Japanese-Western consensus meeting on biomarkers

Soluble Suppression of Tumorigenicity 2 (sST2) as a Diagnostic and Prognostic Marker in Acute Heart Failure and Sepsis: A Comparative Analysis

Background: Suppression of Tumorigenicity 2 (ST2), a member of the interleukin-1 receptor family, plays a crucial role in immune regulation. Elevated sST2 levels are associated with poor prognosis in various inflammatory and cardiovascular diseases, including acute heart failure (AHF), sepsis and transplant rejection. Objectives and methods: This study aimed to evaluate the diagnostic and prognostic accuracy of sST2, along with other biomarkers, such as high-sensitivity C-reactive protein (hs-CRP), N-terminal pro-B-type natriuretic peptide (NT-proBNP), procalcitonin (PCT) and mid-regional pro-adrenomedullin (MR-proADM), in patients with AHF, sepsis and AHF/sepsis overlap. Results: A cohort of 74 patients was analyzed, and comparison statistics revealed that sST2 levels were significantly higher in the AHF/sepsis group (113.88 ng/mL) compared to the AHF group (42.24 ng/mL, p = 0.024), while no significant difference was observed between sepsis and AHF groups (p = 0.10). Other biomarkers, including hs-CRP and PCT, showed significant differences between the AHF and AHF/sepsis groups. ROC curve analysis identified sST2 as a strong predictor of mortality and readmission, with high AUC values for 30-day readmission (0.821) and mortality (0.87). Conclusions: These findings suggest that combining biomarkers, including sST2, could improve the early diagnosis, risk stratification and management of critically ill patients with overlapping AHF and sepsis. Further studies with larger populations are needed to validate these findings and explore the potential of integrating these biomarkers into clinical practice.

Characteristics of Older Patients with Heart Failure Readmitted due to Acute Exacerbations within the Past Year

OBJECTIVE

We aimed to examine the relationship between physical performance and readmission among older patients with heart failure (HF) over the past year.

METHODS

This retrospective cohort study included 325 patients with HF who were aged ≥65 years and were hospitalized for acute exacerbation between November 2017 and December 2021. We investigated age, sex, body mass index, length of hospital stay, initiation of rehabilitation, New York Heart Association (NYHA) class, Charlson comorbidity index (CCI) score, medications, cardiac/renal function, nutrition, maximal quadriceps isometric strength, grip strength, and Short Physical Performance Battery (SPPB) score. Data were analyzed using the χ2 test, Mann-Whitney U test, and logistic regression analysis.

RESULTS

Altogether, 108 patients met the inclusion criteria and were divided into the non-readmission (n = 76) and readmission (n = 32) groups. The readmission group exhibited longer hospital stay, more severe NYHA class, higher CCI score, higher brain natriuretic peptide (BNP) levels, lower muscle strength, and lower SPPB score compared to the non-readmission group. In the logistic regression model, BNP level and SPPB score were independent factors associated with readmission.

CONCLUSION

BNP level and SPPB score were associated with readmission in patients with HF within the past year.

Brain natriuretic peptide levels and short physical performance battery scores independently influence short-term readmission rates in older patients with heart failure

The Short Physical Performance Battery (SPPB) is a well-established tool to assess the lower extremity physical performance status. The purpose of this study is to examine the impact of brain natriuretic peptide (BNP) levels and SPPB scores on short-term readmission in older patients with heart failure (HF). This prospective cohort study enrolled 325 patients with HF who were hospitalized for acute decompensated HF between November 2017 and December 2021. Variables were analyzed using the Cox proportional hazards model, receiver operating characteristic (ROC) curve, and Kaplan-Meier analysis. The 107 patients who met the inclusion criteria were divided into readmission (within 90 days of discharge; n = 25) and non-readmission (n = 82) groups. Multivariate analysis revealed that BNP level and SPPB score were independent risk factors for readmission within 90 days after discharge. Patients were classified into three groups according to the BNP and SPPB cutoff values calculated using ROC curves. The risk of readmission was significantly higher in Group 3 (BNP ≥ 384 pg/mL and SPPB ≤ 7 points) than in Group 1 (BNP < 384 pg/mL and SPPB > 7 points; hazard ratio: 27.68, 95% confidence interval: 3.672 - 208.700, P = 0.0012). Our study showed that HF patients with high BNP levels and low SPPB scores have a dramatically increased risk of readmission within 90 days of discharge.

Prognostic value of an echocardiographic index reflecting right ventricular operating stiffness in patients with heart failure

PURPOSE

We recently reported a noninvasive method for the assessment of right ventricular (RV) operating stiffness that is obtained by dividing the atrial-systolic descent of the pulmonary artery-RV pressure gradient (PRPGD_AC) derived from the pulmonary regurgitant velocity by the tricuspid annular plane movement during atrial contraction (TAPM_AC). Here, we investigated whether this parameter of RV operating stiffness, PRPGD_AC/TAPM_AC, is useful for predicting the prognosis of patients with heart failure (HF).

METHODS

We retrospectively included 127 hospitalized patients with HF who underwent an echocardiographic examination immediately pre-discharge. The PRPGD_AC/TAPM_AC was measured in addition to standard echocardiographic parameters. Patients were followed until 2 years post-discharge. The endpoint was the composite of cardiac death, readmission for acute decompensation, and increased diuretic dose due to worsening HF.

RESULTS

58 patients (46%) experienced the endpoint during follow-up. Univariable and multivariable Cox regression analyses demonstrated that the PRPGD_AC/TAPM_AC was associated with the endpoint. In a Kaplan-Meier analysis, the event rate of the greater PRPGD_AC/TAPM_AC group was significantly higher than that of the lesser PRPGD_AC/TAPM_AC group. In a sequential Cox analysis for predicting the endpoint's occurrence, the addition of PRPGD_AC/TAPM_AC to the model including age, sex, NYHA functional classification, brain natriuretic peptide level, and several echocardiographic parameters including tricuspid annular plane systolic excursion significantly improved the predictive power for prognosis.

CONCLUSION

A completely noninvasive index of RV operating stiffness, PRPGD_AC/TAPM_AC, was useful for predicting prognoses in patients with HF, and it showed an incremental prognostic value over RV systolic function.

Increased Arterial Stiffness Amplifies the Association Between Home Blood Pressure Variability and Cardiac Overload

Increased blood pressure (BP) variability, an index of hemodynamic stress, leads to cardiac overload and worse cardiovascular prognosis. The association between day-by-day home BP variability and NT-proBNP (N-terminal pro-B-type natriuretic peptide) as an index of cardiac overload may be amplified by increased arterial stiffness as assessed by brachial-ankle pulse wave velocity (baPWV). J-HOP (Japan Morning Surge-Home Blood Pressure) Study participants who were selected from a practitioner-based population with at least one cardiovascular risk factor underwent home BP monitoring, and their BP levels and SD, coefficient of variation, and average real variability as indexes of systolic BP variability were assessed. We analyzed 2115 individuals without prevalent heart failure and divided them into lower (<1800 cm/s, n=1464) and higher (≥1800 cm/s, n=651) baPWV groups. The higher baPWV group had significantly higher SD SBP , CV SBP , ARV SBP values, and NT-proBNP levels than the lower baPWV group (all P <0.001). In the higher baPWV group, a multiple linear regression analysis revealed that the SD SBP was associated with the NT-proBNP level after adjustment for traditional cardiovascular risk factors including the average home systolic BP (coefficient per 1 SD increase, 0.049 [95% CI, 0.018–0.081]; P =0.002). Similar trends were found for CV SBP ( P =0.003) and ARV SBP ( P =0.004). However, these associations were not found in the lower baPWV group. There was an interaction between all indexes of systolic BP variability and the NT-proBNP level according to lower or higher baPWV group (all P <0.05). Arterial stiffness amplified the association between home BP variability and cardiac overload.

Heart is the Target Organ of Endogenous Cardiac Natriuretic Peptides

This study aimed to evaluate whether the heart is the target organ of endogenous atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) in patients with heart failure (HF) with reduced ejection fraction (HFrEF).We measured the plasma levels of cyclic guanosine monophosphate (cGMP), which is a second messenger of ANP and BNP, in the aortic root (AO) and coronary sinus (CS) in 237 patients with HFrEF. Plasma levels of cGMP were significantly higher in the CS than those in the AO in 237 patients with HFrEF (10.0 ± 4.5 versus 10.5 ± 4.3 pmoL/mL, P < 0.0001) and were significantly higher in the CS than those in the AO (8.0 ± 3.6 versus 8.9 ± 3.8 pmoL/mL, P < 0.0001) in mild HF patients (New York Heart Association (NYHA) II, n = 114), but there was no difference in plasma cGMP between the AO and the CS (11.9 ± 4.4 versus 11.9 ± 4.3 pmoL/mL, NS) in severe HF patients (NYHA III-IV, n = 123). In mild HF patients, log (ANP + BNP) in the AO was an independent predictor of (CS-AO) cGMP among hemodynamics and nitrate therapy. There was a significant correlation between log [(CS-AO) ANP + (CS-AO) BNP] and (CS-AO) cGMP (r = 0.455, P < 0.0001) in mild HF patients.These findings indicate that cGMP is produced from the failing heart and that the heart is the target organ of endogenous ANP and BNP in patients with HFrEF. In severe HF patients, cGMP production may be attenuated because of the downregulation of biological receptors and/or increased cGMP degradation in the failing heart.

The current status of heart failure diagnostic biomarkers

Heart failure (HF) affects approximately 23 million individuals worldwide and this number is increasing, due to an aging and growing population. Early detection of HF is crucial in the management of this debilitating disease. Current diagnostic methods for HF rely heavily on clinical imaging techniques and blood analysis, which makes them less than ideal for population-based screening purposes. Studies focusing on developing novel biomarkers for HF have utilized various techniques and biological fluids, including urine and saliva. Promising results from these studies imply that these body fluids can be used in evaluating the clinical manifestation of HF and will one day be integrated into a clinical workflow and facilitate HF management.

INTERACTING DISCIPLINES: Cardiac natriuretic peptides and obesity: perspectives from an endocrinologist and a cardiologist

Since their discovery in 1981, the cardiac natriuretic peptides (cNP) atrial natriuretic peptide (also referred to as atrial natriuretic factor) and brain natriuretic peptide have been well characterised in terms of their renal and cardiovascular actions. In addition, it has been shown that cNP plasma levels are strong predictors of cardiovascular events and mortality in populations with no apparent heart disease as well as in patients with established cardiac pathology. cNP secretion from the heart is increased by humoral and mechanical stimuli. The clinical significance of cNP plasma levels has been shown to differ in obese and non-obese subjects. Recent lines of evidence suggest important metabolic effects of the cNP system, which has been shown to activate lipolysis, enhance lipid oxidation and mitochondrial respiration. Clinically, these properties lead to browning of white adipose tissue and to increased muscular oxidative capacity. In human association studies in patients without heart disease higher cNP concentrations were observed in lean, insulin-sensitive subjects. Highly elevated cNP levels are generally observed in patients with systolic heart failure or high blood pressure, while obese and type-2 diabetics display reduced cNP levels. Together, these observations suggest that the cNP system plays a role in the pathophysiology of metabolic vascular disease. Understanding this role should help define novel principles in the treatment of cardiometabolic disease.

Biomarkers for Heart Failure in Asia

Contributions from the Asian biomedical community to knowledge of biomarkers in heart failure have grown rapidly since 2000. Japan has made world-leading contributions in the discovery and application of cardiac natriuretic peptides as biomarkers in heart failure, but there has been rapid growth in reports from China. Contributions also come from Taiwan, South Korea, Singapore, and Hong Kong. Centers in Asia have established clinical cohorts providing powerful platforms for the discovery and validation of biomarkers in heart failure. This century, Asian enquiry into biomarkers in heart failure will include peptides, cytokines, metabolites, nucleic acids, and other analytes.

A multimarker approach to diagnose and stratify heart failure

BACKGROUND

We have previously demonstrated that circulating NT-proBNP is truncated at the N and C termini. Aims of this study are three-fold: firstly to determine whether the NT-proBNP levels correlate with NYHA functional classes when measuring with different antibody pairs; secondly to evaluate the diagnostic potential of ProBNP and; thirdly to investigate whether combining NT-proBNP assays with or without ProBNP would lead to better diagnostic accuracies.

METHODS

Plasma samples were collected from healthy controls (n=52) and HF patients (n=46). Customized AlphaLISA® immunoassays were developed and validated to measure the concentrations of proBNP and NT-proBNP (with antibodies targeting 13-45, 13-76, 28-76). The diagnostic performance and predictive value of proBNP and NT-proBNP assays and their combinations were evaluated.

RESULTS

Plasma proBNP assay showed acceptable diagnostic performance. NT-proBNP13-76 assay is useful in diagnosing and stratifying HF patients. The diagnostic performance of NT-proBNP13-76 demonstrated improvement over commercial NT-proBNP tests. The combination of NT-proBNP13-76 with NT-proBNP28-76 assays gave the best diagnostic assay performance.

CONCLUSION

Our results demonstrate that while there is major heterogeneity in circulating NT-proBNP, specific epitopes of the peptides are extraordinarily stable, providing ideal targets for clinically useful diagnostic assays. Future new clinical diagnostic clinical trials should include a multimarker approach rather than using a single marker to diagnose HF.

Biomarkers in cardiorenal syndromes

Cardiac and renal diseases often coexist and patients with cardiac and renal failure have high morbidity and mortality. Cardiorenal syndromes (CRSs) are disorders of the heart and kidneys whereby dysfunction in one organ may induce dysfunction in the other organ. Five subtypes of CRSs have been defined by the Acute Dialysis Quality Initiative Consensus Group. There is a need for early detection and monitoring of patients with CRSs. Biomarkers play a key role in the diagnosis and monitoring of acute myocardial infarction, chronic heart failure, and chronic kidney disease. In recent years, new biomarkers have been identified that may play a role in the early diagnosis of acute kidney injury. Herein, we review the use of serum and urine biomarkers in the diagnosis and management of CRSs. The established cardiac and renal biomarkers such as the cardiac troponins, natriuretic peptides, urine albumin, and creatinine, as well as the new renal biomarkers cystatin C and neutrophil gelatinase-associated lipocalin are reviewed in detail. The recent advances in assay methods, clinical studies, and recommendations in clinical guidelines are discussed. With advances in biomarker research, in future, perhaps a multimarker approach will become feasible to stratify the diagnosis of CRS for individualized treatment and prognosis.

Atrial endothelial impairment through Toll-like receptor 4 signaling causes atrial thrombogenesis

Low-grade inflammation associated with heart failure (HF) is known to deteriorate cardioembolic stroke in patients with atrial fibrillation (AF). Little is known about the relationship between atrial endothelial impairment induced by innate immunity and thrombus formation. We examined whether atrial endothelial impairment through Toll-like receptor (TLR) 4 signaling causes atrial thrombogenesis. TLR4, heat shock protein 60, and vascular cell adhesion molecule (VCAM)-1 expression were higher in the atrium of AF patients who underwent valve replacement surgery with HF compared with those without it (p < 0.05). We created thoracic transverse aortic constriction (TAC) in TLR4 knock-out (KO) and wild-type (WT) mice. Atrial thrombosis was observed less frequently in TLR4 KO mice (4/15) than in WT mice (16/20) 4 weeks after TAC despite similar severity of heart failure. The decrease in endothelial nitric oxide synthase (eNOS) phosphorylation and increase in VCAM-1 and plasminogen activator inhibitor (PAI)-1 expression, observed in the atrium of WT mice following TAC, were significantly attenuated in TLR4 KO mice (p < 0.05). Nuclear factor-κB (NF-κB) activation after TAC was attenuated in TLR4 KO mice compared with WT mice. Activation of mitogen-activated protein kinase p38 (p38) after TAC was also attenuated in TLR4 KO mice (p < 0.05). Thus, increased VCAM-1 and PAI-1, and decreased eNOS phosphorylation through the TLR4/NFκB/p38 pathway, may be associated with atrial thrombogenesis in the heart failure mice model. Atrial endothelial impairment through the TLR4 signaling may play a role in atrial thrombogenesis in AF patients with HF.

Direct immunochemiluminescent assay for proBNP and total BNP in human plasma proBNP and total BNP levels in normal and heart failure

Background

Recent studies have shown that in addition to brain (or B-type) natriuretic peptide (BNP) and the N-terminal proBNP fragment, levels of intact proBNP are also increased in heart failure. Moreover, present BNP immunoassays also measure proBNP, as the anti-BNP antibody cross-reacts with proBNP. It is important to know the exact levels of proBNP in heart failure, because elevation of the low-activity proBNP may be associated with the development of heart failure.

Methodology/Principal Findings

We therefore established a two-step immunochemiluminescent assay for total BNP (BNP+proBNP) and proBNP using monoclonal antibodies and glycosylated proBNP as a standard. The assay enables measurement of plasma total BNP and proBNP within only 7 h, without prior extraction of the plasma. The detection limit was 0.4 pmol/L for a 50-µl plasma sample. Within-run CVs ranged from 5.2%–8.0% in proBNP assay and from 7.0%–8.4% in total BNP assay, and between-run CVs ranged from 5.3–7.4% in proBNP assay and from 2.9%–9.5% in total BNP assay, respectively. The dilution curves for plasma samples showed good linearity (correlation coefficients = 0.998–1.00), and analytical recovery was 90–101%. The mean total BNP and proBNP in plasma from 116 healthy subjects were 1.4±1.2 pM and 1.0±0.7 pM, respectively, and were 80±129 pM and 42±70 pM in 32 heart failure patients. Plasma proBNP levels significantly correlate with age in normal subjects.

Conclusions/Significance

Our immunochemiluminescent assay is sufficiently rapid and precise for routine determination of total BNP and proBNP in human plasma.