Both Acute and Chronic Myocardial Injury in COVID-19 Impede 6-Month Survival

Among patients admitted to New York hospitals or emergency departments with COVID-19, myocardial injury, whether acute or chronic, is associated with worse survival at 6 months, new data show.

The degree of injury was based on serial troponin sampling between 72 hours before and 48 hours after their diagnosis, using Fourth Universal Definition of MI criteria.

“The reason why we did this study is there is a lot of literature [asking] how much is the heart involved in COVID, what is the extent of cardiac damage, and so on,” co-author Davide Cao, MD (Icahn School of Medicine at Mount Sinai, New York, NY), told TCTMD. “But most of the previous studies evaluated whether there was myocardial injury according to one single troponin measurement.”

It’s common practice to monitor troponin in hospitalized patients—with or without COVID-19—who are known to have elevated biomarkers, he said. “What was missing is the evaluation in a systematic way of these different types and patterns of troponin elevations in terms of myocardial injury in a relatively large-scale study.”

Cao stressed that their analysis was observational and retrospective, with the potential to overestimate the prevalence of myocardial injury since it was only calculated among patients whose troponin values were obtained.

The results were presented at the virtual European Society of Cardiology Congress 2021 and published online in the European Heart Journal - Quality of Care & Clinical Outcomes.

Death Risk More Than Tripled

Led by Annapoorna Kini, MD (Icahn School of Medicine at Mount Sinai), the researchers identified 7,815 patients with lab-confirmed COVID-19 who were hospitalized or admitted to the emergency department within the Mount Sinai Health System between February 27 and October 15, 2020. Troponin values were available for 4,695 (60%).

Myocardial injury was categorized as chronic if cardiac troponin was elevated at both first and subsequent testing with ≤ 20% variation. It was considered acute if troponin was normal on first assessment then later elevated with 50% variation or if it was elevated for both assessments with 20% variation.

Based on these definitions, 319 patients (6.8%) with troponin measurements had values indicating chronic injury, which was associated with more chronic kidney disease and heart failure. Another 1,168 (24.9%) had values indicating acute injury, which was linked to tachypnea, hypotension, lower peripheral oxygen saturation, and higher levels of inflammatory markers.

The total number of deaths was 1,106, a rate of 23.6%. Compared with those without elevated troponins, who had a 6-month mortality rate of 13%, the risk of dying was elevated both for patients with chronic myocardial injury (43.0%; HR 4.17; 95% CI 3.44-5.06) and those with acute myocardial injury (47.3%; HR 4.72; 95% CI 4.15-5.36).

Although the risk peaked early, it wasn’t restricted to the early “convalescent” period—when researchers excluded the first 30 days, patients remained at risk 6 months after chronic (HR 3.97; 95% CI 2.15-7.33) and acute injury (HR 4.14; 95% CI 2.75-6.21). These associations remained significant when adjusting for potential confounders, with hazard ratios of 2.95 and 3.32 at 6 months, respectively, in the two groups.

Patients whose injury was acute were, in general, no more at risk of dying than those whose injury was chronic (HR 1.13; 95% CI 0.94-1.36), unless they were younger than 65 or lacked coronary artery disease.

Implications for Management

“Classifying the type of myocardial injury into acute or chronic on the basis of serial troponin measurements may have important implications in terms of differential diagnosis and subsequent management,” Kini et al write. “In general, preexisting diseases and cardiovascular risk factors, such as renal failure and structural heart disease, are mostly related to chronic myocardial injury, while atherosclerosis and acute systemic illness are more linked to an acute injury.”

The risk factors observed here, they say, “are in consonance with previous reports and highlight the complex interplay between inflammation, thrombosis, and cardiac damage.”

For clinicians, the main takeaway is that patients with myocardial injury merit close monitoring and more-intensive care, the investigators advise, adding that troponin “evaluation can be easily implemented in routine clinical practice with an impact on triage decision-making and the subsequent management of the patients.”

Cao said this knowledge is just a piece of information that adds to a larger body of evidence. Most interesting, he continued, would be “prospective studies aimed at characterizing the myocardial involvement through imaging but also [including] systematic assessment of cardiac events over a very long-term follow-up,” in order to see how patients’ conditions evolve.