Acute infection increases risk for heart attack and stroke

An infection may trigger a coronary event, such as heart attack or stroke, within the next three months, according to a new study.

The study, published in the Journal of the American Heart Association, finds that in-and outpatient infections are associated with cardiovascular disease (CVD) risk. Patients with an inpatient infection, in particular, are at increased CVD risk and should be considered potential candidates for CVD prophylaxis.

Acute infections are linked with CVD, but little is know about how CVD risk varies following inpatient versus outpatient infections.

Logan T. Cowan, Department of Epidemiology and Environmental Health Sciences, Georgia Southern University, and colleagues hypothesized that in-and outpatient infections are associated with CVD risk and that the association is stronger for inpatient infections.

In the study, the researchers examined a patients' registry tracked over multiple years in four U.S. cities. They looked at 1,312 patients who had a heart attack or other type of coronary event, and 727 other patients who had an ischemic stroke, the kind caused by a blood clot.

Key Findings:

• Of the heart disease patients, about 37 percent had some type of infection within the previous three months. Among stroke patients, it was nearly 30 percent.


• Inpatient infections (14‐day, 30‐day, 42‐day, and 90‐day) and outpatient infections (14‐day, 30‐day, 42‐day, and 90‐day) were more common in all CHD case periods compared with control periods.


• Inpatient infection was a stronger CHD trigger for all time periods.


• Inpatient infection was also a stronger stroke trigger with the difference borderline statistically significant for the 42‐ and 90‐day time periods.

Infections generally trigger an inflammatory reaction in the body, said Dr. Kamakshi Lakshminarayan, an associate professor of epidemiology at the University of Minnesota's medical school.

The body triggers its production of white cell to fight an infection, but that process also increases the stickiness of cells called platelets, she said. This encourages the formation of clots that could block the flow of blood to the heart or brain.

"The infection appears to be the trigger for changing the finely tuned balance in the blood and making us more prone to thrombosis or clot formation," said Lakshminarayan. "It's a trigger for the blood vessels to get blocked up and puts us at higher risk of serious events like heart attack and stroke."

The study raises questions about whether patients hospitalized for infections should also begin receiving treatment to protect them from heart disease and stroke. Additional research may provide those answers, according to Lakshminarayan.

Urinary tract infection, or UTI, was the most common type of infection reported in the study, followed by pneumonia and other respiratory infections. Skin and blood infections also were reported.

The study included patients treated for infections while hospitalized and those who received outpatient care. Both groups were more likely to have a cardiovascular event within three months of the infection, but this association appeared to be stronger among the inpatient group.

That's because infections requiring hospitalizations are probably more severe to begin with, said Juan Badimon, a professor of medicine and director of the atherothrombosis research unit at Mount Sinai School of Medicine's Cardiovascular Institute in New York.

"And if the infection is that severe, we can assume a stronger inflammatory response will result in a higher cardiovascular risk," said Badimon, who was not involved in the research but co-authored an editorial that accompanied the study.

He described the study's association between cardiovascular events and all types of infections, not just respiratory ones, a "novel discovery." But, he said, he would like to have seen researchers dig deeper and note whether the infection source – viral or bacterial – played a role in the increased risk for heart attacks and strokes.

Badimon hopes the findings will encourage the public to make sure their vaccinations are up-to-date, especially during flu season.

For further reference follow the link: https://www.ahajournals.org/doi/10.1161/JAHA.118.009683