Cause or Consequence? What is the Relationship between Cardiac Injury and COVID-19 Severity?

Abstract

In most patients, coronavirus disease-2019 (COVID-19) causes minor respiratory symptoms or even no symptoms. SARS-CoV-2 infection can also cause extrapulmonary manifestations and complications. COVID-19 is more severe and fatal among patients with pre-existing cardiovascular risk factors or diseases. 1 Increases in cardiac troponin (cTn) are indicative of myocardial injury and frequently found in patients with COVID-19. 2 The Chinese Center for Disease Control and Prevention published a survey demonstrating that among patients diagnosed with COVID-19, 13% had hypertension, 5% had diabetes mellitus, and 4% had a history of cardiovascular disease. However, in this same cohort, among patients who had not survived, 40% had hypertension, 20% had diabetes, and 22% had pre-existing cardiovascular disease. 3 Patients with cardiovascular disease had the highest case fatality rate (10.5%). In this issue of theInternational Journal of Cardiovascular Sciences, Rocha et al. , 4 studied 192 patients admitted with COVID-19 in a quaternary care cardiac hospital in Rio de Janeiro, Brazil. Mortality rate was 28%. Multivariate analysis demonstrated that elevated cTnI levels (OR=9.504; 95% CI=1.281-70.528; P=0.028) upon admission and the need for mechanical ventilation during hospitalization (OR=46.691; 95% CI=2.360-923.706; P=0.012) were independent predictors of death during hospitalization. 4 The main limitations of the study are a sample from a single Brazilian metropolitan region and a short follow-up period. However, these limitations do not invalidate the main message of the study: the measurement of cardiac troponin at hospital admission may be useful for identification of high-risk patients infected by SARS-CoV-2. Cardiac troponins are not specific markers of ischemic injury of the heart. The Fourth Universal Definition of Myocardial Infarction defines myocardial injury (acute or chronic) as cTn concentrations >99th percentile upper reference limit (URL). While dynamic changes in cardiac troponins characterize acute injury, patients without these changes have chronic injury. 5 Patients with COVID-19 have several conditions that may be associated with myocardial injury such as myocarditis, stress cardiomyopathy, acute heart failure, pulmonary embolism, critical illness, and sepsis. 2 Garcia de 6 demonstrated that elevated troponin levels were common in patients with COVID-19. These authors found abnormal levels of cTn in 26.9% of the patients and in 30% when sex-specific cut-offs were used to detect myocardial injury. 6 Some factors increase the risk of abnormal cTn levels, including older age and the type of troponin measured (troponin T is associated with higher levels). Nascimento et al., 7 studied 61 patients admitted to intensive care unit with COVID-19 in a Brazilian hospital and found a high incidence of myocardial infarction in patients with severe COVID-19, with impact on in-hospital mortality. 7 COVID-19 can damage the cardiovascular system in many ways. A myocardial oxygen supply-demand