Purpose. To assess the functional renal status and the significance of neutrophil gelatinase-associated lipocalin (NGAL) levels as a marker of subclinical kidney injury in patients with acute coronary syndrome (ACS).
Material and Methods. 111 patients (80 men and 31 women, mean age – 59.5±10 years) with diagnosis of ACS were examined. On the third day of hospitalization, serum NGAL (s-NGAL) and urine (u-NGAL) levels, serum creatinine (sCr) levels, presence and albuminuria levels (n=79) were determined. Patients with ACS were divided into 4 subgroups depending on NGAL (s-NGAL and u-NGAL) and sCr levels. The incidence of various cardiovascular complications in the hospital and the outcome 6 months after hospital discharge was assessed.
Results. The u-NGAL levels in ACS patients with albuminuria/proteinuria were 2-fold significantly higher 7.28 (2.6–40.6) than in patients with ACS without albuminuria/proteinuria that 3.2 (1.5–7.2, р=0.02). The presence of albuminuria/proteinuria in ACS was associated with higher u-NGAL level (γ=0.34, р=0.003). The incidence of subclinical acute kidney injury (AKI) (NGAL+/sCr-) in ACS was 44.1 and 6.3% (according to the s-NGAL and u-NGAL levels, respectively). ACS patients with subclinical AK (s-NGAL+/sCr-) compared with patients in the subgroup s-NGAL-/sCr- more often had a complicated hospital period (р=0.04) and an unfavorable outcome in long-term (6 months) (р=0.03) period.
Conclusion. Subclinical AKI (increase in the NGAL level without diagnostically relevant increase in sCr) in ACS patients was more often detected by the serum NGAL level. In ACS patients with subclinical AKI (determined by serum NGAL level), complications in the hospital period and endpoints in the long-term (6 months) period were more often detected than in ACS with NGAL level below the boundary value and regardless of sCr levels.

Keywords: subclinical acute kidney injury, NGAL, acute coronary syndrome