Abstract: 【Abstract】Objective To investigate the levels of serum brain natriuretic peptide (BNP), serum cystatin C (CysC) and kidney injury molecule (KIM-1) in patients with type I cardiorenal syndrome (CRS), and explore the relationship between these factors and acute kidney injury (AKI). Methods 211 patients with acute heart failure admitted to our hospital between March 2017 and March 2020 were recruited. Among them, 89 patients with AKI were in the observation group, and 122 patients without AKI were in the control
group. According to the severity of kidney injury, the observation group was divided into three subgroups: mild group (n=28), moderate group (n=46), and severe group (n=15). The levels of serum BNP, CysC and KIM-1 were tested in all patients. Pearson correlation analysis was used to analyze the correlation between serum BNP, CysC, KIM-1 levels and AKI. The receiver operating characteristic curve (ROC) was used to evaluate the predictive value of serum BNP, CysC, and KIM- 1 for type I CRS AKI. Results The serum BNP [(1124.36±765.61 ng/L)], CysC [(1.81±0.59 mg/L)] and KIM-1[(157.89±16.59 ng/L)] levels in the observation
group were higher than that in the control group [(816.56±631.25)ng/L, (0.92± 0.08)mg/L, [(136.52±13.43)ng/L] (t=3.195, 16.470, 10.328, P=0.001,＜0.001, ＜0.001)]. In the observation group, the serum BNP(1453.65 ± 668.92)ng/L, (1135.13 ± 459.31)ng/L], CysC [(2.37 ± 0.63)mg/L, (1.86 ± 0.51)mg/L] and KIM- 1[(179.86) ±17.12)ng/L,(158.21±15.56)ng/L] in the severe and moderate subgroups were higher than the mild subgroup [(930.26 ± 356.45)ng/L, (1.43 ± 0.46)mg/L, (145.58 ± 14.27)ng/L], and the serum BNP [(1453.65 ±668.92)ng/L], CysC [(2.37±0.63)mg/L] and KIM-1 [(179.86±17.12)ng/L] levels in the severe subgroup were higher than that in the moderate subgroup [(1135.13±459.31)ng/L, (1.86±0.51)mg/L, (158.21±15.56)ng/L (F=
1.956, 12.546, 12.165, P=0.034, 0.009, 0.011)]. Pearson analysis showed that serum BNP, CysC and KIM-1 levels were positively correlated with serum creatinine (Scr) (r=0.713, r=0.727, r=0.715, P＜0.001). ROC curve analysis showed that the AUC of serum BNP for predictive of type I CRS AKI was 0.716 (95% CI: 0.603 to 0.830, P=0.001); the AUC of serum CysC for predictive of type I CRS AKI was 0.792 (95% CI: 0.698 to 0.897, P＜0.001); the AUC of serum KIM-1 for predictive of type I CRS AKI was 0.749 (95% CI: 0.641～0.857, P＜0.001) ; the AUC of the combined index predictive of type I CRS AKI was 0.880 (95% CI: 0.804～0.955, P＜0.001). Conclusion The serum levels of BNP, CysC and KIM-1 were all increased in patients with type I CRS. Serum BNP, CysC, KIM-1 levels are closely related to the severity of AKI, and can be used as indicators to reflect the severity of type I CRS. The combination of serum BNP, CysC and KIM-1 has important value in the prediction of type I CRS AKI.

Key words: Type I cardiorenal syndrome, Acute kidney injury, Brain natriuretic peptide, Serum cystatin C, Kidney injury molecule