Long-Term Consequences of Increased Activity of Urine Enzymes After Cardiac Surgery – A Prospective Observational Study

Figures & data

Figure 1 Flow diagram.

Abbreviations: AKI, acute kidney injury; CSA-AKI, cardiac surgery associated acute kidney injury; POD, post-operative day.

Table 1 Demographic Data and Co-Morbidities of the Study Population

Characteristics	No AKI	AKI	p value
	N = 66	N = 13
Age (years) (mean ± SD)	60 ± 6	70 ± 6	<0.001
BMI (mean ± SD)	28 ± 3	31 ± 3	0.017
LV EF before the surgery (mean ± SD)	53 ± 9	46 ± 12	0.098
Gender (male) (n, %)	55 (83)	9 (69)	0.236
Left ventricular dysfunction NYHA ≥ II (n, %)	41 (62)	11 (83)	0.140
Myocardial infarction (n, %)	29 (44)	10 (77)	0.029
Arterial hypertension (n, %)	56 (84)	11 (84)	0.450
Diabetes mellitus (n, %)	19 (28)	8 (61)	0.022
Peripheral vascular disease (n, %)	55 (83)	10 (77)	0.716
Atrial fibrillation (n, %)	2 (3)	1 (13)	0.660

Abbreviations: AKI, acute kidney injury; BMI, body mass index; LV EF, left ventricle ejection fraction before procedure (%); NYHA, New York Heart Association; SD, standard deviation.

Figure 2 The comparison of NAG (A), ASA (B) and B-GR (C) activity in pre-defined time-points among the AKI group and no-AKI group.

Abbreviations: AKI, acute kidney injury; ASA, lysosomal arylsulfatase A; B-GR, beta-glucuronidase; NAG, N-acetyl-beta-glucosaminidase; POD, post-operative day.

Table 2 Peri-Operative Values of Urine and Serum Parameters in the Study Population

Characteristics (Mean ± SD)	No AKI	AKI	p value
	N = 66	N = 13
Pre-operative (zero sample)
NAG U/L (urine)	2.884 ± 2.9	3.575 ± 3.5	0.500
ASA U/L (urine)	0.103 ± 0.2	0.093 ± 0.1	0.382
B-GR U/L (urine)	0.495 ± 0.5	0.582 ± 0.6	0.781
Creatinine mg. dl-1 (serum)	0.876 ± 0.1	0.95 ± 0.27	0.416
1 hour after the end of CPB (post-OP sample)
NAG U/L (urine)	1.146 ± 2.2	2.281 ± 3.2	0.022
ASA U/L (urine)	0.139 ± 0.2	0.580 ± 1.5	0.028
B-GR U/L (urine)	0.254 ± 0.3	0.340 ± 0.4	0.596
NGAL ng.mL^−1 (urine)	3.093±4.6	12.558 ± 22.1	0.020
24 hours after the beginning of the operation (sample POD 1)
NAG U/L (urine)	5.305 ± 4.0	8.962 ± 3.9	0.004
ASA U/L (urine)	0.170 ± 0.1	0.640 ± 0.6	<0.001
B-GR U/L (urine)	0.600 ± 0.6	0.626 ± 0.5	0.596
Creatinine mg.dl^−1 (serum)	0.851 ± 0.1	1.28 ± 0.1	<0.001
NGAL ng.mL^−1 (urine)	12.489±12.1	25.057 ± 11.8	<0.001

Abbreviations: AKI, acute kidney injury; ASA, lysosomal arylsulfatase A; B-GR, beta-glucuronidase; NAG, N-acetyl-beta-glucosaminidase; NGAL, neutrophil gelatinase-associated lipocalin; CPB, cardio-pulmonary bypass; POD, post-operative day; SD, standard deviation.

Table 3 The Kinetics of Each Enzyme Regarding Long Term Follow Up

5-year Follow Up (Mean ± SD)	AKI	AKI	AKI	No-AKI	No-AKI
	n=4	n=2	n=7	n=7	n=3
Death	No	Yes	No	Yes	No
ChRF	Yes	No	No	No	Yes
NAG [U/g]*	0.97 ± 0.6	1.02	2.90 ± 2.23	1.83 ± 2.21	3.18 ± 2.69
NAG [U/g]**	22.99 ± 17.52	8.82	10.77 ± 8.26	8.76 ± 7.86	10.8 ± 10.31
NAG [U/g]***	9.79 ± 3.02	3.26	4.82 ± 2.95	3.57 ± 2.09	3.31 ± 2.97
ASA [U/g]*	0.01 ± 0.02	0.06	0.06 ± 0.06	0.03 ± 0.05	0.28 ± 0.43
ASA [U/g]**	1.89 ± 0.73	1.63	2.16 ± 2.69	6.82 ± 13.95	2.93 ± 2.54
ASA [U/g]***	0.70 ± 0.78	0.19	0.33 ± 0.29	0.17 ± 0.16	0.12 ± 0.12
BGR [U/g]*	0.09 ± 0.09	0.14	0.63 ± 0.78	0.38 ± 0.37	0.23 ± 0.17
BGR [U/g]**	2.56 ± 1.76	2.69	2.77 ± 3.42	5.98 ± 11.86	1.73 ± 1.34
BGR [U/g]***	0.48 ± 0.31	0.21	0.41 ± 0.42	0.35 ± 0.23	0.21 ± 0.28
NGAL**	32.40 ± 34.34	1.60	4.35 ± 2.94	3.95 ± 2.75	1.70 ± 1.23
NGAL***	30.95 ± 11.17	22.07	22.54 ± 9.55	11.51 ± 9.6	7.31 ± 3.4
Creatinine*	1.09 ± 0.44	0.82	0.92 ± 0.18	0.86 ± 0.16	0.92 ± 0.17
Creatinine*	1.46 ± 0.46	0.87	1.31 ± 0.32	0.93 ± 0.17	0.84 ± 0.13

Notes: *Zero sample, **1 hour after the end of CPB (post-OP sample), ***POD – post-operative day, “5 year follow up” - 5 years after cardiac surgery.

Abbreviations: AKI, acute kidney injury; ASA, lysosomal arylsulfatase A; B-GR, beta-glucuronidase; NAG, N-acetyl-beta-glucosaminidase; NGAL, neutrophil gelatinase-associated lipocalin; ChRF, chronic renal failure.