Particulate Matter Air Pollution and Long-Term Outcomes in Patients Undergoing Percutaneous Coronary Intervention

Background: Fine particulate matter (PM_2.5) promotes atherosclerosis progression and plaque vulnerability. Consequently, patients with a high atherosclerotic burden may be at especially increased risk when exposed to air pollution. Objectives: The purpose of this study was to examine the relationship between chronic ambient PM_2.5 exposure and adverse outcomes after percutaneous coronary interventions (PCI). Methods: Baseline clinical and procedural data from U.S. veterans undergoing elective PCI (2005-2018) were linked to annual ambient PM_2.5 exposure. The association between PM_2.5 exposure and major adverse cardiovascular events (MACEs) (myocardial infarction, stroke, or all-cause mortality) was determined using time-varying Cox regression models. Using flexible parametric models, we also evaluated the average life months lost for specific PM_2.5 levels over the 15-year period. Results: In the 73,425 veterans that underwent an elective PCI, the mean annual PM_2.5 exposure was 8.4 ± 1.8 μg/m³ (median follow-up 6.75 years). The incidence of MACE was 28%, 48%, and 65% at 5, 10, and 15 years, respectively. In adjusted models, each 1-μg/m³ increase in PM_2.5 exposure was associated with an 8.7% (95% CI: 8.4%-8.9%; P < 0.001) increase in MACE. Compared to patients exposed to 5 μg/m³, those exposed to 10 μg/m³ lost 1.1, 3.8, and 7.6 months of life at 5, 10, and 15 years of exposure, respectively. Conclusions: Veterans undergoing elective PCI are at increased risk of MACE and significant life years lost with long-term exposure to fine particulate matter pollution, even at the current low levels in the United States. These findings emphasize the need for improved air quality standards and patient interventions to better protect vulnerable populations.