Subclinical acute kidney injury as assessed by neutrophil gelatinase-associated lipocalin among ST-segment elevation myocardial infarction patients

Introduction: A subgroup of patients with acute kidney disease (AKI) do not fulfill the functional criteria for AKI diagnosis but show elevated levels of new biomarkers reflecting tubular injury, suggesting that these patients suffer from “subclinical AKI". We investigated the incidence and possible implications of "subclinical AKI" among ST-elevation myocardial infarction patients (STEMI) treated with primary percutaneous coronary intervention (PCI).

Material and method: We included 181 patients with STEMI treated with PCI. Patients with functional AKI were excluded. Neutrophil gelatinase-associated lipocalin (NGAL) was used as a marker of renal tubular damage in the absence of functional AKI, with NGAL levels ≥100ng/ml suggesting subclinical AKI. Patients were assessed for the occurrence of in-hospital adverse outcomes.

Results and discussion: Of the study patients, 45 (25%) had subclinical AKI. These patients were more likely to have left ventricular ejection fraction ≤ 45% (33% vs. 23%. p=0.01), in-hospital adverse outcomes (73% vs. 48%; p=0.005), and their combination. Multivariate regression model demonstrated that subclinical AKI was independently associated with in-hospital adverse outcomes (OR 3.71, 95% CI 1.30-11.62, p=0.02).

Conclusion: Subclinical AKI is common among STEMI patients and is independently associated with adverse outcomes, even in the absence of functional AKI.