The prognostic role of cardiac troponin in hospitalized COVID-19 patients

COVID-19 and Cardiovascular Diseases: From Cellular Mechanisms to Clinical Manifestations

Coronavirus disease 2019 (COVID-19) caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), quickly spread worldwide and led to over 581 million confirmed cases and over 6 million deaths as 1 August 2022. The binding of the viral surface spike protein to the human angiotensin-converting enzyme 2 (ACE2) receptor is the primary mechanism of SARS-CoV-2 infection. Not only highly expressed in the lung, ACE2 is also widely distributed in the heart, mainly in cardiomyocytes and pericytes. The strong association between COVID-19 and cardiovascular disease (CVD) has been demonstrated by increased clinical evidence. Preexisting CVD risk factors, including obesity, hypertension, and diabetes etc., increase susceptibility to COVID-19. In turn, COVID-19 exacerbates the progression of CVD, including myocardial damage, arrhythmia, acute myocarditis, heart failure, and thromboembolism. Moreover, cardiovascular risks post recovery and the vaccination-associated cardiovascular problems have become increasingly evident. To demonstrate the association between COVID-19 and CVD, this review detailly illustrated the impact of COVID-19 on different cells (cardiomyocytes, pericytes, endothelial cells, and fibroblasts) in myocardial tissue and provides an overview of the clinical manifestations of cardiovascular involvements in the pandemic. Finally, the issues related to myocardial injury post recovery, as well as vaccination-induced CVD, has also been emphasized.

Cardiac troponins: Mechanisms of release and role in healthy and diseased subjects

The cardiac troponins (cTns), cardiac troponin C (cTnC), cTnT, and cTnI are key elements of myocardial apparatus, fixed as protein complex on the thin filament of sarcomere and are involved in the regulation of excitation-contraction coupling of cardiomyocytes in the presence of Ca²⁺ . Circulating cTnT and cTnI (cTns) increase following cardiac tissue necrosis, and they are consolidated biomarkers of acute myocardial infarction (AMI). However, the use of high sensitivity (hs)-immunoassay tests for cTnT and cTnI has made it possible to identify a multitude of other clinical conditions associated with increased circulating levels of cTns. cTns can be measured also in the peripheral circulation of healthy subjects or athletes, suggesting that different mechanisms are involved in the release of cTns in the blood independently of cardiac cell necrosis. In this review, the molecular/cellular mechanisms involved in cTns release in blood and the exploitation of cTnI and cTnT as biomarkers of cardiac adverse events, in addition to cardiac necrosis, are discussed.

Prognostic value of the TyG index for in-hospital mortality in nondiabetic COVID-19 patients with myocardial injury

OBJECTIVE

The purpose of this study was to explore the efficacy of the triglyceride glucose (TyG) index on in-hospital mortality in nondiabetic coronavirus disease 2019 (COVID-19) patients with myocardial injury.

METHODS

This was a retrospective study, which included 218 nondiabetic COVID-19 patients who had myocardial injury. The TyG index was derived using the following equation: log [serum triglycerides (mg/dL) ×fasting blood glucose (mg/dL)/2].

RESULTS

Overall, 49 (22.4%) patients died during hospitalization. Patients who did not survive had a higher TyG index than survivors. In multivariate Cox regression analysis, it was found that the TyG index was independently associated with in-hospital death. A TyG index cutoff value greater than 4.97 was predicted in-hospital death in nondiabetic COVID-19 patients with myocardial damage, with 82% sensitivity and 66% specificity. A pairwise evaluation of receiver operating characteristic (ROC) curves demonstrated that the TyG index (AUC: 0.786) had higher discriminatory performance than both triglyceride (AUC: 0.738) and fasting blood glucose (AUC: 0.660) in predicting in-hospital mortality among these patients.

CONCLUSIONS

The TyG index might be used to identify high-risk nondiabetic COVID-19 patients with myocardial damage.

Influence of Intermittent Fasting During Ramadan on Circadian Variation of Symptom-Onset and Prehospital Time Delay in Acute ST-Segment Elevation Myocardial Infarction

Ramadan interferes with circadian rhythms mainly by disturbing the routine patterns of feeding and smoking. The objective of this study was to investigate the circadian pattern of ST elevation acute myocardial infarction (STEMI) during the month of Ramadan. We studied consecutive STEMI patients 1 month before and after Ramadan (non-Ramadan group-NRG) and during Ramadan (Ramadan group-RG). The RG group was also divided into two groups, based on whether they chose to fast: fasting (FG) and non-fasting group (NFG). The time of STEMI onset was compared. A total of 742 consecutive STEMI patients were classified into 4 groups by 6 h intervals according to time-of-day at symptom onset. No consistent circadian variation in the onset of STEMI was observed both between the RG (P = .938) and NRG (P = .766) or between the FG (P = .232) and NFG (P = .523). When analyzed for subgroups of the study sample, neither smoking nor diabetes showed circadian rhythm. There was a trend towards a delay from symptom onset to hospital presentation, particularly at evening hours in the RG compared with the control group. In conclusion, there was no significant difference in STEMI onset time, but the time from symptom onset to hospital admission was significantly delayed during Ramadan.

Myocardial Injury Predicts Risk of Short-Term All-Cause Mortality in Patients With COVID-19: A Dose–Response Meta-Analysis

Objective

Predictive value of myocardial injury as defined by elevated cardiac tropnins (cTns) in patients with COVID-19 has not been fully investigated. We performed a meta-analysis to evaluate the dose–response relationship between myocardial injury and short-term all-cause mortality.

Methods

Pubmed, Embase, and the Cochrane Library database were searched for all the studies which evaluated the relationship between cTns and the risk of short-term all-cause mortality in patients with COVID-19.

Results

Compared with patients without myocardial injury, the group with elevated cTns was associated with increased short-term mortality (11 studies, 29,128 subjects, OR 3.17, 95% CI 2.19–4.59, P = 0.000, I2 = 92.4%, P for heterogeneity 0.00). For the dose–response analysis, the elevation of cTns 1 × 99th percentile upper reference limit (URL) was associated with increased short-term mortality (OR 1.99, 95% CI 1.53–2.58, P = 0.000). The pooled OR of short-term mortality for each 1 × URL increment of cTns was 1.25 (95% CI 1.22–1.28, P = 0.000).

Conclusion

We found a positive dose–response relationship between myocardial injury and the risk of short-term all-cause mortality, and propose elevation of cTns > 1 × 99th percentile URL was associated with the increased short-term risk of mortality.

Significance of Cardiac Troponins as an Identification Tool in COVID-19 Patients Using Biosensors: An Update

Coronavirus disease 2019 (COVID-19) has rapidly developed as a global health emergency. Respiratory diseases are significant causes of morbidity and mortality in these patients with a spectrum of different diseases, from asymptomatic subclinical infection to the progression of severe pneumonia and subsequent acute respiratory distress syndrome. Individuals with cardiovascular disease are more likely to become infected with SARS-CoV-2 and develop severe symptoms. Hence, patients with underlying cardiovascular disease mortality rate are over three times. Furthermore, note that patients with a history of cardiovascular disease are more likely to have higher cardiac biomarkers, especially cardiac troponins, than infected patients, especially those with severe disease, making these patients more susceptible to cardiac damage caused by SARS-2-CoV. Biomarkers are important in decision-making to facilitate the efficient allocation of resources. Viral replication in the heart muscle can lead to a cascade of inflammatory processes that lead to fibrosis and, ultimately, cardiac necrosis. Elevated troponin may indicate damage to the heart muscle and may predict death. After the first Chinese analysis, increased cardiac troponin value was observed in a significant proportion of patients, suggesting that myocardial damage is a possible pathogenic mechanism leading to severe disease and death. However, the prognostic performance of troponin and whether its value is affected by different comorbidities present in COVID-19 patients are not known. This review aimed to assess the diagnostic value of troponin to offer insight into pathophysiological mechanisms and reported new assessment methods, including new biosensors for troponin in patients with COVID-19.

Myocardial injuries among patients with COVID-19: a systematic review

This is a systematic review of the literature specifically aimed to explore myocardial injury in coronavirus disease-19 (COVID-19) patients who were hospitalized with severe complicated infections. The medical literature was examined through the large medical databases, including Medline, Ovid, PubMed, and Embase, over the last year between January 2020 and May 2021. The search terms used were a combination of "myocardial injury" AND "COVID-19" AND "Hospitalization". Then we applied a step to filter the results to select original research articles only evaluating the myocardial injuries in severe COVID-19 hospitalized patients. Selected trials mentioned the type of myocardial injury detected with the infection. A total of 245 articles were extracted. Considering the exclusion of ineligible articles, 42 articles appeared. A total of 42 articles were eligible and were included in the review. These studies included a total of 4326 COVID-19 patients. The 30-day mortality was found to be associated with increased cardiac troponin and myocardial infarction could be a systemic reaction rather than the direct action of COVID-19. Patients with myocardial injury were significantly older and with co-morbid conditions. Studies also found a correlation of higher concentrations of cardiac enzymes with disease severity and increased in-hospital mortality. Myocardial injury was a significant predictor for severe COVID-19 infection and in-hospital mortality. Cardiac enzymes should be monitored in hospitalized patients with severe COVID-19 infections.

Association of entirely claims-based frailty indices with long-term outcomes in patients with acute myocardial infarction, heart failure, or pneumonia: a nationwide cohort study in Turkey

BACKGROUND

Several countries have increasingly focused on improving care for acute myocardial infarction (AMI), heart failure (HF), and pneumonia to reduce their readmissions and mortality rates. Frailty is becoming increasingly important to accurately predict healthcare utilization for the aging population. The preferred method for the measurement of frailty remains unclear, and current risk-adjustment models do not account for frailty. We sought to compare commonly used frailty indices in terms of the ability to predict clinical adverse outcomes in AMI, HF, and pneumonia patients.

METHODS

A nationwide cohort study included AMI, HF, and pneumonia with 65 years and older patients in the Turkey between January 1 and December 31, 2018. The primary predictor of interest was frailty. We used two claims-based frailty indices (Johns Hopkins Claims-Based Frailty Index and Hospital Frailty Risk Score) to assess frailty. The main outcome was all-cause long-term mortality up to 3 years. Time to death was calculated as the time period between the date of first admission and the date of death. Patients were censored as of September 30, 2020, which marked the end of the follow-up period.

FINDINGS

Of the 200,948 patients, 35,096 (17.5%) had AMI, 62,403 (31.1%) had HF, and 103,449 (51.5%) had pneumonia. Johns Hopkins Claims-Based Frailty Index (c-statistics for long-term mortality: 0.68 in AMI, 0.61 in HF, 0.64 in pneumonia) was better compared to Hospital Frailty Risk Score (c-statistics for long-term mortality: AMI=0.62, HF=0.58, pneumonia=0.62) (DeLong p<0.001 in all).

INTERPRETATION

Readmission and mortality rates after AMI, HF, and pneumonia gradually increases with increasing frailty score. While the Hospital Frailty Risk Score had a better discrimination for predicting readmissions, Johns Hopkins Claims-Based Frailty Index had a better discrimination for predicting mortality. These findings should be taken into account for a better evaluation of hospital performance.

FUNDING

This study was supported by funding from The Scientific and Technological Research Council of Turkey (grant 120S422, HK).

Cardiac Biomarkers in COVID-19: A Narrative Review

The diagnosis and risk stratification of coronavirus disease 2019 (COVID-19) is primarily based on discretionary use of laboratory resources. Several lines of evidence now attest that cardiovascular disease not only is a frequent complication of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, but its pre-existence may increase the risk of morbidity, disability, and death in patients with COVID-19. To this end, routine assessment of biomarkers of cardiac injury (i.e., cardiac troponin I or T) and dysfunction (e.g., natriuretic peptides) has emerged as an almost essential practice in patients with moderate, severe, and critical COVID-19 illness. Therefore, this narrative review aims to provide an overview of cardiac involvement in patients with SARS-CoV-2 infection as well as the clinical background for including cardiac biomarkers within specific panels of laboratory tests for managing COVID-19 patients.

High-value laboratory testing for hospitalized COVID-19 patients: a review

We present here an evidence-based review of the utility, timing, and indications for laboratory test use in the domains of inflammation, cardiology, hematology, nephrology and co-infection for clinicians managing the care of hospitalized COVID-19 patients. Levels of IL-6, CRP, absolute lymphocyte count, neutrophils and neutrophil-to-lymphocyte ratio obtained upon admission may help predict the severity of COVID-19. Elevated LDH, ferritin, AST, and d-dimer are associated with severe illness and mortality. Elevated cardiac troponin at hospital admission can alert clinicians to patients at risk for cardiac complications. Elevated proBNP may help distinguish a cardiac complication from noncardiac etiologies. Evaluation for co-infection is typically unnecessary in nonsevere cases but is essential in severe COVID-19, intensive care unit patients, and immunocompromised patients.

Doctors managing the complex care of individuals with COVID-19 need timely evidence to guide which lab tests to send to predict outcomes and prevent and treat COVID-19 complications involving the heart, blood clots, the kidney, and other infections that occur during the hospital course. Several lab tests such as IL-6, CRP and white blood cell subset counts may help predict the severity of COVID-19 during the patient’s hospital course if obtained when the patient first presents to the hospital. Other tests such as LDH, ferritin and AST are also associated with severe illness and mortality but have less evidence for their utility beyond IL-6, CRP and other tests. A test related to blood coagulation, d-dimer, is also associated with COVID-19 severity, and it may be used if the patient is suspected of having a blood clot. Two heart biomarkers – cardiac troponin and proBNP – may help doctors diagnose and manage heart-related complications of COVID-19. Patients in the hospital with COVID-19 may be susceptible to other infections, but testing for these is most useful in patients with severe disease, such as those in the intensive care unit. Specific recommendations for testing for viral, bacterial and fungal infections are presented here. The judicious use of laboratory testing can help identify patients at high risk for severe or critical COVID-19 and aid in prevention, diagnosis and treatment of common COVID-19 complications.

COVID-19 and Heart Failure: From Epidemiology During the Pandemic to Myocardial Injury, Myocarditis, and Heart Failure Sequelae

A close and intriguing relationship has been suggested between heart failure (HF) and coronavirus disease 2019 (COVID-19). First, COVID-19 pandemic represented a global public health emergency in the last year and had a catastrophic impact on health systems worldwide. Several studies showed a reduction in HF hospitalizations, ranging from 30 to 66% in different countries and leading to a subsequent increase in HF mortality. Second, pre-existing HF is a risk factor for a more severe clinical course of COVID-19 and an independent predictor of in-hospital mortality. Third, patients hospitalized for COVID-19 may develop both an acute decompensation of chronic HF and de-novo HF as a consequence of myocardial injury and cardiovascular (CV) complications. Myocardial injury occurred in at least 10% of unselected COVID-19 cases and up to 41% in critically ill patients or in those with concomitant CV comorbidities. Few cases of COVID-19-related acute myocarditis, presenting with severe reduction in the left ventricular (LV) ejection fraction and peculiar histopathological findings, were described. However, recent data suggested that COVID-19 may be associated with both systolic and diastolic LV dysfunction, with LV diastolic impairment, pulmonary hypertension, and right ventricular dysfunction representing the most frequent findings in echocardiographic studies. An overview of available data and the potential mechanisms behind myocardial injury, possibly leading to HF, will be presented in this review. Beyond the acute phase, HF as a possible long-term consequence of cardiac involvement in COVID-19 patients has been supposed and need to be investigated yet.