Urinary neutrophil gelatinase-associated lipocalin and clinical outcomes in patients with acute coronary syndrome: a focus on patients with impaired ejection fraction

BACKGROUND: To evaluate the prognostic value of urinary neutrophil gelatinase-associated lipocalin (NGAL) normalized to creatinine in patients with acute coronary syndrome (ACS), focusing on left ventricular ejection fraction (LVEF). METHODS: This retrospective cohort study included 144 patients emergently admitted for ACS, with urinary NGAL measured 4-48 h postadmission. Primary and secondary outcomes were all-cause mortality and major adverse cardiovascular and cerebrovascular events (MACCEs), respectively. Optimal NGAL/creatinine cutoffs were determined using receiver operating characteristic analysis. Associations between urinary NGAL/creatinine and clinical outcomes were evaluated using Cox proportional hazards models. RESULTS: During a median 734.5-day follow-up, 8 deaths and 44 MACCE occurred. The optimal NGAL/creatinine cutoff for predicting MACCE was 20.85 ng/mg creatinine. All deaths occurred in the high NGAL/creatinine group (≥20.85), but mortality analyses were limited by statistical separation. High NGAL/creatinine was significantly associated with MACCE (hazard ratio = 3.47, 95% confidence interval = 1.61-7.47) and remained associated with a higher event hazard after adjustment for age, brain natriuretic peptide, LVEF, and estimated glomerular filtration rate (adjusted hazard ratio = 2.75; P = 0.017). In subgroup analyses, the area under the curve for MACCE was numerically higher in patients with LVEF <50% than in those with LVEF ≥50% (0.753 vs. 0.581). Formal interaction testing in the Cox model, however, did not demonstrate significant effect modification by LVEF category (P for interaction = 0.100). CONCLUSION: Urinary NGAL/creatinine was significantly associated with long-term MACCE in patients with ACS. Although subgroup analyses showed numerically different associations according to LVEF, formal interaction testing did not demonstrate significant effect modification by LVEF.