Subclinical AKI and Clinical Outcomes in Elderly Patients Undergoing Cardiac Surgery: Diagnostic Utility of NGAL versus Standard Creatinine Increase Criteria

Abstract

Background: AKI is a common and serious postoperative complication in patients undergoing cardiac surgery and its incidence is particularly high among elderly patients. Cardiac surgery-associated AKI (CSA-AKI) represents the second most common cause of AKI in the intensive care unit but its true incidence could be underestimated, especially in elderly population. The current biomarkers of AKI are unreliable and delayed during acute changes in kidney function. In the setting of subclinical AKI (SAKI), biomarkers of tubular damage such as NGAL, seems to be an early indicator of kidney damage. The aim of this study was to investigate NGAL utility in the SAKI diagnosis on the first 48 hours after cardiac surgery and its helpfulness in predicting adverse clinical outcomes in comparison to current criteria for AKI. Methods: This is an observational study of 72 patients admitted to San Bortolo’s cardiac surgery department for elective cardiosurgical procedure enrolled over a 5-months period. All patients underwent peripheral venous sample 48 hours after cardiac surgery to assess plasmatic Creatinine (48Cr) and NGAL (48pNGAL) in addition to exams already foreseen by clinical practice. For each patient we studied renal, respiratory and cardiovascular outcome during hospitalization as well as 30 days and 6 months mortality. Creatinine Increase AKI (CrIAKI) was defined by 48CrI≥0.3mg/dL and Subclinical Acute kidney Injury (SAKI) was defined by 48pNGAL≥100pg/dL. We also assessed Respiratory (ArespO) as well as Cardiovascular (ACvO ) outcome. Results: 30 days mortality was 8.3% (6 patients) and 6 months mortality was 12.5% (9 patients). A total of 27 patients (37.5%) presented AKI according to KDIGO (4) and 4 (5.5%) needed RRT. SAKI was significantly associated with 30 days mortality (p=0.0238), six months mortality (p=0.002), Adverse renal outcome ARenO (p=0.004) and need for RRT (p=0.005). CrIAKI was significantly associated with 30 days mortality (p=0.009) and ARenO (p=0.0001), but not with six months mortality nor need for RRT.

Association between the red cell distribution width and mortality in elderly patients with non-traumatic coma: An observational cohort study

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Plasma proenkephalin and neutrophil gelatinase-associated lipocalin predict mortality in ICU patients with acute kidney injury

“…The level of p-NGAL appears to be an independent predictor of kidney complications, as well as cardiovascular and liver-related diseases [ 41 – 43 ]. Overall, p-NGAL has been shown to be the most promising and clinically available kidney injury biomarker and could be used particularly for patients who are critically ill [ 43 , 44 ]. Serum p-NGAL has been found to be a good predictor for AKI and a good predictor of the need for renal replacement therapy.…”

The association between the red cell distribution width and mortality in elderly patients with non- traumatic coma: a retrospective observation study

“…Our ndings suggest that the overall health of patients with high RDW levels was worse than that of patients with low RDW levels. In particular, it is well known that BUN, creatinine and hemoglobin levels, and platelet counts are signi cantly associated with prognosis in elderly patients [22][23][24][25].…”