Diagnostic accuracy and prognostic valued of plasmatic Cystatin-C in children undergoing pediatric cardiac surgery

Using Serum Cystatin C to Predict Acute Kidney Injury Following Infant Cardiac Surgery

Acute kidney injury (AKI) following cardiopulmonary bypass (CPB) is associated with increased morbidity and mortality. Serum Cystatin C (CysC) is a novel biomarker synthesized by all nucleated cells that may act as an early indicator of AKI following infant CPB. Prospective observational study of infants (< 1 year) requiring CPB during cardiac surgery. CysC was measured at baseline and 12, 24, 48, and 72 h following CPB initiation. Each post-op percent difference in CysC (e.g. %CysC_12h) from baseline was calculated. Clinical variables along with urine output (UOP) and serum creatinine (SCr) were followed. Subjects were divided into two groups: AKI and non-AKI based upon the Kidney Disease Improving Global Outcomes (KDIGO) classification. AKI occurred in 41.9% (18) of the 43 infants enrolled. Patient demographics and baseline CysC levels were similar between groups. CysC levels were 0.97 ± 0.28 mg/L over the study period, and directly correlated with SCr (R = 0.71, p < 0.0001). Although absolute CysC levels were not significant between groups, the %CysC_12h was significantly greater in the AKI group (AKI: - 16% ± 22% vs. Non-AKI - 28% ± 9% mg/L; p = 0.003). However, multivariate analysis demonstrated that a lower UOP (Odds Ratio:0.298; 95% CI 0.073, 0.850; p = 0.02) but not %CysC_12h was independently associated with AKI. Despite a significant difference in the %CysC_12h, only UOP was independently associated with AKI. Larger studies of a more homogenous population are needed to understand these results and to explore the variability in this biomarker seen across institutions.

Biomarkers of acute kidney injury in pediatric cardiac surgery

Acute kidney injury (AKI) is characterized by a sudden decrease in kidney function. Children with congenital heart disease are a special group at risk of developing AKI. We performed a systematic review of the literature to search for studies reporting the usefulness of novel urine, serum, and plasma biomarkers in the diagnosis and progression of AKI and their association with clinical outcomes in children undergoing pediatric cardiac surgery. In thirty studies, we analyzed the capacity to predict AKI and poor outcomes of five biomarkers: Cystatin C, Neutrophil gelatinase-associated lipocalin, Interleukin-18, Kidney injury molecule-1, and Liver fatty acid-binding protein. In conclusion, we suggest the need for further meta-analyses with the availability of additional studies.

Evaluation of acute kidney injury with oxidative stress biomarkers and Renal Resistive Index after cardiac surgery

BACKGROUND

We investigated whether cardiopulmonary bypass (CPB) related oxidative stress mediated glycocalyx degradation can cause an increase in renal resistive index (RRI) or postoperative AKI. Additionally, to evaluate whether RRI and early postoperative serum cystatin C levels could improve the prediction sensitivity of acute kidney injury (AKI).

METHODS

Forty-two patients undergoing cardiac surgery were included in this prospective observational study. RRI was measured pre-operatively and in the cardiac intensive care unit. Blood samples were collected for analyzing of cellular injury biomarkers at preoperative and postoperative second hours. We determined areas under the receiver operating characteristic curve (AUC) and odds ratios for postoperative biomarkers and RRI to predict AKI.

RESULTS

While postoperative cystatin C level (AUC: 0.902, 95% CI = 0.79-1.00, p < .001) and RRI (AUC: 0.748, 95% CI = 0.56-0.93, p = .023) have diagnostic and predictive value in the prediction of AKI, we could not identify any relation between products of oxidative stress and the glycocalyx degradation and AKI.

CONCLUSION

These data suggest that CPB leads to structural and oxidative changes at the protein level and the integrity of glycocalyx is disturbing, but these changes are not specific to kidney injury. Our data suggest that serum cystatin C level and RRI could be used as an early biomarker for postoperative AKI after cardiac surgery.

Serum Levels of Cystatin C, N-Terminal Pro-B-Type Natriuretic Peptide (NT-proBNP), and Cardiac Function in Patients with Unstable Angina Pectoris

Background

This study aimed to investigate the association between serum levels of cystatin C, N-terminal pro-B-type natriuretic peptide (NT-proBNP), and cardiac function in patients with unstable angina pectoris (UAP).

Material/Methods

A cross-sectional observational study was conducted at a single center and recruited 300 patients (214 men and 86 women), who were diagnosed with UAP between June 2018 to December 2018. The patients had serum levels of NT-ProBNP measured and were divided into four groups according to the serum levels of cystatin C: Q1, 0.49–0.83 mg/L; Q2, 0.84–1.04 mg/L; Q3, 1.05–1.38 mg/L; Q4, 1.39–4.21 mg/L. Cardiac function was graded according to the New York Heart Association (NYHA) class I to IV criteria.

Results

In the 300 patients with UAP, there were significant differences in cardiac function and NT-ProBNP levels between the four study groups (Q1 to Q4) (p<0.05). Univariate analysis showed that body weight, heart rate, treatment with aspirin, ticagrelor, angiotensin-converting enzyme inhibitor and an angiotensin receptor blocker (ACE/ARB), diuretic use, uric acid level, and serum cystatin C levels were significantly associated with increased levels of NT-ProBNP. After adjusting for confounding factors screened in univariate analysis, multivariate regression analysis showed that increased serum cystatin C levels were significantly associated with increased levels of NT-ProBNP.

Conclusions

Increased serum levels of cystatin C were associated with poor cardiac function and increased levels of NT-ProBNP in patients with UAP.

Prognostic Value of a New Lung Ultrasound Score to Predict Intensive Care Unit Stay in Pediatric Cardiac Surgery

BACKGROUND

Lung ultrasound (LUS) in pediatric cardiac surgery is gaining consensus. We (1) evaluated the prognostic value of a new LUS-score in pediatric cardiac surgery, and (2) compared LUS-score to conventional risk factors including age, The Society of Thoracic Surgeons/European Association of Cardio-Thoracic Surgery (STAT) score, cardiopulmonary bypass time, and prognostic biomarkers including brain natriuretic peptide and cystatin-C.

METHODS

LUS examinations were performed in 237 children (median age, 0.55 years; interquartile range, 0.09-4.15 years) at 12 to 36 hours after surgery. For each hemithorax, 3 areas (anterior/lateral/posterior) were evaluated in the upper and lower halves, constituting 12 total scanning areas. For each site a score was assigned: 0 (rare B lines), 1 (separated B lines), 2 (coalescent B lines), 3 (loss of aeration), and total LUS score was calculated as sum of all sites. The primary endpoints were intensive care unit length of stay and extubation time.

RESULTS

The mean total LUS score was 12.88 ± 6.41 (range, 0-26) and was higher in newborns (16.77 ± 5.25) compared with older children (5.36 ± 5.57; P < .001). On univariate analysis, LUS score was associated inversely with age (beta 0.26; P = .004) and body surface area (beta 3.41 P = .006) and positively with brain natriuretic peptide (beta 1.65; P < .001) and cystatin-C (beta 2.41; P < .001). The LUS score, when added as continuous predictor to a conventional risk model (age, STAT score, and cardiopulmonary bypass time) emerged significant both for intensive care unit length of stay (beta 0.145, P = .047) and extubation time (beta 1.644; P = .024). When single quadrants were analyzed, only anterior LUS score was significant (intensive care unit length of stay beta, 0.471; P = .020; extubation time beta 5.530; P = .007).

CONCLUSIONS

Our data show the prognostic incremental value of a new LUS score over traditional risk factors in pediatric cardiac surgery.