Interpretable machine learning model for early complication prediction after split liver transplantation

Table 1 Comparison of demographic and clinical characteristics and outcomes between non-early postoperative complications and early postoperative complications, n (%)/median (interquartile range)

Characteristics	All (n = 109)	Non-EPC (n = 72, 66.1%)	EPC (n = 37, 33.9%)	P value
Recipient age (years)	53.0 (44.0, 60.0)	53.0 (43.7, 59.0)	53.0 (45.0, 61.0)	0.557
Gender				0.999
Male	69 (63.3)	46 (63.9)	23 (62.2)
Female	40 (36.7)	26 (36.1)	14 (37.8)
BMI (kg/m2)	22.9 (20.7, 25.3)	22.5 (20.7, 25.3)	23.1 (20.7, 25.9)	0.485
Blood pressure				0.769
No	95 (87.2)	62 (86.1)	33 (89.2)
Yes	14 (12.8)	10 (13.9)	4 (10.8)
CHD				0.335
No	92 (84.4)	63 (87.5)	29 (78.4)
Yes	17 (15.6)	9 (12.5)	8 (21.6)
Diabetes				0.999
No	86 (78.9)	57 (79.2)	29 (78.4)
Yes	23 (21.1)	15 (20.8)	8 (21.6)
MELD scores	18.0 (12.0, 23.0)	16.0 (11.0, 21.0)	20.0 (15.0, 26.0)	0.009
Child-Pugh scores	9.0 (7.0, 11.0)	9.0 (6.0, 11.0)	10.0 (8.0, 11.0)	0.131
Transplant indication				0.124
Hepatitis (B and C)	41 (37.6)	24 (33.3)	17 (46.0)
Tumor	39 (35.8)	24 (33.3)	15 (40.5)
Alcohol liver disease	9 (8.2)	7 (9.8)	2 (5.4)
Autoimmune disease	18 (16.5)	16 (22.2)	2 (5.4)
Polycystic liver	2 (1.9)	1 (1.4)	1 (2.7)
GRWR (%)	1.5 (1.2, 1.8)	1.5 (1.2, 1.8)	1.6 (1.2, 2.0)	0.648
Donor age (years)	40.0 (31.0, 45.0)	39.0 (29.7, 44.0)	43.0 (33.0, 46.0)	0.189
ABO incompatibility				0.999
No	104 (95.4)	69 (95.8)	35 (94.6)
Yes	5 (4.6)	3 (4.2)	2 (5.4)
Anhepatic phase	45.0 (40.0, 50.0)	43.50 (37.5, 50.0)	45.0 (40.0, 57.0)	0.153
Blood loss (mL)	1500.0 (1000.0, 2400.0)	1200.0 (800.0, 2000.0)	2000.0 (1000.0, 2800.0)	0.003
Operation time (minutes)	500.0 (440.0, 590.0)	480.0 (408.7, 578.2)	540.0 (468.0, 625.0)	0.040
CIT (minutes)	130.0 (80.0, 210.0)	120.0 (80.0, 190.0)	170.0 (90.0, 230.0)	0.100
WIT (seconds)	83.0 (43.0, 110.0)	85.5 (41.5, 108.2)	82.0 (58.0, 133.0)	0.420
IV PL				0.006
No	71 (65.1)	40 (55.6)	31 (83. 8)
Yes	38 (34.9)	32 (44.4)	6 (16.2)
WBC (109/L)	4.03 (2.66, 5.60)	3.49 (2.30, 5.13)	4.84 (3.90, 5.93)	< 0.001
Neutrophile counts (109/L)	2.64 (1.71, 4.10)	2.16 (1.49, 3.27)	3.51 (2.44, 5.14)	< 0.001
Lymphocyte counts (109/L)	0.70 (0.45, 0.96)	0.71 (0.43, 0.97)	0.60 (0.46, 0.90)	0.650
HB (g/L)	96.0 (83.0, 110.0)	96.8 (85.7, 111.7)	94.0 (77.0, 108.0)	0.146
PLT (109/L)	69.0 (41.0, 101.0)	64.5 (40.7, 96.2)	77.0 (45.0, 111.0)	0.279
ALB (g/L)	32.6 (29.7, 37.6)	32.5 (29.5, 36.6)	32.9 (31.4, 38.4)	0.396
TBIL (μmol/L)	62.3 (27.7, 191.0)	58.7 (23.8, 150.1)	69.4 (34.4, 310.0)	0.117
ALT (U/L)	56.4 (24.9, 117.7)	54.1 (24.9, 98.6)	56.4 (26.4, 129.6)	0.554
AST (U/L)	79.4 (46.1, 194.6)	69.8 (43.4, 187.3)	106.4 (56.3, 226.8)	0.347
ALP (U/L)	144.0 (97.0, 198.0)	142.0 (96.7, 186.0)	144.0 (99.0, 268.0)	0.541
GGT (U/L)	62.0 (32.0, 124.0)	58.0 (31.0, 114.2)	83.0 (37.0, 152.0)	0.301
Cr (μmol/L)	58.0 (49.0, 76.0)	57.5 (49.4, 74.5)	63.0 (48.0, 77.0)	0.663
FIB (g/L)	1.71 (1.26, 2.24)	1.52 (1.12, 2.06)	1.84 (1.54, 2.49)	0.014
APTT (seconds)	40.3 (34.3, 47.3)	40.3 (34.5, 46.1)	40.7 (34.1, 52.4)	0.582
INR	1.63 (1.31, 1.99)	1.54 (1.17, 1.95)	1.70 (1.46, 2.13)	0.014

EPC: Early postoperative complications; BMI: Body mass index; CHD: Coronary heart disease; MELD: Model for end-stage liver disease; GRWR: Graft-to-recipient weight ratio; CIT: Cold ischemia time; WIT: Warm ischemia time; IV PL: Partial lobectomy of segment IV; WBC: White blood counts; HB: Hemoglobin; PLT: Platelets; ALB: Albumin; TBIL: Total bilirubin; ALT: Alanine aminotransferase; AST: Aspartate aminotransferase; ALP: Alkaline phosphatase; GGT: Gamma-glutamyl transferase; Cr: Creatinine; FIB: Fibrinogen; APTT: Activated partial thromboplastin time; INR: International normalized ratio.

Table 2 Logistic regression evaluation of factors associated with early postoperative complications following split liver transplantation

Characteristics1	Univariable		Multivariable
	OR (95%CI)	P value	OR (95%CI)	P value
Recipient age (years)	1.012 (0.970-1.052)	0.544
Gender (female)	1.077 (0.470-2.436)	0.859
BMI (kg/m2)	1.048 (0.950-1.159)	0.349
Blood pressure (yes)	0.752 (0.190-2.440)	0.650
CHD (yes)	1.931 (0.660-5.559)	0.219
Diabetes (yes)	1.048 (0.380-2.711)	0.924
MELD scores2	1.074 (1.020-1.137)	0.012	1.104 (1.027-1.186)	0.008
Child-Pugh class2
A2	Reference
B2	5.600 (1.491-21.036)	0.011
C2	5.778 (1.140-23.342)	0.014
Transplant indication
Hepatitis (B and C)	Reference
Tumor	0.882 (0.360-2.161)	0.784
Alcohol liver disease	0.403 (0.074-2.186)	0.292
Autoimmune disease	0.176 (0.036-0.870)	0.033
polycystic liver	1.412 (0.082-24.178)	0.812
GRWR (%)	1.345 (0.540-3.384)	0.526
Donor age (years)	1.019 (0.980-1.061)	0.331
ABO incompatibility (yes)	1.314 (0.210-8.233)	0.770
Anhepatic phase	1.023 (0.990-1.059)	0.179
Blood loss2 (mL)	1.001 (1.000-1.001)	0.002	1.001 (1.000-1.001)	0.043
Operation time2 (minutes)	1.003 (1.000-1.007)	0.039	1.002 (0.998-1.006)	0.271
CIT (minutes)	1.003 (1.000-1.008)	0.140
WIT (seconds)	1.005 (1.000-1.014)	0.261
IV PL2 (yes)	0.242 (0.080-0.617)	0.005	0.226 (0.070-0.727)	0.013
LnSII2	1.971 (1.290-3.165)	0.003	1.729 (1.028-2.907)	0.039
AFR2	0.942 (0.890-0.986)	0.024	0.942 (0.879-1.010)	0.093
HB (g/L)	0.985 (0.970-1.003)	0.111
ALT (U/L)	1.000 (1.000-1.004)	0.914
AST (U/L)	1.000 (1.000-1.003)	0.706
ALP (U/L)	1.002 (1.000-1.006)	0.240
GGT (U/L)	1.003 (1.000-1.007)	0.200
APTT (seconds)	1.020 (0.990-1.051)	0.171

¹The associations of early postoperative complications with clinical characteristics were assessed by univariate and multivariable logistic regression.

²P values statistical significance.

OR: Odds ratio; CI: Confidence interval; BMI: Body mass index; CHD: Coronary heart disease; MELD: Model for end-stage liver disease; GRWR: Graft-to-recipient weight ratio; CIT: Cold ischemia time; WIT: Warm ischemia time; IV PL: Partial lobectomy of segment IV; LnSII: Log-transformed systemic immune inflammatory index; AFR: Albumin-to-fibrinogen ratio; ALT: Alanine aminotransferase; AST: Aspartate aminotransferase; ALP: Alkaline phosphatase; GGT: Gamma-glutamyl transferase; APTT: Activated partial thromboplastin time.