Comparison between uncovered and covered self-expandable metal stent placement in malignant duodenal obstruction

Table 1 Baseline characteristics

	Stent type		P value
	Uncovered(n = 38)	Covered(n = 29)
Age (yr)	68.9 ± 10.2	68.5 ± 11.2	0.860
Sex (M/F)	18/20 (47.4/52.6)	11/18 (37.9/62.1)	0.440
ECOG PS (0/1/2/3/4)	0/9/16/9/4	0/5/10/8/6	0.2031
Previous treatment
Operation	6 (9.0)	5 (7.5)	1.000
Chemotherapy	10 (14.9)	5 (7.5)	0.377
Previous biliary drainage
PTBD	5 (13.2)	7 (24.1)	0.246
ERBD	19 (50.0)	8 (27.6)	0.064
PTBD and ERBD	5 (13.2)	0 (0.0)	0.064
Underlying malignancy			0.4231
Pancreatic cancer	22 (32.8)	9 (13.4)
Bile duct cancer	4 (6.0)	8 (11.9)
Gallbladder cancer	4 (6.0)	5 (7.5)
Ampullary cancer	3 (4.5)	2 (3.0)
Duodenal cancer	1 (1.5)	3 (4.5)
Hepatocellular carcinoma	1 (1.5)	1 (1.5)
Others	3 (4.5)	1 (1.5)
Cancer stage			0.3351
I	1 (2.6)	1 (3.4)
II	3 (7.9)	5 (17.2)
III	2 (5.3)	1 (3.4)
IV	32 (84.2)	22 (75.9)
Stent diameter (mm)	19.8 ± 0.55	19.4 ± 0.92	0.699
Stent length (mm)	99.5 ± 17.1	101.4 ± 14.3	0.688
Stent number			0.256
1 stent	35 (53.0)	28 (42.4)
2 stents	3 (4.5)	0 (0.0)
Median time interval to intervention from	96.5 (3-803)	118.0 (1-2930)	0.699
Initial diagnosis (d)
Chemotherapy after procedure	11 (28.9)	5 (17.2)	0.265
Median duration of follow-up (d)	71 (8-592)	60 (9-827)	0.411

¹Linear by linear association. Values are presented as n (%), mean ± SD, or d (range). ECOG PS: Eastern cooperative oncology group performance status; PTBD: Percutaneous biliary drainage; ERBD: Endoscopic retrograde biliary drainage.

Table 2 Main outcomes and complications

	Stent type		P value
	Uncovered(n = 38)	Covered(n = 29)
Technical success	38 (100)	28 (96.6)	0.433
Clinical success	34 (89.5)	24 (82.8)	0.485
GOOSS score
Pre-stenting (0/1/2/3)	31/3/4/0	25/2/2/0	0.5841
Post-stenting (0/1/2/3)	4/10/18/61	5/11/10/32	0.1661
Causes of clinical failure	4 (10.5)	4 (13.8)	0.485
Poor expansion	2 (5.3)	0 (0.0)	0.502
Migration	0 (0.0)	2 (6.9)	0.184
Perforation	0 (0.0)	1 (3.4)	0.433
Peritoneal seeding	1 (2.7)	0 (0.0)	1.000
Septic shock	1 (2.7)	1 (3.4)	1.000
Complications	12 (31.6)	12 (41.4)	0.407
Migration	0 (0.0)	6 (20.7)	0.005
Tumor ingrowth	6 (15.8)	1 (3.4)	0.129
Perforation	0 (0.0)	2 (6.9)	0.184
Biliary obstruction	3 (7.9)	0 (0.0)	0.252
Stent collapse	0 (0.0)	3 (10.3)	0.076
Poor expansion	2 (5.3)	0 (0.0)	0.502
Food impact	1 (2.6)	0 (0.0)	1.000
Retreatment rate	12 (31.6)	10 (34.5)	0.802
Stenting	5 (13.2)	9 (31.0)	0.075
Operation	1 (2.6)	1 (3.4)	1.000
Removal of food materials	1 (2.6)	0 (0.0)	1.000
Ballooning	2 (5.3)	0 (0.0)	0.502
PTBD	3 (7.9)	0 (0.0)	0.252
30-d mortality	6 (15.8)	8 (27.6)	0.239
Median time interval to reintervention from initial intervention (d)	60 (14-251)	71 (2-147)	0.573

¹Linear by linear association;

²The GOOSS score improved significantly after stent placement than those before stent placement (P < 0.001, Wilcoxon signed-rank test). Values are presented as number (%) or d (range). GOOSS: Gastric outlet obstruction scoring system = no oral intake, 0; liquid only, 1; soft solids, 2; low-residue or full diet; PTBD: Percutaneous biliary drainage.

Table 3 Prognostic factors for stent patency

	Univariate analysis		Multivariate analysis
	HR (95%CI)	P value	HR (95%CI)	P value
Age (> 70 yr)	1.792 (0.731-4.391)	0.202
Sex (M)	0.998 (0.418-2.384)	0.996
ECOG PS (> 2)	1.436 (0.590-3.492)	0.425
Underlying malignancy (pancreatic cancer)	0.512 (0.205-1.276)	0.151
Stage (> III)	0.955 (0.345-2.648)	0.930
Obstruction site		0.414
Proximal of 2nd portion	1.000
2nd portion	0.552 (0.211-1.441)	0.225
Distal of 2nd portion	0.486 (0.116-2.042)	0.325
Stent
Covered	2.586 (1.046-6.388)	0.040	2.586 (1.046-6.388)	0.040
Length (> 100 mm)	1.261 (0.480-3.307)	0.638
Diameter (> 18 mm)	0.664 (0.221-1.997)	0.466
Chemotherapy after stent insertion	0.425 (0.125-1.449)	0.172
Chemotherapy before stent insertion	0.261 (0.059-1.158)	0.077
Biliary drainage before stent insertion	0.799 (0.306-2.086)	0.646

ECOG PS: Eastern cooperative oncology group performance status.