Coronavirus Disease 2019 (COVID-19) and Cardiac Injury—Reply
Shaobo Shi, Mu Qin, Bo Yang
Abstract
To the Editor We read with great interest the important findings of Shi et al 1 exploring cardiac injury in patients with confirmed coronavirus disease 2019 (COVID-19).Approximately 20% of patients diagnosed with COVID-19 had signs of cardiac injury as measured by elevated high-sensitivity troponin I (hs-TNI) levels.Moreover, evidence of cardiac injury was associated with 4-fold increased mortality risk even after accounting for age and preexisting cardiovascular disease (CVD).Shi et al 1 acknowledged that with this severe acute respiratory infection may come cytokine storm syndrome leading to inflammation and cardiac myocyte apoptosis or necrosis.We wish to underscore a few key points.High-sensitivity troponin I is detectable in more than 80% of the general population and, as a reflection of subclinical myocardial damage, has been shown to predict all-cause mortality even in those without CVD. 2 High hs-TNI levels within the normal range may be a marker of patients with increased vulnerability to experiencing the more severe complications resulting from the systemic inflammatory effects of COVID-19.While elevated hs-TNI levels clearly portend poor prognosis, the question remains-why?Is hs-TNI a marker of underlying subclinical CVD that confers risk in the setting of hypoxia from profound respiratory disease or hypoperfusion from viral sepsis (ie, type 2 myocardial infarction reflecting supply/demand imbalance), both made worse in the presence of comorbidities?Is it a reflection of direct viral myocarditis or a marker of cardiac damage from the cytokine storm?Effective treatment will likely be guided by the underlying cause of the elevated hs-TNI levels (eg, interleukin 6 inhibitors for cytokine toxic effects).Ethnic and racial variation in the US will bring unique challenges for diagnosis, prognosis, and management of COVID-19.The Chinese experience has shown a high comorbidity of hypertension, diabetes, and CVD in patients with COVID-19. 3 Shi et al 1 also noted that prominent comorbidities in those with cardiac injury included hypertension, diabetes, coronary disease, heart failure, and cerebrovascular disease-all more prevalent in African American individuals.African American individuals have higher circulating biomarkers of systemic inflammation and myocyte injury, 4 and subclinical CVD occurs at a young age in African American individuals. 5Thus, African American individuals may be a particularly vulnerable group in the US to the untoward effects of COVID-19.Finally, whether cardiac injury as a consequence of COVID-19 infection results in permanent cardiac damage in survivors also remains to be determined.Long-term cardiovascular consequences of COVID-19 will need to be monitored to ensure that this cytokine storm does not bring with it a secondary tsunami wave of cardiovascular events in the future.