Lee et al[5] 2009 South Korea	Pros, n = 154 GC: n = 122 PC: n = 19 GBC: n = 3 BDC: n = 3 APC: n = 4 DC: n = 2 OT: n = 1	No. of stents: NR Biliary obstruction: NR	UCSEMS: -Niti-S PCSEMS: -Niti-S	100% (154/154)	97.4% (150/154) -PCSEMS: 98.6% (69/70) -UCSEMS: 96.4% (81/84) Relief of vomiting and resumption of diet	No procedure-related complications	Migration: 7.8% (12/154) -PCSEMS: 17.1% (12/70) -UCSEMS: 0% Re-obstruction: 13.6% (21/154) -PCSEMS: 7.1% (5/70) -UCSEMS: 19.0% (16/84) Re-intervention rate: 17.5% (27/154) -PCSEMS: 21.4% (15/70) -UCSEMS: 14.3% (12/84)	UCSEMS: 73 (95%CI: 44-102) d PCSEMS: 75 (95%CI: 47-134) d	UCSEMS: 108 (95%CI: 60-151) d PCSEMS: 115 (95%CI: 80-156) d FU: until death
Piesman et al[28] 2009 United States	Pros, n = 43 PC: n = 21 GC: n = 8 BDC: n = 3 GBC: n = 1 OT: n = 9 Unk: n = 1	No. of stents: 1: n = 39 2: n = 4 Biliary drainage: Yes: n = 23 No: n = 20	UCSEMS: -WallFlex	95.3% (41/43)	81.4% (35/43) GOOSS increase of ≥ 1 point	Duodenal perforation: 4.7% (2/43) Vomiting: 9.3% (4/43) Cholangitis: 2.3% (1/43) Hemorrhage: 2.3% (1/43) -Endoscopy performed Nausea: 2.3% (1/43) Sepsis: 2.3% (1/43)	Overall: 18.6% (8/43) Re-obstruction: 9.3% (4/43) Malposition: 2.3% (1/43) Stent collapse: 2.3% (1/43) Incomplete expansion: 4.7% (2/43) Occlusion by jejunal wall: 2.3% (1/43) Migration: 0%	GOOS score increase of ≥ 1 until death or end of follow-up: 45% (95%CI: 27-74)	49 d; At 24 wk: 44.1% (19/43) FU: until 24 wk
Van Hooft et al[29] 2009 Netherlands	Pros, n = 51 PC: n = 35 GC: n = 2 BDC: n = 3 DC: n = 3 GBC: n = 2 APC: n = 1 OT: n = 5	No. of stents: 1: n = 48 2: n = 3 Biliary drainage: Yes: n = 38 No: n = 13	UCSEMS: -WallFlex	98.0% (50/51)	84.3% (43/51) Relief of symptoms or improvement of GOOSS after 1 wk	Motility dysfunction: 3.9% (2/51) Intermittent pain: 3.9% (2/51) Cholangitis: 5.9% (3/51) Major bleeding: 3.9% (2/51)	Re-obstruction: 11.8% (6/51) Migration: 2.0% (1/51)	307 d; 75% functional at 135 d, 25% functional at 470 d	62 d; 75% alive at 35 d, 25% alive at 156 d FU: until death

¹Number of enteral stents inserted at the initial procedure. Pros: Prospective; Retro: Retrospective; RCT: Randomized controlled trial; GC: Gastric cancer; PC: Pancreatic cancer; BDC: Bile duct cancer; GBC: Gallbladder cancer; APC: Ampullary cancer; DC: Duodenal cancer; OT: Other malignancies; UCSEMS: Uncovered self-expandable metal stent; PCSEMS: Partially covered self-expandable metal stent; FU: Follow-up; GOOSS: Gastric outlet obstruction severity score; NR: Not reported; IQR: Interquartile range; GI: Gastrointestinal; CVA: Cerebrovascular accident.

Table 2 Baseline characteristics n (%)

Patients with MGOO	1281 (100)
Cause of MGOO
Gastric cancer	536 (41.8)
Pancreatic cancer	479 (37.4)
Bile duct cancer	79 (6.2)
Duodenal cancer	42 (3.3)
Gallbladder cancer	37 (2.9)
Ampullary cancer	14 (1.1)
Other malignancies	86 (6.7)
Unknown	8 (0.6)
Biliary obstruction1
Yes	432 (52.9)
No	384 (47.1)
Stent type
Uncovered SEMS	970 (75.7)
Partially covered SEMS	311 (24.3)
No. of enteral stents inserted at initial procedure2
Single stent	692 (93.5)
Two stents	48 (6.5)

¹Total group: n = 816, no data of 465 patients;

²Total group: n = 740, no data of 541 patients. MGOO: Malignant gastric outlet obstruction; SEMS: Self-expandable metal stent.

Table 3 Technical and clinical success of enteral stent placement n (%)

	Overall (n = 1281)	UCSEMS (n = 970)	PCSEMS (n = 311)	P value1
Technical success	1246 (97.3)	937 (96.6)	309 (99.4)	0.008
Reasons for technical failure
Inability to pass guidewire	13 (1.0)	13 (1.3)	0
Looping/buckling of delivery system	2 (0.2)	0	2 (0.6)
Stent malposition	1 (0.1)	1 (0.1)	0
Stent migration during deployment	4 (0.3)	4 (0.4)	0
Insufficient deployment	4 (0.3)	4 (0.4)	0
Colonic stent inserted	1 (0.1)	1 (0.1)	0
No stenosis at endoscopy	1 (0.1)	1 (0.1)	0
Procedural perforation	1 (0.1)	1 (0.1)	0
Not specified	8 (0.6)	8 (0.8)	0
Clinical success	1098 (85.7)	811 (83.6)	287 (92.3)	< 0.001

¹Comparison of UCSEMS and PCSEMS using Fisher’s exact test. UCSEMS: Uncovered self-expandable metal stents; PCSEMS: Partially covered self-expandable metal stents.

Table 4 Adverse events n (%)

	Overall (n = 1281)	UCSEMS (n = 970)	PCSEMS (n = 311)	P value1
Stent dysfunction	251 (19.6)	185 (19.1)	66 (21.2)	0.412
Re-obstruction by tumor growth	161 (12.6)	145 (14.9)	16 (5.1)	< 0.001
Stent migration	55 (4.3)	21 (2.2)	34 (10.9)	< 0.001
Stent compression by tumor pressure	9 (0.7)	3 (0.3)	6 (1.9)	0.008
Stent fracture	7 (0.5)	3 (0.3)	4 (1.3)	0.064
Insufficient expansion	11 (0.9)	8 (0.8)	3 (1.0)	0.734
Food occlusion	9 (0.7)	6 (0.6)	3 (1.0)	0.460
Other	2 (0.2)	2 (0.2)	0	-
Perforation	15 (1.2)	12 (1.2)	3 (1.0)	1.000
Bleeding	52 (4.1)	25 (2.6)	27 (8.7)	< 0.001
Major bleeding requiring intervention	10 (0.8)	9 (0.9)	1 (0.3)	0.466

¹Comparison of UCSEMS and PCSEMS using Fisher’s exact test. UCSEMS: Uncovered self-expandable metal stents; PCSEMS: Partially covered self-expandable metal stents.

Table 5 Details on the perforation cases

No.	Description	Day of onset	Treatment
1	Jejunal perforation at distal end of the stent[15]	173	Surgical closure
2	Intraprocedural perforation while the stricture was crossed with the catheter and guidewire[1]	0	Successfully treated with covered SEMS
3	Duodenal perforation after biliary stent placement[1]	82	Laparotomy, abdominal drainage and duodenal covered SEMS
4	Acute abdomen[18]	42	Refused treatment
5	Guidewire perforation[18]	0	Conservative treatment with antibiotics
6	Perforation likely due to stent-induced ischemia[2]	15	Surgical suture and gastrojejunostomy
7	Minor perforation after balloon dilation because of insufficient stent expansion[19]	7	Recovered without surgery
8	Late perforation, not related to dilatation[21]	NR	NR
9	Late perforation, not related to dilatation[21]	NR	NR
10	Late intestinal perforation by migrated stent[24]	NR	Surgical intervention
11	Perforation while pushing the delivery system across the initially placed stent[25]	0	Surgical closure and gastrojejunostomy
12	Perforation by the guidewire and/or ERCP catheter with subsequent misplacement of the stent[27]	0	Surgical suture, bowel patch and gastroenteric bypass
13	Perforation by the guidewire and/or ERCP catheter with subsequent misplacement of the stent[27]	0	Surgical suture, bowel patch and gastroenteric bypass
14	Abdominal pain and pneumoperitoneum immediately after stent placement[28]	0	Loop gastrojejunostomy and combined gastrostomy-jejunostomy tube placement
15	Abdominal pain, distension, vomiting, and free air on x-ray 6 d after second stent placement[28]	12	Nasogastric tube placement and hospitalized; died two days later of sepsis

SEMS: Self-expandable metal stent; NR: Not reported; ERCP: Endoscopic retrograde cholangiopancreatography.