Predictors of the technical success of ultrasound-guided percutaneous transhepatic biliary drainage for biliary obstruction

Table 1 Domain-specific multivariable analysis of medical provider-related factors

	Success/failure	P value	Exp(B)	95%CI for Exp(B)
Operator experience		0.007
> 20 cases	112/65		1.92	1.19	3.10
≤ 20 cases	136/42		0.52	0.32	0.84
Operator title		0.001
Senior	83/27		4.22	1.77	10.06
Junior	165/80		0.24	0.10	0.57
Guide experience		0.818
> 20 cases	86/38		1.06	0.64	1.75
≤ 20 cases	162/69		0.94	0.57	1.55
Guide title		0.327
Senior	89/32		1.29	0.78	2.14
Junior	159/75		0.78	0.47	1.29
Specialty		0.250
Surgery	125/49		0.68	0.35	1.32
Internal medicine	85/38		2.36	0.93	5.97
Emergency medicine	38/20		1.48	0.76	2.89
Level of cooperation		0.039
Good	235/95		2.53	1.05	6.09
Poor	13/12		0.40	0.16	0.95

“Senior” denotes attending physician or equivalent title.

Table 2 Domain-specific multivariable analysis of patient-related factors

	Success/failure	P value	Exp(B)	95%CI for Exp(B)
Age		0.848
> 65 years	151/67		0.93	0.568	1.522
≤ 65 years	97/40		1.075	0.657	1.759
Gender		0.823
Male	180/77		0.907	0.532	1.545
Female	68/30		1.103	0.647	1.879
BMI		0.781
≤ 24 (kg/m2)	208/90		1.097	0.567	2.125
> 24 (kg/m2)	40/17		0.911	0.47	1.765
History of upper abdominal surgery		0.343
No	239/102		0.616	0.19	1.996
Yes	9/5		1.625	0.501	5.269
Liver cirrhosis/fibrosis		0.827
No	229/92		0.967	0.41	2.283
Yes	20/11		1.034	0.438	2.439
Ascites		0.695
No	241/103		0.832	0.215	3.218
Yes	7/4		1.202	0.311	4.648
Etiology		0.917
Tumor	234/97		0.798	0.295	2.157
Other	15/6		1.254	0.464	3.392
Obstruction site		0.696
Supra-confluence	114/47		0.964	0.595	1.563
Infra-confluence	134/60		1.037	0.64	1.681
Bilirubin		0.038
> 340 (μmol/L)	123/27		3.366	1.157	9.796
170-340 (μmol/L)	119/75		1.737	0.627	4.811
< 170 (μmol/L)	6/5		0.576	0.208	1.595
Bile duct diameter		0.002
≥ 6 (mm)	167/60		2.845	1.738	4.656
< 6 (mm)	81/57		0.351	0.215	0.575

Bilirubin > 340 μmol/L is defined as severe hyperbilirubinemia. BMI: Body mass index.

Table 3 Domain-specific multivariable analysis of strategy selection-related factors

Characteristics	Success/failure	P value	Exp(B)	95%CI for Exp(B)
Timing		0.300
Emergency	56/30		0.757	0.447	1.282
Elective	192/77		1.321	0.78	2.237
Location		0.672
Operating room	129/50		1.155	0.593	2.25
Puncture room	81/40		0.863	0.43	1.732
Bedside	38/17		0.866	0.444	1.687
Angle		0.835
45°-135°	185/80		0.945	0.556	1.607
Other	63/27		1.058	0.622	1.799
Length		0.649
≥ 12 (cm)	63/30		1.129	0.67	1.901
< 12 (cm)	185/77		0.886	0.526	1.492
Position		0.598
Right side	31/12		1.214	0.59	2.497
Left side	217/95		0.824	0.4	1.695
Ultrasound probe		0.026
Conventional	198/96		0.451	0.223	0.911
Puncture-specific	50/11		2.219	1.098	4.486
Catheter diameter		0.440
≤ 8 French	191/78		0.812	0.478	1.379
> 8 French	57/29		1.232	0.725	2.094
Operator change		0.762
Yes	8/1		1.242	0.306	5.04
No	47/34		0.805	0.198	3.267
Target change		0.101
Yes	6/4		5.962	0.704	50.501
No	49/31		0.168	0.02	1.421

“Puncture-specific” refers to dedicated biopsy/guidance ultrasound probes.

Table 4 Final comprehensive multivariable logistic regression model of factors associated with procedural success

Variable	β coefficient	Odds ratio (95%CI)	P value
Puncture performer’s title (high vs low)	0.353	1.423 (0.823-2.461)	0.207
Puncture experience (more vs less)	0.606	1.833 (1.124-2.989)	0.015
Dedicated probe (special vs ordinary)	0.901	2.462 (1.157-5.238)	0.019
Patient cooperation (good vs poor)	1.005	2.732 (1.136-6.568)	0.025
Bile duct diameter (≥ 6 mm vs < 6 mm)	0.754	2.126 (1.300-3.478)	0.003
Bilirubin level (> 340 μmol/L vs < 340 μmol/L)	0.946	2.576 (1.523-4.357)	< 0.001
Constant	-3.187	0.041	< 0.001

This final multivariable model identified five independent predictors of procedural success (P < 0.05). Operator seniority was not statistically significant (P = 0.207). The model’s predictive performance is summarized in Figure 4.

Table 5 Bedside scoring system for predicting the probability of successful percutaneous transhepatic biliary drainage

Predictor	Points assigned if:	Points
Operator experience	More experience	2
Dedicated probe	Specialized probe used	3
Procedural cooperation	Good cooperation	3
Bile duct diameter	≥ 6 mm	2
Serum bilirubin	> 340 μmol/L	3
Operator seniority	High title	1
Total score		0-14
Predicted success probability	Corresponding score range
Low	0-4
Intermediate	5-9
High	10-14

Points are assigned based on the regression coefficients and clinical weight. Operator seniority, while not statistically significant in the multivariate model (P = 0.207), was included due to its established clinical relevance in procedural settings.