A small Italian study has detected microplastics and nanoplastics in the coronary blood of 84% of patients experiencing a serious heart attack. The figure was lower among patients with chronic ischemic heart disease, at 40%, and among people with normal coronary arteries, at 32%.
That sounds alarming. But the study does not show that plastic particles caused the heart attacks, and several independent scientists say the detection method and study design leave major questions unanswered. The central message is more cautious than the headline numbers suggest.
What the researchers measured
The study included 61 adults undergoing coronary angiography, a procedure that lets doctors examine the arteries supplying the heart. Nineteen patients had a major heart attack, 20 had chronic coronary disease, and 22 had normal coronary arteries.
Researchers collected blood from the coronary circulation and from arteries elsewhere in the body. The work was led by Pasquale Paolisso and Emanuele Barbato, with scientists from Sapienza University of Rome, the University of Verona, and the University of Campania Luigi Vanvitelli.
Microplastics are tiny fragments shed as larger plastic products break down. Nanoplastics are smaller still, and both can be difficult to distinguish from the fats, proteins, and other natural material already present in blood.
A pattern around the heart
Patients having heart attacks had more frequent detections and a wider range of reported polymers. Polyethylene, commonly used in packaging and consumer goods, was identified in 97% of positive cases, while concentrations were generally higher in coronary blood than in peripheral blood.
The heart attack group also showed higher levels of two inflammatory markers. Inflammation is part of the body’s defense system, but an excessive response can damage blood vessels and help destabilize arterial plaque.
The researchers also found links with smoking and fine-particle air pollution known as PM2.5. Smokers were about six times more likely to have detectable plastic signals, although smoking history was the only independent predictor remaining after statistical adjustment.
Association is not causation
“These findings do not prove that microplastics cause heart attacks,” Barbato said. That distinction matters because the study took a single snapshot during treatment rather than tracking healthy people over time.
Ria Devereux, an environmental researcher at the University of East London, noted that this design cannot reveal what came first. The particles could have been present before the heart attack, increased during the event or medical care, or reflected environmental exposure.
Diet, drinking water, indoor dust, workplace conditions, and medical equipment were not fully assessed. That makes it difficult to separate plastic exposure from the many other factors surrounding a cardiac emergency.
The measurement dispute
The sharpest criticism concerns a technique called pyrolysis gas chromatography mass spectrometry. The method heats a sample, breaks its contents into smaller chemicals, and identifies the resulting chemical pattern.
Roberto Rosal, a chemical engineering professor at the University of Alcalá, warned that heated blood fats can produce some of the same signals as plastics.
Kevin Thomas, director of the Queensland Alliance for Environmental Health Sciences at the University of Queensland, said the key question is whether the researchers detected plastics or molecules that merely resemble them.
The authors also used an infrared method and extensive controls intended to reduce contamination from clothing, tubes, catheters, and surrounding air. Still, critics note that no internationally standardized method exists for measuring the smallest plastic particles in human blood.
Why the finding still matters
Thava Palanisami, who leads the Australian Plastics Research and Innovation Laboratory at the University of Newcastle, called the work an important step while stressing that it cannot establish a direct cause.
Other experts see a growing signal across human, animal, and cell studies, but not yet a settled medical conclusion.
A 2024 study in The New England Journal of Medicine found plastic particles in removed carotid artery plaques and linked their presence with a higher rate of heart attack, stroke, or death during follow-up.
That research was also observational, so it strengthened the association without proving plastics produced those outcomes.
For now, the evidence is more like a warning light than a diagnosis. Plastic pollution may belong in the broader conversation about environmental heart risks, alongside dirty air and tobacco smoke, but larger studies must show whether it plays an independent role.
What happens next
Researchers need prospective studies that follow much larger and more diverse groups before disease develops. They also need standardized laboratory methods and detailed records of diet, occupation, medical treatment, and personal exposure.
The authors themselves describe the results as exploratory and designed to generate new hypotheses, not as a confirmed estimate of risk. For patients, that means the study raises an important research question rather than creating a new diagnosis or treatment rule.
Reducing unnecessary plastic use and pollution may still be sensible under a precautionary approach. But this study should not be read as proof that one plastic bottle, food container, or daily habit directly triggers a heart attack. Not yet.
The main study was published in the European Heart Journal.
