Angle of covered self-expandable metallic stents after placement is a risk factor for recurrent biliary obstruction

Table 3 Baseline characteristics of patients and treatment (recurrent biliary obstruction group vs non-recurrent biliary obstruction group)

		RBO group (n = 18)	Non-RBO group (n = 69)	P value
Age (IQR, yr)		66.5 (61-77)	69 (63.5-77)	0.63
Sex, n (%)	Female	5 (27.8)	27 (39.1)	0.42
	Male	13 (72.2)	42 (60.9)
ASA-PS, n (%)	1	2 (11.1)	22 (31.9)	0.07
	2	9 (50.0)	35 (50.7)
	3	7 (38.9)	12 (17.4)
Primary disease, n (%)	Other cancers	8 (44.4)	21 (30.4)	0.28
	Pancreatic cancer	10 (55.6)	48 (69.6)
Clinical stage, n (%)	II	1 (5.6)	2 (2.9)	0.08
	III	4 (22.2)	4 (5.8)
	IV	13 (72.2)	63 (89.9)
Chemotherapy, n (%)	No	8 (44.4)	31 (44.9)	1.00
	Yes	10 (55.6)	38 (55.1)
Radiotherapy, n (%)	No	17 (94.4)	59 (85.5)	0.45
	Yes	1 (5.6)	10 (14.5)
Total bilirubin level (continuous, mg/dL)		2.7 (1.1-6.7)	4.4 (2.3-9.0)	0.07
Length of stricture (IQR, mm)		34.9 (25.9-47.2)	30.9 (21.4-37.8)	0.13
Total procedure time (IQR, min)		35.5 (25-50.8)	32.0 (24-47)	0.65
EST, n (%)	No	5 (27.8)	22 (31.9)	1.00
	Yes	13 (72.2)	47 (68.1)
CSEMS type (1), n (%)	Partially	9 (50.0)	29 (42.0)	0.60
	Fully	9 (50.0)	40 (58.0)
CSEMS type (2), n (%)	Laser-cut	1 (5.6)	5 (7.2)	1.00
	Braided	17 (94.4)	64 (92.8)
Length of CSEMS, n (%)	≤ 6 cm	8 (44.4)	40 (58.0)	0.55
	7 cm	3 (16.7)	7 (10.2)
	8 cm	7 (38.9)	22 (31.9)
Diameter of CSEMS, n (%)	6 mm	0 (0.0)	3 (4.4)	0.58
	8 mm	1 (5.6)	2 (2.9)
	10 mm	17 (94.4)	64 (92.8)
Angle of CSEMS (IQR, °)		135.5 (114.8-149.3)	149.0 (138.5-158)	0.01

ASA-PS: American Society of Anesthesiologist Physical Status classification; EST: Endoscopic sphincterotomy; CSEMS: Covered self-expandable metallic stents; IQR: Interquartile range; RBO: Recurrent biliary obstruction.