Two-Year Data from International COVID-19 STEMI Research Reveals Mortality is Decreasing for COVID-19 Patients with Heart Attacks but Remains High for Unvaccinated Patients

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April 12, 2022 – The Minneapolis Heart Institute Foundation (MHIF) has announced the first presentation and simultaneous publication of two-year outcomes from the North American COVID-19 ST-Segment Elevation Myocardial Infarction Registry (NACMI) showing improvements in survival in 2021 relative to 2020. However, mortality remains high in unvaccinated patients with STEMI and COVID-19 infection. The data underscore significant changes have occurred in clinical characteristics, management strategies and outcomes of STEMI patients with COVID-19 infection during the pandemic, including a 25 percent reduction in mortality in patients during 2021. This research led an international effort to understand and inform optimal care and management of patients during a rapidly evolving pandemic. These data were presented at the American College of Cardiology Scientific Session (ACC.22) and simultaneously published in the Journal of the American College of Cardiology.

“The mortality for patients who were vaccinated in this research was zero; none of them died in the hospital and all the data suggest that we're getting back to pre-pandemic success of heart attack outcomes in vaccinated patients,” said Santiago Garcia, MD, interventional cardiologist, researcher and primary investigator for MHIF, which is the international data coordinating center for the study. “The mortality for people that were treated in 2021 and were not vaccinated was 22 percent, which is quite high for heart attack patients. There's a powerful message here and it certainly supports the recommendations to get people vaccinated.”

Highlights from the research:

586 COVID-positive patients with STEMI were included in the present analysis
In 2021, none of the 22 vaccinated patients expired in hospital; in-hospital death was recorded in 37 (22 percent) of unvaccinated patients
227 treated in 2020; 359 treated in 2021
Significant changes in patients’ characteristics occurred over time; patients treated in 2021 (vs. 2020) were more likely:
- To be Caucasian (58 percent vs. 39 percent, p<0.001)
- Present with chest pain (59 percent vs 51 percent, p=0.04) rather than dyspnea (42 percent vs 56 percent, p=0.002)
- In-hospital mortality decreased from 33 percent to 23 percent (p=0.008) with no differences in stroke or reinfarction

At the start of the pandemic, there was a 38 percent reduction in heart attack patients coming to hospitals in the United States and that was what prompted the NACMI registry. This is noted as an indirect effect of COVID-19 because it is most likely explained by the response to COVID (lockdowns, cancellation of outpatient procedures, strict visitation policies, etc.) rather than the virus itself. There are also direct effects of COVID on heart attacks.

“We have learned when a patient contracts COVID, there is increased risk of developing blood clots within the first two weeks and it tends to affect the venous system, so patients can develop clots in the legs, lungs, as well as the arterial circulation, including heart attacks,” said Dr. Garcia. “In our follow-up analysis we looked at trends in ST segment elevation and myocardial infarction care. We compared the characteristics of patients, the treatments and the outcomes in 2021 versus 2020, a cutoff that is not arbitrary; that's the time where vaccines were commercially approved in North America and we wanted to see if that made any difference.”

In this newly published research, the primary endpoint was in-hospital mortality. The secondary endpoint was a composite of in-hospital death, stroke, or reinfarction. The new analysis focused only on COVID-positive STEMI patients from the NACMI registry. The NACMI registry was developed in early 2020, prior to the availability of COVID-9 vaccines, so vaccine status was not routinely captured. Once vaccines were commercially available, the registry protocol was amended (and approved by 20 enrolling sites at time of publication) to include details about immunization status.

The NACMI registry involves 64 sites from across the U.S. and Canada and MHIF is the data coordinating center. The registry is a collaborative effort between the Society for Cardiovascular Angiography and Interventions (SCAI), The American College of Cardiology (ACC), and the Canadian Association of Interventional Cardiology (CAIC). It is a research study designed to collect data on COVID-19 positive patients with ST-Elevation Myocardial Infarction (STEMI), a serious heart attack involving a blockage in one of the heart's major arteries.

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