Cardiac troponin assays in the management of heart failure

Exercise training and high-sensitivity cardiac troponin-I in patients with heart failure with reduced ejection fraction

AIMS

The aims of this sub-study of the SMARTEX trial were (1) to evaluate the effects of a 12-week exercise training programme on serum levels of high sensitivity cardiac troponin I (hs-cTnI) in patients with moderate chronic heart failure (CHF), in New York Heart Association class II-III with reduced ejection fraction (HFrEF) and (2) to explore the associations with left ventricular remodelling, functional capacity and filling pressures measured with N-terminal pro brain natriuretic peptide (NT-proBNP).

METHODS AND RESULTS

In this sub-study, 196 patients were randomly assigned to high intensity interval training (HIIT, n = 70), moderate continuous training (MCT, n = 59) or recommendation of regular exercise (RRE), (n = 67) for 12 weeks. To reveal potential difference between structured intervention and control, HIIT and MCT groups were merged and named supervised exercise training (SET) group. The RRE group constituted the control group (CG). To avoid contributing factors to myocardial injury, we also evaluated changes in patients without additional co-morbidities (atrial fibrillation, hypertension, diabetes mellitus, and chronic obstructive pulmonary disease). The relationship between hs-cTnI and left ventricular end-diastolic diameter (LVEDD), VO2peak, and NT-proBNP was analysed by linear mixed models. At 12 weeks, Hs-cTnI levels were modestly but significantly reduced in the SET group from median 11.9 ng/L (interquartile ratio, IQR 7.1-21.8) to 11.5 ng/L (IQR 7.0-20.7), P = 0.030. There was no between-group difference (SET vs. CG, P = 0.116). There was a numerical but not significant reduction in hs-cTnI for the whole population (P = 0.067) after 12 weeks. For the sub-group of patients without additional co-morbidities, there was a significant between-group difference: SET group (delta -1.2 ng/L, IQR -2.7 to 0.1) versus CG (delta -0.1 ng/L, IQR -0.4 to 0.7), P = 0.007. In the SET group, hs-cTnI changed from 10.9 ng/L (IQR 6.0-22.7) to 9.2 ng/L (IQR 5.2-20.5) (P = 0.002), whereas there was no change in the CG (6.4 to 5.8 ng/L, P = 0.64). Changes in hs-cTnI (all patients) were significantly associated with changes in; LVEDD, VO2peak, and NT-proBNP, respectively.

CONCLUSIONS

In patients with stable HFrEF, 12 weeks of structured exercise intervention was associated with a modest, but significant reduction of hs-cTnI. There was no significant difference between intervention group and control group. In the sub-group of patients without additional co-morbidities, this difference was highly significant. The alterations in hs-cTnI were associated with reduction of LVEDD and natriuretic peptide concentrations as well as improved functional capacity.

Cardiac Troponin Serum Concentration Measurement Is Useful Not Only in the Diagnosis of Acute Cardiovascular Events

Cardiac troponin serum concentration is the primary marker used for the diagnosis of acute coronary syndrome. Moreover, the measurement of cardiac troponin concentration is important for risk stratification in patients with pulmonary embolism. The cardiac troponin level is also a general marker of myocardial damage, regardless of etiology. The purpose of this study is to conduct a literature review and present the most important information regarding the current state of knowledge on the cardiac troponin serum concentration in patients with chronic cardiovascular disease (CVD), as well as on the relationships between cardiac troponin serum concentration and features of subclinical cardiovascular dysfunction. According to research conducted to date, patients with CVDs, such as chronic coronary syndrome, chronic lower extremities' ischemia, and cerebrovascular disease, are characterized by higher cardiac troponin concentrations than people without a CVD. Moreover, the literature data indicate that the concentration of cardiac troponin is correlated with markers of subclinical dysfunction of the cardiovascular system, such as the intima-media thickness, pulse wave velocity, ankle-brachial index, coronary artery calcium index (the Agatston score), and flow-mediated dilation. However, further research is needed in various patient subpopulations and in different clinical contexts.

Relationship Between Albumin-Corrected Anion Gap and Mortality in Hospitalized Heart Failure Patients

BACKGROUND

Heart failure (HF) is a disease with high morbidity and mortality. Despite the efforts to reduce mortality rates through medical progress, it is necessary to develop markers to identify critically ill patients. In our study, we aimed to investigate the relationship between albumin-corrected anion gap (ACAG) and mortality in hospitalized patients with HF.

METHODOLOGY

We performed a retrospective study that included patients with HF hospitalized in the Erzurum City Hospital between 2015 and 2022. The basal clinical, hematological, and biochemical findings of the patients were obtained from the electronic medical records. ACAG was calculated. The date and causes of death of the patients were searched and recorded through the Republic of Türkiye Ministry of Health Death Notification System (ÖBYS) and Central Population Administration System (MERNIS). Thus, the relationship between ACAG and mortality in hospitalized patients with HF was evaluated.

RESULTS

A total of 205 patients hospitalized for HF were included in the study. The mean age of all people in this study was 71.8 ± 10.7 years. A total of 104 (50.7%) of the patients included in the study were women. The mean left ventricular ejection fraction was 47.2 ± 13.6%. The mean follow-up period of the entire population was 76.5 ± 18.9 months. The mortality rate was 11.7% (24 patients). Serum anion gap (SAG) and ACAG were significantly higher in the group with death outcomes (p = 0.043 and p = 0.012, respectively). Cox regression analysis showed that ACAG was an independent predictor of HF mortality (p = 0.003). ACAG area under the curve was 0.773 (95% CI 0.634 - 0.914), the cut-off was 13, sensitivity was 75%, and specificity was 75.9% (p = 0.002).

CONCLUSION

Statistical analysis showed a meaningful connection between an increase in ACAG and mortality in hospitalized patients with HF. Consequently, ACAG can be used as an independent predictor of mortality in patients with HF.

Inhibition of transglutaminase 2 (TG2) ameliorates ventricular fibrosis in isoproterenol-induced heart failure in rats

AIMS

Transglutaminase (TG) inhibitors represent promising therapeutic interventions in cardiac fibrosis and related dysfunctions. However, it remains unknown how TG inhibition, TG2 in particular, affects the signaling systems that drive pathological fibrosis. This study aimed to examine the effect TG inhibition by cystamine on the progression of isoproterenol (ISO)-induced cardiac fibrosis and dysfunction in rats.

MATERIALS AND METHODS

Cardiac fibrosis was established by intraperitoneal injection of ISO to rats (ISO group), followed by 6 weeks of cystamine injection (ISO + Cys group). The control groups were administered normal saline alone or with cystamine. Hemodynamics, lipid profile, liver enzymes, urea, and creatinine were assessed in conjunction with heart failure markers (serum NT-proANP and cTnI). Left ventricular (LV) and atrial (LA) fibrosis, total collagen content, and mRNA expression of profibrotic markers including TG2 were quantified by Masson's trichrome staining, LC-MS/MS and quantitative PCR, respectively.

KEY FINDINGS

Cystamine administration to ISO rats significantly decreased diastolic and mean arterial pressures, total cholesterol, triglycerides, LDL, liver enzymes, urea, and creatinine levels, while increasing HDL. NT-proANP and cTnI serum levels remained unchanged. In LV tissues, significant reductions in ISO-induced fibrosis and elevated total collagen content were achieved after cystamine treatment, together with a reduction in TG2 concentration. Reduced mRNA expression of several profibrotic genes (COL1A1, FN1, MMP-2, CTGF, periostin, CX43) was also evidenced in LV tissues of ISO rats upon cystamine administration, whereas TGF-β1 expression was depressed in LA tissues. Cystamine decreased TG2 mRNA expression in the LV of control rats, while LV expression of TG2 was relatively low in ISO rats irrespective of cystamine treatment.

SIGNIFICANCE

TG2 inhibition by cystamine in vivo exerted cardioprotective effects against ISO-induced cardiac fibrosis in rats decreasing the LV abundance of several profibrotic markers and the content of TG2 and collagen, suggesting that TG2 pharmacological inhibition could be beneficial to alleviate cardiac fibrosis.

Predictive value of heart failure with reduced versus preserved ejection fraction for outcome in pulmonary embolism

AIMS

This study aimed to investigate whether the risk of short-term mortality is different in pulmonary embolism (PE) patients who have heart failure with reduced ejection fraction (HFrEF) as compared with those with heart failure with preserved ejection fraction (HFpEF).

METHODS AND RESULTS

Predictive value of HFrEF or HFpEF for 7-day (intrahospital) and 30-day all-cause mortality was determined in the cohort of 1055 out of 1201 consecutive acute PE patients from the Serbian multicentre PE registry. Patients were classified into either HFrEF or HFpEF group, according to guideline-proposed criteria. A 7-day (intrahospital) and 30-day all-cause mortality was 18.5% vs. 7.3% vs. 4.5% (P < 0.001) and 22.2% vs. 16.3% vs. 7.9% (P < 0.001) for patients with the history of HFrEF, HFpEF, and without HF, respectively. Multivariable analysis adjusted to age, gender, history of chronic obstructive pulmonary disease, diabetes mellitus, arterial hypertension, presence of atrial fibrillation, and mortality risk assessment at admission has shown that only HFrEF, but not HFpEF, was an independent predictor for 7-day mortality (hazard ratio 2.22, 95% confidence interval 1.25-4,38.41, P = 0.021) and neither HFrEF or HFpEF was an independent predictor for 30-day mortality. Among various admission parameters associated to PE outcome, only systolic pressure in HFrEF patients (P < 0.001), heart rate (P = 0.01), and right ventricle systolic pressure (P = 0.039) in HFpEF patients were significantly different in patients who died compared with those who survived at 7 days.

CONCLUSIONS

Our study has shown that the presence of previous history of HFrEF, but not HFpEF, in acute PE is an independent risk factor for mortality at 7 days.

Serial Troponin for Early Detection of Nivolumab Cardiotoxicity in Advanced Non-Small Cell Lung Cancer Patients

BACKGROUND

Rare cases of severe myocarditis are reported during treatment with nivolumab. Troponin, a biomarker of cardiac damage, is a key component of the diagnostic workup of many cardiac disorders, including myocarditis. This study investigates the role of troponin to assess cardiac involvement during nivolumab therapy for non-small cell lung cancer (NSCLC).

MATERIALS AND METHODS

We evaluated 59 NSCLC patients, analyzing serum samples collected within a translational research study. Troponin above the upper normal limit (0.046 ng/mL) was defined as Tn+, whereas normal but detectable troponin (0.015-0.045) was defined as Tn^det. Troponin alterations were interpreted on the grounds of the following elements: peak values and time curve, cardiac comorbidities, signs and symptoms coincident to troponin elevation, ECG, echocardiography, and disease progression.

RESULTS

No patient had cardiovascular events. Among 362 available blood samples, Tn+ (max 0.317 ng/mL) was found in 13 determinations belonging to 6 patients. Seven other patients had isolated Tn^det. In five patients, Tn+ was attributed to cardiac comorbidities, disease progression, or worsening clinical status. One patient without cardiac history and in good clinical condition had a sustained troponin increase-soon after the start of therapy-and after careful evaluation of all relevant elements, it was interpreted as a marker of nivolumab-related subclinical myocarditis.

CONCLUSION

Tn+ may occur in NSCLC patients treated with nivolumab, but in most cases it does not indicate nivolumab cardiotoxicity. In some cases, however, a careful interpretation of troponin alteration, especially at the beginning of therapy, enables identification of subclinical myocarditis, thus allowing early cardiac treatment.

IMPLICATIONS FOR PRACTICE

Myocarditis is a rare but serious adverse event of immune checkpoint blockade with nivolumab, which needs to be recognized as soon as possible. This article suggests that troponin, a user-friendly biomarker of myocardial cytotoxicity, might be useful for early detection of immune-mediated myocarditis. However, because troponin abnormalities might also be related to a number of conditions capable of causing myocardial oxygen demand-supply mismatch, a careful cardiac assessment should be performed in non-small cell lung cancer patients in order to properly interpret any troponin increase. According to the available evidence, monitoring troponin during the first weeks of treatment can be considered reasonable.

Terminology of cardiac troponin assays and data censoring

We discuss the sensitivity terminology of cardiac troponin assays and its dependence on the selection of the reference population. In addition, the need for reasonable censoring of clinical laboratory test results is contrasted with potential loss of valuable clinical information.

Treatment of Heart Failure With Reduced Ejection Fraction-Recent Developments

Heart failure with reduced ejection fraction (HFrEF) represents at least half of the cases of heart failure, which is a syndrome defined as the inability of the heart to supply the body's tissues with an adequate amount of blood under conditions of normal cardiac filling pressure. HFrEF is responsible for high costs and rates of mortality, morbidity, and hospital admissions, mainly in developed countries. Thus, the need for better diagnostic methods and therapeutic approaches and consequently better outcomes is clear. In this article, we review the principal aspects of pathophysiology and diagnosis of HFrEF, with focus on emerging biomarkers and on recent echocardiographic methods for the assessment of left ventricular function. Furthermore, we discuss several major developments in pharmacological and nonpharmacological treatment of HFrEF in the last years, including cardiac resynchronization therapy, implantable cardioverter defibrillators, and the recent and promising drug LCZ696, focusing on current indications, unanswered questions, and other relevant aspects.