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Brain scans give clues to stress-heart attack link

Staff writer ▼ | March 29, 2016
A new brain study might help explain why a high level of stress is linked to an increased risk of heart attack and stroke.
Brain scans
Diagnostics   Increased activity in the amygdala
Increased activity in the amygdala - the fear center of the brain - appears to create an immune system reaction that increases inflammation in the arteries, researchers plan to report at the upcoming American College of Cardiology meeting in Chicago.

Such arterial inflammation is a precursor to heart disease, heart attack and stroke, said senior researcher Dr. Ahmed Tawakol, a cardiologist at Massachusetts General Hospital in Boston.

Tawakol and his colleagues followed nearly 300 people and found their amygdala activity - as seen on brain scans - indicated whether they would suffer a major cardiac event in the near future.

"By the end of the study, roughly 5 percent with low activity had events, compared to roughly 40 percent of the individuals with high amygdala activity," Tawakol said.

Doctors need to be aware of the heart-health consequences of current events such as the Syrian crisis and this week's terror attacks in Brussels, said Dr. Richard Becker, director of cardiovascular health and disease at the University of Cincinnati College of Medicine. He is also director of the university's Heart, Lung & Vascular Institute.

"After there's an earthquake or a tsunami, the incidence of heart attacks over the next six to eight weeks increases substantially," said Becker, an American Heart Association spokesman, citing prior research.

"The same thing happens with human disasters, with terrorism, particularly if it's on a large scale."

Evidence of the strong link between stress and heart disease has been mounting. The heart-health risk posed by stress is now believed to be on par with factors like smoking, cholesterol, high blood pressure and diabetes, Tawakol said.

But little is known about how stress from anger, hostility, hopelessness or uncertainty might directly affect the heart, Tawakol said.

Animal studies have suggested that stress can cause bone marrow to release inflammatory cells, which then increase inflammation in the arteries, he said.

To see whether that happens in humans, researchers examined PET/CT scans for 293 patients, average age 55, who originally received the test between 2005 and 2008 for cancer screening but were found to be cancer-free.

The scans allowed researchers to measure activity in regions of the brain, the bone marrow and arteries. Patients were excluded if they had evidence of cancer, established heart disease or were younger than 30 years old.

During the five-year study, 22 patients experienced a heart attack or stroke.

Researchers found that increased amygdala activity meant greater activity in the bone marrow and increased inflammation in arteries.

Further, amygdala activity was linked to an increased risk of heart attack or stroke. Patients experienced a 14-fold greater risk of heart attack or stroke for every unit increase in measured brain stress activity, researchers said. The amygdala also affected the timing of a heart attack or stroke.