Biomarkers of acute kidney injury

Renal Doppler and Novel Biomarkers to Assess Acute Kidney Injury in a Swine Model of Ventricular Fibrillation Cardiac Arrest

Background:

Majority of the research on cardiac arrest (CA) have focused on post-CA brain injury and myocardial dysfunction, the renal dysfunction and acute kidney injury (AKI) in other critical illnesses after CA have not been well described. This study was designed to assess AKI with renal Doppler and novel AKI biomarkers in a swine model of ventricular fibrillation cardiac arrest (VFCA).

Methods:

Thirty healthy piglets were divided into VFCA group (n = 22) and Sham group (n = 8) in a blinded manner. Mean arterial pressure, heart rate, and cardiac output were recorded continuously. Cardiac arrest (CA) was induced by programmed electric stimulation in the VFCA group, and then cardiopulmonary resuscitation was performed. Twenty piglets returned of spontaneous circulation (ROSC) and received intensive care. Blood and urine samples were collected for AKI biomarkers testing, and Color Doppler flow imaging was performed at baseline, 6 h, 12 h, and 24 h, respectively after ROSC. At ROSC 24 h, the animals were sacrificed and a semi-quantitative evaluation of pathologic kidney injury was performed.

Results:

In the VFCA group, corrected resistive index (cRI) increased from 0.47 ± 0.03 to 0.64 ± 0.06, and pulsatility index (PI) decreased from 0.82 ± 0.03 to 0.68 ± 0.04 after ROSC. Cystatin C (CysC) in both serum and urine samples increased at ROSC 6 h, but neutrophil gelatinase-associated lipocalin (NGAL) in serum increased to 5.34 ± 1.68 ng/ml at ROSC 6 h, and then decreased to 3.16 ± 0.69 ng/ml at ROSC 24 h while CysC increasing constantly. According to the renal histopathology, 18 of 20 animals suffered from kidney injury. The grade of renal injury was highly correlated with RI, cRI, NGAL, and CysC. Linear regression equation was established: Grade of renal injury = 0.002 × serum CysC + 6.489 × PI + 4.544 × cRI – 8.358 (r² = 0.698, F = 18.506, P < 0.001).

Conclusions:

AKI is common in post-CA syndrome. Renal Doppler and novel AKI biomarkers in serum and urine are of significant importance as early predictors of post-CA AKI.

Acute kidney injury after cardiac arrest of ventricular fibrillation and asphyxiation swine model

PURPOSES

The purposes of the study are to investigate the renal function in ventricular fibrillation (VF) and asphyxiation cardiac arrest in a swine model and to estimate the value of novel biomarkers in the acute kidney injury (AKI) after cardiac arrest.

METHOD

Thirty-two healthy inbred Wu-Zhi-Shan miniature piglets were randomized into 2 groups (n = 16 per group). Cardiac arrest was induced by programmed electric stimulation and clamping the endotracheal tube in the VF group and asphyxiation group, respectively. Cardiopulmonary resuscitation was done for return of spontaneous circulation (ROSC).

RESULTS

One hundred percent (16/16) ROSC was observed in the VF group, and 50% (8/16) in the asphyxiation group (P < .01). All AKI biomarkers elevated significantly after ROSC. The novel biomarkers changed much earlier than the creatinine. The concentration of novel biomarkers in the asphyxiation group was higher than the VF group. Live animals had an oliguria and developed AKI. Characteristic morphological injuries in renal tissues were observed under light microscope and transmission electron microscope and were more serious in the asphyxiation group.

CONCLUSIONS

Acute kidney injury at early stage of postresuscitation is common in different causes of cardiac arrest. Asphyxiation has more severe kidney injury and gets worse prognosis.