Utility of traditional circulating and imaging-based cardiac biomarkers in patients with predialysis CKD

Determining kidney function-specific thresholds for N-terminal pro-B-type natriuretic peptide in heart failure risk prediction among patients with chronic kidney disease: a multicentre, observational, cohort study

BACKGROUND

Elevated N-terminal pro-B-type natriuretic peptide (NT-proBNP) levels are common in patients with chronic kidney disease (CKD), but uniform thresholds derived from the general population may not accurately predict heart failure (HF) risk across stages of kidney function. This study aimed to determine whether thresholds specific to kidney function categories improve HF risk prediction in CKD.

METHODS

This retrospective cohort study used data from the China Renal Data System, including 18 261 patients with CKD without prior HF. Kidney function-specific thresholds for NT-proBNP were established based on estimated glomerular filtration rate (eGFR) categories, and associations with HF risk were assessed using multivariable Cox proportional hazard models. The predictive value of these thresholds was compared with a uniform threshold of 125 pg/mL using Net Reclassification Improvement (NRI).

RESULTS

Elevated NT-proBNP was observed in 67% of patients using the uniform threshold compared with 23% when using eGFR-specific thresholds. Optimal NT-proBNP thresholds increased with declining kidney function, reaching the highest level in stage 5 CKD (eGFR <15 mL/min/1.73 m²). eGFR-specific thresholds significantly improved HF risk prediction, with NRI gains of 19% to 55% across stages 1 to 5, while the uniform threshold added no predictive value for patients with stage 5 CKD.

CONCLUSIONS

In patients with CKD, NT-proBNP levels must be interpreted in the context of kidney function, as eGFR-specific thresholds provide superior HF risk stratification. These findings support adopting kidney function-adjusted thresholds rather than a uniform cut-off to improve HF risk prediction.

The Dual Burden: Exploring Cardiovascular Complications in Chronic Kidney Disease

Chronic kidney disease (CKD) represents a significant global health challenge, affecting millions of individuals and leading to substantial morbidity and mortality. This review aims to explore the epidemiology, cardiovascular complications, and management strategies associated with CKD, emphasizing the importance of preventing cardiovascular disease and early intervention. CKD is primarily driven by conditions such as diabetes mellitus, hypertension, and cardiovascular diseases, which often coexist and exacerbate renal impairment. Effective management requires a multifaceted approach, including lifestyle modifications, pharmacological interventions, and regular monitoring. Dietary changes, such as sodium restriction and a controlled intake of phosphorus and potassium, play a vital role in preserving renal function. Pharmacological therapies, particularly angiotensin-converting enzyme (ACE) inhibitors, angiotensin receptor blockers (ARBs), and emerging agents like SGLT2 inhibitors, have shown efficacy in slowing disease progression and improving patient outcomes. Furthermore, patients undergoing dialysis face increased cardiovascular risk, necessitating comprehensive management strategies to address both renal and cardiac health. As the landscape of CKD treatment evolves, ongoing research into novel therapeutic options and personalized medical approaches are essential. This review underscores the urgent need for awareness, education, and effective preventive measures to mitigate the burden of CKD and enhance the quality of life for affected individuals.

N-terminal pro-B-type natriuretic peptide, eGFR, and progression of kidney disease in chronic kidney disease patients without heart failure

Background

Cardiorenal syndrome highlights the bidirectional relationship between kidney and heart dysfunction. N-terminal pro-B-type natriuretic peptide (NT-proBNP), which is the gold standard biomarker in heart failure (HF), may be an important biomarker for chronic kidney disease (CKD) progression. However, NT-proBNP is negatively related with estimated glomerular filtration rate (eGFR). In this study, we investigated the association of NT-proBNP, eGFR, and progression of kidney disease in CKD patients without HF.

Methods

This multicentric retrospective cohort study recruited 23 860 CKD patients without HF, who had at least one NT-proBNP record from China Renal Data System database. Linear regression model evaluated the relationship between eGFR and NT-proBNP. Cox regression analysis assessed the association between NT-proBNP and CKD progression. Sensitivity analysis examined the robustness of the main findings.

Results

This study involved 23 860 CKD patients without HF, distributed across different CKD stages: 10 526 in stages G1-2, 4665 in G3a, 3702 in G3b, 2704 in G4, and 2263 in G5. NT-proBNP was negatively correlated with eGFR, particularly in stages 4-5 CKD. A 15-unit decrease in eGFR was associated with increases in log (NT-proBNP) levels by 1.04-fold, 1.27-fold, 1.29-fold, 1.80-fold, and 3.50-fold for stages 1-2, 3a, 3b, 4, and 5, respectively. After excluding patients who developed CKD progression within 1 year, the Cox regression analysis revealed that the relationship between NT-proBNP and CKD progression was not significant in stages 4 and 5. However, for stages 1-3, each standard deviation increase in log (NT-proBNP) was associated with a 26%, 36%, and 28% higher risk of CKD progression, with P interaction ≤.001. The hazard ratios were 1.26 (95% confidence intervals (CI), 1.18 to 1.35), 1.36 (95% CI, 1.22 to 1.51), and 1.28 (95% CI, 1.14 to 1.43) for stages 1-2, stage 3a, and stage 3b, respectively.

Conclusions

Despite its strong inverse association with eGFR, NT-proBNP was positively associated with the risk of progression of kidney disease in CKD patients with stages 1-3 without HF. Future studies should investigate the effectiveness of NT-proBNP as a predictive biomarker for the progression of kidney disease across diverse racial groups and healthcare settings.

Disorder of neuroplasticity aggravates cognitive impairment via neuroinflammation associated with intestinal flora dysbiosis in chronic heart failure

BACKGROUND

Chronic heart failure (CHF) impairs cognitive function, yet its effects on brain structure and underlying mechanisms remain elusive. This study aims to explore the mechanisms behind cognitive impairment.

METHODS

CHF models in rats were induced by ligation of the left anterior descending coronary artery. Cardiac function was analyzed by cardiac ultrasound and hemodynamics. ELISA, immunofluorescence, Western blot, Golgi staining and transmission electron microscopy were performed on hippocampal tissues. The alterations of intestinal flora under the morbid state were investigated via 16S rRNA sequencing. The connection between neuroinflammation and synapses is confirmed by a co-culture system of BV2 microglia and HT22 cells in vitro. Results: CHF rats exhibited deteriorated cognitive behaviors. CHF induced neuronal structural disruption, loss of Nissl bodies, and synaptic damage, exhibiting alterations in multiple parameters. CHF rats showed increased hippocampal levels of inflammatory cytokines and activated microglia and astrocytes. Furthermore, the study highlights dysregulated PDE4-dependent cAMP signaling and intestinal flora dysbiosis, closely associated with neuroinflammation, and altered synaptic proteins. In vitro, microglial neuroinflammation impaired synaptic plasticity via PDE4-dependent cAMP signaling.

CONCLUSIONS

Neuroinflammation worsens CHF-related cognitive impairment through neuroplasticity disorder, tied to intestinal flora dysbiosis. PDE4 emerges as a potential therapeutic target. These findings provide insightful perspectives on the heart-gut-brain axis.

Insights into the Novel Cardiac Biomarker in Acute Heart Failure: Mybp-C

(1) Background: Given its high cardiac specificity and its capacity to directly assess the cardiac function, cardiac myosin-binding protein (MyBP-C) is a promising biomarker in patients with acute heart failure (AHF). The aim of our study was to investigate the clinical utility of this novel marker for diagnosis and short-term prognosis in subjects with AHF. (2) Methods: We measured plasma levels of MyBP-C at admission in 49 subjects (27 patients admitted with AHF and 22 controls). (3) Results: The plasma concentration of MyBP-C was significantly higher in patients with AHF compared to controls (54.88 vs. 0.01 ng/L, p < 0.001). For 30-day prognosis, MyBP-C showed significantly greater AUC (0.972, p < 0.001) than NT-proBNP (0.849, p = 0.001) and hs-TnI (0.714, p = 0.047). In a multivariate logistic regression analysis, an elevated level of MyBP-C was the best independent predictor of 30-day mortality (OR = 1.08, p = 0.039) or combined death/recurrent 30-days rehospitalization (OR = 1.12, p = 0.014). (4) Conclusions: Our data show that circulating MyBP-C is a sensitive and cardiac-specific biomarker with potential utility for the accurate diagnosis and prognosis of AHF.

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.

Protein Biomarkers and Major Cardiovascular Events in Older People With Advanced CKD: The European Quality (EQUAL) Study

Rationale & Objective

Cardiovascular disease is the leading cause of morbidity and mortality in chronic kidney disease (CKD). We investigated 184 inflammatory and cardiovascular proteins to determine their potential as biomarkers for major cardiovascular events (MACEs).

Study Design

The European Quality (EQUAL) is an observational cohort study that enrolled people aged ≥65 years with an estimated glomerular filtration rate ≤20 mL/min/1.73 m2.

Setting & Participants

Recruited participants were split into the discovery (n = 611) and replication cohorts (n = 292).

Exposure

Levels of 184 blood proteins were measured at the baseline visit, and each protein was analyzed individually.

Outcome

MACE.

Analytical Approach

Cox proportional hazard models adjusted for age, sex, estimated glomerular filtration rate, previous MACE, and country were used to determine the risk of MACE. Proteins with false discovery rate adjusted P values of <0.05 in the discovery cohort were tested in the replication cohort. Sensitivity analyses were performed by adjusting for traditional risk factors, CKD-specific risk factors, and level of proteinuria and segregating atherosclerotic and nonatherosclerotic MACE.

Results

During a median follow-up of 2.9 years, 349 people (39%) experienced a MACE. Forty-eight proteins were associated with MACE in the discovery cohort; 9 of these were reproduced in the replication cohort. Three of these proteins maintained a strong association with MACE after adjustment for traditional and CKD-specific risk factors and proteinuria. Tenascin (TNC), fibroblast growth factor-23 (FGF-23), and V-set and immunoglobulin domain-containing protein 2 (VSIG2) were associated with both atherosclerotic and nonatherosclerotic MACE. All replicated proteins except carbonic anhydrase 1 and carbonic anhydrase 3 were associated with nonatherosclerotic MACE.

Limitations

Single protein concentration measurements and limited follow-up time.

Conclusions

Our findings corroborate previously reported relationships between FGF-23, vascular cell adhesion protein-1, TNC, and placental growth factor with cardiovascular outcomes in CKD. We identify 5 proteins not previously linked with MACE in CKD that may be targets for future therapies.

Plain-Language Summary

Kidney disease increases the risk of heart disease, stroke, and other vascular conditions. Blood tests that predict the likelihood of these problems may help to guide treatment, but studies are needed in people with kidney disease. We analyzed blood tests from older people with kidney disease, looking for proteins associated with higher risk of these conditions. Nine proteins were identified, of which 3 showed a strong effect after all other information was considered. This work supports previous research regarding 4 of these proteins and identifies 5 additional proteins that may be associated with higher risk. Further work is needed to confirm our findings and to determine whether these proteins can be used to guide treatment.

Diagnosis of cardiovascular disease in patients with chronic kidney disease

Patients with chronic kidney disease (CKD) are at high risk of cardiovascular disease (CVD) and cardiovascular death. Identifying and monitoring cardiovascular complications and hypertension is important for managing patients with CKD or kidney failure and transplant recipients. Biomarkers of myocardial ischaemia, such as troponins and electrocardiography (ECG), have limited utility for diagnosing cardiac ischaemia in patients with advanced CKD. Dobutamine stress echocardiography, myocardial perfusion scintigraphy and dipyridamole stress testing can be used to detect coronary disease in these patients. Left ventricular hypertrophy and left ventricular dysfunction can be detected and monitored using various techniques with differing complexity and cost, including ECG, echocardiography, nuclear magnetic resonance, CT and myocardial scintigraphy. Atrial fibrillation and other major arrhythmias are common in all stages of CKD, and ambulatory heart rhythm monitoring enables precise time profiling of these disorders. Screening for cerebrovascular disease is only indicated in asymptomatic patients with autosomal dominant polycystic kidney disease. Standardized blood pressure is recommended for hypertension diagnosis and treatment monitoring and can be complemented by ambulatory blood pressure monitoring. Judicious use of these diagnostic techniques may assist clinicians in detecting the whole range of cardiovascular alterations in patients with CKD and enable timely treatment of CVD in this high-risk population.

Associations between eGFR and albuminuria with right ventricular measures: the MESA-Right Ventricle study

Background

Chronic kidney disease (CKD) is associated with an increased risk of pulmonary hypertension, which may lead to right ventricular (RV) pressure overload and RV dysfunction. However, the presence of subclinical changes in RV structure or function in early CKD and the influence of these changes on mortality are not well studied. We hypothesized that early CKD, as indicated by elevated albuminuria or mild reductions in estimated glomerular filtration rate (eGFR), is associated with greater RV dilation and RV mass.

Methods

We included 4063 participants (age 45-84 years) without baseline clinical cardiovascular disease from the Multi-Ethnic Study of Atherosclerosis. The associations of baseline creatinine-cystatin C-based eGFR and albuminuria with cardiac magnetic resonance-derived RV measures (2000-02) were examined cross-sectionally with linear regression models. Cox regression models were used to examine whether RV parameters modified the associations of eGFR and albuminuria with all-cause mortality.

Results

Participants with reductions in eGFR primarily within the 60-89 mL/min/1.73 m2 category had smaller RV end-diastolic and end-systolic volumes and stroke volume (all adjusted P-trends <.001) than those with eGFR ≥90 mL/min/1.73 m2, an association that was predominantly seen in participants with albuminuria below 30 mg/g creatinine. Albuminuria was more strongly associated with death among those with lower RV volumes (P-values for interaction <.03).

Conclusions

Among community-dwelling adults, reductions in eGFR primarily within the normal range were associated with smaller RV volumes and the association of albuminuria with worse survival was stronger among those with smaller RV volumes. Further studies are needed to elucidate the underlying mechanistic pathways that link kidney measures and RV morphology.

A comprehensive review of acute cardio-renal syndrome: need for novel biomarkers

Cardiorenal syndrome represents a wide-spectrum disorder involving the heart and kidneys as the primary affected organs. India has an increasingly high burden of acute CRS, coinciding with the rise in global statistics. Up to 2022, approximately 46.1% of all cardiorenal patients have been diagnosed with acute CRS in India. Acute CRS involves a sudden deterioration of kidney functionalities, referred to as acute kidney injury (AKI) in acute heart failure patients. The pathophysiology of CRS involves hyperactivation of the sympathetic nervous system (SNS) and the renin-angiotensin-aldosterone system (RAAS) following acute myocardial stress. The pathological phenotype of acute CRS is associated with perturbed inflammatory, cellular, and neurohormonal markers in circulation. These complications increase the risk of mortality in clinically diagnosed acute CRS patients, making it a worldwide healthcare burden. Hence, effective diagnosis and early prevention are crucial to prevent the progression of CRS in AHF patients. Present biomarkers, such as serum creatinine (sCr), cystatin C (CysC), glomerular filtration rate (GFR), blood urea nitrogen (BUN), serum and/or urine neutrophil gelatinase-associated lipocalin (NGAL), B-type natriuretic peptide (BNP), and NT-proBNP, are clinically used to diagnose AKI stages in CRS patients but are limitedly sensitive to the early detection of the pathology. Therefore, the need for protein biomarkers is emerging for early intervention in CRS progression. Here, we summarized the cardio-renal nexus in acute CRS, with an emphasis on the present clinicopathological biomarkers and their limitations. The objective of this review is to highlight the need for novel proteomic biomarkers that will curb the burgeoning concern and direct future research trials.

The Cardio-Kidney Patient: Epidemiology, Clinical Characteristics and Therapy

Patients with chronic kidney disease (CKD) are at high risk to develop cardiovascular disease with its manifestations coronary artery disease, heart failure, arrhythmias, and sudden cardiac death. In addition, the presence of CKD has a major impact on the prognosis of patients with cardiovascular disease, leading to an increased morbidity and mortality if both comorbidities are present. Therapeutic options including medical therapy and interventional treatment are often limited in patients with advanced CKD, and in most cardiovascular outcome trials, patients with advanced CKD have been excluded. Thus, in many patients, treatment strategies for cardiovascular disease need to be extrapolated from trials conducted in patients without CKD. The current article summarizes the epidemiology, clinical presentation, and treatment options for the most prevalent manifestations of cardiovascular disease in CKD and discusses the currently available treatment options to reduce morbidity and mortality in this high-risk population.

Right Heart Function in Cardiorenal Syndrome

PURPOSE OF REVIEW

Since CRS is critically dependent on right heart function and involved in interorgan crosstalk, assessment and monitoring of both right heart and kidney function are of utmost importance for clinical outcomes. This systematic review aims to comprehensively report on novel diagnostic and therapeutic paradigms that are gaining importance for the clinical management of the growing heart failure population suffering from CRS.

RECENT FINDINGS

Cardiorenal syndrome (CRS) in patients with heart failure is associated with poor outcome. Although systemic venous congestion and elevated central venous pressure have been recognized as main contributors to CRS, they are often neglected in clinical practice. The delicate hemodynamic balance in CRS is particularly determined by the respective status of the right heart. The consideration of hemodynamic and CRS profiles is advantageous in tailoring treatment for better preservation of renal function. Assessment and monitoring of right heart and renal function by known and emerging tools like renal Doppler ultrasonography or new biomarkers may have direct clinical implications.

Heart Failure and Cardiorenal Syndrome: A Narrative Review on Pathophysiology, Diagnostic and Therapeutic Regimens-From a Cardiologist's View

In cardiorenal syndrome (CRS), heart failure and renal failure are pathophysiologically closely intertwined by the reciprocal relationship between cardiac and renal injury. Type 1 CRS is most common and associated with acute heart failure. A preexistent chronic kidney disease (CKD) is common and contributes to acute kidney injury (AKI) in CRS type 1 patients (acute cardiorenal syndrome). The remaining CRS types are found in patients with chronic heart failure (type 2), acute and chronic kidney diseases (types 3 and 4), and systemic diseases that affect both the heart and the kidney (type 5). Establishing the diagnosis of CRS requires various tools based on the type of CRS, including non-invasive imaging modalities such as TTE, CT, and MRI, adjuvant volume measurement techniques, invasive hemodynamic monitoring, and biomarkers. Albuminuria and Cystatin C (CysC) are biomarkers of glomerular filtration and integrity in CRS and have a prognostic impact. Comprehensive "all-in-one" magnetic resonance imaging (MRI) approaches, including cardiac magnetic resonance imaging (CMR) combined with functional MRI of the kidneys and with brain MRI are proposed for CRS. Hospitalizations due to CRS and mortality are high. Timely diagnosis and initiation of effective adequate therapy, as well as multidisciplinary care, are pertinent for the improvement of quality of life and survival. In addition to the standard pharmacological heart failure medication, including SGLT2 inhibitors (SGLT2i), renal aspects must be strongly considered in the context of CRS, including control of the volume overload (diuretics) with special caution on diuretic resistance. Devices involved in the improvement of myocardial function (e.g., cardiac resynchronization treatment in left bundle branch block, mechanical circulatory support in advanced heart failure) have also shown beneficial effects on renal function.

Applications of cardiac biomarkers in chronic kidney disease

PURPOSE OF REVIEW

Cardiovascular disease is the leading cause of death in individuals with chronic kidney disease (CKD). The mechanisms connecting CKD and cardiovascular disease are complex, and serum biomarkers can help improve our understanding. Nt-proBNP and troponin have documented success as biomarkers to diagnose and provide mechanistic insights in non-CKD populations. The purpose of this review is to summarize evidence suggesting efficacy and potential for clinical application of Nt-proBNP and troponin in individuals with CKD.

RECENT FINDINGS

Our understanding of how Nt-proBNP and Troponin should be interpreted in those with CKD is evolving. Although both biomarkers are in part cleared by the kidney, elevated levels predominantly reflect cardiovascular disease. Both Nt-proBNP and troponin are associated with risk for future cardiovascular events in CKD. Determining CKD-specific cutoffs and using biomarkers to guide therapy remains under active investigation.

SUMMARY

Of the many serum biomarkers under investigation, Nt-proBNP and troponin best meet the criteria for effective biomarkers in CKD. Assays are widely available and proven to be accurate in CKD populations. Nt-proBNP and troponin deserve special focus in ongoing research of cardiovascular risk reduction in CKD, especially to identify patients at the highest risk, suggest targetable mechanisms and assess treatment efficacy.

Natriuretic peptides, extracellular volume, and subclinical cardiovascular changes in chronic kidney disease stages 1-3: a pilot study

Natriuretic peptide levels are elevated in persons with chronic kidney disease (CKD) stages 1-3, but it remains unclear whether this is associated with extracellular volume excess or early cardiovascular changes. We hypothesized that patients with CKD stages 1-3 would have evidence of cardiovascular changes, which would associate with brain natriuretic peptide (BNP), amino-terminal-pro-BNP (NT-pro-BNP), and patient-reported symptoms.Outpatients with CKD stages 1-3 and non-CKD controls were enrolled. Cardiovascular parameters included extracellular water (ECW) normalized to body weight measured using whole-body multifrequency bioimpedance spectroscopy, and total peripheral resistance index (TPRI) and cardiac index measured by impedance cardiography. Dyspnea, fatigue, depression, and quality of life were quantified using questionnaires.Among 21 participants (13 with CKD), median (IQR) BNP was 47.0 (28.0-302.5) vs 19.0 (12.3-92.3) pg/mL, p=0.07, and NT-pro-BNP was 245.0 (52.0-976.8) vs 26.0 (14.5-225.8) pg/mL, p=0.08, in the CKD and control groups, respectively. Those with CKD had higher pulse pressure (79 (66-87) vs 64 (49-67) mm Hg, p=0.046) and TPRI (3721 (3283-4278) vs 2933 (2745-3198) dyn×s/cm5/m2, p=0.01) and lower cardiac index (2.28 (2.08-2.78) vs 3.08 (2.43-3.37) L/min/m2, p=0.02). In the overall cohort, natriuretic peptides correlated with pulse pressure (BNP r=0.59; NT-pro-BNP r=0.58), cardiac index (BNP r=-0.76; NT-pro-BNP r=-0.62), and TPRI (BNP r=0.48), p<0.05 for each, but not with ECW/weight. TPRI and blood pressure correlated moderately with symptoms.Elevated natriuretic peptides may coincide with low cardiac index and elevated peripheral resistance in patients with CKD stages 1-3. The role of these biomarkers to detect subclinical cardiovascular changes needs to be further explored.

The Diabetic Cardiorenal Nexus

The end-stage of the clinical combination of heart failure and kidney disease has become known as cardiorenal syndrome. Adverse consequences related to diabetes, hyperlipidemia, obesity, hypertension and renal impairment on cardiovascular function, morbidity and mortality are well known. Guidelines for the treatment of these risk factors have led to the improved prognosis of patients with coronary artery disease and reduced ejection fraction. Heart failure hospital admissions and readmission often occur, however, in the presence of metabolic, renal dysfunction and relatively preserved systolic function. In this domain, few advances have been described. Diabetes, kidney and cardiac dysfunction act synergistically to magnify healthcare costs. Current therapy relies on improving hemodynamic factors destructive to both the heart and kidney. We consider that additional hemodynamic solutions may be limited without the use of animal models focusing on the cardiomyocyte, nephron and extracellular matrices. We review herein potential common pathophysiologic targets for treatment to prevent and ameliorate this syndrome.

Advances in Multimodality Cardiovascular Imaging in the Diagnosis of Heart Failure With Preserved Ejection Fraction

Heart failure with preserved ejection fraction (HFpEF) is a syndrome defined by the presence of heart failure symptoms and increased levels of circulating natriuretic peptide (NP) in patients with preserved left ventricular ejection fraction and various degrees of diastolic dysfunction (DD). HFpEF is a complex condition that encompasses a wide range of different etiologies. Cardiovascular imaging plays a pivotal role in diagnosing HFpEF, in identifying specific underlying etiologies, in prognostic stratification, and in therapeutic individualization. Echocardiography is the first line imaging modality with its wide availability; it has high spatial and temporal resolution and can reliably assess systolic and diastolic function. Cardiovascular magnetic resonance (CMR) is the gold standard for cardiac morphology and function assessment, and has superior contrast resolution to look in depth into tissue changes and help to identify specific HFpEF etiologies. Differently, the most important role of nuclear imaging [i.e., planar scintigraphy and/or single photon emission CT (SPECT)] consists in the screening and diagnosis of cardiac transthyretin amyloidosis (ATTR) in patients with HFpEF. Cardiac CT can accurately evaluate coronary artery disease both from an anatomical and functional point of view, but tissue characterization methods have also been developed. The aim of this review is to critically summarize the current uses and future perspectives of echocardiography, nuclear imaging, CT, and CMR in patients with HFpEF.

Upper Reference Limits for High-Sensitivity Cardiac Troponin T and N-Terminal Fragment of the Prohormone Brain Natriuretic Peptide in Patients With CKD

RATIONALE & OBJECTIVE

The utility of conventional upper reference limits (URL) for N-terminal pro-brain natriuretic peptide (NT-proBNP) and high-sensitivity cardiac troponin T (hsTnT) in chronic kidney disease (CKD) remains debated. We analyzed the distribution of hsTnT and NT-proBNP in people with CKD in ambulatory settings to examine the diagnostic value of conventional URL in this population.

STUDY DESIGN

Observational study.

SETTING & PARTICIPANTS

We studied participants of the Chronic Renal Insufficiency Cohort (CRIC) with CKD and no self-reported history of cardiovascular disease.

EXPOSURE

Estimated glomerular filtration rate (eGFR).

OUTCOME

NT-proBNP and hsTnT at baseline.

ANALYTICAL APPROACH

We described the proportion of participants above the conventional URL for NT-proBNP (125pg/mL) and hsTnT (14ng/L) overall and by eGFR. We then estimated 99th percentile URL for NT-proBNP and hsTnT. Using quantile regression of the 99th percentile, we modeled the association of eGFR with NT-proBNP and hsTnT.

RESULTS

Among 2,312 CKD participants, 40% and 43% had levels of NT-proBNP and hsTnT above the conventional URL, respectively. In those with eGFR <30mL/min/1.73m², 71% and 68% of participants had concentrations of NT-proBNP and hsTnT above the conventional URL, respectively. Among all CKD participants, the 99th percentile for NT-proBNP was 3,592 (95% CI, 2,470-4,849) pg/mL and for hsTnT it was 126 (95% CI, 100-144) ng/L. Each 15mL/min/1.73m² decrement in eGFR was associated with a ~40% higher threshold for the 99th percentile of NT-proBNP (1.43 [95% CI, 1.21-1.69]) and hsTnT (1.45 [95% CI, 1.31-1.60]).

LIMITATIONS

Study included ambulatory patients, and we could not test the accuracy of the URL of NT-proBNP and hsTnT in the acute care setting.

CONCLUSIONS

In this ambulatory CKD population with no self-reported history of cardiovascular disease, a range of 40%-88% of participants had concentrations of NT-proBNP and hsTnT above the conventional URL, depending on eGFR strata. Developing eGFR-specific thresholds for these commonly used cardiac biomarkers in the setting of CKD may improve their utility for evaluation of suspected heart failure and myocardial infarction.

Impact of Chronic Kidney Disease on the Associations of Cardiovascular Biomarkers With Adverse Outcomes in Patients With Suspected or Known Coronary Artery Disease: The EXCEED-J Study

Background

The impact of chronic kidney disease (CKD) on the prognostic utility of cardiovascular biomarkers in high‐risk patients remains unclear.

Methods and Results

We performed a multicenter, prospective cohort study of 3255 patients with suspected or known coronary artery disease (CAD) to investigate whether CKD modifies the prognostic utility of cardiovascular biomarkers. Serum levels of cardiovascular and renal biomarkers, including soluble fms‐like tyrosine kinase‐1 (sFlt‐1), N‐terminal pro‐brain natriuretic peptide (NT‐proBNP), high‐sensitivity cardiac troponin‐I (hs‐cTnI), cystatin C, and placental growth factor, were measured in 1301 CKD and 1954 patients without CKD. The urine albumin to creatinine ratio (UACR) was measured in patients with CKD. The primary outcome was 3‐point MACE (3P‐MACE) defined as a composite of cardiovascular death, nonfatal myocardial infarction, and nonfatal stroke. The secondary outcomes were all‐cause death, cardiovascular death, and 5P‐MACE defined as a composite of 3P‐MACE, heart failure hospitalization, and coronary/peripheral artery revascularization. After adjustment for clinical confounders, sFlt‐1, NT‐proBNP, and hs‐cTnI, but not other biomarkers, were significantly associated with 3P‐MACE, all‐cause death, and cardiovascular death in the entire cohort and in patients without CKD. These associations were still significant in CKD only for NT‐proBNP and hs‐cTnI. NT‐proBNP and hs‐cTnI were also significantly associated with 5P‐MACE in CKD. The UACR was not significantly associated with any outcomes in CKD. NT‐proBNP and hs‐cTnI added incremental prognostic information for all outcomes to the model with potential clinical confounders in CKD.

Conclusions

NT‐proBNP and hs‐cTnI were the most powerful prognostic biomarkers in patients with suspected or known CAD and concomitant CKD.

Troponin Cut-Offs for Acute Myocardial Infarction in Patients with Impaired Renal Function—A Systematic Review and Meta-Analysis

Identifying acute myocardial infarction in patients with renal disease is notoriously difficult, due to atypical presentation and chronically elevated troponin. The aim of this study was to identify a specific troponin T/troponin I cut-off value for diagnosis of acute myocardial infarction in patients with renal impairment via meta-analysis. Two investigators screened 2590 publications from MEDLINE, Embase, PubMed, Web of Science, and the Cochrane library. Only studies that investigated alternative cut-offs according to renal impairment were included. Fifteen articles fulfilled the inclusion criteria. Six studies were combined for meta-analysis. The manufacturer’s upper reference level for troponin T is 14 ng/L. Based on the meta-analyses, cut-off values for troponin in patients with renal impairment with myocardial infarction was 42 ng/L for troponin I and 48 ng/L for troponin T. For patients on dialysis the troponin T cut-off is even higher at 239 ng/L. A troponin I cut-off value for dialysis patients could not be established due to lack of data. The 15 studies analyzed showed considerable diversity in study design, study population, and the definition of myocardial infarction. Further studies are needed to define a reliable troponin cut-off value for patients with kidney disease, especially in dialysis patients, and to allow necessary subanalysis.

Factors associated with baseline and serial changes in circulating NT-proBNP and high-sensitivity cardiac troponin T in a population-based cohort (Dallas Heart Study)

Aim: N-terminal pro-B-type natriuretic peptide (NT-proBNP) and high-sensitivity cardiac troponin T (hs-cTnT) associate with structural heart disease and heart failure risk in individuals without known cardiovascular disease (CVD). However, few data are available regarding whether factors influencing levels of these two biomarkers are similar or distinct. We performed serial measurement of NT-proBNP and hs-cTnT in a contemporary multiethnic cohort with extensive phenotyping, with the goal of identifying their respective biological determinants in a population without known or suspected CVD. Methods: We evaluated 1877 participants of the Dallas Heart Study who had NT-proBNP and hs-cTnT measured and were free from clinical CVD at the each of its two examinations (2000-2002 and 2007-2009). Variables collected included demographic and risk factors, high-sensitivity C-reactive protein, body composition via dual-energy x-ray absorptiometry, coronary artery calcium by computed tomography, and cardiac dimensions and function by cardiac MRI. Linear regression was used to identify associations of these factors with each biomarker at baseline and with changes in biomarkers over follow-up. Results: NT-proBNP and hs-cTnT were poorly correlated at baseline (Spearman rho 0.083, p = 0.015), with only moderate correlation between change values (rho 0.18, p < 0.001). hs-cTnT positively associated and NT-proBNP inversely associated with male gender and black race. At baseline, both NT-proBNP and hs-cTnT associated with left ventricular end-diastolic volume and wall thickness, but only NT-proBNP associated with left atrial size. Changes in cardiac dimensions between phases were more strongly associated with changes in NT-proBNP than hs-cTnT. NT-proBNP was more strongly associated with high-sensitivity C-reactive protein and measures of body composition than hs-cTnT. Conclusion: Among individuals without CVD in the general population, NT-proBNP and hs-cTnT are nonredundant biomarkers that are differentially associated with demographic and cardiac factors. These findings indicate that hs-cTnT and NT-proBNP may reflect different pathophysiological pathways.

Plasma biomarkers outperform echocardiographic measurements for cardiovascular risk prediction in kidney transplant recipients: results of the HOME ALONE study

Background

Since kidney transplant recipients (KTRs) have a high cardiovascular disease burden, adequate risk prediction is of importance. Whether echocardiographic parameters and plasma biomarkers, natriuretic peptides [N-terminal pro-B-type natriuretic peptide (NT-proBNP)] and troponin T provide complementary or overlapping prognostic information on cardiovascular events remains uncertain.

Methods

The prospective Heterogeneity of Monocytes and Echocardiography Among Allograft Recipients in Nephrology (HOME ALONE) study followed 177 KTRs for 5.4 ± 1.7 years. Predefined endpoints were hospitalization for acute decompensated heart failure or all-cause death (HF/D) and major atherosclerotic cardiovascular events or all-cause death (MACE/D). At baseline, plasma NT-proBNP, plasma troponin T and echocardiographic parameters [left atrial volume index, left ventricular (LV) mass index, LV ejection fraction, and LV filling pressure] were assessed.

Results

Among all echocardiographic and plasma biomarkers measured, only NT-proBNP was consistently associated with HF/D in univariate and multivariate {third versus first tertile: hazard ratio [HR] 4.20 [95% confidence interval (CI) 1.02–17.27]} analysis, and only troponin T was consistently associated with MACE/D in univariate and multivariate [third versus first tertile: HR 8.15 (95% CI 2.75–24.18)] analysis.

Conclusion

Our data suggest that plasma biomarkers are robust and independent predictors of heart failure and atherosclerotic cardiovascular events after kidney transplantation, whereas standard echocardiographic follow-up does not add to risk prediction.

NT-proBNP as a Potential Marker of Cardiovascular Damage in Children with Chronic Kidney Disease

Assessing cardiovascular disease (CVD) in children with chronic kidney disease (CKD) is difficult. Great expectations have been associated with biomarkers, including the N-terminal pro-brain natriuretic peptide (NT-proBNP). This study aimed to determine the correlation between NT-proBNP and cardiovascular complications in children with CKD. Serum NT-proBNP, arterial stiffness, common carotid artery intima-media thickness (cIMT), echocardiographic (ECHO) parameters (including tissue Doppler imaging), and biochemical and clinical data were analyzed in 38 pediatric patients with CKD (21 boys, 12.2 ± 4.2 years). Mean NT-proBNP in CKD patients was 1068.1 ± 4630 pg/mL. NT-proBNP above the norm (125 pg/mL) was found in 16 (42.1%) subjects. NT-proBNP correlated with glomerular filtration rate (GFR) (r = -0.423, p = 0.008), and was significantly higher in CKD G5 (glomerular filtration rate grade) patients compared to CKD G2, G3, and G4 children (p = 0.010, p = 0.004, and p = 0.018, respectively). Moreover, NT-proBNP correlated positively with augmentation index (AP/PP: r = 0.451, p = 0.018, P2/P: r = 0.460, p = 0.016), cIMT (r = 0.504, p = 0.020), and E/E' in ECHO (r = 0.400, p = 0.032). In multivariate analysis, logNT-proBNP was the only significant predictor of cIMT Z-score (beta = 0.402, 95CI (0.082-0.721), p = 0.014) and P2/P1 (beta = 0.130, 95CI (0.082-0.721), p = 0.014). Conclusions: NT-proBNP may serve as a possible marker of thickening of the carotid artery wall in pediatric patients with CKD. The final role of NT-proBNP as a biomarker of arterial damage, left ventricular hypertrophy, or cardiac diastolic dysfunction in CKD children needs confirmation in prospective studies.

Managing heart failure in dialysis patients

The heart and the kidney are intimately connected. They communicate in a bidirectional manner through a variety of pathways, forming an interdependent relationship. Recognition of this co-dependency is crucial in managing patients with cardiorenal syndrome, as we begin to realise the inevitability of disease progression to both organs; and an approach that focuses treatment on one organ may result in worsening outcome on the other organ. When faced with patients with deteriorating cardiac disease, nephrologists tend to focus on stabilisation of cardiac function and accept the heart disease to be unmodifiable. Likewise, cardiac patients with persistent kidney failure are presented with a poor renal prognosis and prepared for kidney transplantation. Adopting a cardio-protective approach in combination with dialysis optimisation raises hope for a more positive outcome with evidence of cardiac and renal recovery in some patients.

High-Sensitive Cardiac Troponin T for Prediction of Cardiovascular Outcomes in Stable Maintenance Hemodialysis Patients: A 3-Year Prospective Study

BACKGROUND

Hemodialysis patients, who are often excluded from cardiovascular (CV) clinical trials, are associated with higher CV morbidity and mortality. The risk stratification scheme for these patients is lacking. Therefore, this investigation examined the independent CV prognostic value of high-sensitive cardiac troponin T (hs-cTnT) and added prognostic value over echocardiographic parameters and other clinical risk predictors in asymptomatic stable maintenance hemodialysis (MHD) patients.

METHODS

181 patients with end-stage renal disease undergoing MHD were eligible from the dialysis center of Tongren Hospital, Shanghai Jiao Tong University School of Medicine between October 2017 and September 2018. These patients were followed until September 2020 or until death. The median follow-up was 31 (IQR: 21-33) months. Outcome measures were all-cause mortality, first fatal or nonfatal CV events (CVEs), and 4-point composite major adverse CVEs (MACE). We performed multivariable Cox regression analysis using demographic, clinical, laboratory, and echocardiographic data to identify predictors of CV outcomes. We also evaluated the increased discriminative value associated with the addition of echocardiographic parameters and hs-cTnT using net reclassification improvement (NRI) and integrated discrimination improvement (IDI).

RESULTS

During follow-up, 37 patients died, 84 patients suffered one or more CVEs, and 78 patients developed 4-point MACE. In univariable analyses, age, dialysis vintage, diastolic blood pressure, parathyroid hormone concentrations, hs-cTnT, B-type natriuretic peptide, left ventricular mass index (LVMI), and E/E' predicted all end points. hs-cTnT remained a strong predictor for each end point in multivariate analysis, whereas LVMI and E/E' did not. The addition of hs-cTnT on top of clinical and echocardiographic variables was associated with improvements in reclassification for CVEs (NRI = 44.6% [15.9-74.3%], IDI = 15.9% [5.7-31.0%], all p < 0.001), all-cause mortality (NRI = 35.5% [10.1-50.2%], p < 0.001, IDI = 4.4% [1.3-8.5%], p = 0.005), and 4-point MACE (NRI = 47.2% [16.1-64.9%], p < 0.001, IDI = 16.9% [5.5-37.3%], p = 0.005). Adding echocardiographic variables on top of clinical variables and hs-cTnT was not associated with significant improvements in NRI and IDI (all p > 0.05).

CONCLUSIONS

Our data suggest that hs-cTnT is a powerful independent predictor of CV outcome and all-cause mortality in stable MHD patients. The additional use of echocardiography for improvement of risk stratification is not supported by our results.

Cardiovascular evaluation in advanced chronic kidney disease

Patients with chronic kidney disease (CKD) display an increased cardiovascular comorbidity, which is often underdiagnosed. Thus, effective cardiovascular diagnostic testing is of particular importance for this group of patients. Data from prospective randomized trials with cardiovascular diagnostic testing in CKD patients and improved outcome are limited. Diagnostic stress testing for CKD patients requires special consideration. Guidelines recommend cardiovascular diagnostic testing for patients undergoing an evaluation before transplantation.

High percent body fat mass predicts lower risk of cardiac events in patients with heart failure: an explanation of the obesity paradox

Background

Although high body mass index (BMI) is a risk factor of heart failure (HF), HF patients with a higher BMI had a lower mortality rate than that in HF patients with normal or lower BMI, a phenomenon that has been termed the “obesity paradox”. However, the relationship between body composition, i.e., fat or muscle mass, and clinical outcome in HF remains unclear.

Methods

We retrospectively analyzed data for 198 consecutive HF patients (76 years of age; males, 49%). Patients who were admitted to our institute for diagnosis and management of HF and received a dual-energy X-ray absorptiometry scan were included regardless of left ventricular ejection fraction (LVEF) categories. Muscle wasting was defined as appendicular skeletal muscle mass index < 7.0 kg/m² in males and < 5.4 kg/m² in females. Increased percent body fat mass (increased FM) was defined as percent body fat > 25% in males and > 30% in females.

Results

The median age of the patients was 76 years (interquartile range [IQR], 67–82 years) and 49% of them were male. The median LVEF was 47% (IQR, 33–63%) and 33% of the patients had heart failure with reduced ejection fraction. Increased FM and muscle wasting were observed in 58 and 67% of the enrolled patients, respectively. During a 180-day follow-up period, 32 patients (16%) had cardiac events defined as cardiac death or readmission by worsening HF or arrhythmia. Kaplan-Meier survival curves showed that patients with increased FM had a lower cardiac event rate than did patients without increased FM (11.4% vs. 22.6%, p = 0.03). Kaplan-Meier curves of cardiac event rates did not differ between patients with and those without muscle wasting (16.5% vs. 15.4%, p = 0.93). In multivariate Cox regression analyses, increased FM was independently associated with lower cardiac event rates (hazard ratio: 0.45, 95% confidence interval: 0.22–0.93) after adjustment for age, sex, diabetes, muscle wasting, and renal function.

Conclusions

High percent body fat mass is associated with lower risk of short-term cardiac events in HF patients.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12877-020-01950-9.

Association of circulating cardiac biomarkers with electrocardiographic abnormalities in chronic kidney disease

BACKGROUND

Among patients with chronic kidney disease (CKD), the circulating cardiac biomarkers soluble ST2 (SST2), galectin-3, growth differentiation factor-15 (GDF-15), N-terminal pro-B-type natriuretic peptide (NT-proBNP) and high-sensitivity troponin-T (hsTnT) possibly reflect pathophysiologic processes and are associated with clinical cardiovascular disease. Whether these biomarkers are associated with electrocardiographic findings is not known. The aim of this study was to test the association between serum cardiac biomarkers and the presence of electrocardiographic changes potentially indicative of subclinical myocardial disease in patients with CKD.

METHODS

We performed a cross-sectional analysis using 3048 participants from the Chronic Renal Insufficiency Cohort (CRIC) without atrial fibrillation, atrioventricular block, bundle branch block or a pacemaker at the baseline visit. Using logistic regression, we tested the association of each of the five cardiac biomarkers with baseline electrocardiogram (ECG) findings: PR interval >200 ms, QRS interval >100 ms and a prolonged QTc interval. Models were adjusted for demographic variables, measures of kidney function, prevalent cardiovascular disease and cardiovascular risk factors.

RESULTS

In adjusted models, hsTnT levels associated with prolonged PR {odds ratio [OR] 1.23 [95% confidence interval (CI) 1.08-1.40]}, QRS [OR 1.28 (95% CI 1.16-1.42)] and QTc [OR 1.94 (95% CI 1.50-2.51)] intervals. NT-proBNP levels were associated with prolonged QRS [OR 1.11 (95% CI 1.06-1.16)] and QTc [OR 1.82 (95% CI 1.58-2.10)] intervals. SST2, galectin-3 and GDF-15 were not significantly associated with any of the ECG parameters.

CONCLUSIONS

hsTnT and NT-proBNP were associated with ECG measures indicative of subclinical myocardial dysfunction. These results may support future research investigating the significance of myocardial ischemia and volume overload in the pathogenesis of dysfunctional myocardial conduction in CKD.

Coexistence of acute poststreptococcal glomerulonephritis and acute rheumatic fever in a Japanese girl with primary Sjögren's syndrome

Although acute poststreptococcal glomerulonephritis (APSGN) and acute rheumatic fever (ARF) are well-known complications of group A streptococcus infection, concomitant occurrence of both diseases is rare. We report an 11-year-old Japanese girl with primary Sjögren's syndrome complicated by acute renal failure about 2 weeks after the onset of pharyngitis. Although histopathological findings of the kidney were not confirmative, APSGN was suggested by the spontaneous recovery of her renal function, typical latent period with high levels of antistreptolysin O and low serum levels of C3 but not of C4. In addition, cardiac hypomotility and regurgitation of the 4 valves progressed in the convalescent phase of APSGN, which was accompanied by elevation of serum C-reactive protein and plasma brain natriuretic peptide (BNP) levels. Myocarditis was suggested by delayed gadolinium-enhancement of cardiac walls on cardiac magnetic resonance imaging. She was diagnosed with APSGN and ARF and was treated with a combination of short course prednisolone and prophylactic penicillin G. There is no relapse of renal or cardiac symptoms during 6 years follow-up. Unexpected elevation of plasma BNP in a convalescent stage of APSGN suggests the development of ARF. Underlying Sjögren's syndrome (SS) may modify the histopathological findings and make it difficult to differentiate APSGN from CTD-associated nephritis such as lupus nephritis (LN) even by renal biopsy.

Novel Biomarkers in Patients with Chronic Kidney Disease: An Analysis of Patients Enrolled in the GCKD-Study

Background: Chronic kidney disease (CKD) and cardiovascular diseases (CVD) often occur concomitantly, and CKD is a major risk factor for cardiovascular mortality. Since some of the most commonly used biomarkers in CVD are permanently elevated in patients with CKD, novel biomarkers are warranted for clinical practice. Methods: Plasma concentrations of five cardiovascular biomarkers (soluble suppression of tumorigenicity (sST2), growth differentiation factor 15 (GDF-15), heart-type fatty acid-binding protein (H-FABP), insulin-like growth factor-binding protein 2 (IGF-BP2), and soluble urokinase plasminogen activator receptor) were analyzed by means of enzyme-linked immunosorbent assay (ELISA) in 219 patients with CKD enrolled in the German Chronic Kidney Disease (GCKD) study. Results: Except for sST2, all of the investigated biomarkers were significantly elevated in patients with CKD (2.0- to 4.4-fold increase in advanced CKD (estimated glomerular filtration rate (eGFR) < 30 mL/min/1.73 m² body surface area (BSA)) and showed a significant inverse correlation with eGFR. Moreover, all but H-FABP and sST2 were additionally elevated in patients with micro- and macro-albuminuria. Conclusions: Based on our findings, sST2 appears to be the biomarker whose diagnostic performance is least affected by decreased renal function, thus suggesting potential viability in the management of patients with CVD and concomitant CKD. The predictive potential of sST2 remains to be proven in endpoint studies.

Right Heart Failure and Cardiorenal Syndrome

Cardiorenal syndrome is a complex interplay of dysregulated heart and kidney interaction that leads to multiorgan system dysfunction, which is not an uncommon occurrence in the setting of right heart failure. The traditional concept of impaired perfusion and forward flow recently has been modified to include the recognition of systemic venous congestion as a contributor, with direct and indirect mechanisms, including elevated renal venous pressure, reduced renal perfusion pressure, increased renal interstitial pressure, tubular dysfunction, splanchnic congestion, and neurohormonal and inflammatory activation. Treatment options beyond diuretics and vasoactive drugs remain limited and lack supportive evidence.

Should We Consider the Cardiovascular System While Evaluating CKD-MBD?

Cardiovascular (CV) disease is highly prevalent in the population with chronic kidney disease (CKD), where the risk of CV death in early stages far exceeds the risk of progression to dialysis. The presence of chronic kidney disease-mineral and bone disorder (CKD-MBD) has shown a strong correlation with CV events and mortality. As a non-atheromatous process, it could be partially explained why standard CV disease-modifying drugs do not provide such an impact on CV mortality in CKD as observed in the general population. We summarize the potential association of CV comorbidities with the older (parathyroid hormone, phosphate) and newer (FGF23, Klotho, sclerostin) CKD-MBD biomarkers.

Cardiorenal Syndrome: Classification, Pathophysiology, Diagnosis, and Treatment Strategies: A Scientific Statement From the American Heart Association

Cardiorenal syndrome encompasses a spectrum of disorders involving both the heart and kidneys in which acute or chronic dysfunction in 1 organ may induce acute or chronic dysfunction in the other organ. It represents the confluence of heart-kidney interactions across several interfaces. These include the hemodynamic cross-talk between the failing heart and the response of the kidneys and vice versa, as well as alterations in neurohormonal markers and inflammatory molecular signatures characteristic of its clinical phenotypes. The mission of this scientific statement is to describe the epidemiology and pathogenesis of cardiorenal syndrome in the context of the continuously evolving nature of its clinicopathological description over the past decade. It also describes diagnostic and therapeutic strategies applicable to cardiorenal syndrome, summarizes cardiac-kidney interactions in special populations such as patients with diabetes mellitus and kidney transplant recipients, and emphasizes the role of palliative care in patients with cardiorenal syndrome. Finally, it outlines the need for a cardiorenal education track that will guide future cardiorenal trials and integrate the clinical and research needs of this important field in the future.

[Cardiovascular diagnostic testing in advanced chronic kidney disease: which tests are useful?]

Against the background of drastically increased cardiovascular comorbidity in patients with chronic kidney disease (CKD), an effective cardiovascular diagnostic approach appears essential. However, patients with CKD are often underdiagnosed. Prospective randomized studies showing an improved outcome for cardiovascular diagnostic in patients with CKD are limited. Special attention is paid to stress diagnostics in CKD patients. Guidelines recommend cardiovascular diagnostic evaluation prior to inclusion on the transplantation waiting list.

Do plasma neprilysin activity and plasma neprilysin concentration predict cardiac events in chronic kidney disease patients?

Background

Since the introduction of sacubitril/valsartan in clinical cardiology, neprilysin has become a major target for heart failure treatment. Plasma neprilysin concentration has been discussed as a novel biomarker that predicts cardiac events. Natriuretic peptides may inhibit plasma neprilysin. As they accumulate in chronic kidney disease (CKD), we hypothesized that high plasma neprilysin loses its predictive role in CKD patients.

Methods

We measured plasma levels of neprilysin concentration, neprilysin activity and brain natriuretic peptide (BNP) in 542 CKD G2-G4 patients within the CARE FOR HOMe study. Patients were followed for predefined endpoints of hospitalization for acute decompensated heart failure and incident atherosclerotic cardiovascular events.

Results

During 5.1 ± 2.1 years, 63 patients had acute decompensated heart failure and 125 patients had incident atherosclerotic cardiovascular events. In both Kaplan-Meier and multivariate Cox regression analyses, high plasma BNP and low, rather than elevated, neprilysin activity predicted future hospitalization for acute decompensated heart failure; neprilysin concentration was not predictive. Furthermore, only BNP was an independent predictor of incident atherosclerotic cardiovascular events.

Conclusions

In line with experimental studies, high natriuretic peptides may inhibit neprilysin activity in CKD. Therefore, high neprilysin activity and concentrations are not predictors of adverse cardiovascular outcome in CKD patients. Thus neprilysin inhibitors should be implemented with caution in patients with advanced CKD.

Estimated Glomerular Filtration Rate, Activation of Cardiac Biomarkers and Long-Term Cardiovascular Outcomes: A Population-Based Cohort

OBJECTIVE

To classify subjects in a general population per their renal function and characterize the cardiac biomarker levels, left ventricular function and cardiovascular outcomes over a 10.2 year follow-up period (interquartile range, 5.1-11.4 years).

METHODS

This was a retrospective review of a population-based random sample of residents aged ≥45 years. Data were collected between January 1, 1997, and December 31, 2000. One thousand nine hundred eighty-one individuals were classified based on estimated glomerular filtration rate (eGFR) into group I (>90 mL/min/1.73 m²), group II (60 to 89 mL/min/1.73 m²) and group III (<60 mL/min/1.73 m²; chronic kidney disease [CKD]). Age/sex-adjusted baseline characteristics, tertiles of N-terminal pro B-type natriuretic peptide (NT-proBNP) and high-sensitivity troponin T (hs-TnT) and their interactions with eGFR were examined. Outcomes measured included incident myocardial infarction (MI), congestive heart failure, stroke, and all-cause mortality.

RESULTS

Eight hundred nineteen patients were classified as group I, 1036 as group II, and 126 of 1981 (6.4%) as group III or CKD. Subjects in group III were older and had a higher incidence of hypertension, diabetes, and MI at baseline. Over a 10.2-year follow-up period, CKD was associated with an increased risk of MI (hazard ratio, 1.95; 95% CI, 1.2-3.14; P=.006) and composite cardiovascular outcomes including MI, congestive heart failure, stroke, and all-cause mortality (hazard ratio, 1.38; 95% CI, 1.05-1.83 ;P=.02). Subjects with NT-proBNP or hs-TnT in the third tertile were at greater risk of cardiovascular events without significant interactions between eGFR and levels of NT-proBNP and hs-TnT.

CONCLUSION

Subjects with CKD had significantly elevated cardiac biomarkers and were at an increased risk of MI and adverse cardiovascular events. This warrants future studies to investigate whether these cardiac biomarkers could identify high-risk CKD patients for aggressive management of cardiovascular risk factors.

Glomerular Filtration Rate-Specific Cutoffs Can Refine the Prognostic Value of Circulating Cardiac Biomarkers in Advanced Chronic Kidney Disease

BACKGROUND

Using standard cutoffs derived from healthy adults, high-sensitivity cardiac troponin T (hs-cTnT) and N-terminal pro-B-type natriuretic peptide (NT-proBNP) are frequently elevated in patients with reduced glomerular filtration rate (GFR), with unclear implications. We sought to compare GFR-specific cutoffs of each biomarker with standard cutoffs for discrimination of cardiovascular risk in asymptomatic patients with chronic kidney disease.

METHODS

We investigated a prospective cohort of 1956 participants with median GFR of 27 mL/min/1.73 m². Cox proportional hazards models were used to examine the association between each biomarker and first adjudicated cardiovascular event (unstable angina, myocardial infarction, heart failure, stroke, cardiovascular death). We used an outcome-based approach to identify optimal risk-based cutoffs for each biomarker within GFR strata (< 20, 20-29, 30-44 mL/min/1.73 m²). We evaluated the added prognostic value of each biomarker to a multivariable base model, comparing GFR-specific with standard cutoffs.

RESULTS

Hs-cTnT and NT-proBNP were elevated in 76% and 82% of participants, respectively. A total of 401 events were recorded during 6772 person-years at risk. Both biomarkers were independent predictors of cardiovascular events. Optimal cutoffs for each biomarker were higher than standard thresholds, being highest at GFR values < 20 mL/min/1.73 m². Addition of hs-cTnT to the base model using GFR-specific cutoffs significantly improved reclassification for events (52%) and nonevents (21%). Similar findings were observed for NT-proBNP. In contrast, use of standard cutoffs failed to reclassify patients who had no event as lower risk.

CONCLUSIONS

Among asymptomatic patients with advanced chronic kidney disease, optimal cutoffs for hs-cTnT and NT-proBNP differed according to GFR level and outperformed standard cutoffs for discrimination of cardiovascular risk.

Heart failure in chronic kidney disease: conclusions from a Kidney Disease: Improving Global Outcomes (KDIGO) Controversies Conference

The incidence and prevalence of heart failure (HF) and chronic kidney disease (CKD) are increasing, and as such a better understanding of the interface between both conditions is imperative for developing optimal strategies for their detection, prevention, diagnosis, and management. To this end, Kidney Disease: Improving Global Outcomes (KDIGO) convened an international, multidisciplinary Controversies Conference titled Heart Failure in CKD. Breakout group discussions included (i) HF with preserved ejection fraction (HFpEF) and nondialysis CKD, (ii) HF with reduced ejection fraction (HFrEF) and nondialysis CKD, (iii) HFpEF and dialysis-dependent CKD, (iv) HFrEF and dialysis-dependent CKD, and (v) HF in kidney transplant patients. The questions that formed the basis of discussions are available on the KDIGO website http://kdigo.org/conferences/heart-failure-in-ckd/, and the deliberations from the conference are summarized here.

Assessment of abdominal aortic calcification by computed tomography for prediction of latent left ventricular stiffness and future cardiovascular risk in pre-dialysis patients with chronic kidney disease: A single center cross-sectional study

Introduction: There is general interest in finding clinical markers for left ventricular diastolic dysfunction (LVDD), a major cause of cardiorenal syndrome leading to heart failure in chronic kidney disease (CKD) patients. The aim was to assess the utility of computed tomography (CT)-based abdominal aortic calcification (AAC) for the prediction of LVDD and prognosis of asymptomatic pre-dialysis CKD patients. Materials and methods: We prospectively evaluated 218 pre-dialysis CKD patients [median estimated glomerular filtration rate (eGFR); 40.9 mL/min/1.73m²]. Non-contrast CT scan and echocardiography were performed to determine the aortic calcification index (ACI) as a semi-quantitative measure of AAC. Results: The median ACI was 11.4. AAC and LVDD were diagnosed in 193 patients (89%) and 75 patients (34%), respectively. Using receiver operating characteristic curve analysis for the estimation of LVDD, ACI of 20 showed optimal sensitivity (52.0%) and specificity (62.8 %) (AUC = 0.664, p < .001). High ACI group included more patients with LVDD-related factors, such as old age, hypertension, diabetes, and more severe CKD. LVDD was significantly more common in patients with high ACI group [39 (50%) and 36 (26%), respectively, p<0.001]. Multivariate analysis showed that ACI correlated significantly with E/A (β=-0.993, p=0.003), E/e' (β=0.077, p<0.001), and cardio-ankle vascular index (β=0.209, p=0.001). Correspondingly, E/e' correlated with logBNP and log(ACI+1), and increased proportionately and significantly with the quartiles of ACI values. Cox proportional hazard models showed that ACI was an independent predictor of CV outcome (hazard ratio 1.03, 95% confidence interval 1.00-1.06, p=0.029). Conclusion: The results would suggest the usefulness of AAC assessment by CT to predict latent LVDD and future CV risk in asymptomatic pre-dialysis CKD patients.

Determinants of Left Ventricular Characteristics Assessed by Cardiac Magnetic Resonance Imaging and Cardiovascular Biomarkers Related to Kidney Transplantation

Background:

Cardiac magnetic resonance (CMR) imaging accurately and precisely measures left ventricular (LV) mass and function. Identifying mechanisms by which LV mass change and functional improvement occur in some end-stage kidney disease (ESKD) patients may help to appropriately target kidney transplant (KT) recipients for further investigation and intervention. The concentration of serum adiponectin, a cardiovascular biomarker, increases in cardiac failure, its production being enhanced by B-type natriuretic peptide (BNP), and both serum adiponectin and BNP concentrations decline posttransplantation.

Objective:

We tested the hypothesis that kidney transplantation alters LV characteristics that relate to serum adiponectin concentrations.

Design:

Prospective and observational cohort study.

Setting:

The study was performed at 3 adult kidney transplant and dialysis centers in Ontario, Canada.

Patients:

A total of 82 KT candidate subjects were recruited (39 to the KT group and 43 to the dialysis group). Predialysis patients were excluded.

Measurements:

Subjects underwent CMR with a 1.5-tesla whole-body magnetic resonance scanner using a phased-array cardiac coil and retrospective vectorographic gating. LV mass, LV ejection fraction (LVEF), LV end-systolic volume (LVESV), and LV end-diastolic volume (LVEDV) were measured by CMR pre-KT and again 12 months post-KT (N = 39), or 12 months later if still receiving dialysis (N = 43). LV mass, LVESV, and LVEDV were indexed for height (m^2.7) to calculate left ventricular mass index (LVMI), left ventricular end-systolic volume index (LVESVI), and left ventricular end-diastolic volume index (LVEDVI), respectively. Serum total adiponectin and N-terminal proBNP (NT-proBNP) concentrations were measured at baseline, 3 months, and 12 months.

Methods:

We performed a prospective 1:1 observational study comparing KT candidates with ESKD either receiving a living donor organ (KT group) or waiting for a deceased donor organ (dialysis group).

Results:

Left ventricular mass index change was −1.98 ± 5.5 and −0.36 ± 5.7 g/m^2.7 for KT versus dialysis subjects (P = .44). Left ventricular mass change was associated with systolic blood pressure (SBP) (P = .0008) and average LV mass (P = .0001). Left ventricular ejection fraction did not improve (2.9 ± 6.6 vs 0.7 ± 4.9 %, P = .09), while LVESVI and LVEDVI decreased more post-KT than with continued dialysis (−3.36 ± 5.6 vs −0.22 ± 4.4 mL/m^2.7, P < .01 and −4.9 ± 8.5 vs −0.3 ± 9.2 mL/m^2.7, P = .02). Both adiponectin (−7.1 ± 11.3 vs −0.11 ± 7.9 µg/mL, P < .0001) and NT-proBNP (−3811 ± 8130 vs 1665 ± 20013 pg/mL, P < .0001) declined post-KT. Post-KT adiponectin correlated with NT-proBNP (P = .001), but not estimated glomerular filtration rate (eGFR) (P = .13). Change in adiponectin did not correlate with change in LVEF in the KT group (Spearman ρ = 0.16, P = .31) or dialysis group (Spearman ρ = 0.19, P = .21).

Limitations:

Few biomarkers of cardiac function were measured to fully contextualize their role during changing kidney function. Limited intrapatient biomarker sampling and CMR measurements precluded constructing dose-response curves of biomarkers to LV mass and function. The CMR timing in relation to dialysis was not standardized.

Conclusions:

The LVESVI and LVEDVI but not LVMI or LVEF improve post-KT. LVMI and LVEF change is independent of renal function and adiponectin. As adiponectin correlates with NT-proBNP post-KT, improved renal function through KT restores the normal heart-endocrine axis.

Red blood cell volume is not decreased in ESA-naive anemic chronic kidney disease patients

Anemia is defined according to decreased blood hemoglobin concentration ([Hb]), which is considered a marker of low total red blood cell volume (RBCV). Alterations of plasma volume (PV) may also modify [Hb] without concomitant changes in RBCV. Since anemia and fluid retention are frequent complications of chronic kidney disease (CKD), we hypothesized that anemia during CKD may in part be related to expanded PV without a simultaneous decrease in RBCV. We quantified hemoglobin mass, RBCV, PV, and total blood volume (BV) using an automated carbon monoxide device in 40 consecutive stage 3-5 CKD patients not on dialysis and in seven healthy male controls of the same age range. These were compared within and to predicted volumes according to Nadler's formula. Arterial stiffness and NT-proBNP were measured. RBCV was similar to predicted values range in anemic CKD patients 2073 (1818-2704) versus, 2061 (1725-2473) mL, P > 0.05. In contrast, PV was largely increased in anemic CKD patients (3881 (3212-4352) vs. 2916 (2851-3201)), P = 0.01. Of 26 anemic patients, only six had a >20% decrease in RBCV as the cause for their anemia, whereas 14 had a >20% increase of PV as a cause for their anemia. NT-pro BNP correlated with eGFR but neither with PV nor BV, whereas arterial stiffness was not correlated to blood volumes. Anemia in CKD as diagnosed by low [Hb] is not necessarily associated to low RBCV but may reflect increased PV. This finding has implications for the treatment of CKD patients and may refrain from normalizing [Hb] levels in all CKD patients.

Abnormal Cardiac Biomarkers in Patients with Systemic Lupus Erythematosus and No Prior Heart Disease: A Consequence of Antimalarials?

OBJECTIVE

Cardiac involvement in systemic lupus erythematosus (SLE) is often undiagnosed in its early phases. Specific heart biomarkers may identify patients at risk. We sought to investigate the prevalence and associated factors for such biomarkers in SLE.

METHODS

Brain natriuretic peptide (BNP) and cardiac troponin I (cTnI) were measured simultaneously in 151 consecutive patients with no history of heart disease or pulmonary arterial hypertension (PAH). None had electrocardiographic abnormalities suggestive of acute coronary syndrome. Cross-sectional comparisons and logistic regression analyses were performed. Patients with abnormal biomarkers were investigated to delineate the specific cause.

RESULTS

Sixteen patients (16/151, 10.6%) had elevated BNP, and 9 of them also had abnormal cTnI. Compared to subjects with normal biomarkers, they were older, had longer disease and antimalarial (AM) use duration, and more frequently persistent creatine phosphokinase (CPK) elevation. Multivariable regression analysis showed prolonged AM treatment (> 5.6 yrs) and persistent CPK elevation to be important predictors for elevated cardiac biomarkers. Six patients were diagnosed with definite (based on endomyocardial biopsy, n = 2) or possible (based on cardiac magnetic resonance after exclusion of other causes) AM-induced cardiomyopathy (AMIC); all had both BNP and cTnI elevated. Alternative causes were identified in 5, while no definitive diagnosis could be made in the remaining patients.

CONCLUSION

About 10% of patients with SLE had elevated myocardial biomarkers, in the absence of prior cardiac disease or PAH. One-third of them were diagnosed with AMIC. Prolonged AM therapy and persistent CPK elevation conferred an increased risk for abnormal BNP and cTnI, which might predict AMIC.

Global kidney health 2017 and beyond: a roadmap for closing gaps in care, research, and policy

The global nephrology community recognises the need for a cohesive plan to address the problem of chronic kidney disease (CKD). In July, 2016, the International Society of Nephrology hosted a CKD summit of more than 85 people with diverse expertise and professional backgrounds from around the globe. The purpose was to identify and prioritise key activities for the next 5-10 years in the domains of clinical care, research, and advocacy and to create an action plan and performance framework based on ten themes: strengthen CKD surveillance; tackle major risk factors for CKD; reduce acute kidney injury-a special risk factor for CKD; enhance understanding of the genetic causes of CKD; establish better diagnostic methods in CKD; improve understanding of the natural course of CKD; assess and implement established treatment options in patients with CKD; improve management of symptoms and complications of CKD; develop novel therapeutic interventions to slow CKD progression and reduce CKD complications; and increase the quantity and quality of clinical trials in CKD. Each group produced a prioritised list of goals, activities, and a set of key deliverable objectives for each of the themes. The intended users of this action plan are clinicians, patients, scientists, industry partners, governments, and advocacy organisations. Implementation of this integrated comprehensive plan will benefit people who are at risk for or affected by CKD worldwide.

Effect Modification of Chronic Kidney Disease on the Association of Circulating and Imaging Cardiac Biomarkers With Outcomes

Background

Cardiac troponin T and brain natriuretic peptide (BNP) are elevated in >50% of dialysis patients and are associated with poor outcomes. Few data investigated these associations in earlier chronic kidney disease (CKD).

Methods and Results

We studied whether CKD modified associations of elevated BNP, N‐terminal‐pro‐BNP, high‐sensitivity cardiac troponin T, coronary artery calcification, and left ventricular hypertrophy with all‐cause death and cardiovascular death/events in 3218 multiethnic individuals followed for 12.5 years, and whether biomarkers added prognostic information to traditional cardiovascular risk factors in CKD. Of the cohort, 279 (9%) had CKD. There were 296 deaths and 218 cardiovascular deaths/events. Of non‐CKD individuals, 7% died and 6% had cardiovascular death/event versus 32% and 30% of CKD participants, P<0.001 for both. The interaction between BNP and CKD on death was significant (P=0.01): the adjusted hazard ratio in CKD was 2.05, 95% CI (1.34, 3.14), but not significant in non‐CKD, 1.04 (0.76, 1.41). CKD modified the association of high‐sensitivity cardiac troponin T with cardiovascular death/event, adjusted hazard ratio 3.34 (1.56, 7.18) in CKD versus 1.65 (1.16, 2.35) in non‐CKD, interaction P=0.09. There was an interaction between N‐terminal‐pro‐BNP and CKD for death in those without prior cardiovascular disease. Addition of each biomarker to traditional risk factors improved risk prediction, except coronary artery calcification was not discriminatory for cardiovascular death/event in CKD.

Conclusions

Cardiac biomarkers, with the exception of coronary artery calcification, prognosticated outcomes in early‐stage CKD as well as, if not better than, in non‐CKD individuals, even after controlling for estimated glomerular filtration rate, and added to information obtained from traditional cardiovascular risk factors alone.