Study finds significant clotting in arteries of patients with ST-segment elevation and COVID-19 myocardial infarction

The latest analysis from North American COVID-19 STEMI NACMI is presented today as an Advanced Clinical Investigation at the Scientific Sessions of the Society for Cardiovascular Imaging and Interventions (SCAI) 2023. Results show that patients with ST-elevation myocardial infarction, or STEMI, and COVID-19 have significantly less clotting in their blood vessels. Arteries before and after the intervention. Importantly, clots in multiple arteries were seen in approximately 30% of patients, a phenomenon observed in less than 5% of patients who had heart attacks and who did not have COVID-19.

In the United States, someone has a heart attack every 40 seconds (CDC). Of these patients, more than 25% will have a more severe type of heart attack, ST-elevation myocardial infarction, or STEMI caused by sudden total occlusion of a coronary artery. Pre-COVID-19 mortality in STEMI patients was less than 5% (JACC). Previous NACMI research has shown that the death rate jumps to 20% to 25% in patients who develop COVID-19 and have a heart attack.

In this blinded angiographic analysis, sites were invited to send images of vessels to the Cardiovascular Imaging Research Core Laboratory (Vancouver, CA). Quantitative coronary vessel diameter narrowing (DS), thrombolysis in myocardial infarction flow (TIMI), myocardial redness score (MBG) and thromboembolic burden (TGB) score were evaluated. Percutaneous coronary intervention (PCI) was classified as unsuccessful if there was a residual DS >50% and/or 0 and DS >50% in >arterioles, respectively.

Vascular images of 234 patients from 17 sites (12 US, 5 CAN) were analyzed. Elevated TGB was observed in 74% of all patients before the intervention and in 29% of the patients after the intervention. A high proportion of patients (19%) had no causative lesions (sites within the arteries easily identified by treating physicians) suggesting other mechanisms of heart attack may be at play in this group of patients. The Core Laboratory identified stent thrombosis (thrombosis of previously placed stents) in 12% of the entire cohort – a recurrence never seen in other cohorts of ST-elevation elevation myocardial infarction. Of the 49 patients, the Core lab determined that PCI failure rates were 34% and a high complication rate of 23%, mostly related to stroke.

COVID-19 is an inflammatory and clot-forming disease, and we are now seeing its effect in the coronary arteries. These new insights point to the need for clinicians to be meticulous about blood thinning strategies, early interventions, and patient follow-up.”

Payam Dehghani, MD, FRCPC, FACC, FSCAI, co-director of Prairie Vascular Research Inc and associate professor at the University of Saskatchewan, Canada

The NACMI Registry is a collaboration between SCAI, the American College of Cardiology, and the Canadian Society of Interventional Cardiology. The registry was established in 2020 with the goal of defining baseline characteristics, management strategies, and outcome data for COVID-19 patients with ST-segment elevation myocardial infarction. More than 60 medical centers across North America and Canada contributed data to the registry.

The researchers note that more research is needed to understand the impact of COVID-19 and vaccination related to heart attacks as well as long-term outcomes.