The Link Between Microplastics, Air Pollution and Heart Attacks

Microplastics are everywhere. They have been found in drinking water, table salt, seafood, the air we breathe and even human blood. Now, a new study published in European Heart Journal has found them in a place that raises particularly urgent questions: the coronary arteries, the blood vessels that supply the heart with oxygen and nutrients. And the patients with the highest levels of microplastics in their coronary blood were those experiencing the most severe form of heart attack.

“In recent years, scientists have begun to detect these particles in human tissues and organs, raising concerns about their potential health effects,” explained study investigator Pasquale Paolisso, M.D., Ph.D., from Sant’Andrea Hospital Sapienza University of Rome, Italy. “However, very little was known about whether these particles are present in the coronary circulation — the blood flowing through the arteries that supply the heart — or whether environmental exposures such as smoking and air pollution might influence their presence.”

A Closer Look at the Research

Investigators conducted a cross-sectional study of 61 patients undergoing coronary angiography, a procedure that uses imaging to examine the arteries of the heart. Patients were divided into three groups: 19 people experiencing a ST-segment elevation myocardial infarction (STEMI), which is the most serious type of heart attack caused by a complete blockage of a coronary artery; 20 people with chronic coronary syndrome, meaning stable but ongoing coronary artery disease; and 22 people with normal coronary arteries who served as controls.

The team measured micro- and nanoplastics in both coronary blood, drawn directly from the heart’s blood vessels, and peripheral blood drawn from elsewhere in the body. They also collected data on each patient’s air pollution exposure, both on the day of the procedure and over the preceding two years, and measured inflammatory markers in the blood.

Plastics in the Heart

The results were striking. Microplastics were detected in 84.2% of STEMI patients, compared with 40% of those with chronic coronary syndrome and 31.8% of those with normal coronary arteries. The STEMI group also had higher concentrations of microplastics and a greater variety of plastic polymer types, with a median of three different polymers detected per patient. Polyethylene, the most common plastic in everyday consumer products, was the predominant polymer found, appearing in 97% of cases where plastics were detected.

Crucially, the same types of plastics found in patients’ peripheral blood were also found in their coronary blood, confirming that these particles are circulating through the bloodstream and reaching the heart’s own blood vessels. Concentrations were highest in the coronary blood itself.

The STEMI group also showed significantly higher levels of two inflammatory markers, interleukin-6 and tumor necrosis factor-alpha, both of which signal active inflammation in the body. They had also been exposed to higher levels of fine particulate air pollution, known as PM2.5, in the period leading up to their heart attack.

When investigators looked at factors associated with microplastic detection across all patients, they found it was more common in smokers and in people exposed to PM2.5 levels above 15 micrograms per cubic meter. Most strikingly, every single patient who both smoked and had elevated PM2.5 exposure had detectable microplastics in their blood. In the final statistical analysis, smoking history emerged as the strongest independent predictor of microplastic presence, with smokers nearly six times more likely to have detectable microplastics than nonsmokers.

What This Does and Does Not Mean

It is important to be clear about what this study can and cannot tell us. This is an observational, cross-sectional study, meaning it captures a snapshot in time and cannot prove that microplastics caused the heart attacks or the inflammation. The sample size of 61 patients is relatively small. And the relationship between microplastics, air pollution, smoking and cardiovascular disease is complex, with all of these factors intertwined in ways that are difficult to fully separate.

The Takeaway for Your Heart Health

The study shows a meaningful association between higher microplastic burden in coronary blood and the most severe form of heart attack, alongside elevated inflammation and greater environmental exposure. It adds to a growing body of evidence suggesting that microplastics may be more than a passive presence in the human body.

More broadly, this study is part of a rapidly expanding field examining what chronic low-level exposure to environmental contaminants does to the cardiovascular system over time. While it is too early to draw firm clinical conclusions, the presence of microplastics in the coronary blood of heart attack patients is a finding that the scientific community will be watching closely.

“The results highlight the need to consider microplastic pollution as part of the broader environmental determinants of health,” said lead investigator Emanuele Barbato, professor of cardiology at Sapienza University of Rome and the director of the Cardiology Unit of Sant’Andrea University Hospital. “Policies that reduce air pollution, tobacco exposure and environmental plastic contamination could have benefits that extend beyond environmental protection and potentially improve cardiovascular health.”