Does neutrophil gelatinase-associated lipocalin have got prognostic value in patients with stable angina undergoing elective PCI? A 3-year follow-up study

Abstract

Background: Neutrophil gelatinase-associated lipocalin (NGAL) is highlighted as an early and specific marker of contrast-induced nephropathy (CIN) and acute kidney injury (AKI). However, the long term prognostic value of NGAL is still undefined. Purpose: The aim of the study was to assess the prognostic significance of serum and urinary NGAL and serum cystatin C in patients with stable angina undergoing elective percutaneous coronary intervention (PCI) on a 3-year follow-up. Methods: We included in the study 132 consecutive patients with stable angina undergoing elective PCI. Serum NGAL (ANTIBODYSHOP, Gentofte, Denmark) and cystatin C (Dade Behring, Germany) were evaluated before and 4h, 8 h after PCI using commercially available kits. Urinary NGAL was evaluated before and 12h, 24h after the procedure. Serum creatinine and eGFR according to MDRD formula was assessed before and 24h after PCI. All patients were given either NaHCO3 or 0,9% NaCl within 24 hours. The primary end-point was all-cause mortality on a 3-year follow-up. Results: Among 132 patients there were 49 (37%) females, mean age was 64,5±9,8 years.Total mortality was evaluated during 1054±159 days of follow-up. 118 (89%) patients had hypertension, 33 (25%) diabetes, 42 (32%) hypercholesterolemia; 54 (40%) were smokers. Left ventricular ejection fraction (EF) was 48±12%. Mean eGFR was high - 86,2±28,5 ml/min. Mean contrast volume used during coronary angiography was 154,2±84,2 ml. The elective PCI was successful in 97%. During follow-up 10 (8%) of the patients died. All-cause mortality was significantly higher in patients with increased urinary NGAL level 12h after PCI (p=0,04). There was no significant increase in mortality in patients with rise in serum NGAL concentration 4h (p= 0,13) and 8h (p= 1,0) after PCI. Furthermore urinary NGAL concentration 24h after PCI (p=0,85) and cystatin C concentration 4h (p= 0,27) and 8h (p=0,84) after PCI also did not correlate with mortality. Conclusions: In population with preserved renal function and stable angina undergoing elective PCI urinary NGAL concentration 12h after PCI may represent a sensitive marker of late all-cause mortality as it may reflect subclinical kidney injury.