[Relationship between short-term exposure to atmospheric sulfur dioxide and obstructive lesions in acute coronary syndrome].

BACKGROUND AND OBJECTIVES: Urban air pollutants are composed of a heterogeneous mixture of substances in gas and aerosol states. The aim of this study was to compare the effects caused by exposure to contaminants in the gas phase and atmospheric particles in ambient air in patients hospitalized for acute coronary syndrome (ACS) regarding the presence or absence of significant obstructive lesions (SOL) in epicardial coronary arteries.

PATIENTS AND METHODS: Prospectively analyzed a total of 2,110 patients with a diagnosis of ACS. We determined the mean concentrations of contaminants in the gas phase and atmospheric particles from the day before until 7 days prior to admission (1 to 7 days lag time). We divided the study population into those with presence or absence of SOL.

RESULTS: Of the 2,110 patients with ACS, 1,892 presented SOL and 218 without SOL. When comparing the concentrations of contaminants in the gas phase, we observed that the sulfur dioxide in patients with SOL had a trend toward higher values (10.93 ± 8.33 versus 9.31 ± 6.77 μg/m(3); P = .004). Multivariate analysis shows that for every 10 μg/m(3) increase of sulfur dioxide, there is an increase in the risk of hospitalization for ACS with SOL a 41% (odds ratio 1.41; 95% confidence interval 1.039-1.931; P = .028).

CONCLUSIONS: In our study population, exposure to high concentrations of sulfur dioxide is a precipitating factor for admission of patients with ACS and SOL.