Lipoprotein a Combined with Fibrinogen As an Independent Predictor of Long-Term Prognosis in Patients with Acute Coronary Syndrome: A Multi-Center Retrospective Study

Background: Patients with acute coronary syndrome (ACS) still have a high risk of recurrence of major adverse cardiovascular and cerebrovascular events (MACCE). However, there are rare studies on the prediction of MACCE in patients with ACS using lipoprotein a [Lp(a)] combined with fibrinogen. The aim of this study was to analyze the predictive value of Lp(a) combined with fibrinogen for the long-term prognosis of patients with ACS. Methods: 804 patients with ACS admitted to 11 tertiary general hospitals in Chengdu from January 2017 to June 2019 were included in the study. According to the Lp(a) 300 mg/L, patients were assigned to the non-high Lp(a) group and high Lp(a) group. Patients were assigned to the non-high or high fibrinogen groups using the fibrinogen level of 3.08 g/L. Subsequently, patients were divided into group A, B, or C by Lp(a) combined with fibrinogen. The study endpoints were MACCE, including all-cause death, non-fatal myocardial infarction, non-fatal stroke, and revascularization. The incidences of MACCE among groups were compared. Lp(a), fibrinogen, Lp(a) combined with fibrinogen classifications were each added into the basic model to construct three new models. The C-index, net reclassification index (NRI) and integrated discrimination improvement (IDI) of the three new models were then compared. Results: The median follow-up was 16 months. During follow-up, the cumulative incidence of MACCE in group C was significantly higher than that measured in group A and B (p < 0.001). The results of the multivariate Cox regression analysis of MACCE showed that Lp(a) ≥300 mg/L with fibrinogen ≥3.08 g/L was an independent predictor of MACCE. According to the GRACE score and the statistical analyses, the basic model was constructed, which had a C-index of 0.694. The C-index, NRI, and IDI of the new model constructed using the basic model + Lp(a) combined with fibrinogen classification were 0.736, 0.095, and 0.094 respectively. Conclusions: Single Lp(a), single fibrinogen and Lp(a) combined with fibrinogen were independent predictors of MACCE in patients with ACS. The predictive value of Lp(a) combined with fibrinogen in patients with ACS was better than that of single Lp(a) and single fibrinogen.