Abstract P37: Evidence of Impaired Vascular Reactivity Following Dust Exposure in Participants in the World Trade Center Medical Monitoring and Treatment Program
INTRODUCTION: Exposure to particulate matter (PM) has been investigated as an additional risk factor for cardiovascular disease (CVD). It is likely that different mechanisms, including vascular dysfunction, are responsible for acute and chronic toxic effects. In participants of the Law Enforcement Cardiovascular Screening Program (LECS), a subset of the WTC Medical Monitoring and Treatment Program, we look to characterize the relationship between PM exposure and vascular reactivity (surrogate for endothelial function), as measured by peripheral arterial tonometry (PAT). METHODS: PAT, a system comprised of a finger probe to assess digital volume changes accompanying pulse waves, was used. Digital pulse volume changes during reactive hyperemia was assessed in 60 patients with either high (n=33) or low (n=27) PM exposure. PAT index, a measure of reactive hyperemia, was calculated as the ratio of the digital pulse volume during reactive hyperemia divided by that at baseline. All data were prospectively obtained. We define highest inhaled PM exposure as occurring on 9/11/2001, and lower inhaled PM exposure as occurring on or after 9/13/2001. A PAT index of 1.67 or less was considered to represent abnormal vascular reactivity. RESULTS: Mean age was 49 years (range 45-53), 83% were male. There were no significant differences in baseline characteristics, including CVD risk factors. Median PAT was 1.87 (1.30-2.75) for subjects with lower exposure and 1.68 (1.15-3.22) for subjects with highest exposure to PM. Of subjects with highest exposure to PM, 68% (17/33) had a PAT index 1.67 or less, compared with 32% (8/27), of subjects with lower exposure (p value=0.17). The odds of having abnormal PAT index to normal PAT index was 2.1 times higher in subjects with highest exposure compared to those with lower exposure to PM (95%CI 0.7-6.2). CONCLUSION: We observe a trend correlating highest WTC inhaled PM exposure with abnormal vascular reactivity as measured by peripheral arterial tonometry index of 1.67 or less. The clinical impact of this finding, in this pilot study, requires further investigation.