Relation of troponin elevation to outcome in patients with infective endocarditis

Clinical Interpretation of Serum Troponin in the Era of High-Sensitivity Testing

Cardiac troponin (Tn) plays a central role in the evaluation of patients with angina presenting with acute coronary syndrome. The advent of high-sensitivity assays has improved the analytic sensitivity and precision of serum Tn measurement, but this advancement has come at the cost of poorer specificity. The role of clinical judgment is of heightened importance because, more so than ever, the interpretation of serum Tn elevation hinges on the careful integration of findings from electrocardiographic, echocardiographic, physical exam, interview, and other imaging and laboratory data to formulate a weighted differential diagnosis. A thorough understanding of the epidemiology, mechanisms, and prognostic implications of Tn elevations in each cardiac and non-cardiac etiology allows the clinician to better distinguish between presentations of myocardial ischemia and myocardial injury-an important discernment to make, as the treatment of acute coronary syndrome is vastly different from the workup and management of myocardial injury and should be directed at the underlying cause.

Exploring the Risk Factors and Possible Role of Calcium in Infective Endocarditis

Infective endocarditis (IE) is a severe and potentially life-threatening infection that affects the endocardium, the inner lining of the heart chambers and valves. Although rare, it is a potentially fatal condition, with an incidence of 3-10 cases per 100,000 people per year in developed countries and a mortality rate of up to 30% within 30 days. Early identification and diagnosis are critical for improving outcomes. The diagnosis of IE typically involves a combination of biomarkers, blood cultures, and echocardiography. However, currently, there are no specific biomarkers for the early detection of IE. Given the lack of specific biomarkers for IE, serum calcium levels have been suggested to play a unique role in IE. There have been few articles on the correlation between serum calcium and IE, suggesting that patients with endocarditis and lower levels of serum calcium may have a poorer prognosis. Therefore, in this article, we focus on biomarkers of endocarditis and discuss the evidence showing serum calcium as a potential indicator of IE.

Acute coronary syndrome complicating infective endocarditis: A case report with an etiological review

Introduction

Acute coronary syndrome (ACS) is an uncommon complication associated with high mortality in patients with endocarditis. It requires prompt and appropriate management to cure the patient.

Cases presentation

We report the case of a 52-year-old patient, initially admitted for an acute non-ST-segment elevation coronary syndrome at very high ischemic risk, in whom coronary exploration was negative, and whose echocardiography showed a mobile image on the aortic valve, suggesting infective endocarditis. The patient benefited from an aortic valve replacement because of the size and the embolic complications he presented, with a favorable evolution.

Discussion

Acute coronary syndrome during infective endocarditis is a rare complication with a high mortality rate. Several mechanisms are possible: the embolic mechanism, coronary extraluminal compression due to coronary mycotic aneurysm and obstruction of the coronary ostium by a large vegetation. The management remains multidisciplinary and personalized according to the phenotype of the patient, with the need to have the endocarditis team to be able to take the best therapeutic choice.

Conclusion

Infective endocarditis must be evoked in any patient without usual cardiovascular risk factors who presents with an ACS that is accompanied by fever and elevated inflammatory markers, and a thorough clinical examination as well as the performance of additional tests.

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Acute coronary syndrome (ACS) is an uncommon complication associated with high mortality in patients with endocarditis.

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Our case presents a diagnostic challenge in the face of an initial misleading clinical presentation evoking ACS in a patient finally diagnosed with infective endocarditis.

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The management of endocarditis remains multidisciplinary, between cardiologist, infectiologist, radiologist, resuscitator and heart surgeons.

The Main Causes and Mechanisms of Increase in Cardiac Troponin Concentrations Other Than Acute Myocardial Infarction (Part 1): Physical Exertion, Inflammatory Heart Disease, Pulmonary Embolism, Renal Failure, Sepsis

The causes and mechanisms of increased cardiac troponin T and I (cTnT and cTnI) concentrations are numerous and are not limited to acute myocardial infarction (AMI) (ischemic necrosis of cardiac myocytes). Any type of reversible or irreversible cardiomyocyte injury can result in elevated serum cTnT and cTnI levels. Researchers and practitioners involved in the diagnosis and treatment of cardiovascular disease, including AMI, should know the key causes and mechanisms of elevated serum cTnT and cTnI levels. This will allow to reduce or completely avoid diagnostic errors and help to choose the most correct tactics for further patient management. The purpose of this article is to discuss the main causes and mechanisms of increase in cardiac troponins concentrations in frequently occurring physiological (physical exertion, psycho-emotional stress) and pathological conditions (inflammatory heart disease, pulmonary embolism, chronic renal failure and sepsis (systemic inflammatory response)) not related to myocardial infarction.

Elevation Mechanisms and Diagnostic Consideration of Cardiac Troponins under Conditions Not Associated with Myocardial Infarction. Part 1

Although cardiac troponins are considered the most specific biomarkers for the diagnosis of acute myocardial infarction (AMI), their diagnostic consideration goes far beyond the detection of this dangerous disease. The mechanisms of cardiac troponin elevation are extremely numerous and not limited to ischemic necrosis of cardiac myocytes. Practitioners should be well aware of the underlying pathological and physiological conditions that can lead to elevated serum levels of cardiac troponins to avoid differential diagnostic errors, which will be greatly increased if clinicians rely on laboratory data alone. This article presents a classification of the main causes of an elevation in cardiac troponins and discusses in detail the mechanisms of such elevation and the diagnostic consideration of cardiac troponins in some conditions not associated with AMI, such as physical exertion, inflammatory heart diseases (myocarditis and endocarditis), pulmonary embolism (PE), renal failure, and systemic inflammation (sepsis).

Evaluation of serum cardiac troponin-I concentrations for diagnosis of infective endocarditis in dogs

Background

Infective endocarditis (IE) in dogs is associated with severe disease and a high case fatality rate but often presents with nonspecific clinical signs.

Hypothesis/Objectives

Serum concentration of cardiac troponin‐I (cTnI) is elevated in dogs with IE and can differentiate dogs with IE from dogs with other diseases with similar clinical features. Concentration of serum cTnI is negatively correlated with survival time in dogs with IE.

Animals

Seventy‐two client‐owned dogs; 29 with IE, 27 with stage‐B myxomatous mitral valve disease (MMVD), and 16 with immune‐mediated disease (IMD).

Methods

Retrospective clinical cohort study. Concentration of serum cTnI was measured in all dogs at time of diagnosis. Clinical findings and echocardiographic interpretation were also recorded. Statistical analyses included Kruskal‐Wallis test, pairwise Mann‐Whitney U tests, receiver operator characteristic, and Cox proportional hazards.

Results

Serum concentration of cTnI was significantly higher in the IE group (0.69 ng/mL [0.03‐80.8]) than in the MMVD (0.05 ng/mL [0.02‐0.11], P < .001) and IMD groups (0.05 ng/mL [0.03‐0.57], P < .001). Increased cTnI was a moderately accurate predictor of IE (area under the curve 0.857 (95% confidence interval [CI] 0.745‐0.968, P < .001). A cTnI cutoff of 0.625 ng/mL had 100% specificity (95% CI 90%‐100%) and 52% sensitivity (95% CI 33%‐70%) in this study sample. There was no association between cTnI concentration and survival time in dogs with IE (hazard ratio 1.013, 95% CI 0.993‐1.034, P = .2).

Conclusions and Clinical Importance

Cardiac troponin‐I concentrations are higher in dogs with IE compared to dogs with preclinical MMVD or IMD. In dogs with a compatible clinical presentation, serum cTnI concentrations >0.625 ng/mL are supportive of IE.

Low dose gamma irradiation attenuates cyclophosphamide-induced cardiotoxicity in rats: role of NF-κB signaling pathway

PURPOSE

Cyclophosphamide (Cyp) is one of the most commonly used, wide spectrum chemotherapeutic agents. Cyp has multi-organ toxicities that are dose limiting, thus it's mostly used in chemotherapeutic combinations. Radiation is well known as a hazardous sort of energy, recent studies are interested in studying the beneficial therapeutic effects of low-dose gamma radiation. This study examined the protective effect of two different doses/dose-rates of irradiation either alone or combined with telmisartan against Cyp-induced cardiotoxicity.

MATERIALS AND METHODS

Rats were divided into seven groups; (1): Control, (2): Cyp, (3-4): 0.05 Gy low dose rate (LDR) irradiation, 0.25 Gy high dose rate (HDR) irradiation, respectively, prior to Cyp dose, (5-7): telmisartan either alone or with 0.05 Gy LDR-irradiation or 0.25 Gy HDR-irradiation, respectively, prior to Cyp dose. The current investigation studied the effect of Cyp alone or combined with different treatment regimens on serum cTn-I and LDH, nuclear factor-κB (NF-κB) pathway (p65/IκB/IKK-α/IKK-ß) in the myocardium. Pro-inflammatory cytokines IL-1ß, IL-6 and TNF-α were assessed in addition to histopathological examination of the heart.

RESULTS

Low-dose irradiation attenuated cardiac enzymes, pro-inflammatory cytokines, NF-κB content, and histology, in both low and HDRs. Furthermore, the combination of low-dose irradiation with telmisartan (an angiotensin-II receptor type-1 blocker and a known cardio-protective drug) offered the best histological results.

CONCLUSIONS

Low-dose irradiation-induced amelioration is partially but not completely through canonical activation of NF-κB, and may have another atypical pathway. While telmisartan probably ameliorates NF-κB totally through canonical pathway.

Cardiac troponin and infective endocarditis prognosis: a systematic review and meta-analysis

AIMS

Infective endocarditis (IE) is associated with high mortality and morbidity. Cardiac troponin (Tn) elevation seems to be common in patients with IE and could be associated with a poor prognosis. The aim of this study was to synthesize the prognostic value of Tn in patients with IE.

METHODS AND RESULTS

We searched in MEDLINE, EMBASE, and the Cochrane library, including the Cochrane Central Register of Controlled Trials (CENTRAL) until February 2020. Observational studies reporting on the association between Tn and in-hospital and 1-year mortality, and IE complications were considered eligible. As each centre uses different conventional or ultra-sensitive Tn, with different normality threshold, we considered them as normal or elevated according to the criteria specified in each article. Articles were systematically selected, assessed for bias, and, when possible, meta-analysed using a random effect model. After retrieving 542 articles, 18 were included for qualitative synthesis and 9 for quantitative meta-analysis. Compared with patients with normal Tn levels, patients with Tn elevation presented higher in-hospital mortality [odds ratio (OR) 5.96, 95% confidence interval (CI) 3.46-10.26; P < 0.0001], 1-year mortality (OR 2.67, 95% CI 1.42-5.02; P = 0.002), and surgery rates (OR 2.34, 95% CI 1.42-3.85; P = 0.0008). They also suffered more frequent complications: central nervous system events (OR 8.85, 95% CI 3.23-24.26; P < 0.0001) and cardiac abscesses (OR 4.96, 95% CI 1.94-12.70; P = 0.0008).

CONCLUSION

Tn elevation is associated with a poor prognosis in patients with IE. Troponin determination seems to provide additional help in the prognostic assessment of these patients.

Biomarkers for prediction of mortality in left-sided infective endocarditis

BACKGROUND

Evidence regarding biomarkers for risk prediction in patients with infective endocarditis (IE) is limited. We aimed to investigate the value of a panel of biomarkers for the prediction of in-hospital mortality in patients with IE.

METHODS

Between 2016 and 2018, consecutive IE patients admitted to the emergency department were prospectively included. Blood concentrations of nine biomarkers were measured at admission (D0) and on the seventh day (D7) of antibiotic therapy: C-reactive protein (CRP), sensitive troponin I (s-cTnI), procalcitonin, B-type natriuretic peptide (BNP), neutrophil gelatinase-associated lipocalin (NGAL), interleukin 6 (IL6), tumor necrosis factor α (TNF-α), proadrenomedullin, alpha-1-acid glycoprotein, and galectin 3. The primary endpoint was in-hospital mortality.

RESULTS

Among 97 patients, 56% underwent cardiac surgery, and in-hospital mortality was 27%. At admission, six biomarkers were independent predictors of in-hospital mortality: s-cTnI (OR 3.4; 95%CI 1.8-6.4; P<0.001), BNP (OR 2.7; 95%CI 1.4-5.1; P=0.002), IL-6 (OR 2.06; 95%CI 1.3-3.7; P=0.019), procalcitonin (OR 1.9; 95%CI 1.1-3.2; P=0.018), TNF-α (OR 1.8; 95%CI 1.1-2.9; P=0.019), and CRP (OR 1.8; 95%CI 1.0-3.3; P=0.037). At admission, S-cTnI provided the highest accuracy for predicting mortality (area under the ROC curve: s-cTnI 0.812, BNP 0.727, IL-6 0.734, procalcitonin 0.684, TNF-α 0.675, CRP 0.670). After 7 days of antibiotic therapy, BNP and inflammatory biomarkers improved their performance (s-cTnI 0.814, BNP 0.823, IL-6 0.695, procalcitonin 0.802, TNF-α 0.554, CRP 0.759).

CONCLUSION

S-cTnI concentration measured at admission had the highest accuracy for mortality prediction in patients with IE.

Towards identification of novel putative biomarkers for infective endocarditis by serum proteomic analysis

INTRODUCTION

Infective endocarditis (IE) has high mortality, partly due to delayed diagnosis. No biomarker can identify IE in patients with fever and clinical picture of infection. To find putative biomarkers we analyzed serum levels of two proteins found in cardiac valves, fibulin-1 (n=696) and osteoprotegerin (n=689) among patients on clinical suspicion of IE. Proteomic analyses were performed in 24 patients with bacteremia, 12 patients with definite IE and 12 patients with excluded IE.

METHODS

Fibulin-1 and osteoprotegerin were studied by enzyme linked immunosorbent assay (ELISA). Proteomic analyses were conducted by 2-dimensional polyacrylamid gel electrophoresis (2D-PAGE) and label-free quantitative liquid chromatography - tandem mass spectrometry (LFQ LC-MS/MS). Controls for 2D 2D-PAGE and LFQ LC-MS/MS had bacteremia and excluded IE.

RESULTS

Osteoprotegerin levels were significantly increased in IE patients compared with non-IE patients. Fibulin-1 showed no difference. 2D-PAGE showed significant differences of 6 proteoforms: haptoglobin, haptoglobin-related protein, α-2-macroglobulin, apolipoprotein A-I and ficolin-3. LFQ LC-MS/MS analysis revealed significant level changes of 7 proteins: apolipoprotein L1, complement C1q subcomponent B and C, leukocyte immunoglobulin-like receptor subfamily A member 3, neuropilin-2, multimerin-1 and adiponectin.

CONCLUSIONS

The concentration changes in a set of proteoforms/proteins suggest that stress and inflammation responses are perturbed in patients with IE compared to patients with bacteremia without IE.

Non-coronarogenic causes of increased cardiac troponins in clinical practice

Cardiospecific isoforms of troponins are the most sensitive and specific biomarkers for the diagnosis of myocardial infarction. However, though elevated troponin levels indicate myocardial damage, they do not determine the cause and mechanism of the damage. With the new highly sensitive methods, very minor damages of the heart muscle can be detected. Myocardial damage can occur in many non-coronarogenic diseases. In this review, we discuss the mechanisms of elevation, the diagnostic value of cardiac troponins in the renal failure, tachyarrhythmias, endocarditis, myocarditis, pericarditis, sepsis, neurogenic pathologies (stroke), pulmonary embolism. In addition, we pay attention to the main reasons for a false-positive increase of the concentration of cardiac troponins: heterophilic antibodies, rheumatoid factor, alkaline phosphatase, cross-reactions with skeletal muscle troponins.

Elevated troponin level as a predictor of inpatient mortality in patients with infective endocarditis in the Southeast United States

Background

Despite recent improvement in management, infective endocarditis (IE) continues to be associated with considerable risk of morbidity and mortality. Early identification of predictors of inpatient mortality is key in improving patient outcomes in IE. The aim of our study was to evaluate the role of serum troponin levels measurements as a marker of increased mortality.

Methods

A case-control study included adult patients with IE admitted to a tertiary care hospital in east Tennessee between December 2012 and July 2017. Cases were defined as patients with definitive IE who died in-hospital; controls were patients who did not die in hospital. First patient admission was included only. Data collected included the patients’ demographic and baseline clinical information, microbiological data, injection drug use status, elevated serum troponins levels.

Results

Two hundred eighty three patients with definitive IE were included; median (IQR) age was 41 (30–57) years, and 153 (54%) patients were men. One-hundred sixty-four (58%) were injection drug users. The most frequent IE type was: 167 (59%) right-sided, 86 (30%) left-sided, 24 (9%) both left and right-sided, and 10 (4%) device related. The most commonly isolated organism was Staphylococcus aureus (n = 141), and 64% were methicillin-resistant. Two-hundred twelve (75%) patients had a troponin level obtained, and 57 (27%) had an elevated troponin value. Thirty-six (13%) patients died in-hospital; in-hospital mortality was associated elevated troponin values (adjusted odds ratio [adjOR], 7.3; 95%CI, 3.3–15.9), and methicillin-resistant S. aureus IE (adjOR 2.6; 95%CI, 1.2–5.8). Forty-four (16%) patients received IE valve surgery, and none of these patients died in the hospital.

Conclusion

Inpatient mortality was higher in patients with IE and elevated cardiac troponin levels compared to patients with normal levels.

Role of High-sensitivity Cardiac Troponin in Acute Coronary Syndrome

Chest pain is one of the most common reasons for an emergency room (ER) visit in the US, with almost 6 million ER visits annually. High-sensitivity cardiac troponin (hscTn) assays have the ability to rapidly rule in or rule out acute coronary syndrome with improved sensitivity, and they are increasingly being used. Though hscTn assays have been approved for use in European, Australian, and Canadian guidelines since 2010, the FDA only approved their use in 2017. There is no consensus on how to compare the results from various hscTn assays. A literature review was performed to analyze the advantages and limitations of using hscTn as a standard biomarker to evaluate patients with suspected ACS in the emergency setting.

A systematic review of biomarkers in the diagnosis of infective endocarditis

Timely diagnosis of bacterial infective endocarditis (IE) is crucial, as mortality remains high in this severe bacterial infection, currently without any distinct biological markers. Our goal was to evaluate potential diagnostic biomarkers by reviewing current literature. The MEDLINE, Embase and Scopus databases were searched for articles published from 1980 through June 2015 restricted to English, Norwegian, Danish and Swedish. Eighteen studies qualified, providing a review of the most promising candidates for future studies. Several studies are inconclusive, since they are characterized by using improper control groups. Patients with IE have bacteremia, and control groups should therefore be patients with bacteremia without IE. Based on current research, N-terminal-pro-B-type natriuretic peptide (NT-proBNP) alone or in combination with Cystatin C (Cys C), lipopolysaccharide-binding protein (LBP), troponins, aquaporin-9 (AQP9), S100 calcium binding protein A11 (S100A11), E-selectin (CD62E) and VCAM-1 (CD54) and interleukin-6 (IL-6) are potential biomarkers for future studies.

Association of troponin T, detected with highly sensitive assay, and outcomes in infective endocarditis

Troponin levels have been correlated with adverse outcomes in multiple disease processes, including congestive heart failure, acute coronary syndromes, sepsis, and, in a few small series, infective endocarditis. We hypothesized that a novel measurement of troponin using a highly sensitive assay would correlate with adverse outcomes when prospectively studied in patients with infective endocarditis. At a single center in the International Collaboration on Endocarditis, 42 patients met the inclusion criteria and underwent testing for cardiac troponin T (cTnT) using both a standard and a highly sensitive precommercial assay. The cTnT levels were associated with the prespecified primary composite outcome of death, central nervous system event, and cardiac abscess. Secondary outcomes included the individual components of the composite outcome and the need for cardiac surgery. A receiver operating characteristic curve was derived and used to identify the optimal cutpoint for cTnT using the highly sensitive assay. cTnT was detectable with the highly sensitive assay in 39 (93%) of 42 patients with infective endocarditis and with the standard assay in 25 (56%) of 42 (p <0.05). Of the 42 patients, 15 experienced the composite outcome, 4 died, 9 had a central nervous system event, and 5 had a cardiac abscess. With the hs-cTnT assay, the median cTnT was greater in the patients who experienced the primary outcome (0.12 vs 0.02 ng/ml, p <0.05). According to the receiver operating characteristic curve analysis (area under the curve of 0.74), cTnT levels of ≥0.08 ng/ml produced optimal specificity (78%) for the primary outcome. The patients with a cTnT level of ≥0.08 ng/ml were more likely to experience the primary outcome (odds ratio 7.0, 95% confidence interval 1.7 to 28.6, p <0.01) and a central nervous system event (odds ratio 9.3, 95% confidence interval 1.3 to 24.1, p = 0.02). In conclusion, cTnT is detectable in 93% of patients with infective endocarditis using a novel highly sensitive assay, with higher levels correlating with poor clinical outcomes.

Relation of level of B-type natriuretic peptide with outcomes in patients with infective endocarditis

Elevated B-type natriuretic peptide (BNP) is a marker of poor outcomes in heart failure, acute coronary syndromes, and sepsis. Elevated cardiac troponin I (cTnI) is associated with adverse outcomes in infective endocarditis. It was hypothesized that elevated BNP would be associated with increased rates of morbidity and mortality in patients with infective endocarditis, particularly when combined with elevated cTnI. Consecutively enrolled patients in the International Collaboration on Endocarditis Prospective Cohort Study (ICE-PCS) were evaluated at a single center. The association between elevated BNP and a composite outcome of death, intracardiac abscess, and central nervous system event and the individual components of the composite was determined. Similar analyses were performed in patients who had BNP and cTnI measured. Of 103 patients, 45 had BNP measured for clinical indications. The median BNP level was higher in patients with the composite outcome (1,498 vs 433 pg/ml, p = 0.03) and in those who died (2,150 vs 628 pg/ml, p = 0.04). Elevated BNP was significantly associated with the composite outcome (p <0.01) and intracardiac abscess (p = 0.02). Patients with elevation of BNP and cTnI had a significantly higher probability of the composite outcome (69%) than patients with either BNP or cTnI elevated (29%) or neither BNP nor troponin elevated (0%) (p for trend <0.01). In conclusion, these data demonstrate a significant association between elevated BNP alone and in combination with cTnI for serious outcomes in infective endocarditis and warrant prospective evaluation.

Increases of cardiac troponin in conditions other than acute coronary syndrome and heart failure

BACKGROUND

Although cardiac troponin (cTn) is a cornerstone marker in the assessment and management of patients with acute coronary syndrome (ACS) and heart failure (HF), cTn is not diagnostically specific for any single myocardial disease process. This narrative review discusses increases in cTn that result from acute and chronic diseases, iatrogenic causes, and myocardial injury other than ACS and HF.

CONTENT

Increased cTn concentrations have been reported in cardiac, vascular, and respiratory disease and in association with infectious processes. In cases involving acute aortic dissection, cerebrovascular accident, treatment in an intensive care unit, and upper gastrointestinal bleeding, increased cTn predicts a longer time to diagnosis and treatment, increased length of hospital stay, and increased mortality. cTn increases are diagnostically and prognostically useful in patients with cardiac inflammatory diseases and in patients with respiratory disease; in respiratory disease cTn can help identify patients who would benefit from aggressive management. In chronic renal failure patients the diagnostic sensitivity of cTn for ACS is decreased, but cTn is prognostic for the development of cardiovascular disease. cTn also provides useful information when increases are attributable to various iatrogenic causes and blunt chest trauma.

SUMMARY

Information on the diagnostic and prognostic uses of cTn in conditions other than ACS and heart failure is accumulating. Although increased cTn in settings other than ACS or heart failure is frequently considered a clinical confounder, the astute physician must be able to interpret cTn as a dynamic marker of myocardial damage, using clinical acumen to determine the source and significance of any reported cTn increase.