Effect of brush rinse on the diagnostic accuracy of biliary stricture evaluation: A multicenter trial

Table 1 Baseline characteristics, n (%)

Demographic factors	N = 112
Age (years)	71.2 ± 9.6
Male sex	66 (58.9)
Baseline bilirubin level (mg/dL)	6.8 (2.1-13.4)
Baseline cancer antigen 19-9 level (IU/L)	220 (37-628.5)
Location of brushing
Common bile duct	66 (58.9)
Common hepatic duct	8 (7.1)
Hepatic hilum	36 (32.1)
Intrahepatic duct	2 (1.9)
Diagnosis
Malignancy
Pancreatic adenocarcinoma	32 (28.6)
Hilar cholangiocarcinoma	32 (28.6)
Distal cholangiocarcinoma	29 (25.9)
Gallbladder adenocarcinoma	7 (6.3)
Intrahepatic cholangiocarcinoma	2 (1.8)
Hepatocellular carcinoma	1 (0.9)
Benign
Benign common bile duct stricture	8 (7.1)
Immunoglobulin G 4-related sclerosing cholangitis	1 (0.9)

Values are expressed as mean ± SD, n (%), or median (interquartile range).

Table 2 Median number of cell clusters per method

	Brush-wash (n = 112)	Sheath-rinse (n = 112)	P value1
Total cell clusters	3 (1-6)	12 (4-21)	< 0.001
Large (> 50 cells) clusters	3 (1-13)	8 (3-38)	< 0.001
Medium (6-49 cells) clusters	3 (1-9)	7 (3-27)	< 0.001
Small (2-5 cells) clusters	3 (1-14)	9 (2-36)	< 0.001
Single-cell clusters	6 (0-41)	20 (4-111)	< 0.001

¹Wilcoxon rank sum test.

Values are expressed as median (interquartile range).

Table 3 Median number of cell cluster according to bile duct location

Proximal bile duct	Brush-wash (n = 38)	Sheath-rinse (n = 38)	P value1
Total cell clusters	3 (1-7)	14 (8-23)	< 0.001
Large (> 50 cells) clusters	5 (1-19)	12 (4-77)	< 0.009
Medium (6-49 cells) clusters	5 (1-13)	8 (3-53)	< 0.019
Small (2-5 cells) clusters	5 (1-19)	13 (3-54)	< 0.017
Single-cell clusters	18 (1-70)	54 (9-207)	< 0.0021
Distal bile duct	Brush-wash (n = 74)	Sheath-rinse (n = 74)	P value1
Total cell clusters	3 (2-6)	10 (3-19)	< 0.001
Large (> 50 cells) clusters	2 (1-11)	7 (2-28)	< 0.001
Medium (6-49 cells) clusters	2 (1-6)	7 (3-18)	< 0.001
Small (2-5 cells) clusters	3 (1-9)	8 (2-22)	< 0.001
Single-cell clusters	4 (0-28)	18 (3-82)	< 0.001

¹Wilcoxon rank sum test.

Values are expressed as median (interquartile range).

Table 4 Diagnostic performance of the brush-wash vs. sheath-rinse specimens

	Brush-wash (n = 112)	Sheath-rinse (n = 112)	Combined (n = 112)	P value
Accuracy	62.5 (52.9-71.5)	72.3 (63.1-80.4)	74.1 (65.0-81.9)	< 0.0011
				< 0.0012
				0.1573
Sensitivity	59.2 (49.1-68.8)	69.9 (60.1-78.5)	71.8 (62.1-80.3)	< 0.0011
				< 0.0012
				0.1573
Specificity	100 (66.3-100)	100 (66.4-100)	100 (66.3-100)	NA
Positive predictive value	100 (94.1-100)	100 (95.0-100)	100 (95.1-100)	NA
Negative predictive value	17.6 (8.4-30.9)	22.5 (10.8-38.5)	23.7 (11.4-40.2)	0.5644
				0.4835
				0.9016

¹Brush-wash vs sheath-rinse.

²Brush-wash vs combined.

³Sheath-rinse vs combined (McNemar’s test).

⁴Brush-wash vs sheath-rinse.

⁵Brush-wash vs combined.

⁶Sheath-rinse vs combined (χ² test).

Values are expressed as n or 95%CI (case/number for analysis). NA: Not applicable.