Microplastics Found in 58% of Carotid Artery Plaques, Linked to 4.5 Times the Risk of Cardiovascular Events

An observational finding published in the New England Journal of Medicine suggests that micro- and nanoplastics (MNPs) in atherosclerotic plaque (atheroma) may be associated with later cardiovascular events. Researchers at the University of Campania Luigi Vanvitelli in Italy and elsewhere analysed plaques removed from 304 patients who underwent endarterectomy for asymptomatic carotid stenosis, and 257 of them completed an average of 33.7 months of follow-up.

Analysis by pyrolysis-gas chromatography-mass spectrometry (Py-GC-MS) found polyethylene in the plaques of 150 people (58.4%), at an average of 21.7 μg per mg of plaque, and polyvinyl chloride (PVC) was also measured in 31 people (12.1%). Electron microscopy showed foreign particles with jagged edges among macrophages. The group in which plastics were detected had a higher risk of the primary endpoint, a composite of heart attack, stroke and all-cause death, than the group in which they were not (hazard ratio 4.53, 95% confidence interval 2.00 to 10.27).

An Exposure Marker, Not Proof of Cause

The study drew attention for being the first to link the presence of plastics in human tissue to clinical outcomes. However, because it is an observational study, it cannot tell whether plastics are a direct cause, and the possibility remains that factors that raise both plastic exposure and cardiovascular risk, such as smoking, income and occupation, explain the results. The two groups were divided only by whether plastics were detected, and the participants were high-risk patients needing surgery, so it is hard to apply the findings directly to the general public. A limitation of the analytical method has also been raised, namely that polyethylene signals can be false positives in biological samples.