Relationship between Exposure to Sulphur Dioxide Air Pollution, White Cell Inflammatory Biomarkers and Enzymatic Infarct Size in Patients with ST-segment Elevation Acute Coronary Syndromes

Abstract

Aims: To analyse the relationship among air pollutants, markers of inflammation and infarct size in patients with acute coronary syndrome (ACS). Methods: This was a prospective analysis of consecutive patients admitted to hospital because of ACS. Cardiac biomarkers were drawn. The daily mean values of the air pollutants from the day before until 7 days before admission were analysed. The study population was stratified according to infarct size, based on median peak troponin value. Results: Patients were divided into two groups of 108 subjects each, according to median peak troponin value. Patients with extensive MIs had a higher neutrophil:lymphocyte ratio and leukocyte and neutrophil counts than patients with smaller MIs. In addition, they were exposed to higher concentrations of sulphur dioxide (9.7 ± 4.1 versus 8.4 ± 3.1 μg/m3; p=0.009) and lower concentrations of ozone (33.8 ± 13.7 versus 38.6 ± 14.5 μg/m3; p=0.014). Multivariate analysis showed that sulphur dioxide levels (OR 1.12; 95% CI [1.031-1.21]; p=0.007) and neutrophil/lymphocyte ratio (OR 1.08; 95% CI [1.011-1.17]; p=0.024) were independent predictors of infarct size. Conclusion: Patients with extensive MIs had higher white cell inflammatory levels and had been exposed to higher sulphur dioxide concentrations in the ambient air.