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Duluth doctor studying outcomes of heart attacks in COVID-19 patients

The national studies have found that patients with COVID-19 were much more likely to die of a heart attack in the hospital compared to pre-pandemic averages. The studies also discovered that patients who are vaccinated against COVID had better outcomes.

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Dr. Catherine Benziger
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DULUTH — Essentia cardiologist Catherine Benziger has co-authored research in the Journal of the American College of Cardiology detailing the outcomes of COVID-19 patients who experienced heart attacks in 2020 and 2021. According to the research, in-hospital mortality was 33% in 2020 and 23% in 2021 for these patients. Benziger said in-hospital mortality rates for heart attacks have been less than 5% over the last decade.

The research shows that patients who were most at risk to suffer a heart attack during COVID-19 infection included patients with diabetes, and patients who are Black or Hispanic.

“Diabetes seemed to be the biggest driver — 44% had diabetes,” Benziger said.

Benziger and the other researchers suspect that the heart attacks are occurring due to inflammation from the immune response to the coronavirus.

"Diabetes is a disease that causes a lot of inflammation in the body. Rheumatoid arthritis is another one," she said. "These patients are just at higher risk of having heart attacks at baseline, when they have a lot of inflammation. The COVID infection itself doesn’t seem to attack the heart muscle and cause issues, it’s the immune response that is triggered by the infection that causes heart issues and the inflammation.”


Of the 586 COVID-positive patients with an ST-elevation myocardial infarction (STEMI) heart attack included in the study, about 30 were treated at Essentia in Duluth. Benziger said the Duluth patient volume was one of the five largest participating in the research.

Benziger said the ultimate goal of the research is to understand what happens to COVID-19 patients who have heart attacks and how their treatment led to the outcomes. She speculates that there may not have been adequate personal protective equipment for staff in 2020, when outcomes were the worst.

She also said hospitals have seen so much overcrowding at points during the pandemic that at times Essentia has been unable to accept patients from other hospitals. Longer wait times at emergency rooms were likely a factor in the hospital being unable to provide successful care to some STEMI patients, Benziger said.

Typically, a person experiencing heart attack symptoms like shortness of breath, chest pains or fatigue should call 911. In the ambulance, first responders can take an EKG and alert hospitals to prepare for the patient. Patients can be given a cardiac catheterization to locate a blockage in blood vessels and to measure pressure and oxygen levels in the heart.

“We’ve spent the last 20 years trying to optimize heart attack care,” Benziger said. “During COVID, there was a lot of disruption to that care, and one of the main findings was actually that about 20% of these patients didn’t go to the cath lab at all, so we’re trying to understand why — if they were just too sick, or what other risk factors they had.”

Some good news found in the study is that risk of in-hospital mortality decreased 10% from 2020 to 2021, which is widely credited to the availability of vaccines. Because health care staff was more protected against the virus, they were better able to perform the standard systems of care for STEMI patients. Benziger said she and the other researchers didn't have vaccination status of all 356 patients treated in 2021, but none of the 22 vaccinated patients died. Thirty-seven deaths were recorded in unvaccinated patients.

"We feel like it’s another reason why, if you have diabetes or if you’re at risk, getting vaccinated — as we know — is really important to prevent adverse effects of COVID,” she said. “People don’t think of preventing death after heart attacks from getting a vaccine, but that may push somebody who has had a prior heart attack or who has diabetes to maybe decide to get vaccinated.”

Benziger said people who have had heart attacks in the past are always at some risk of having another, but they made up a small percentage of people registered in the study.


In addition, no research was found to show a risk factor between prior COVID-19 infection and a future heart attack. However, some long COVID symptoms do include fast heart rates and fatigue.

The research by the North American COVID-19 Myocardial Infarction (NACMI) Registry is ongoing with another article to be published later this month. Benziger said statistically, women's STEMI symptoms are not recognized as quickly as men's, and women tend to have worse outcomes.

“We’ve found, in our registry, there’s a number of young women whose only risk factor is smoking," Benziger said. "And we know that in our community, particularly in the Iron Range, about 30% of our adult population smokes.”

She recommends that the public stay alert for possible heart attack symptoms, and call 911 if a person is experiencing prolonged fatigue, shortness of breath, or chest, arm or jaw pain. People should get a stress test or see a cardiologist if they have any lingering concerns. In addition, she recommends people live healthy lifestyles and take immediate action if they are in the prediabetes range to reverse its course and reduce their risk factors.

Laura Butterbrodt covers health for the Duluth News Tribune. She has a bachelor of arts in journalism from South Dakota State University and has been working as a reporter in Minnesota and South Dakota since 2014.
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