NACMI Analysis Shows Increased Incidence of Clotting in STEMI Patients With COVID-19

May 19, 2023—A core-lab analysis from the North American COVID-19 STEMI (NACMI) registry showed patients with an ST-segment elevated myocardial infarction (STEMI) and COVID-19 had a significant amount of clotting in their arteries both before and after interventions. Clots were seen in multiple arteries in approximately 30% of patients, a phenomenon observed in < 5% of patients with myocardial infarction who do not have COVID-19.

The findings were presented as late-breaking clinical research at the Society for Cardiovascular Angiography & Interventions (SCAI) 2023 Scientific Sessions held May 18-20 in Phoenix, Arizona.

As noted in the SCAI press release, the NACMI registry is a collaboration of SCAI, the American College of Cardiology, and the Canadian Association of Interventional Cardiology. The registry was established in 2020 to define baseline characteristics and management strategies and outcome data for COVID-19 patients presenting with STEMI. More than 60 medical centers across North America and Canada contributed data to the registry.

According to the press release from SCAI, pre–COVID-19 mortality in STEMI patients was < 5%; however, previous NACMI research has shown that mortality increases to 20% to 25% in patients who present with COVID-19 and a heart attack.

SCAI reported that in the blinded angiographic analysis of NACMI, investigation sites were invited to send angiograms to the Cardiovascular Imaging Research Core Lab in Vancouver, Canada.

The analysis assessed quantitative coronary angiography percent diameter stenosis (DS), thrombolysis in myocardial infarction (TIMI) flow, myocardial blush grade, and thrombus grade burden (TGB).

Percutaneous coronary intervention (PCI) was classified as unsuccessful if there was residual DS > 50% and/or < TIMI 2 flow and/or untreated complication(s). Multivessel thrombotic disease and stenotic disease was defined as TGB > 0 and DS > 50% in more than two arteries, respectively.

As summarized in the SCAI press release, angiograms of 234 patients from 17 sites (12 in the United States, five in Canada) were analyzed.

The findings included the following:

• High TGB was observed in 74% of all patients before intervention and 29% of patients after intervention.
• A high proportion of patients (19%) did not have culprit lesions, suggesting other mechanisms for heart attack may be at play in this patient population.
• The core lab identified stent thrombosis in 12% of the entire cohort—a frequency that has never been observed in other STEMI cohorts.
• Of the 49 patients, the core lab-identified PCI failure rate was 34% with a high complication rate of 23%, mostly related to thrombus.

“COVID-19 is a pro-inflammatory, clot-forming disease and we now see its effect in the coronary arteries,” commented Payam Dehghani, MD, in the SCAI press release. Dr. Dehghani is Codirector of Prairie Vascular Research, Inc. and Associate Professor at the University of Saskatchewan in Saskatoon, Canada. “These new insights point to the need for clinicians to be meticulous with blood-thinning strategies, early interventions and patient follow-up.”

Further investigation is needed to better understand the impact of COVID-19 and heart attacks related to vaccination as well as long-term outcomes, noted the investigators in the SCAI press release.