Predictive factors for the failure of endoscopic stent-in-stent self-expandable metallic stent placement to treat malignant hilar biliary obstruction

Table 2 Comparison of the endoscopic retrograde cholangiopancreatography procedures and outcomes employed in the success and failure groups n (%)

	Success (n = 49)	Failure (n = 13)	P value
Procedure time, median (range), min	70 (20-160)	90 (40-150)1	0.30
Clinically effective rate	49 (100)	11 (84.6)	0.04
Adverse effects	1 (2)	1 (7.7)	0.38
Post-ERCP pancreatitis	1	0
Perforation of biliary duct	0	1
Wire passage of the first SEMS cell	49 (100)	9 (69.2)	0.006
Diameter of wire (0.025/0.035)	32/142	6/61	0.31
Catheter usage to dilate the a first SEMS cell	24	8	0.54
Catheter passage of the first SEMS cell	22 (92)	4 (50)	0.02
Dilator usage to dilate first SEMS cell	18	5	1.00
Dilator passage of the first SEMS cell	17 (94)	2 (40)	0.02
Balloon catheter usage to dilate the first SEMS lumen	5	1	1.00
Balloon catheter usage to dilate the first SEMS cell	18	3	0.51
Balloon catheter passage of the first SEMS cell	18 (100)	0 (0)	< 0.001
The number of used dilation devices, median (range)	1 (0-3)	1 (0-3)	0.79
Type of first SEMS used (braided/laser), n	41/8	9/4	0.26
Stenting order			0.22
Left→Left	2	1
Left→Right	28	6
Right→Left	12	6
Right→Right	7	0
Procedure sessions			0.328
1	42	13
2	7	0
Area of first SEMS cell, median (range), mm2	18.3 (3.5-39.3)	18.3 (3.5-18.3)3	0.59

¹Data for one patient were not available;

²Data for three patients were not available;

³Data for two patients were not available. ERCP: Endoscopic retrograde cholangiopancreatography; SEMS: Self-expandable metallic stent.