Role of sonographic hepatorenal index and renal resistive index in monitoring of acute kidney injury after liver transplantation

Table 1 Postoperative characteristics of the acute kidney injury group, n (%)

Postoperative characteristics
AKI	53 (43.80)
Stage 1	30 (56.60)
Stage 2	18 (33.96)
Stage 3	5 (9.43)
PODs of AKI diagnosis
1	49 (92.45)
2	4 (7.55)
PODs when AKI resolved
2	4 (9.30)
3	6 (13.95)
4	19 (44.19)
5	6 (13.95)
6	8 (18.60)
AKI not resolved	10 (18.87)
Stage 1	2 (20)
Stage 2	3 (30)
Stage 3	5 (50)

AKI: Acute kidney injury; POD: Postoperative day.

Table 2 Comparison of perioperative variables between the acute kidney injury and non-acute-kidney-injury groups, mean ± SD/n (%)

	AKI	Non-AKI	P value
Age, years	50.49 ± 8.51	44.94 ± 9.04	0.73
Female sex	8 (15.09)	13 (19.12)	0.56
BMI, kg/m2	26.02 ± 4.17	22.96 ± 3.46	< 0.01
Comorbidities
Diabetes mellitus	7 (13.21)	4 (5.88)	0.17
Hypertension	6 (8.82)	5 (9.43)	0.91
Etiology of liver failure			0.77
Malignant neoplastic disease	23 (43.40)	29 (42.60)
Virus (HBV)	24 (45.30)	23 (33.80)
Ethanol	4 (7.50)	7 (10.30)
Cholestatic liver disease	1 (1.9)	4 (5.90)
Autoimmune disease	1 (1.9)	5 (7.40)
MELD score	14.61 ± 5.94	12.94 ± 6.45	0.15
Creatinine, μmol/L	78.47 ± 19.49	74.25 ± 19.26	0.24
Urea nitrogen, mmol/L	5.21± 2.00	5.14± 1.84	0.85
Cys C, mg/L	1.32 ± 0.42	1.14 ± 0.33	0.02
eGFR, mL/minute/1.73 m2	81.84 ± 4.18	88.63 ± 30.58	0.19
Albumin, g/L	33.27 ± 5.10	33.09 ± 7.32	0.88
IVC cross clamp			0.86
Partial (n = 2)	1 (1.89)	1 (1.47)
Complete (n = 119)	52 (98.11)	67 (98.53)
Mean intraoperative blood products transfused
Erythrocytes	4.5 (2-10)	6 (4-8.5)	0.72
Platelets	0 (0-1)	0 (0-0)	< 0.01
Surgical duration, hours	8.69 ± 1.66	8.03 ± 1.54	0.03
Anhepatic duration, minutes	41.26 ± 12.94	38.13 ± 10.23	0.14
HRI on POD 1	1.08 ± 0.21	1.40 ± 0.35	< 0.01
RRI on POD 1	0.69 ± 0.04	0.63 ± 0.05	< 0.01

AKI: Acute kidney injury; BMI: Body mass index; HBV: Hepatitis B virus; MELD: Model for end stage liver disease; Cys C: Cystatin C; eGFR: Glomerular filtration rate; IVC: Inferior R vena cava; RRI: Renal resistive index; HRI: Hepatorenal index; POD: Postoperative day.

Table 3 Paired comparisons

		n	P value
HRId vs HRIm	1.13 vs 1.38	43	< 0.01
HRIr-1 vs HRIm	1.28 vs 1.38	43	0.04
HRIr vs HRIm	1.37 vs 1.38	43	0.92
HRId vs HRIr-1	1.13 vs 1.28	43	< 0.01
HRId vs HRIr	1.13 vs 1.37	43	< 0.01
HRIr-1 vs HRIr	1.28 vs 1.37	43	< 0.01
RRId vs RRIm	0.69 vs 0.61	43	< 0.01
RRIr-1 vs RRIm	0.63 vs 0.61	43	< 0.01
RRIr vs RRIm	0.61 vs 0.61	43	0.62
RRId vs RRIr-1	0.69 vs 0.63	43	< 0.01
RRId vs RRIr	0.69 vs 0.61	43	< 0.01
RRIr-1 vs RRIr	0.63 vs 0.61	43	0.001

HRId: Hepatorenal index on the day of acute kidney injury diagnosis; HRIm: Hepatorenal index at 1 month after liver transplantation surgery; HRIr-1: Hepatorenal index at 1 day before acute kidney injury resolution; RRId: Renal resistive index on the day of acute kidney injury diagnosis; RRIm: Renal resistive index at 1 month after liver transplantation surgery; RRIr-1: Renal resistive index at 1 day before acute kidney injury resolution.