Prognostic impact of neutrophil gelatinase-associated lipocalin and B-type natriuretic in patients with ST-elevation myocardial infarction treated by primary PCI: a prospective observational cohort study

OBJECTIVES: Neutrophil gelatinase-associated lipocalin (NGAL) from a pathophysiological perspective connects various pathways that affect the prognosis after myocardial infarction. The objective was to evaluate the benefits of measuring NGAL for prognostic stratification in addition to the Thrombolysis in Myocardial Infarction (TIMI) score, and to compare it with the prognostic value of B-type natriuretic peptide (BNP). DESIGN: Prospective observational cohort study. SETTING: One university/tertiary centre. PARTICIPANTS: A total of 673 patients with ST segment elevation myocardial infarction were treated by primary percutaneous coronary intervention. NGAL and BNP were assessed on hospital admission. OUTCOMES: Primary outcome: 1-year mortality. Secondary outcomes: 1-year hospitalisation due to acute heart failure, unplanned revascularisation, reinfarction, stroke and combined end point of 1-year mortality and hospitalisation due to heart failure. STATISTICAL METHODS: Using the c-statistic, the ability of NGAL, BNP and TIMI score to predict 1-year mortality alone and in combination with readmission for heart failure was evaluated. The addition of the predictive value of biomarkers to the score was assessed by category free net reclassification improvement (cfNRI) and the integrated discrimination index (IDI). RESULTS: The NGAL level was significantly higher in non-survivors (67 vs 115 pg/mL; p<0.001). The area under the curve (AUC) values for mortality prediction for NGAL, BNP and TIMI score were 75.5, 78.7 and 74.4, respectively (all p<0.001) with optimal cut-off values of 84 pg/mL for NGAL and 150 pg/mL for BNP. The addition of NGAL and BNP to the TIMI score significantly improved risk stratification according to cfNRI and IDI. A BNP and the combination of the TIMI score with NGAL predicted the occurrence of the combined end point with an AUC of 80.6 or 82.2, respectively. NGAL alone is a simple tool to identify very high-risk patients. NGAL >110 pg/mL was associated with a 1-year mortality of 20%. CONCLUSIONS: The measurement of NGAL together with the TIMI score results in a strong prognostic model for the 1-year mortality rate in patients with STEMI.