Elevated Plasma Soluble ST2 Is Associated with Heart Failure Symptoms and Outcome in Aortic Stenosis

Novel Biomarkers and Advanced Cardiac Imaging in Aortic Stenosis: Old and New

Currently, the symptomatic status and left ventricular ejection fraction (LVEF) play a crucial role in aortic stenosis (AS) assessment. However, the symptoms are often subjective, and LVEF is not a sensitive marker of left ventricle (LV) decompensation. Over the past years, the cardiac structure and function research on AS has increased due to advanced imaging modalities and potential therapies. New imaging parameters emerged as predictors of disease progression in AS. LV global longitudinal strain has proved useful for risk stratification in asymptomatic severe AS patients with preserved LVEF. The assessment of myocardial fibrosis by cardiac magnetic resonance is the most studied application and offers prognostic information on AS. Moreover, the usage of biomarkers in AS as objective measures of LV decompensation has recently gained more interest. The present review focuses on the transition from compensatory LV hypertrophy (H) to LV dysfunction and the biomarkers associated with myocardial wall stress, fibrosis, and myocyte death. Moreover, we discuss the potential impact of non-invasive imaging parameters for optimizing the timing of aortic valve replacement and provide insight into novel biomarkers for possible prognostic use in AS. However, data from randomized clinical trials are necessary to define their utility in daily practice.

Establishment of growth stimulating gene 2 protein time-resolved fluorescence immunoassay and its application in sepsis

AIM

This study aimed to establish a highly sensitive time-resolved fluorescence immunoassay of growth stimulating express gene 2 protein (ST2-TRFIA) and evaluate its application value for sepsis.

METHODS

Two types of ST2 monoclonal specific antibodies against different epitopes of antigen molecule were used as coating and Eu3+-labeled antibodies. The double-antibody sandwich method was used in establishing ST2-TRFIA, and the methodology was evaluated. The established ST2-TRFIA was used in detecting ST2 concentration in the plasma samples of healthy controls and sepsis.

RESULTS

The linear range of ST2-TRFIA was 1.446-500 ng/mL. Plasma ST2 concentrations detected through ST2-TRFIA were consistent with the results of fluorescence quantitative immunochromatography (ρ = 0.946). The plasma ST2 concentrations of patients with sepsis were significantly higher than those of healthy controls (P < 0.01).

CONCLUSION

This study successfully established a highly sensitive ST2-TRFIA, which was highly comparable to commercially available fluorescent quantitative immunochromatographic kits and can facilitate the timely diagnosis of sepsis.

Soluble ST2 levels are related to replacement myocardial fibrosis in severe aortic stenosis

INTRODUCTION AND OBJECTIVES

Patients with aortic stenosis (AS) exhibit left ventricular (LV) remodeling and replacement myocardial fibrosis (RMF). Whether sST2 is associated with RMF measured by cardiac magnetic resonance and with sex remains unknown.

METHODS

We recruited 79 consecutive patients (73.0 [68.0-78.0] years; 61% men) with severe isolated AS underdoing valve replacement. RMF was identified and quantified by late gadolinium enhancement (LGE). Serum sST2 levels were determined.

RESULTS

RMF was associated with higher circulating sST2 levels, LV hypertrophy and dilation, and lower LV ejection fraction. All patients with LV dysfunction had RMF. Circulating levels of sST2 ≥ 28.8 ng/mL were associated with RMF and greater LV hypertrophy. LGE mass was correlated with LV remodeling and sST2. Of note, sST2 levels were also associated with the RMF pattern, being higher in midwall than in subendocardial fibrosis. Multivariate analyses showed that only LV ejection fraction and sST2 levels were associated with RMF. Moreover, men had higher levels of sST2 and RMF. RMF was associated with higher LV dilation and hypertrophy only in men and was correlated with LGE mass.

CONCLUSIONS

SST2 was an independent factor for RMF in patients with severe isolated AS. The presence of RMF was predicted by sST2 ≥ 28.2 ng/mL, and was associated with greater LV hypertrophy. sST2 expression and clinical associations may be sex-specific.

The ST2/IL-33 Pathway in Adult and Paediatric Heart Disease and Transplantation

ST2 is a member of interleukin 1 receptor family with soluble sST2 and transmembrane ST2L isoforms. The ligand of ST2 is IL-33, which determines the activation of numerous intracytoplasmic mediators following the binding with ST2L and IL-1RAcP, leading to nuclear signal and cardiovascular effect. Differently, sST2 is released in the blood and works as a decoy receptor, binding IL-33 and blocking IL-33/ST2L interaction. sST2 is mainly involved in maintaining homeostasis and/or alterations of different tissues, as counterbalance/activation of IL-33/ST2L axis is typically involved in the development of fibrosis, tissue damage, inflammation and remodeling. sST2 has been described in different clinical reports as a fundamental prognostic marker in patients with cardiovascular disease, as well as marker for the treatment monitoring of patients with heart failure; however, further studies are needed to better elucidate its role. In this review we reported the current knowledge about its role in coronary artery disease, heart failure, heart transplantation, heart valve disease, pulmonary arterial hypertension, and cardiovascular interventions.

Growth Differentiation Factor-15 as a Predictor of Functional Capacity, Frailty, and Ventricular Dysfunction in Patients With Aortic Stenosis and Preserved Left Ventricular Ejection Fraction

In aortic stenosis (AS), left ventricular (LV) remodeling often occurs before symptom onset, and early intervention may be beneficial. Risk stratification remains challenging and identification of biomarkers may be useful. We evaluated the association between growth differentiation factor-15 (GDF-15) and soluble suppression of tumorigenicity 2 (sST2) and known markers of poor prognosis in AS. Baseline plasma GDF-15 and sST2 levels were measured in 70 patients with moderate-severe AS (aortic valve area <1.5 cm²) and preserved LV ejection fraction (>45%). Patients were categorized into "low GDF-15" versus "high GDF-15" and "low sST2" versus "high sST2" groups. Groups were compared for differences in cardiovascular risk factors, 6-minute walk test, 5 m gait speed, cognitive function (Montreal Cognitive Assessment), and echocardiographic parameters. Overall, 44% of patients were deemed asymptomatic by New York Heart Association class, 61% had severe AS (aortic valve area <1 cm²) and all patients had preserved LV ejection fraction. GDF-15 levels were not predictive of AS severity. However, high GDF-15 (>1,050 pg/ml) was associated with LV dysfunction as shown by lower indexed stroke volume (p <0.01), worse LV global longitudinal strain (p = 0.04), greater mean E/e' (p = 0.02) and indexed left atrial volume (p <0.01). It was also associated with decreased functional capacity with shorter 6-minute walk test (p = 0.01) and slower 5 m gait speed (p = 0.02). Associations between sST2 levels and markers of poor prognosis were less compelling. In this study of patients with moderate to severe AS, elevated GDF-15 levels are associated with impaired functional capacity, poorer performance on fragility testing, and LV dysfunction. In conclusion, GDF-15 may integrate these markers of adverse outcomes into a single biomarker of poor prognosis.

Soluble ST2: a valuable prognostic marker in heart failure

Natriuretic peptides have been at the forefront of biomarker use in heart disease and have been universally recommended as the ideal biomarker in the setting of heart failure. Soluble ST2 is one such biomarker which has found value as a prognostic marker and can be used individually or along with natriuretic peptides in order to prognosticate patients with heart failure. Leading cardiovascular organisations have recognised this biomarker, though its role as a diagnostic marker is yet to be determined. We aim to investigate the role of sST2 in heart failure in the existing literature.

Severe Aortic Valve Stenosis and Pulmonary Hypertension: A Systematic Review of Non-Invasive Ways of Risk Stratification, Especially in Patients Undergoing Transcatheter Aortic Valve Replacement

Patients with severe aortic valve stenosis and concomitant pulmonary hypertension show a significantly reduced survival prognosis. Right heart catheterization as a preoperative diagnostic tool to determine pulmonary hypertension has been largely abandoned in recent years in favor of echocardiographic criteria. Clinically, determination of echocardiographically estimated systolic pulmonary artery pressure falls far short of invasive right heart catheterization data in terms of accuracy. The aim of the present systematic review was to highlight noninvasive possibilities for the detection of pulmonary hypertension in patients with severe aortic valve stenosis, with a special focus on cardiovascular biomarkers. A total of 525 publications regarding echocardiography, cardiovascular imaging and biomarkers related to severe aortic valve stenosis and pulmonary hypertension were analyzed in a systematic database analysis using PubMed Central®. Finally, 39 publications were included in the following review. It was shown that the current scientific data situation, especially regarding cardiovascular biomarkers as non-invasive diagnostic tools for the determination of pulmonary hypertension in severe aortic valve stenosis patients, is poor. Thus, there is a great scientific potential to combine different biomarkers (biomarker scores) in a non-invasive way to determine the presence or absence of PH.

Mountain Ultra-Marathon (UTMB) Impact on Usual and Emerging Cardiac Biomarkers

The number of participants in ultra-marathons is increasing. However, the data regarding the impact of this type of exercise on the cardiovascular system are contradictory. In our study, 28 ultra-trail runners were enrolled. Blood samples were collected at three time points: immediately before, immediately after, and 7 days after the ultra-marathon. Different biomarkers were measured. Immediately after the race, the blood concentrations of the different cardiac and inflammatory biomarkers increased significantly. Interestingly, some biomarkers remained high even after 7 days of recovery.

Soluble ST2 as a Potential Biomarker for Risk Assessment of Pulmonary Hypertension in Patients Undergoing TAVR?

Background: Severe aortic valve stenosis (AS) is associated with pulmonary hypertension (PH) and has been shown to limit patient survival. Soluble suppression of tumorigenicity-2 (sST2) is a cardiovascular biomarker that has proven to be an important prognostic marker for survival in patients undergoing transcatheter aortic valve replacement (TAVR). The aim of this study was to assess the importance of the sST2 biomarker for risk stratification in patients with severe AS in presence or absence of PH. Methods: In 260 patients with severe AS undergoing TAVR procedure, sST2 serum level concentrations were analyzed. Right heart catheter measurements were performed in 152 patients, with no PH detection in 43 patients and with PH detection in 109 patients. Correlation analyses according to Spearman, AUROC analyses and Kaplan–Meier curves were calculated. Results: Patients with severe AS and PH showed significantly higher serum sST2 concentrations (p = 0.006). The sST2 cut-off value for non-PH patients regarding 1-year survival yielded 5521.15 pg/mL, whereas the cut-off value of PH patients was at a considerably higher level of 10,268.78 pg/mL. A cut-off value of 6990.12 pg/mL was related with a significant probability of PH presence. Survival curves showed that patients with severe AS and PH not only had higher 1-year mortality, but also that increased levels of sST2 plasma concentration were associated with earlier death. Conclusion: sST2 definitely has the potential to provide information about the presence of PH in patients with severe AS, in a noninvasive way.

Plasma biomarkers associated with adverse outcomes in patients with calcific aortic stenosis

AIMS

Enhanced risk stratification of patients with aortic stenosis (AS) is necessary to identify patients at high risk for adverse outcomes, and may allow for better management of patient subgroups at high risk of myocardial damage. The objective of this study was to identify plasma biomarkers and multimarker profiles associated with adverse outcomes in AS.

METHODS AND RESULTS

We studied 708 patients with calcific AS and measured 49 biomarkers using a Luminex platform. We studied the correlation between biomarkers and the risk of (i) death and (ii) death or heart failure-related hospital admission (DHFA). We also utilized machine-learning methods (a tree-based pipeline optimizer platform) to develop multimarker models associated with the risk of death and DHFA. In this cohort with a median follow-up of 2.8 years, multiple biomarkers were significantly predictive of death in analyses adjusted for clinical confounders, including tumour necrosis factor (TNF)-α [hazard ratio (HR) 1.28, P < 0.0001], TNF receptor 1 (TNFRSF1A; HR 1.38, P < 0.0001), fibroblast growth factor (FGF)-23 (HR 1.22, P < 0.0001), N-terminal pro B-type natriuretic peptide (NT-proBNP) (HR 1.58, P < 0.0001), matrix metalloproteinase-7 (HR 1.24, P = 0.0002), syndecan-1 (HR 1.27, P = 0.0002), suppression of tumorigenicity-2 (ST2) (IL1RL1; HR 1.22, P = 0.0002), interleukin (IL)-8 (CXCL8; HR 1.22, P = 0.0005), pentraxin (PTX)-3 (HR 1.17, P = 0.001), neutrophil gelatinase-associated lipocalin (LCN2; HR 1.18, P < 0.0001), osteoprotegerin (OPG) (TNFRSF11B; HR 1.26, P = 0.0002), and endostatin (COL18A1; HR 1.28, P = 0.0012). Several biomarkers were also significantly predictive of DHFA in adjusted analyses including FGF-23 (HR 1.36, P < 0.0001), TNF-α (HR 1.26, P < 0.0001), TNFR1 (HR 1.34, P < 0.0001), angiopoietin-2 (HR 1.26, P < 0.0001), syndecan-1 (HR 1.23, P = 0.0006), ST2 (HR 1.27, P < 0.0001), IL-8 (HR 1.18, P = 0.0009), PTX-3 (HR 1.18, P = 0.0002), OPG (HR 1.20, P = 0.0013), and NT-proBNP (HR 1.63, P < 0.0001). Machine-learning multimarker models were strongly associated with adverse outcomes (mean 1-year probability of death of 0%, 2%, and 60%; mean 1-year probability of DHFA of 0%, 4%, 97%; P < 0.0001). In these models, IL-6 (a biomarker of inflammation) and FGF-23 (a biomarker of calcification) emerged as the biomarkers of highest importance.

CONCLUSIONS

Plasma biomarkers are strongly associated with the risk of adverse outcomes in patients with AS. Biomarkers of inflammation and calcification were most strongly related to prognosis.

Natriuretic peptide release during exercise in patients with valvular heart disease: A systematic review

AIM

Serum biomarkers have a potential role in the risk stratification of patients with heart valve disease and may help determine the optimal timing of intervention. Much of the published literature relates to biomarker sampling in a resting state, but the relationship of exercise biomarkers is less well described. We performed a systematic review to examine the significance of exercise natriuretic peptides on echocardiographic variables and cardiovascular events, in valvular heart disease.

METHODS

A search for studies that assessed exercise biomarkers in patients with moderate to severe valve lesions was performed. We examined the relationship between rest and exercise BNP and also the endpoints of symptoms, haemodynamic or echocardiographic variables and clinical outcomes.

RESULTS

Eleven prospective studies were identified (844 participants). 61% were male and the mean age was 55.2 ± 9.6 years. The majority of the blood samples were taken at baseline and within 3 minutes of stopping exercise. There was a significant increase in exercise BNP compared with rest, in patients with aortic stenosis, mitral regurgitation and mitral stenosis. Elevated exercise BNP levels correlated with mean gradient and left atrial area, and there was a relationship between a higher exercise BNP and a blunted blood pressure response, in aortic stenosis. Furthermore, exercise BNP was independently associated with cardiac events, over and above resting values, in patients with mitral regurgitation and aortic stenosis.

CONCLUSION

The results suggesting that exercise natriuretic peptide levels may have additive prognostic importance over resting levels, as well as demographic and echocardiographic data.

Biomarkers Associated With Aortic Valve Calcification: Should We Focus on Sex Specific Processes?

Objective

Circulating biomarkers are useful in detection and monitoring of cardiovascular diseases. However, their role in aortic valve disease is unclear. Mechanisms are rapidly elucidated and sex differences are suggested to be involved. Therefore, we sought to identify biomarkers involved in aortic valve calcification (AVC) stratified by sex.

Methods

Blood samples of 34 patients with AVC (without further overt cardiovascular disease, including absence of hemodynamic consequences of valvular calcification) were compared with 136 patients without AVC. AVC was determined using computed tomography calcium scoring. Circulating biomarkers were quantified using a novel antibody-based method (Olink Proseek Multiplex Cardiovascular Panel I) and 92 biomarkers were compared between patients with and without AVC.

Results

In the overall population, Interleukin-1 Receptor Antagonist and pappalysin-1 were associated with increased and decreased odds of having AVC. These differences were driven by the male population [IL1RA: OR 2.79 (1.16-6.70), p = 0.022; PAPPA: OR 0.30 (0.11-0.84), p = 0.021]. Furthermore, TNF-related activation-induced cytokine (TRANCE) and fibroblast growth factor-23 were associated decreased odds of having AVC, and monocyte chemotactic protein-1 was associated with increased odds of having AVC [TRANCE: OR 0.32 (0.12-0.80), p = 0.015; FGF23: OR 0.41 (0.170-0.991), p = 0.048; MCP1: OR 2.64 (1.02-6.81), p = 0.045]. In contrast, galanin peptides and ST2 were associated with increased odds of having AVC in females [GAL: OR 12.38 (1.31-116.7), p = 0.028; ST2: OR13.64 (1.21-153.33), p = 0.034].

Conclusion

In this exploratory study, we identified biomarkers involved in inflammation, fibrosis and calcification which may be associated with having AVC. Biomarkers involved in fibrosis may show higher expression in females, whilst biomarkers involved in inflammation and calcification could associate with AVC in males.

Urea level is an independent predictor of mortality in patients with severe aortic valve stenosis

Introduction

Severe aortic stenosis (AS) is the most common valvular heart disease in the western world. Various factors are related to severe AS prognosis, including chronic kidney disease. The aim of this study was to evaluate the prognostic value of urea level in patients with severe AS.

Methods

We prospectively enrolled 142 patients (79.1±9.4 years, 88 women) with severe AS (mean valve area 0.67± 0.17 cm²). Clinical assessment, blood tests and echocardiography were performed at enrollment and follow up. The patient population was divided into low and high urea level groups, according to the median urea level at enrollment (72 patients, mean urea 35.5±6.2 mg/dL and 70 patients, mean urea 61.1±17.8 mg/dL, respectively). Hundred and twelve patients (79%) underwent aortic valve intervention. The primary endpoint was all-cause and cardiovascular mortality.

Outcomes

During follow-up of 37±19.5 months, 56 (37.1%) patients died, 39 due to cardiovascular causes. In univariate analysis, age, urea level, creatinine, New York Heart Association (NYHA) class and aortic valve intervention were associated with all-cause mortality. However, in multivariate analysis only aortic valve intervention and blood urea were independent predictors of all-cause mortality (HR 0.494; 95% CI 0.226–0.918, P = 0.026 and HR 1.015; 95% CI 1.003–1.029, P = 0.046 respectively). Urea level, NYHA class and age were also significant predictors of cardiovascular mortality. Whereas, in multivariate analysis, only urea level predicted cardiovascular mortality in these patients (HR 1.017; CI 1.003–1.031 P = 0.019).

Conclusions

Blood urea, a generally readily available and routinely determined marker of renal function, is an independent prognostic factor in patients with severe AS.

Aortic valve calcification in the era of non-coding RNAs: The revolution to come in aortic stenosis management?

Aortic valve stenosis remains the most frequent structural heart disease, especially in the elderly. During the last decade, we noticed an important consideration and a huge number of publications related to the medical and surgical treatment of this disease. However, the molecular aspect of this degenerative issue has also been more widely studied recently. As evidenced in oncologic but also cardiac research fields, the emergence of microRNAs in the molecular screening and follow-up makes them potential biomarkers in the future, for the diagnosis, follow-up and treatment of aortic stenosis. Herein, we present a review on the implication of microRNAs in the aortic valve disease management. After listing and describing the main miRNAs of interest in the field, we provide an outline to develop miRNAs as innovative biomarkers and innovative therapeutic strategies, and describe a groundbreaking pre-clinical study using inhibitors of miR-34a in a pre-clinical model of aortic valve stenosis.

Multimarker Approach to Identify Patients With Higher Mortality and Rehospitalization Rate After Surgical Aortic Valve Replacement for Aortic Stenosis

OBJECTIVES

This study sought to evaluate whether a multimarker approach might identify patients with higher mortality and hospitalization rates after aortic valve replacement (AVR) for aortic stenosis (AS).

BACKGROUND

The society valve guidelines include accepted triggers for AVR in patients with severe asymptomatic AS, but circulating biomarkers do not have a clear role.

METHOD

From a prospective registry of patients undergoing cardiac surgery between 2000 and 2012, 665 treated with surgical AVR (441 isolated) were evaluated. Seven biomarkers were measured on blood samples obtained before AVR. Biomarker levels were adjusted to account for the influence of age, sex, body mass index, and renal function; the median was used to determine an elevated value. Endpoints included all-cause mortality and all-cause and cardiovascular hospitalizations. Mean follow-up was 10.7 years and 299 (45%) died.

RESULTS

Patients with 0 to 1, 2 to 3, 4 to 6, and 7 biomarkers elevated had 5-year mortality of 10%, 12%, 24%, and 33%, respectively, and 10-year mortality of 24%, 35%, 58%, and 71%, respectively (log-rank p < 0.001). The association between an increasing number of elevated biomarkers and increased all-cause mortality was observed among those with minimal symptoms (New York Heart Association functional class I or II) and those with a low N-terminal pro-B-type natriuretic peptide (p < 0.01 for both). Compared with those with 0 to 1 biomarkers elevated, patients with 4 to 6 or 7 biomarkers elevated had an increased hazard of mortality after adjustment for clinical risk scores (p < 0.01) and a 2- to 3-fold higher rate of all-cause and cardiovascular rehospitalization after AVR. Similar findings were obtained when evaluating cardiovascular mortality. Among patients with no or minimal symptoms, 42% had ≥4 biomarkers elevated.

CONCLUSIONS

Among patients with severe AS treated with surgical AVR, an increasing number of elevated biomarkers of cardiovascular stress was associated with higher all-cause and cardiovascular mortality and a higher rate of repeat hospitalization. A multimarker approach may be useful in the surveillance of asymptomatic patients with severe AS to optimize surgical timing.

ST2 in patients with severe aortic stenosis and heart failure

BACKGROUND

ST2 is a circulating biomarker that is well established for predicting outcome in heart failure (HF). This is the first study to look at ST2 concentrations in optimally treated patients with stable but significant left ventricular systolic dysfunction (LVSD) compared to patients with severe aortic stenosis (AS).

METHODS

Two cohorts were retrospectively studied: 94 patients undergoing transcatheter aortic valve implantation for severe AS (63 with normal ejection fraction [EF] and 31 with reduced EF), and 50 patients with severe LVSD from non-valvular causes. ST2 pre-procedural samples were taken, and repeated again at 3 and 6 months. Patients were followed-up for 2 years. Data was analyzed using SPSS software.

RESULTS

Baseline concentrations of soluble ST2 did not differ significantly between the HF group and AS group with normal EF (EF ≥ 50%). However, in the AS group with a low EF (EF < 50%) ST2 concentrations were significantly higher that the HF group (p = 0.009). New York Heart Association class IV HF, baseline N-terminal pro-B-type natriuretic peptide and gender were all independent predictors of soluble ST2 (sST2) baseline concentrations.

CONCLUSIONS

Raised ST2 concentrations in the context of severe AS may be a marker for subclinical or clinical left ventricular dysfunction. More research is required to assess its use for assessment of prognosis and response to treatment.

Clinical Implications of Serum Biomarkers of Cardiac Stress in Aortic Stenosis

PURPOSE OF REVIEW

The purpose of this review is to outline the relationship between serum biomarkers of cardiac stress and the pathophysiologic progression of aortic stenosis, to identify studies exploring the utility of biomarkers in the risk stratification and management of patients with aortic stenosis, and to highlight the biomarkers most practical to management of patients with aortic stenosis.

RECENT FINDINGS

Several biomarkers have been identified that reflect various aspects of the pathogenesis of calcific aortic stenosis, subsequent hemodynamic obstruction leading to myocardial remodeling, oxidative stress and injury, and concomitant systemic inflammation. These markers are associated with adverse outcomes in aortic stenosis and offer incremental value in risk prediction over traditional clinical assessment for aortic stenosis. NTproBNP and troponin are the most rigorously studied serum biomarkers in aortic stenosis, and only NTproBNP is currently reflected in any major guideline on aortic stenosis management. Serum biomarkers show promise in guiding management of aortic stenosis, but still require significant prospective investigation before they can be incorporated in major guidelines.

Biological variation of cardiac markers in patients with aortic valve stenosis

Objective

Cardiac biomarkers hold promise for follow-up and management of aortic valve stenosis (AVS). When interpreting serial biomarker measurements of patients with AVS, it can be challenging to distinguish ‘real changes’ from ‘random fluctuation’. Hence, robust estimation of the biological variation of these biomarkers is essential. In the present study we assessed biological variation of B-type natriuretic peptide (BNP), N-terminus pro-brain natriuretic peptide (NT-proBNP), high-sensitivity troponin-T and high-sensitivity troponin-I (hs-TnT and hs-TnI), and ST2 in subjects with stable AVS.

Methods

Serial blood sampling was performed in 25 subjects with moderate AVS—confirmed by echocardiography—and all free from acute cardiovascular events in the past 6 months. Blood samples were taken on seven standardised occasions during 1 year. Analytical variation (CV_A), within-subject biological variation (CV_I), between-subject biological variation (CV_G), index of individuality (II) and reference change values were calculated for all cardiac biomarkers.

Results

CV_I was highest for BNP (62.0%, 95% CI 52.5 to 75.4) and lowest for hs-TnI (9.2%, 95% CI 2.8 to 13.8). CV_G exceeded the CV_I for all biomarkers except BNP, and ranged from 19.8% (95% CI 13.8 to 33.4) for ST2 to 57.2% (95% CI 40.4 to 97.3) for hs-TnT. NT-proBNP, hs-TnT and ST2 revealed CV_A <5%, while BNP and hs-TnI showed a higher CV_A (19.7 and 14.9, respectively). All biomarkers except BNP showed marked individuality, with II ranging from 0.21 to 0.67 (BNP 1.34).

Conclusion

This study provides the first biological variation estimates of cardiac biomarkers in patients with stable AVS. These estimates allow a more evidence-based interpretation of biomarker changes in the follow-up and management of patients with AVS.

Trial registration number

NCT02510482

Adaptive immune cells in calcific aortic valve disease

Calcific aortic valve disease (CAVD) is highly prevalent and has no pharmaceutical treatment. Surgical replacement of the aortic valve has proved effective in advanced disease but is costly, time limited, and in many cases not optimal for elderly patients. This has driven an increasing interest in noninvasive therapies for patients with CAVD. Adaptive immune cell signaling in the aortic valve has shown potential as a target for such a therapy. Up to 15% of cells in the healthy aortic valve are hematopoietic in origin, and these cells, which include macrophages, T lymphocytes, and B lymphocytes, are increased further in calcified specimens. Additionally, cytokine signaling has been shown to play a causative role in aortic valve calcification both in vitro and in vivo. This review summarizes the physiological presence of hematopoietic cells in the valve, innate and adaptive immune cell infiltration in disease states, and the cytokine signaling pathways that play a significant role in CAVD pathophysiology and may prove to be pharmaceutical targets for this disease in the near future.

High-sensitivity troponin T in asymptomatic severe aortic stenosis

Background: In asymptomatic severe aortic stenosis (ASAS), treatment decisions are made on an individual basis, and case management presents a clinical conundrum. Methods: We prospectively phenotyped consecutive patients with ASAS using echocardiography, exercise echocardiography, cardiac MRI and biomarkers (NT-proBNP, high-sensitivity troponin T (hs-TnT) and ST2) (n = 58). The primary endpoint was a composite of cardiovascular death, new-onset symptoms, cardiac hospitalization, guideline-driven indication for valve replacement and cardiovascular death at 12 months. Results: During the first year, 46.6% patients met primary endpoint. In multivariable analysis, aortic regurgitation ≥2 (p = 0.01) and hs-TnT (p = 0.007) were the only independent predictors of the primary endpoint. The best cutoff value was identified as hs-TnT >10ng/L, which was associated with a ∼10-fold greater risk of the primary endpoint (HR, 9.62; 95% CI, 2.27-40.8; p = 0.002). A baseline predictive model including age, sex and variables showing p < 0.10 in univariable analyses showed an area under the curve (AUC) of 0.79(0.66-0.91). Incorporation of hs-TnT into this model increased the AUC to 0.90(0.81-0.98) (p = 0.03). Patient reclassification with the model including hs-TnT yielded an NRI of 1.28(0.46-1.78), corresponding to 43% adequately reclassified patients. Conclusions: In patients with ASAS, hs-TnT >10ng/L was associated with high risk of events within 12 months. Including hs-TnT in routine ASAS management markedly improved prediction metrics.

Predicting Disease Progression and Mortality in Aortic Stenosis: A Systematic Review of Imaging Biomarkers and Meta-Analysis

Background: Detecting among patients with aortic stenosis (AS) those who are likely to rapidly progress, yet potentially benefiting from prophylactic aortic valve replacement, is needed for improved patient care. The objective of this study was to evaluate the role of imaging biomarkers in predicting the progression to clinical symptoms and death in patients with AS. Methods: We searched the Pubmed and the International Clinical Trials Registry Platform databases for studies including patients with AS, and investigating imaging techniques, published in any language until Jan 1, 2018. Eligible sets of data include effect of imaging biomarkers relative to: (1) Overall mortality, (2) Cardiac mortality, and (3) Overall events (Symptom onset and Major Adverse Cardiovascular Events). Meta-analysis was used to examine associations between the imaging biomarkers and outcomes of AS using Random Effect models. Results: Eight studies and 1,639 patients were included after systematic review. Four studies investigated aortic valve calcification (AVC) whereas the remaining investigated biomarkers provided by cardiac magnetic resonance (CMR). Four articles investigated the presence of midwall fibrosis on late-gadolinium enhancement imaging, three reported its extent (LGE%) and two, the myocardial extracellular volume (ECV). By decreasing strength of association, there were significant associations between cardiac mortality and LGE% [Relative Risk (RR) = 1.05, 95% Confidence Interval (CI) 1.01-1.10]; overall mortality and AVC (RR = 1.19, 95%CI: 1.05-1.36); overall events and ECV (RR = 1.68, 95%CI: 1.17-2.41); cardiac mortality and midwall fibrosis (RR = 2.88, 95%CI: 1.12-7.39). Conclusion: AVC and myocardial fibrosis imaging biomarkers predict the outcomes in AS, and help understanding AS pathophysiology and setting therapeutic targets.

GDF-15 (Growth Differentiation Factor 15) Is Associated With Lack of Ventricular Recovery and Mortality After Transcatheter Aortic Valve Replacement

BACKGROUND

Recent data suggest that circulating biomarkers may predict outcome in patients undergoing transcatheter aortic valve replacement (TAVR). We examined the association between inflammatory, myocardial, and renal biomarkers and their role in ventricular recovery and outcome after TAVR.

METHODS AND RESULTS

A total of 112 subjects undergoing TAVR were included in the prospective registry. Plasma levels of B-type natriuretic peptide, hs-TnI (high-sensitivity troponin I), CRP (C-reactive protein), GDF-15 (growth differentiation factor 15), GAL-3 (galectin-3), and Cys-C (cystatin-C) were assessed before TAVR and in 100 sex-matched healthy controls. Among echocardiographic parameters, we measured global longitudinal strain, indexed left ventricular mass, and indexed left atrial volume. The TAVR group included 59% male, with an average age of 84 years, and 1-year mortality of 18%. Among biomarkers, we found GDF-15 and CRP to be strongly associated with all-cause mortality (P<0.001). Inclusion of GDF-15 and CRP to the Society of Thoracic Surgeons score significantly improved C index (0.65-0.79; P<0.05) and provided a category-free net reclassification improvement of 106% at 2 years (P=0.01). Among survivors, functional recovery in global longitudinal strain (>15% improvement) and indexed left ventricular mass (>20% decrease) at 1 year occurred in 48% and 22%, respectively. On multivariate logistic regression, lower baseline GDF-15 was associated with improved global longitudinal strain at 1 year (hazard ratio=0.29; P<0.001). Furthermore, improvement in global longitudinal strain at 1 month correlated with lower overall mortality (hazard ratio=0.45; P=0.03).

CONCLUSIONS

Elevated GDF-15 correlates with lack of reverse remodeling and increased mortality after TAVR and improves risk prediction of mortality when added to the Society of Thoracic Surgeons score.

Can Blood Biomarkers Help Predicting Outcome in Transcatheter Aortic Valve Implantation?

Transcatheter aortic valve implantation (TAVI) has become the method of choice for patients with severe aortic valve stenosis, who are ineligible or at high risk for surgery. In this high risk patient population, early and late mortality and rehospitalization rates after TAVI are still relatively high. In spite of recent improvements in procedural TAVI, and establishment of risk models for poor outcome, determining individual risk remains challenging. In this context, current data from several small studies strongly suggest that blood biomarkers of myocardial injury, cardiac mechanical stretch, inflammation, and hemostasis imbalance might play an important role by providing informations on patient risk at baseline, and postprocedural progression of patient clinical conditions from days up to years post-TAVI. Although the role of biomarkers for predicting survival post-TAVI remains to be validated in large randomized studies, implementing biomarkers in clinical practice might improve risk stratification, thereby further reducing TAVI-associated morbidity and mortality.

Blood, tissue and imaging biomarkers in calcific aortic valve stenosis: past, present and future

PURPOSE OF REVIEW

Calcific aortic valve stenosis is the most prevalent valvular heart disease in the high-income countries. To this date, no medical therapy has been proven to prevent or to stop the progression of aortic valve stenosis. The physiopathology of aortic valve stenosis is highly complex and involves several signalling pathways, as well as genetic related factors, which delay the elaboration of effective pharmacotherapies. Moreover, it is difficult to predict accurately the progression of the valve stenosis and finding the optimal timing for aortic valve replacement remains challenging. Therefore, the present review makes an inventory of the most recent and promising circulating and imaging biomarkers related to the underlying mechanisms involved in the physiopathology of aortic valve stenosis, as well as the biomarkers associated with the left ventricular (LV) remodelling and subsequent dysfunction in patients with aortic valve stenosis.

RECENT FINDINGS

Over the last decade, several blood, tissue and imaging biomarkers have been investigated in aortic valve stenosis patients. At the aortic valve level, these biomarkers are mostly associated and/or involved with processes such as lipid infiltration and oxidation, chronic inflammation and fibrocalcific remodelling of the valve. Moreover, recent findings suggest that aging and sex hormones might interact with these multiple processes. Several studies demonstrated the usefulness of circulating biomarkers such as lipoprotein(a), brain natriuretic peptides and high-sensitivity cardiac troponin, which are very close to clinical routine. Furthermore, noninvasive imaging biomarkers including positron emission tomography and cardiac magnetic resonance, which provide a detailed view of the disease activity within the aortic valve and its repercussion on the left ventricle, may help to improve the understanding of aortic valve stenosis physiopathology and enhance the risk stratification. Other biomarkers such as von Willebrand factor and microRNAs are promising but further studies are needed to prove their additive value in aortic valve stenosis.

SUMMARY

Most of the biomarkers are used in research and thus, are still being investigated. However, some biomarkers including plasma level of lipoprotein(a), F-sodium fluoride, brain natriuretic peptides and high-sensitivity cardiac troponin can be or are very close to be used for the clinical management of patients with aortic valve stenosis. Moreover, a multibiomarker approach might provide a more global view of the disease activity and improve the management strategies of these patients.

Soluble ST2 for Risk Stratification and the Prediction of Mortality in Patients Undergoing Transcatheter Aortic Valve Implantation

This study aimed to assess the prognostic value of soluble ST2 (sST2) for risk stratification in patients undergoing transcatheter aortic valve implantation (TAVI). In 461 patients undergoing TAVI, sST2 was determined at baseline and categorized into quartiles. An optimum cutoff of 29 ng/ml was calculated. Primary end point was 1-year all-cause mortality. Results were validated in an independent cohort. Patients with sST2 >29 ng/ml had an increased 30-day (9.7% vs 4.6%, p = 0.043) and 1-year mortality (38.1% vs 21.8%, p = 0.001). In accordance, patients with N-terminal pro-brain natriuretic peptide (NT-proBNP) >8145 pg/ml revealed a comparable 30-day mortality (7.9% vs 4.7%, p = 0.189) and 1-year mortality (39.5% vs 21.0%, p <0.001). In univariate regression analysis, sST2 and NT-proBNP were associated with increased mortality risk. In multivariate regression analysis, independent predictors of mortality were logistic EuroSCORE, chronic renal failure, left ventricular ejection fraction, and sST2. In receiver operating characteristic curve analysis, sST2 did not provide incremental prognostic information beyond that obtained from surgical risk scores such as the STS-PROM or NT-proBNP. Similar findings could be achieved in an independent validation cohort. In conclusion, sST2 is independently associated with adverse outcome after TAVI but was not superior to NT-proBNP or surgical risk scores for the prediction of postprocedural outcomes.

Diagnostic utility of biomarkers of left ventricular stress in patients with aortic stenosis and preserved left ventricular ejection fraction

INTRODUCTION

Aortic stenosis (AS) is the most common acquired valvular heart disease. The early identification of patients with severe AS is crucial. NT-proBNP is a well-known biomarker of pressure overload, and its role in patients with AS has been demonstrated in previous studies. Another, less well-known biomarker of pressure overload is sST2 protein, and its role in AS is unclear.

AIM

To evaluate the utility of sST2 protein, NT-proBNP and selected clinical parameters in the assessment of degenerative AS severity in a population with preserved left ventricular ejection fraction (LVEF).

MATERIAL AND METHODS

Sixty-nine consecutive patients (mean age: 68.42 ±12.58 years, 55.07% male) with symptomatic degenerative AS and preserved LVEF ≥ 45% were prospectively included. At enrollment complete transthoracic echocardiographic examination, ECG analysis, and standard laboratory tests including NT-proBNP were performed and blood samples for sST2 were obtained.

RESULTS

There were 43 (62.32%) patients with severe AS. The multivariate stepwise linear regression models revealed that only systolic blood pressure (SBP), Sokolow-Lyon index and left ventricular end-diastolic diameter (LVEDD) were independently associated with severe AS. Spearman correlation coefficients analysis showed no correlations between sST2 levels and a mild to moderate correlation between NT-proBNP concentration and parameters of AS severity. However, levels of NT-proBNP (p = 0.1857) and sST2 (p = 0.7851) did not differentiate patients according to severity of AS.

CONCLUSIONS

In the study population with degenerative AS and preserved LVEF neither the NT-proBNP nor sST2 concentrations can be used to differentiate patients according to the severity of AS.

Prognostic Impact of Peak Aortic Jet Velocity in Conservatively Managed Patients With Severe Aortic Stenosis: An Observation From the CURRENT AS Registry

BACKGROUND

There are limited data regarding the risk stratification based on peak aortic jet velocity (Vmax) in patients with severe aortic stenosis (AS).

METHODS AND RESULTS

Among 3815 consecutive patients with severe AS enrolled in the CURRENT AS (Contemporary Outcomes After Surgery and Medical Treatment in Patients With Severe Aortic Stenosis) registry, the study population consisted of 1075 conservatively managed patients with Vmax ≥4.0 m/s and left ventricular ejection fraction ≥50%. The study patients were subdivided into 3 groups based on Vmax (group 1, 4.0 ≤ Vmax <4.5 m/s, N=550; group 2, 4.5 ≤ Vmax <5 m/s, N=279; and group 3, Vmax ≥5 m/s, N=246). Cumulative 5-year incidence of AS-related events (aortic valve-related death or heart failure hospitalization) was incrementally higher with increasing Vmax (entire population; 38.0%, 49.4%, and 62.8%, P<0.001; symptomatic patients; 55.7%, 60.9%, and 72.2%, P=0.008; and asymptomatic patients; 29.4%, 38.9%, and 47.7%, P=0.005). After adjusting for confounders, the excess risk of group 2 and group 3 relative to group 1 for AS-related events remained significant (hazard ratio, 1.39; 95% CI, 1.07-1.81; P=0.02, and hazard ratio, 1.53; 95% CI, 1.17-2.00; P=0.002, respectively). The effect size of group 3 relative to group 1 for AS-related events in asymptomatic patients (N=479) was similar to that in symptomatic patients (N=596; hazard ratio, 1.59; 95% CI, 1.01-2.52; P=0.047, and hazard ratio, 1.67; 95% CI, 1.16-2.40, P=0.008, respectively), and there was no significant overall interaction between the symptomatic status and the effect of the Vmax categories on AS-related events (interaction, P=0.88).

CONCLUSIONS

In conservatively managed severe AS patients with preserved left ventricular ejection fraction, increasing Vmax was associated with incrementally higher risk for AS-related events. However, the cumulative 5-year incidence of the AS-related events remained very high even in asymptomatic patients with less greater Vmax.

The integrated value of sST2 and global longitudinal strain in the early stratification of patients with severe aortic valve stenosis: a translational imaging approach

Aortic valve stenosis (AVS) is associated with significant myocardial fibrosis (MF). Global longitudinal strain (GLS) is a sensible indicator of systolic dysfunction. ST2 is a member of the interleukin (IL)-1 receptor family and a modulator of hypertrophic and fibrotic responses. We aimed at assessing: (a) the association between adverse LV remodeling, LV functional parameters (including GLS) and sST2 level. (b) The association between MF (detected by endo-myocardial biopsy) and sST2 in patients with AVS undergoing surgical valve replacement. Twenty-two patients with severe AVS and preserved EF underwent aortic valve replacement. They performed laboratory analysis, including serum ST2 (sST2), echocardiography and inter-ventricular septum biopsy to assess MF (%). We included ten controls for comparison. Compared to controls, patients showed higher sST2 levels (p < 0.0001). sST2 showed correlation with Age (r = 0.58; p = 0.0004), E/e' average (r = 0.58; p = 0.0007), GLS (r = 0.61; p = 0.0002), LAVi (r = 0.51; p = 0.003), LVMi (r = 0.43; p = 0.01), sPAP (r = 0.36; p = 0.04) and SVi (r = -0.47; p < 0.005). No correlation was found between MF and sST2. At ROC analysis, a sST2 ≥ 284 ng/mL had the best accuracy to discriminate controls from patients with impaired GLS, i.e. GLS ≤ 17% (AUC 0.80; p = 0.003; sensitivity 95%; specificity 83%) and increased E/e' average (AUC 0.87; p = 0.0001; sensitivity 96%; specificity 74%). At multivariate regression analysis GLS resulted the only independent predictor of sST2 levels (R² = 0.35; p =  0.0004). Patients with severe AVS present elevated sST2 levels. LV GLS resulted the only independent predictor of sST2 levels.

Soluble ST2 predicts 1-year outcome in patients undergoing transcatheter aortic valve implantation

BACKGROUND

Soluble ST2 (sST2) has been introduced as a novel biomarker in patients suffering from heart failure for risk stratification. In this study, we sought to investigate whether sST2 is useful for risk stratification and prediction of mortality in patients undergoing transcatheter aortic valve implantation (TAVI).

MATERIALS AND METHODS

A total of 274 patients undergoing TAVI were included in this study (149 female; age 81 ± 1 years; EUROSCORE 25 ± 1; STS score 3·8 ± 0·2). Plasma samples were obtained preinterventional and analysed for sST2. Patients were followed up 1 month and 1 year after TAVI.

RESULTS

In a Cox regression analysis, sST2 plasma concentration was associated with increased mortality (changes per pg/mL sST2 concentration; HR 1·00006 95% (1·00004-1·00009); P < 0·001). A cut-off by means of the Youden Index was calculated (10 070·27 pg/mL), and patients were retrospectively divided into two cohorts, in those above (31·3%) and those below (68·7%) this value. These two groups were then compared regarding mortality both after 30 days and 1 year: whereas 1-month mortality did not differ (7·0% vs. 10·3%, OR 1·50 95% CI (0·60-3·79; P = 0·46)), patients with a sST2 concentration above the cut-off of 10 070·27 pg/mL showed a significantly worse outcome after 1 year (49·2% vs. 23·2%; OR 3·21 95% CI (1·70-6·04); P < 0·001). After correction for confounders in a multivariate Cox regression analysis, sST2 (1·0002 95% CI (1·0001-1·0003); P = 0·001) concentration remained associated with mortality.

CONCLUSIONS

sST2 levels were associated with 1-year mortality after TAVI. Based on these results, we assume that sST2 might help to identify patients at high risk for death in whom conservative treatment should be considered.

Natural History, Diagnostic Approaches, and Therapeutic Strategies for Patients With Asymptomatic Severe Aortic Stenosis

Aortic stenosis (AS) is one of the most common valvular diseases encountered in clinical practice. Current guidelines recommend aortic valve replacement (AVR) when the aortic valve is severely stenotic and the patient is symptomatic; however, a substantial proportion of patients with severe AS are asymptomatic at the time of first diagnosis. Although specific morphological valve features, exercise testing, stress imaging, and biomarkers can help to identify patients with asymptomatic severe AS who may benefit from early AVR, the optimal management of these patients remains uncertain and controversial. The current report presents a comprehensive review of the natural history and the diagnostic evaluation of asymptomatic patients with severe AS, and is followed by a meta-analysis from reported studies comparing an early AVR strategy to active surveillance, with an emphasis on the level of evidence substantiating the current guideline recommendations. Finally, perspectives on directions for future investigation are discussed.

Rationale and design of the Aortic Valve replAcemenT versus conservative treatment in Asymptomatic seveRe aortic stenosis (AVATAR trial): A randomized multicenter controlled event-driven trial

Aortic valve replacement (AVR) therapy is an obvious choice for symptomatic severe aortic stenosis (AS) patients as it improves symptoms, left ventricular function, and survival. The treatment decisions and indication for AVR in asymptomatic patients with severe AS and normal left ventricular ejection fraction are less well established and the subject of ongoing debate. Many efforts have been made to define the best treatment option in asymptomatic AS patients with normal left ventricular ejection fraction. Retrospective and observational data imply that elective AVR for asymptomatic severe AS may lead to improvement in outcomes in comparison to surgery performed after onset of symptoms. The AVATAR trial will aim to assess outcomes among asymptomatic AS patients randomized to either elective early AVR or medical management with vigilant follow-up. In the latter group, AVR would be delayed until either the onset of symptoms or changes in predefined echocardiographic parameters. To the best of the authors' knowledge, it will be the first large prospective, randomized, controlled, multicenter clinical trial that will evaluate the safety and efficacy of elective AVR in this specific group of patients.