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.

Clinical predictors of acute cardiac injury and normalization of troponin after hospital discharge from COVID-19.

BACKGROUND: Although acute cardiac injury (ACI) is a known COVID-19 complication, whether ACI acquired during COVID-19 recovers is unknown. This study investigated the incidence of persistent ACI and identified clinical predictors of ACI recovery in hospitalized patients with COVID-19 2.5 months post-discharge. METHODS: This retrospective study consisted of 10,696 hospitalized COVID-19 patients from March 11, 2020 to June 3, 2021. Demographics, comorbidities, and laboratory tests were collected at ACI onset, hospital discharge, and 2.5 months post-discharge. ACI was defined as serum troponin-T (TNT) level >99th-percentile upper reference limit (0.014ng/mL) during hospitalization, and recovery was defined as TNT below this threshold 2.5 months post-discharge. Four models were used to predict ACI recovery status. RESULTS: There were 4,248 (39.7%) COVID-19 patients with ACI, with most (93%) developed ACI on or within a day after admission. In-hospital mortality odds ratio of ACI patients was 4.45 [95%CI: 3.92, 5.05, p<0.001] compared to non-ACI patients. Of the 2,880 ACI survivors, 1,114 (38.7%) returned to our hospitals 2.5 months on average post-discharge, of which only 302 (44.9%) out of 673 patients recovered from ACI. There were no significant differences in demographics, race, ethnicity, major commodities, and length of hospital stay between groups. Prediction of ACI recovery post-discharge using the top predictors (troponin, creatinine, lymphocyte, sodium, lactate dehydrogenase, lymphocytes and hematocrit) at discharge yielded 63.73%-75.73% accuracy. INTERPRETATION: Persistent cardiac injury is common among COVID-19 survivors. Readily available patient data accurately predict ACI recovery post-discharge. Early identification of at-risk patients could help prevent long-term cardiovascular complications. FUNDING: None.

Frequency of Cardiovascular Complications and Its Association with Prognosis of COVID-19 Patients.

Coronavirus disease 2019 (COVID-19) may lead to acute respiratory disease; cardiovascular, gastrointestinal, and coagulation complications; and even death. One of the major complications is cardiovascular disorders, including arrhythmias, myocarditis, pericarditis, and acute coronary artery disease. The aim of this study was to evaluate the frequency of cardiovascular complications and to determine its association with the prognosis of COVID-19 patients. In a prospective analytic study, 137 hospitalized COVID-19 patients were enrolled. During hospitalization, an electrocardiogram (ECG) was performed every other day, and laboratory tests such as cardiac troponin I (cTnI) and creatine kinase-MB (CK-MB) were done 0, 6, and 12 hours after admission. These tests were repeated for patients with chest pain or ECG changes. Patients were categorized into three groups (improved, complicated, and expired patients) and assessed for the rate and type of arrhythmias, cardiac complications, lab tests, and outcomes of treatments. There was no significant relationship among the three groups related to primary arrhythmia and arrhythmias during treatment. The most common arrhythmia during hospitalization and after treatment was ST-T fragment changes. There was a significant age difference between the three groups (P = 0.001). There was a significant difference among the three groups for some underlying diseases, including diabetes mellitus (P = 0.003) and hyperlipidemia (P = 0.004). In our study, different types of arrhythmias had no association with patients' outcomes but age over 60 years, diabetes mellitus, and hyperlipidemia played an important role in the prognosis of COVID-19 cases.

High-dose vitamin C ameliorates cardiac injury in COVID-19 pandemic: a retrospective cohort study.

BACKGROUND: Cardiac injury is common and associated with poor clinical outcomes in COVID-19. Data are lacking whether high-dose intravenous vitamin C (HIVC) could help to ameliorate myocardial injury in the pandemic. METHODS: The retrospective cohort study included consecutive severe and critically ill COVID-19 patients with cardiac injury receiving symptomatic supportive treatments alone or together with HIVC. Troponin I and inflammatory markers were collected at admission and day 21 during hospitalization from the electronic medical records. RESULTS: The patients (n = 113) were categorized into the ameliorated cardiac injury (ACI) group (n = 70) and the non-ameliorated cardiac injury (NACI) group (n = 43). Overall, fifty-one (45.1%) patients were administered with HIVC, the percentages of patients with HIVC were higher in the ACI group than those in the NACI group. Logistic regression analysis revealed that HIVC was independently associated with the improvement of myocardial injury. Further analysis showed that inflammatory markers levels significantly decreased at day 21 during hospitalization in patients with HIVC therapy compared to those administered with symptomatic supportive treatments alone. Meanwhile, similar results were also observed regarding changes in inflammatory markers levels from baseline to day 21 during hospitalization in the patients treated with HIVC. CONCLUSIONS: HIVC can ameliorate cardiac injury through alleviating hyperinflammation in severe and critically ill patients with COVID-19.

Can we predict the severe course of COVID-19 - a systematic review and meta-analysis of indicators of clinical outcome?

BACKGROUND: COVID-19 has been reported in over 40million people globally with variable clinical outcomes. In this systematic review and meta-analysis, we assessed demographic, laboratory and clinical indicators as predictors for severe courses of COVID-19. METHODS: This systematic review was registered at PROSPERO under CRD42020177154. We systematically searched multiple databases (PubMed, Web of Science Core Collection, MedRvix and bioRvix) for publications from December 2019 to May 31st 2020. Random-effects meta-analyses were used to calculate pooled odds ratios and differences of medians between (1) patients admitted to ICU versus non-ICU patients and (2) patients who died versus those who survived. We adapted an existing Cochrane risk-of-bias assessment tool for outcome studies. RESULTS: Of 6,702 unique citations, we included 88 articles with 69,762 patients. There was concern for bias across all articles included. Age was strongly associated with mortality with a difference of medians (DoM) of 13.15 years (95% confidence interval (CI) 11.37 to 14.94) between those who died and those who survived. We found a clinically relevant difference between non-survivors and survivors for C-reactive protein (CRP; DoM 69.10 mg/L, CI 50.43 to 87.77), lactate dehydrogenase (LDH; DoM 189.49 U/L, CI 155.00 to 223.98), cardiac troponin I (cTnI; DoM 21.88 pg/mL, CI 9.78 to 33.99) and D-Dimer (DoM 1.29mg/L, CI 0.9 to 1.69). Furthermore, cerebrovascular disease was the co-morbidity most strongly associated with mortality (Odds Ratio 3.45, CI 2.42 to 4.91) and ICU admission (Odds Ratio 5.88, CI 2.35 to 14.73). DISCUSSION: This comprehensive meta-analysis found age, cerebrovascular disease, CRP, LDH and cTnI to be the most important risk-factors that predict severe COVID-19 outcomes and will inform clinical scores to support early decision-making.

Cardiac Troponin I association with critical illness and death risk in 726 seriously ill COVID-19 patients: A retrospective cohort study.

Background: For coronavirus disease 2019 (COVID-19), early identification of patients with serious symptoms at risk of critical illness and death is important for personalized treatment and balancing medical resources. Methods: Demographics, clinical characteristics, and laboratory tests data from 726 patients with serious COVID-19 at Tongji Hospital (Wuhan, China) were analyzed. Patients were classified into critical group (n = 174) and severe group (n= 552), the critical group was sub-divided into survivors (n = 47) and non-survivors (n = 127). Results: Multivariable analyses revealed the risk factors associated with critical illness in serious patients were: Advanced age, high respiratory rate (RR), high lactate dehydrogenase (LDH) level, high hypersensitive cardiac troponin I (hs-cTnI) level, and thrombocytopenia on admission. High hs-cTnI level was the independent risk factor of mortality among critically ill patients in the unadjusted and adjusted models. ROC curves demonstrated that hs-cTnI and LDH were predictive factors for critical illness in patients with serious COVID-19 whereas procalcitonin and D-Dimer with hs-cTnI and LDH were predictive parameters in mortality risk. Conclusions: Advanced age, high RR, LDH, hs-cTnI, and thrombocytopenia, constitute risk factors for critical illness among patients with serious COVID-19, and the hs-cTnI level helps predict fatal outcomes in critically ill patients.

Cardiac Biomarker Abnormalities Are Closely Related to Prognosis in Patients with COVID-19.

Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) is erupting and spreading globally. Cardiovascular complications secondary to the infection have caught notice. This study aims to delineate the relationship of cardiac biomarkers and outcomes in severe cases of corona virus disease 2019 (COVID-19). One hundred forty-eight critically ill adult patients with COVID-19 were enrolled. From these patients, the demographic data, symptoms, cardiac biomarkers, treatments, and clinical outcomes were collected. Data were compared between survivors and non-survivors. Four patients in the non-survivor group were selected, and their cardiac biomarkers were collected and analyzed. Among the 148 patients, the incidence of cardiovascular complications was 19 (12.8%). Five of them were survivors (5.2%), and 14 of them were non-survivors (26.9%). Compared with the survivors, the non-survivors had higher levels of high-sensitivity cardiac troponin I, creatine kinase isoenzyme-MB, myoglobin, and N-terminal pro-brain natriuretic peptide (P < 0.05). The occurrence of cardiovascular events began at 11-15 days after the onset of the disease and reached a peak at 14-20 days. COVID-19 not only is a respiratory disease but also causes damage to the cardiovascular system. Cardiac biomarkers have the potential for early warning and prognostic evaluation in patients with COVID-19. It is recommended that cardiac biomarker monitoring in patients with COVID-19 should be initiated at least from the 11th day of the disease course.

The Clinical Characteristics and Risk Factors of Severe COVID-19.

OBJECTIVE: We aim to investigate the clinical characteristics and risk factors for the severe cases of coronavirus disease 2019 (COVID-19) in comparison with the non-severe patients. METHODS: We searched PubMed, EMBASE, Web of Science, and CNKI to collect all relevant studies published before July 26, 2020, and a total of 30 papers were included in this meta-analysis. RESULTS: In the severe COVID-19 patients, 60% (95% CI = 56-64%) were male, 25% (95% CI = 21-29%) were over 65 years old, 34% (95% CI = 24-44%) were obese, and 55% (95% CI = 41-70%) had comorbidities. The most prevalent comorbidities were hypertension (34%, 95% CI = 25-44%), diabetes (20%, 95% CI = 15-25%), and cardiovascular disease (CVD; 12%, 95% CI = 9-16%). The most common blood test abnormalities were elevated C-reactive protein (CRP; 87%, 82-92%), decreased lymphocyte count (68%, 58-77%), and increased lactate dehydrogenase (69%, 95% CI = 57-81%). In addition, abnormal laboratory findings revealing organ dysfunctions were frequently observed in the severe cases, including decrease in albumin (43%, 95% CI = 24-63%) and increase in aspartate aminotransferase (47%, 95% CI = 38-56%), alanine aminotransferase (28%, 95% CI = 16-39%), troponin I/troponin T (TnI/TnT; 29%, 95% CI = 13-45%), and serum Cr (SCr; 10%, 95% CI = 5-15%). CONCLUSION: The male, elderly and obese patients and those with any comorbidities, especially with hypertension, diabetes, and CVD, were more likely to develop into severe cases. But the association between hypertension, diabetes, CVD, and severity of COVID-19 was declined by the increase of age. A significant elevation in cardiac TnI/TnT, the hepatic enzymes, and SCr and the reduction in lymphocytes with elevated CRPs are important markers for the severity. Specific attention should be given to the elderly male and obese patients and those with indications of severe immune injury in combination with bacterial infection and indication of multi-organ dysfunction or damages.

Characteristics and Outcomes of Patients 80 Years and Older Hospitalized With Coronavirus Disease 2019 (COVID-19).

Patients older than 65 years hospitalized with COVID-19 have higher rates of intensive care unit admission and death when compared with younger patients. Cardiovascular conditions associated with COVID-19 include myocardial injury, acute myocarditis, cardiac arrhythmias, cardiomyopathies, cardiogenic shock, thromboembolic disease, and cardiac arrest. Few studies have described the clinical course of those at the upper extreme of age. We characterize the clinical course and outcomes of 73 patients with 80 years of age or older hospitalized at an academic center between March 15 and May 13, 2020. These patients had multiple comorbidities and often presented with atypical clinical findings such as altered sensorium, generalized weakness and falls. Cardiovascular manifestations observed at the time of presentation included new arrhythmia in 7/73 (10%), stroke/intracranial hemorrhage in 5/73 (7%), and elevated troponin in 27/58 (47%). During hospitalization, 38% of all patients required intensive care, 13% developed a need for renal replacement therapy, and 32% required vasopressor support. All-cause mortality was 47% and was highest in patients who were ever in intensive care (71%), required mechanical ventilation (83%), or vasopressors (91%), or developed a need for renal replacement therapy (100%). Patients older than 80 years old with COVID-19 have multiple unique risk factors which can be associated with increased cardiovascular involvement and death.

The Implication of Cardiac Injury Score on In-hospital Mortality of Coronavirus Disease 2019.

BACKGROUNDS: The severe acute respiratory syndrome-coronavirus 2 (SARS-CoV-2) has spread worldwide. Cardiac injury after SARS-CoV-2 infection is a major concern. The present study investigated impact of the biomarkers indicating cardiac injury in coronavirus disease 2019 (COVID-19) on patients' outcomes. METHODS: This study enrolled patients who were confirmed to have COVID-19 and admitted at a tertiary university referral hospital between February 19, 2020 and March 15, 2020. Cardiac injury was defined as an abnormality in one of the following result markers: 1) myocardial damage marker (creatine kinase-MB or troponin-I), 2) heart failure marker (N-terminal-pro B-type natriuretic peptide), and 3) electrical abnormality marker (electrocardiography). The relationship between each cardiac injury marker and mortality was evaluated. Survival analysis of mortality according to the scoring by numbers of cardiac injury markers was also performed. RESULTS: A total of 38 patients with COVID-19 were enrolled. Twenty-two patients (57.9%) had at least one of cardiac injury markers. The patients with cardiac injuries were older (69.6 ± 14.9 vs. 58.6 ± 13.9 years old, P = 0.026), and were more male (59.1% vs. 18.8%, P = 0.013). They showed lower initial oxygen saturation (92.8 vs. 97.1%, P = 0.002) and a trend toward higher mortality (27.3 vs. 6.3%, P = 0.099). The increased number of cardiac injury markers was significantly related to a higher incidence of in-hospital mortality which was also evidenced by Kaplan-Meier survival analysis (P = 0.008). CONCLUSION: The increased number of cardiac injury markers is related to in-hospital mortality in patients with COVID-19.

From SARS-CoV to SARS-CoV2: a potential guide to better understanding of pathophysiology of the disease and potential therapeutic modality.

Currently, the outbreak and spread of coronavirus disease 2019 (COVID-19) caused by Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), are increasing worldwide. Furthermore, it has been considered as a major challenge, which threatens human beings and affects all aspects of their life. Understanding the cellular and molecular pathophysiology of the disease is currently under the focus of investigations. Accordingly, this turns the human scientific community attention to find a solution for addressing the challenge. The development of vaccines and efficient therapeutic modality is critical. So, both primary and clinical scientists are not only trying to decipher the structure of SARS-CoV-2, but also attempting to understand the underlying molecular mechanisms that cause tissues and cell injuries. SARS-CoV and SARS-CoV2 are highly homologous and share a highly similar function and behavior patterns. Therefore, this might guide us toward decoding the molecular mechanisms that are behind the SARS-CoV2 pathologic effects. It is noteworthy to mention that, the undesired host immune reactions play important roles in the pathophysiology of the disease, and it also seems that, renin-angiotensin signaling (RAS) is a key contributor in this regard. In this review, we provided a vision, highlight as well as discussing on potential therapeutic targets that might be considered to address the COVID-19 challenge.