Abstract
BACKGROUND: Admission lactate level has been reported as a useful marker of mortality. In this study, we compared the relative value of different lactate indices to predict survival in patients with ST-segment elevation myocardial infarction (STEMI) undergoing primary percutaneous coronary intervention (PCI). METHODS: This was a retrospective observational study including consecutive patients with STEMI undergoing primary PCI who admitted to the Coronary Care Unit of the First Affiliated Hospital of Wenzhou Medical University between 2014 and 2017. The predictive value of lactate indices for mortality was compared using receiver operator characteristic (ROC) analysis, and DeLong's test was used to compare the AUC. We compared the AUC between GRACE score and GRACE score + lactate index. RESULTS: A total of 1080 patients were included. Fifty-nine died in 30 days and 68 died in 180 days. Most lactate indices (Lac(adm), Lac(24max), Lac(24min) and Lac(24tw)) were significantly lower in survivors (all P<0.001). In Cox proportional hazards model, each lactate index showed as an independent factor of 30-day and 180-day mortality except Lac(Δ). Kaplan-Meier curves demonstrated that the patients of higher lactate indices group had higher rates of mortality (all P<0.0001, except Lac(Δ) P=0.0485). In receiver operator characteristic analysis, Lac(24max) was significantly larger than Lac(adm)(P<0.001) while the AUC value for Lac(adm) was similar to Lac(24min) and Lac(24tw). Lac(24tw) improved the predictive probability of 30-day mortality (P=0.0415). Lac(24max) improved the predictive probability of GRACE score for both 30-day and 180-day mortality (P<0.05). CONCLUSION: In patients with STEMI undergoing primary PCI, most lactate indices are all associated with 30-day and 180-day mortality except LacΔ. In prediction of both 30-day and 180-day mortality, Lac(24max) is superior to Lac(adm) and significantly enhances the ability of risk stratification and prognostic evaluation when adding Lac(24max) to the GRACE score.