High-sensitivity troponin T and N-terminal pro-B-type natriuretic peptide (NT-proBNP) and risk of incident heart failure in patients with CKD: the Chronic Renal Insufficiency Cohort (CRIC) Study

Plasma B-type natriuretic peptide is independently associated with cardiovascular events and mortality in patients with chronic kidney disease

The association between B-type natriuretic peptide (BNP) and cardiovascular (CV) events and mortality has not been well characterized in patients with chronic kidney disease (CKD). We prospectively investigated whether BNP was associated with CV events or mortality beyond cardiac alterations in 1078 patients with CKD. Participants were divided into the following 3 groups according to circulating BNP concentration: < 40 pg/mL, low; 40-100 pg/mL, middle; and > 100 pg/mL, high. Primary outcome was fatal or nonfatal CV events, and alternative outcome was a composite of fatal or nonfatal CV events, or non-CV deaths. During a median follow-up of 2.6 years, CV and composite events occurred in 158 and 248 participants, respectively. Cox analyses after adjustment for covariates, including cardiac parameters, showed that the hazard ratios (HRs) (95% confidence intervals [CIs]) for CV events of middle and high groups were 1.00 (0.63, 1.58) and 1.72 (1.06, 2.79), respectively, compared with low group. Additionally, similar results were obtained for composite events; the HRs (95% CIs) of middle and high groups were 1.10 (0.77, 1.57) and 1.54 (1.04, 2.27), respectively, compared with low group. Thus, in CKD, high BNP concentrations were independently associated with CV events and mortality, independent of cardiac alterations.

N-Terminal Pro-Brain Natriuretic Peptide Correlates with Ghrelin and Acyl-Ghrelin in Pre-Dialysis Chronic Kidney Disease

Pro-B amino-terminal natriuretic peptide (NT-proBNP) is a diagnostic marker for heart failure (HF), a severe complication of chronic kidney disease (CKD). However, its significance in CKD is not clear, as other factors, such as renal function, may also have an impact. Recent studies have shown that ghrelin treatment is effective in HF in the general population, but the impact of ghrelin on cardiac function in CKD patients is still unknown. Our study aimed to investigate the factors associated with NT-proBNP in pre-dialysis CKD patients and to evaluate the correlation between NT-proBNP and ghrelin and acyl-ghrelin, molecules determined using ELISA methods. In a cross-sectional observational study, we included 80 patients with pre-dialysis CKD, with a mean age of 68 years and 50% men. The median values for NT-proBNP were 351.8 pg/mL, for acyl ghrelin 16.39 pg/mL, and for ghrelin 543.32 pg/mL. NT-proBNP was correlated with ghrelin (p = 0.034, r = 0.24), acyl-ghrelin (p = 0.033, r = -0.24), estimated glomerular filtration rate (p = 0.027, r = -0.25), serum urea (p = 0.006, r = 0.31), and ferritin (p = 0.041, r = 0.28). In multivariate analysis, ghrelin (p = 0.040) and blood urea (p = 0.040) remained significant predictors for NT-proBNP levels. NT-proBNP was a significant predictor for acyl-ghrelin (p = 0.036). In conclusion, in pre-dialysis CKD patients, a high value of NT-proBNP was associated with a high value of total ghrelin and a low value of acyl-ghrelin.

Circulating osteoprotegerin as a cardiac biomarker for left ventricular diastolic dysfunction in patients with pre-dialysis chronic kidney disease: the KNOW-CKD study

BACKGROUND

Heart failure with preserved ejection fraction (HFpEF) is a major cause of mortality in patients with chronic kidney disease (CKD), and diagnosis is challenging. Moreover, no specific biomarker for HFpEF has been validated in patients with CKD. The present study aimed to investigate the association between serum osteoprotegerin (OPG) levels and the risk of left ventricular diastolic dysfunction (LVDD), a surrogate of HFpEF, in patients with pre-dialysis CKD.

METHODS

A total of 2039 patients with CKD at stage 1 to pre-dialysis 5 were categorized into quartiles (Q1 to Q4) by serum OPG levels, and were cross-sectionally analyzed. The study outcome was LVDD, which was operationally defined as the ratio of early transmitral blood flow velocity to early diastolic velocity of the mitral annulus (E/e') > 14.

RESULTS

In the analysis of baseline characteristics, higher serum OPG levels were clearly related to the risk factors of HFpEF. A scatter plot analysis revealed a moderate correlation between serum OPG levels and E/e' (R = 0.351, P < 0.001). Logistic regression analysis demonstrated that the risk of LVDD in Q3 (adjusted odds ratio 2.576, 95% confidence interval 1.279 to 5.188) and Q4 (adjusted odds ratio 3.536, 95% confidence interval 1.657 to 7.544) was significantly higher than that in Q1.

CONCLUSIONS

Elevated serum OPG levels are associated with the risk of LVDD in patients with pre-dialysis CKD. The measurement of serum OPG levels may help the diagnosis of LVDD, which is an important echocardiographic feature of HFpEF.

Optimal Screening for Predicting and Preventing the Risk of Heart Failure Among Adults With Diabetes Without Atherosclerotic Cardiovascular Disease: A Pooled Cohort Analysis

BACKGROUND

The optimal approach to identify individuals with diabetes who are at a high risk for developing heart failure (HF) to inform implementation of preventive therapies is unknown, especially in those without atherosclerotic cardiovascular disease (ASCVD).

METHODS

Adults with diabetes and no HF at baseline from 7 community-based cohorts were included. Participants without ASCVD who were at high risk for developing HF were identified using 1-step screening strategies: risk score (WATCH-DM [Weight, Age, Hypertension, Creatinine, HDL-C, Diabetes Control, QRS Duration, MI, and CABG] ≥12), NT-proBNP (N-terminal pro-B-type natriuretic peptide ≥125 pg/mL), hs-cTn (high-sensitivity cardiac troponin T ≥14 ng/L; hs-cTnI ≥31 ng/L), and echocardiography-based diabetic cardiomyopathy (echo-DbCM; left atrial enlargement, left ventricular hypertrophy, or diastolic dysfunction). High-risk participants were also identified using 2-step screening strategies with a second test to identify residual risk among those deemed low risk by the first test: WATCH-DM/NT-proBNP, NT-proBNP/hs-cTn, NT-proBNP/echo-DbCM. Across screening strategies, the proportion of HF events identified, 5-year number needed to treat and number needed to screen to prevent 1 HF event with an SGLT2i (sodium-glucose cotransporter 2 inhibitor) among high-risk participants, and cost of screening were estimated.

RESULTS

The initial study cohort included 6293 participants (48.2% women), of whom 77.7% without prevalent ASCVD were evaluated with different HF screening strategies. At 5-year follow-up, 6.2% of participants without ASCVD developed incident HF. The 5-year number needed to treat to prevent 1 HF event with an SGLT2i among participants without ASCVD was 43 (95% CI, 29-72). In the cohort without ASCVD, high-risk participants identified using 1-step screening strategies had a low 5-year number needed to treat (22 for NT-proBNP to 37 for echo-DbCM). However, a substantial proportion of HF events occurred among participants identified as low risk using 1-step screening approaches (29% for echo-DbCM to 47% for hs-cTn). Two-step screening strategies captured most HF events (75-89%) in the high-risk subgroup with a comparable 5-year number needed to treat as the 1-step screening approaches (30-32). The 5-year number needed to screen to prevent 1 HF event was similar across 2-step screening strategies (45-61). However, the number of tests and associated costs were lowest for WATCH-DM/NT-proBNP ($1061) compared with other 2-step screening strategies (NT-proBNP/hs-cTn: $2894; NT-proBNP/echo-DbCM: $16 358).

CONCLUSIONS

Selective NT-proBNP testing based on the WATCH-DM score efficiently identified a high-risk primary prevention population with diabetes expected to derive marked absolute benefits from SGLT2i to prevent HF.

Utility of Cardiac Troponins in Patients With Chronic Kidney Disease

Cardiovascular disease is a major cause of death worldwide especially in patients with chronic kidney disease (CKD). Troponin T and troponin I are cardiac biomarkers used not only to diagnose acute myocardial infarction (AMI) but also to prognosticate cardiovascular and all-cause mortality. The diagnosis of AMI in the CKD population is challenging because of their elevated troponins at baseline. The development of high-sensitivity cardiac troponins shortens the time needed to rule in and rule out AMI in patients with normal renal function. While the sensitivity of high-sensitivity cardiac troponins is preserved in the CKD population, the specificity of these tests is compromised. Hence, diagnosing AMI in CKD remains problematic even with the introduction of high-sensitivity assays. The prognostic significance of troponins did not differ whether it is detected with standard or high-sensitivity assays. The elevation of both troponin T and troponin I in CKD patients remains strongly correlated with adverse cardiovascular and all-cause mortality, and the prognosis becomes poorer with advanced CKD stages. Interestingly, the degree of troponin elevation appears to be predictive of the rate of renal decline via unclear mechanisms though activation of the renin-angiotensin and other hormonal/oxidative stress systems remain suspect. In this review, we present the latest evidence of the use of cardiac troponins in both the diagnosis of AMI and the prognosis of cardiovascular and all-cause mortality. We also suggest strategies to improve on the diagnostic capability of these troponins in the CKD/end-stage kidney disease population.

Association of cardiac biomarkers, kidney function, and mortality among adults with chronic kidney disease

Background and Aims

The performance of high sensitivity troponin T (hs-cTnT), hs-cTnI, and N-terminal pro-hormone brain natriuretic peptide (NT-proBNP) in patients with chronic kidney disease (CKD) is poorly understood.

Methods

We included adults with CKD (eGFR<60 ml/min/1.73m2) in the 1999-2004 NHANES. We calculated the 99th percentile of hs-cTnT, hs-cTnI (Abbott, Ortho, and Siemens assays), and NT-proBNP, measured the association between eGFR and cardiac biomarker concentration, and used Cox regression models to assess the relationship between cardiac biomarkers and CVD mortality.

Results

Across 1,068 adults with CKD, the mean [SD] age was 71.9[12.7] years and 61.2% were female; 78.8% had elevated NT-proBNP and 42.6% had elevated hs-cTnT based on traditional clinical reference limits. The 99th percentile of hs-cTnT was 122 ng/L (95% confidence interval (CI) 101-143), hs-cTnIAbbott was 69 ng/L (95% CI 38-99), and NT-proBNP was 8952 pg/mL (95% CI 7506-10,399). A 10 ml/min decrease in eGFR was associated with greater increases in hs-cTnT and NT-proBNP than hs-cTnI (hs-cTnT: 27.5% increase (β=27.5, 95% CI 28.2-43.3)), NT-proBNP 46.0% increase (β=46.0, 95% CI 36.0-56.8), hs-cTnISiemens 17.9% (β=17.9, 95% CI 9.7-26.7). Each doubling of hs-cTnT, hs-cTnI, and NT-proBNP were associated with CVD mortality (hs-cTnT HR 1.62 [95% CI 1.32-1.98], p<0.0001; hs-cTnISiemens HR 1.40 [95% CI 1.26-1.55], p<0.0001; NT-proBNP HR 1.29 [95% CI 1.19-1.41], p<0.0001).

Conclusions and Relevance

Community dwelling adults with CKD have elevated concentrations of cardiac biomarkers, above established reference ranges. Of the troponin assays, hs-cTnI concentration appears to be most stable across eGFR categories and is associated with CVD mortality.

Resting Heart Rate Independent of Cardiovascular Disease Risk Factors Is Associated With End-Stage Renal Disease: A Cohort Study Based on 476 347 Adults

BACKGROUND

The relationship between resting heart rate (RHR) and the risk of end-stage renal disease (ESRD) among those without cardiovascular disease remains unclear. We aim to establish temporal consistency and elucidate the independent relationship between RHR and the risk of ESRD.

METHODS AND RESULTS

This cohort enrolled participants from 476 347 individuals who had taken part in a screening program from 1996 to 2017. We identified 2504 participants who had ESRD, and the median follow-up was 13 years. RHR was extracted from electrocardiography results, and the study assessed the relationship between RHR and the risk of ESRD using the Cox proportional hazards model. Of the participants, 32.6% had an RHR of 60 to 69 beats per minute (bpm), and 22.2% had an RHR of ≥80 bpm. Participants with an RHR of ≥80 bpm had a higher stage of chronic kidney disease, lower estimated glomerular filtration rate, and more proteinuria than those with an RHR of 60 to 69 bpm. Participants with an RHR of 80 to 89 and ≥90 bpm had a 24% (hazard ratio [HR], 1.24 [95% CI, 1.09-1.42]) and 64% (HR, 1.64 [95% CI, 1.42-1.90]) higher risk of ESRD, respectively. The risk of ESRD remained significantly elevated (HR, 1.32 [95% CI, 1.10-1.58] per 10-beat increase from 60 bpm) after excluding participants who smoked; had hypertension, diabetes, or hyperlipidemia; or were overweight.

CONCLUSIONS

An RHR of ≥80 bpm is significantly associated with an increased risk of ESRD. These results suggest that RHR may serve as a risk factor for kidney disease in individuals without established cardiovascular disease risk factors.

Association of malnutrition with all-cause and cardiovascular mortality in patients with mild to severe chronic kidney disease undergoing coronary angiography: a large multicenter longitudinal study

PURPOSE

Evidence on the prognostic impact of malnutrition was focused on patients with advanced kidney disease. The relationships between malnutrition and all-cause and cardiovascular mortality in patients with different severity of chronic kidney disease (CKD) have not been adequately addressed. We aimed to reveal the prevalence of malnutrition and its prognostic value in patients with different severity of CKD undergoing coronary angiography (CAG).

METHODS

This was a multicenter, longitudinal, and retrospective cohort study of 12,652 patients with non-dialysis dependent CKD (defined as estimated glomerular filtration rate [eGFR] < 60 mL/min/1.73 m2) undergoing CAG from five tertiary hospitals between January 2007 and December 2020. The controlling nutritional status (CONUT) score was applied to assess nutritional status. Cox regression models and competing risk Fine and Gray models were used to examine the relationships between malnutrition, all-cause and cardiovascular mortality. Further stratified analysis was performed according to baseline CKD severity (mild, moderate and severe, defined by eGFR < 30, 30-44 and 45-59 ml/min/1.73 m2).

RESULTS

During a median follow-up of 5.5 years (interquartile range: 3.2 to 8.6 years), 3801 patients (30.0%) died, and 2150 (17.0%) definitely died of cardiovascular disease. After controlling for confounders, patients had higher all-cause mortality (mild, moderate, and severe vs. absent: HR 1.27, 95 CI % [1.17-1.39]; HR 1.54, 95 CI % [1.39-1.71]; HR 2.22, 95 CI % [1.78-2.77], respectively; P for trend < 0.001) and cardiovascular mortality (mild, moderate and severe vs. absent: HR 1.35, 95 CI % [1.21-1.52]; HR 1.67, 95 CI % [1.45-1.92]; HR 2.10, 95 CI % [1.55-2.85], respectively; P for trend < 0.001) with the severity of malnutrition. In further stratified analysis, a similar prognostic impact of malnutrition was observed in patients with mild to moderate CKD, while mild malnutrition did not seem to have a consistent effect on severe CKD patients.

CONCLUSION

Malnutrition is common among patients with mild to severe CKD undergoing CAG and is strongly associated with increased risk of all-cause and cardiovascular mortality. Malnutrition seems to have a modestly stronger impact on mortality in patients with mild to moderate CKD. This study was registered at Clinicaltrials.gov as NCT05050877.

Comparison of cardiac biomarkers on risk assessment of contrast-associated acute kidney injury in patients undergoing cardiac catheterization: A multicenter retrospective study

AIM

Cardiac biomarkers' predictive value of contrast-associated acute kidney injury (CA-AKI) remains unclear. We analysed whether creatine kinase isoenzyme-MB (CKMB), cardiac troponin I (cTnI) and preoperative N-terminal pro-brain natriuretic peptide (NT-proBNP) are tied to CA-AKI patients undergoing cardiac catheterization.

METHODS

In the multi-center study, we included 3553 people underwent cardiac catheterization for analysis. CA-AKI was defined as the absolute increase of over 0.3 mg/dL or an increase of more than 50% compared with the baseline serum creatinine within 48 hours following cardiac catheterization. Logistic regression model and receiver operating characteristic (ROC) curves were used to examine the association between cardiac biomarkers and CA-AKI and the efficacy of Mehran risk score (MRS) model on CA-AKI prediction with and without cardiac biomarkers.

RESULTS

Among 3553 people, 200 people eventually developed CA-AKI. The logistic regression model showed that log10 CKMB (odds ratio (OR): 1.97, 95%CI:1.51-2.57, p < .001), cTnI (OR: 1.03, 95%CI: 1.02-1.04, p < .001) and log10 NT-proBNP (OR: 3.19, 95%CI: 2.46-4.17, p < .001) were independent predictors of CA-AKI. The ROC curve demonstrated that area under the curve (AUC) of MRS was 0.733. CKMB, cTnI and NT-proBNP all significantly improved the AUC value in combination with MRS model. (NT-proBNP: 0.798, p < .001; CKMB: 0.758, p = .003; cTnI: 0.755, p = .002), among which the NT-proBNP had the best predictive efficacy improvement.

CONCLUSION

Cardiac biomarkers of CKMB, cTnI and NT-proBNP are all independently associated with CA-AKI among patients undergoing cardiac catheterization while NT-proBNP remains the best indicator. Adding CKMB, cTnI and NT-proBNP to MRS improved the prognostic efficacy and may be considered effective tools to predict the risk of CA-AKI in clinical practice.

A 4-Variable Model to Predict Cardio-Kidney Events and Mortality in Chronic Kidney Disease: The Chronic Renal Insufficiency Cohort (CRIC) Study

INTRODUCTION

Current prognostic models for chronic kidney disease (CKD) are complex and were designed to predict a single outcome. We aimed to develop and validate a simple and parsimonious prognostic model to predict cardio-kidney events and mortality.

METHODS

Patients from the CRIC Study (n = 3,718) were randomly divided into derivation (n = 2,478) and validation (n = 1,240) cohorts. Twenty-nine candidate variables were preselected. Multivariable Cox regression models were developed using stepwise selection for various cardio-kidney endpoints, namely, (i) the primary composite outcome of 50% decline in estimated glomerular filtration rate (eGFR) from baseline, end-stage renal disease, or cardiovascular (CV) mortality; (ii) hospitalization for heart failure (HHF) or CV mortality; (iii) 3-point major CV endpoints (3P-MACE); (iv) all-cause death.

RESULTS

During a median follow-up of 9 years, the primary outcome occurred in 977 patients of the derivation cohort and 501 patients of the validation cohort. Log-transformed N-terminal pro-B-type natriuretic peptide (NT-proBNP), log-transformed high-sensitive cardiac troponin T (hs-cTnT), log-transformed albuminuria, and eGFR were the dominant predictors. The primary outcome risk score discriminated well (c-statistic = 0.83) with a proportion of events of 11.4% in the lowest tertile of risk and 91.5% in the highest tertile at 10 years. The risk model presented good discrimination for HHF or CV mortality, 3P-MACE, and all-cause death (c-statistics = 0.80, 0.75, and 0.75, respectively). The 4-variable risk model achieved similar c-statistics for all tested outcomes in the validation cohort. The discrimination of the 4-variable risk model was mostly superior to that of published models.

CONCLUSION

The combination of NT-proBNP, hs-cTnT, albuminuria, and eGFR in a single 4-variable model provides a unique individual prognostic assessment of multiple cardio-kidney outcomes in CKD.

The Role of Two Heart Biomarkers in IgA Nephropathy

Cardiovascular mortality is a leading cause of death in chronic kidney disease (CKD), as is IgA nephropathy (IgAN). The purpose of this study is to find different biomarkers to estimate the outcome of the disease, which is significantly influenced by the changes in vessels (characterized by arterial stiffness) and the heart. In our cross-sectional study, 90 patients with IgAN were examined. The N-terminal prohormone of brain natriuretic peptide (NT-proBNP) was measured as a heart failure biomarker by an automated immonoassay method, while the carboxy-terminal telopeptide of collagen type I (CITP) as a fibrosis marker was determined using ELISA kits. Arterial stiffness was determined by measuring carotid-femoral pulse wave velocity (cfPWV). Renal function and routine echocardiography examinations were performed as well. Based on eGFR, patients were separated into two categories, CKD 1-2 and CKD 3-5. There were significantly higher NT-proBNP (p = 0.035), cfPWV (p = 0.004), and central aortic systolic pressure (p = 0.037), but not CITP, in the CKD 3-5 group. Both biomarker positivities were significantly higher in the CKD 3-5 group (p = 0.035) compared to the CKD 1-2 group. The central aortic systolic pressure was significantly higher in the diastolic dysfunction group (p = 0.034), while the systolic blood pressure was not. eGFR and hemoglobin levels showed a strong negative correlation, while left ventricular mass index (LVMI), aortic pulse pressure, central aortic systolic pressure, and cfPWV showed a positive correlation with NT-proBNP. cfPWV, aortic pulse pressure, and LVMI showed a strong positive correlation with CITP. Only eGFR was an independent predictor of NT-proBNP by linear regression analysis. NT-proBNP and CITP biomarkers may help to identify IgAN patients at high risk for subclinical heart failure and further atherosclerotic disease.

Left ventricular dysfunction with preserved ejection fraction: the most common left ventricular disorder in chronic kidney disease patients

Chronic kidney disease (CKD) is a risk factor for premature cardiovascular disease. As kidney function declines, the presence of left ventricular abnormalities increases such that by the time kidney replacement therapy is required with dialysis or kidney transplantation, more than two-thirds of patients have left ventricular hypertrophy. Historically, much research in nephrology has focussed on the structural and functional aspects of cardiac disease in CKD, particularly using echocardiography to describe these abnormalities. There is a need to translate knowledge around these imaging findings to clinical outcomes such as unplanned hospital admission with heart failure and premature cardiovascular death. Left ventricular hypertrophy and cardiac fibrosis, which are common in CKD, predispose to the clinical syndrome of heart failure with preserved left ventricular ejection fraction (HFpEF). There is a bidirectional relationship between CKD and HFpEF, whereby CKD is a risk factor for HFpEF and CKD impacts outcomes for patients with HFpEF. There have been major improvements in outcomes for patients with heart failure and reduced left ventricular ejection fraction as a result of several large randomized controlled trials. Finding therapy for HFpEF has been more elusive, although recent data suggest that sodium-glucose cotransporter 2 inhibition offers a novel evidence-based class of therapy that improves outcomes in HFpEF. These observations have emerged as this class of drugs has also become the standard of care for many patients with proteinuric CKD, suggesting that there is now hope for addressing the combination of HFpEF and CKD in parallel. In this review we summarize the epidemiology, pathophysiology, diagnostic strategies and treatment of HFpEF with a focus on patients with CKD.

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.

Prognostic value of soluble ST2, high-sensitivity cardiac troponin, and NT-proBNP in type 2 diabetes: a 15-year retrospective study

Background

Patients with type 2 diabetes (T2DM) present an increased risk of cardiovascular (CV) disease and excess CV-related mortality. Beyond the established role of brain natriuretic peptide (BNP) and cardiac troponins (cTn), other non-cardiac-specific biomarkers are emerging as predictors of CV outcomes in T2DM.

Methods

Serum levels of soluble suppression of tumorigenesis 2 (sST2), high-sensitivity (hs)-cTnI, and N-terminal (NT)-proBNP were assessed in 568 patients with T2DM and 115 healthy controls (CTR). Their association with all-cause mortality and the development of diabetic complications was tested in T2DM patients over a median follow-up of 16.8 years using Cox models and logistic regressions.

Results

sST2 followed an increasing trend from CTR to uncomplicated T2DM patients (T2DM-NC) to patients with at least one complication (T2DM-C), while hs-cTnI was significantly higher in T2DM-C compared to CTR but not to T2DM-NC. A graded association was found between sST2 (HR 2.76 [95% CI 1.20–6.33] for ≥ 32.0 ng/mL and 2.00 [1.02–3.94] for 16.5–32.0 ng/mL compared to < 16.5 ng/mL, C-statistic = 0.729), NT-proBNP (HR 2.04 [1.90–4.55] for ≥ 337 ng/L and 1.48 [1.05–2.10] for 89–337 ng/L compared to < 89 ng/L, C-statistic = 0.741), and 15-year mortality in T2DM, whereas increased mortality was observed in patients with hs-cTnI ≥ 7.8 ng/L (HR 1.63 [1.01–2.62]). A ‘cardiac score’ based on the combination of sST2, hs-cTnI, and NT-proBNP was significantly associated with all-cause mortality (HR 1.35 [1.19–1.53], C-statistic = 0.739) and development of CV events.

Conclusions

sST2, hs-cTnI, and NT-proBNP are associated with 15-year mortality and onset of CV events in T2DM. The long-term prognostic value of sST2 and its ability to track variables related to insulin resistance and associated metabolic disorders support its implementation into routine clinical practice.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12933-022-01616-3.

Cardiac Biomarkers and Risk of Atherosclerotic Cardiovascular Disease in Patients with CKD

Background

Several cardiac biomarkers of cardiac stress, inflammation, and fibrosis (N-terminal pro brain-type natriuretic peptide [NT-proBNP], high-sensitivity troponin T [hsTnT], growth differentiation factor 15 [GDF-15], and soluble ST2 [sST2]) have been associated with atherosclerotic disease in the general population. We hypothesized that these cardiac biomarkers may also be associated with the atherosclerotic cardiovascular disease in patients with CKD.

Methods

We analyzed levels of NT-proBNP, hsTnT, GDF-15, and sST2 in a cohort of 2732 participants with mild to moderate CKD from the Chronic Renal Insufficiency Cohort (CRIC) study. Outcomes included incident atherosclerotic disease, defined as the first instance of myocardial infarction, stroke, or peripheral vascular disease. We used Cox proportional hazard models to the test the association of each cardiac biomarker with risk of incident atherosclerotic disease, adjusting for multiple possible confounders.

Results

When modeled continuously (per SD increase in the log-transformed biomarker), NT-proBNP, hsTnT, GDF-15, and sST2 were significantly associated with incident atherosclerotic disease after adjustment for multiple potential confounders: (NT-proBNP HR, 1.51; 95% CI, 1.27 to 1.81; hsTnT HR, 1.61; 95% CI, 1.38 to 1.89; GDF-15 HR, 1.44; 95% CI, 1.19 to 1.73; and sST2 HR, 1.19; 95% CI, 1.04 to 1.36).

Conclusions

NT-proBNP, hsTnT, GDF-15, and sST2 were significantly associated with incident atherosclerotic cardiovascular disease in patients with CKD. These associations may highlight important mechanisms for the development of atherosclerotic disease in CKD.

Risk Prediction Models for Atherosclerotic Cardiovascular Disease in Patients with Chronic Kidney Disease: The CRIC Study

BACKGROUND

Individuals with CKD may be at high risk for atherosclerotic cardiovascular disease (ASCVD). However, there are no ASCVD risk prediction models developed in CKD populations to inform clinical care and prevention.

METHODS

We developed and validated 10-year ASCVD risk prediction models in patients with CKD that included participants without self-reported cardiovascular disease from the Chronic Renal Insufficiency Cohort (CRIC) study. ASCVD was defined as the first occurrence of adjudicated fatal and nonfatal stroke or myocardial infarction. Our models used clinically available variables and novel biomarkers. Model performance was evaluated based on discrimination, calibration, and net reclassification improvement.

RESULTS

Of 2604 participants (mean age 55.8 years; 52.0% male) included in the analyses, 252 had incident ASCVD within 10 years of baseline. Compared with the American College of Cardiology/American Heart Association pooled cohort equations (area under the receiver operating characteristic curve [AUC]=0.730), a model with coefficients estimated within the CRIC sample had higher discrimination (P=0.03), achieving an AUC of 0.736 (95% confidence interval [CI], 0.649 to 0.826). The CRIC model developed using clinically available variables had an AUC of 0.760 (95% CI, 0.678 to 0.851). The CRIC biomarker-enriched model had an AUC of 0.771 (95% CI, 0.674 to 0.853), which was significantly higher than the clinical model (P=0.001). Both the clinical and biomarker-enriched models were well-calibrated and improved reclassification of nonevents compared with the pooled cohort equations (6.6%; 95% CI, 3.7% to 9.6% and 10.0%; 95% CI, 6.8% to 13.3%, respectively).

CONCLUSIONS

The 10-year ASCVD risk prediction models developed in patients with CKD, including novel kidney and cardiac biomarkers, performed better than equations developed for the general population using only traditional risk factors.

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.

Routinely measured cardiac troponin I and N-terminal pro-B-type natriuretic peptide as predictors of mortality in haemodialysis patients

Aims

Cardiac troponin (cTn) and B‐type natriuretic peptide (BNP) are elevated in haemodialysis (HD) patients, and this elevation is associated with HD‐induced myocardial stunning/myocardial strain. However, studies using data from the international Dialysis Outcomes and Practice Patterns Study (DOPPS) have shown that these cardiac biomarkers are measured in <2% of HD patients in real‐world practice. This study aimed to examine whether routinely measured N‐terminal pro‐BNP (NT‐proBNP) and cTnI (contemporary assay) are more appropriate than clinical models for reclassifying the risk of HD patients who have the highest risk of death.

Methods and results

Pre‐dialysis levels of cTnI and NT‐proBNP at study enrolment were measured in 1152 HD patients (Japan DOPPS Phase 5). The patients were prospectively followed for 3 years. Cox regression was used to test the associations of cardiac biomarkers with all‐cause mortality, adjusting for potential confounders. Subgroup analyses were performed to assess potential effect modification of clinical characteristics, such as age, systolic blood pressure, HD vintage, diabetes mellitus, coronary artery disease, and a history of congestive heart failure. At baseline, 337 (29%) patients had elevated cTnI (99th percentile of a healthy population: >0.04 ng/mL) with a median (inter‐quartile range) level of 0.020 (0.005–0.041) ng/mL, and 1140 (99%) patients had elevated NT‐proBNP (cut‐off for heart failure: >125 pg/mL) with a median level of 3658 (1689–9356) pg/mL. There were 167 deaths during a median follow‐up of 2.8 (2.2–2.8) years. Higher levels of both cardiac biomarkers were incrementally associated with mortality after adjustment for potential confounders. Even after adjustment for alternative cardiac biomarkers, the overall P value for the association was <0.01 for both biomarkers. However, the prognostic significance of NT‐proBNP was moderately diminished when cTnI was added to the model. The hazard ratios of mortality for cTnI > 0.04 ng/mL (vs. cTnI < 0.006 ng/mL) and NT‐proBNP > 8000 pg/mL (vs. NT‐proBNP < 2000 pg/mL) were 2.56 (95% confidence interval: 1.37–4.81) and 1.90 (95% confidence interval: 0.95–3.79), respectively. Subgroup analyses showed that the associations of both cardiac biomarkers with mortality were generally consistent between stratified groups.

Conclusions

Routinely measured NT‐proBNP and cTnI levels are strongly associated with mortality among prevalent HD patients. These associations remain robust, even after adjustment for alternative biomarkers, suggesting that cTnI and NT‐proBNP have identical prognostic significance and may reflect different pathological aspects of cardiac abnormalities.

Time-Updated Changes in Estimated GFR and Proteinuria and Major Adverse Cardiac Events: Findings from the Chronic Renal Insufficiency Cohort (CRIC) Study

RATIONALE & OBJECTIVE

Evaluating repeated measures of estimated glomerular filtration rate (eGFR) and urinary protein-creatinine ratio (UPCR) over time may enhance our ability to understand the association between changes in kidney parameters and cardiovascular disease risk.

STUDY DESIGN

Prospective cohort study.

SETTING & PARTICIPANTS

Annual visit data from 2,438 participants in the Chronic Renal Insufficiency Cohort (CRIC).

EXPOSURES

Average and slope of eGFR and UPCR in time-updated, 1-year exposure windows.

OUTCOMES

Incident heart failure, atherosclerotic cardiovascular disease events, death, and a composite of incident heart failure, atherosclerotic cardiovascular disease events, and death.

ANALYTICAL APPROACH

A landmark analysis, a dynamic approach to survival modeling that leverages longitudinal, iterative profiles of laboratory and clinical information to assess the time-updated 3-year risk of adverse cardiovascular outcomes.

RESULTS

Adjusting for baseline and time-updated covariates, every standard deviation lower mean eGFR (19mL/min/1.73m²) and declining slope of eGFR (8mL/min/1.73m² per year) were independently associated with higher risks of heart failure (hazard ratios [HRs] of 1.82 [95% CI, 1.39-2.44] and 1.28 [95% CI, 1.12-1.45], respectively) and the composite outcome (HRs of 1.32 [95% CI, 1.11-1.54] and 1.11 [95% CI, 1.03-1.20], respectively). Every standard deviation higher mean UPCR (136mg/g) and increasing UPCR (240mg/g per year) were also independently associated with higher risks of heart failure (HRs of 1.58 [95% CI, 1.28-1.97] and 1.20 [95% CI, 1.10-1.29], respectively) and the composite outcome (HRs of 1.33 [95% CI, 1.17-1.50] and 1.12 [95% CI, 1.06-1.18], respectively).

LIMITATIONS

Limited generalizability of annual eGFR and UPCR assessments; several biomarkers for cardiovascular disease risk were not available annually.

CONCLUSIONS

Using the landmark approach to account for time-updated patterns of kidney function, average and slope of eGFR and proteinuria were independently associated with 3-year cardiovascular risk. Short-term changes in kidney function provide information about cardiovascular risk incremental to level of kidney function, representing possible opportunities for more effective management of patients with chronic kidney disease.

Cardiac biomarkers in pediatric CKD-a prospective follow-up study

BACKGROUND

The N-terminal pro-B-type natriuretic peptide (NT-proBNP) and high-sensitive cardiac-specific troponin T (hs-cTnT) are associated with abnormal cardiac structure and function and an increased risk of cardiovascular death in chronic kidney disease (CKD) patients. There is limited knowledge about these cardiac markers in pediatric CKD patients.

METHODS

Longitudinal levels of NT-proBNP and hs-cTnT were analyzed in 48 pediatric patients, 22 with CKD (GFR range 8.8-68 mL/min/1.73 m²) and 26 transplanted patients (CKD-T; GFR range 30-99 mL/min/1.73 m²). Follow-up was scheduled after 1 and 3 years. Longitudinal patterns and associations to kidney function, cardiovascular risk markers, and echocardiographic parameters were assessed.

RESULTS

High NT-proBNP was present in 27% of CKD and 11% of CKD-T patients. Similarly 32% of CKD and 8% of CKD-T patients had elevated hs-cTnT levels. In longitudinal multivariate analyses, high log NT-proBNP was associated with low GFR (β =  - 0.01, p = 0.01) and elevated left ventricular mass index (LVMI; β = 0.02, p = 0.05). The strong association to LVMI remained when using GFR-adjusted NT-proBNP in similar analysis. Patients with left ventricular hypertrophy (LVH) also had higher NT-proBNP (235 [146-301] ng/L) than patients without LVH (86 [11-477] ng/L), p = 0.02. High hs-cTnT over-time was also associated with low GFR (β =  - 0.007, p = 0.01) and a low cc-TDI e´/a´, indicating a worse LV diastolic function (β =  - 0.09, p = 0.05). This association did not persist for GFR-adjusted hs-cTnT.

CONCLUSIONS

NT-proBNP and hs-cTnT are elevated in pediatric CKD and CKD-T patients. GFR-adjusted NT-proBNP was associated with longitudinal levels of elevated LVMI suggesting this might be a marker for early subclinical myocardial damage. A higher resolution version of the Graphical abstract is available as Supplementary information.

Abnormalities in Cardiac Structure and Function among Individuals with CKD: The COMBINE Trial

Background

Individuals with CKD have a high burden of cardiovascular disease (CVD). Abnormalities in cardiac structure and function represent subclinical CVD and can be assessed by cardiac magnetic resonance imaging (cMRI).

Methods

We investigated differences in cMRI parameters in 140 individuals with CKD stages 3b-4 who participated in the CKD Optimal Management with BInders and NicotinamidE (COMBINE) trial and in 24 age- and sex-matched healthy volunteers. Among COMBINE participants, we examined the associations of eGFR, urine albumin-creatinine ratio (UACR), phosphate, fibroblast growth factor 23 (FGF23), and parathyroid hormone (PTH) with baseline (N=140) and 12-month change (N=112) in cMRI parameters.

Results

Mean (SD) ages of the COMBINE participants and healthy volunteers were 64.9 (11.9) and 60.4 (7.3) years, respectively. The mean (SD) baseline eGFR values in COMBINE participants were 32.1 (8.0) and 85.9 (16.0) ml/min per 1.73 m² in healthy volunteers. The median (interquartile range [IQR]) UACR in COMBINE participants was 154 (20.3-540.0) mg/g. Individuals with CKD had lower mitral valve E/A ratio compared with healthy volunteers (for CKD versus non-CKD, β estimate, -0.13; 95% CI, -0.24 to -0.012). Among COMBINE participants, multivariable linear regression analyses showed that higher UACR was significantly associated with lower mitral valve E/A ratio (β estimate per 1 unit increase in natural-log UACR, -0.06; 95% CI, -0.09 to -0.03). This finding was preserved among individuals without baseline CVD. UACR was not associated with 12-month change in any cMRI parameter. eGFR, phosphate, FGF23, and PTH were not associated with any cMRI parameter in cross-sectional or change analyses.

Conclusions

Individuals with CKD stages 3b-4 have evidence of cMRI abnormalities. Albuminuria was independently associated with diastolic dysfunction, as assessed by mitral valve E/A ratio, in individuals with CKD with and without clinical CVD. Albuminuria was not associated with change in any cMRI parameter.

Cardiovascular remodeling as a result of fibroblast growth factor-23 (FGF-23)/Klotho imbalance in patients with CKD

BACKGROUND

In chronic kidney disease (CKD) cardiovascular remodeling (CVR) is very frequent compared with general population and, as suppose, may be associated with «new» renal risk factors. The aim of study was to estimate association of new serum biomarkers (FGF-23, Klotho) and traditional biomarker of cardiac damage-serum Troponin I (sTr-I) with signs of CVR.

METHODS

One hundred thirty CKD G1-5D patients without cardiovascular disease (CVD) clinical manifestation were included. We measured serum FGF-23, Klotho and sTr-I. The instrumental methods were: echocardiography, SphygmoCor test [Pulse Wave Velocity (PWV), Central (aortic) Blood Pressure (CBP), Subendocardial Blood Supply (SBS)].

RESULTS

FGF-23 level correlated with: sTr-I (r = 0.512; p < 0.01), eccentric left ventricular hypertrophy, LVH (r = 0.543; p < 0.01), SBS (r = - 0.499; p < 0.05). There were no differences of FGF-23 level in patients with normal and high CBP. Klotho correlated with concentric LVH (r = - 0.451; p < 0.01), PWV (r = - 0.667; p < 0.001), Cardiac Calcification Score, CCS (r = - 0.581; p < 0.01). Multivariate analysis revealed positive independent association of FGF-23 with eccentric LVH (OR = 1.036, 95% CI (1.004-1.068); p = 0.038). Klotho was a negative determinant for concentric LVH (OR = 0.990, 95% CI 0.987-0.994; p < 0.001), increased PWV (OR = 0.984, 95% CI (0.977-0.991); p < 0.001) and CCS (OR = 0.991, 95% CI (0.988-0.995); p < 0.001). In addition, multivariate analysis revealed a relationship between serum Klotho (OR = 0.980, 95% CI (0.964-0.996); p = 0.016), FGF-23 (OR = 3.145, 95% CI (1.020-9.695); p = 0.046) and troponin I level.

CONCLUSION

In CKD patients without CVD clinical manifestation increased serum FGF-23 level and decreased Klotho are associated with CVR: FGF-23 with eccentric LVH (independently of CBP), Klotho determinate concentric LVH, PWV and CCS. Moderately elevated sTr-I levels may be a manifestation of FGF-23/Klotho imbalance in CKD.

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.

Sex Differences in Cardiovascular Outcomes in CKD: Findings From the CRIC Study

RATIONALE & OBJECTIVE

Cardiovascular events are less common in women than men in general populations; however, studies in chronic kidney disease (CKD) are less conclusive. We evaluated sex-related differences in cardiovascular events and death in adults with CKD.

STUDY DESIGN

Prospective cohort study.

SETTING & PARTICIPANTS

1,778 women and 2,161 men enrolled in the Chronic Renal Insufficiency Cohort (CRIC).

EXPOSURE

Sex (women vs men).

OUTCOME

Atherosclerotic composite outcome (myocardial infarction, stroke, or peripheral artery disease), incident heart failure, cardiovascular death, and all-cause death.

ANALYTICAL APPROACH

Cox proportional hazards regression.

RESULTS

During a median follow-up period of 9.6 years, we observed 698 atherosclerotic events (women, 264; men, 434), 762 heart failure events (women, 331; men, 431), 435 cardiovascular deaths (women, 163; men, 274), and 1,158 deaths from any cause (women, 449; men, 709). In analyses adjusted for sociodemographic, clinical, and metabolic parameters, women had a lower risk of atherosclerotic events (HR, 0.71 [95% CI, 0.57-0.88]), heart failure (HR, 0.76 [95% CI, 0.62-0.93]), cardiovascular death (HR, 0.55 [95% CI, 0.42-0.72]), and death from any cause (HR, 0.58 [95% CI, 0.49-0.69]) compared with men. These associations remained statistically significant after adjusting for cardiac and inflammation biomarkers.

LIMITATIONS

Assessment of sex hormones, which may play a role in cardiovascular risk, was not included.

CONCLUSIONS

In a large, diverse cohort of adults with CKD, compared with men, women had lower risks of cardiovascular events, cardiovascular mortality, and mortality from any cause. These differences were not explained by measured cardiovascular risk factors.

Subtyping CKD Patients by Consensus Clustering: The Chronic Renal Insufficiency Cohort (CRIC) Study

BACKGROUND

CKD is a heterogeneous condition with multiple underlying causes, risk factors, and outcomes. Subtyping CKD with multidimensional patient data holds the key to precision medicine. Consensus clustering may reveal CKD subgroups with different risk profiles of adverse outcomes.

METHODS

We used unsupervised consensus clustering on 72 baseline characteristics among 2696 participants in the prospective Chronic Renal Insufficiency Cohort (CRIC) study to identify novel CKD subgroups that best represent the data pattern. Calculation of the standardized difference of each parameter used the cutoff of ±0.3 to show subgroup features. CKD subgroup associations were examined with the clinical end points of kidney failure, the composite outcome of cardiovascular diseases, and death.

RESULTS

The algorithm revealed three unique CKD subgroups that best represented patients' baseline characteristics. Patients with relatively favorable levels of bone density and cardiac and kidney function markers, with lower prevalence of diabetes and obesity, and who used fewer medications formed cluster 1 (n=1203). Patients with higher prevalence of diabetes and obesity and who used more medications formed cluster 2 (n=1098). Patients with less favorable levels of bone mineral density, poor cardiac and kidney function markers, and inflammation delineated cluster 3 (n=395). These three subgroups, when linked with future clinical end points, were associated with different risks of CKD progression, cardiovascular disease, and death. Furthermore, patient heterogeneity among predefined subgroups with similar baseline kidney function emerged.

CONCLUSIONS

Consensus clustering synthesized the patterns of baseline clinical and laboratory measures and revealed distinct CKD subgroups, which were associated with markedly different risks of important clinical outcomes. Further examination of patient subgroups and associated biomarkers may provide next steps toward precision medicine.

Results from the TRIBE-AKI Study found associations between post-operative blood biomarkers and risk of chronic kidney disease after cardiac surgery

Patients undergoing cardiac surgery are placed under intense physiologic stress. Blood and urine biomarkers measured peri-operatively may help identify patients at higher risk for adverse long-term kidney outcomes.We sought to determine independent associations of various biomarkers with development or progression of chronic kidney disease (CKD) following cardiac surgery. In this sub-study of the prospective cohort -TRIBE-AKI Study, we evaluated 613 adult patients undergoing cardiac surgery in Canada in our primary analysis and tested the association of 40 blood and urinary biomarkers with the primary composite outcome of CKD incidence or progression. In those with baseline estimated glomerular filtration rate (eGFR) over 60 mL/min/1.73m2, we defined CKD incidence as a 25% reduction in eGFR and an eGFR under 60. In those with baseline eGFR under 60 mL/min/1.73m2, we defined CKD progression as a 50% reduction in eGFR or eGFR under 15. Results were evaluated in a replication cohort of 310 patients from one study site in the United States. Over a median follow-up of 5.6 years, 172 patients developed the primary outcome. Each log increase in basic fibroblast growth factor (adjusted hazard ratio 1.52 [95% confidence interval 1.19, 1.93]), Kidney Injury Molecule-1 (1.51 [0.98, 2.32]), N-terminal pro-B-type natriuretic peptide (1.19 [1.01, 1.41]), and tumor necrosis factor receptor 1 (1.75 [1.18, 2.59]) were associated with outcome after adjustment for demographic factors, serum creatinine, and albuminuria. Similar results were noted in the replication cohort. Although there was no interaction by acute kidney injury in continuous analysis, mortality was higher in the no acute kidney injury group by biomarker tertile. Thus, elevated post-operative levels of blood biomarkers following cardiac surgery were independently associated with the development of CKD. These biomarkers can provide additional value in evaluating CKD incidence and progression after cardiac surgery.

Association Between Kidney Clearance of Secretory Solutes and Cardiovascular Events: The Chronic Renal Insufficiency Cohort (CRIC) Study

RATIONALE & OBJECTIVE

The clearance of protein-bound solutes by the proximal tubules is an innate kidney mechanism for removing putative uremic toxins that could exert cardiovascular toxicity in humans. However, potential associations between impaired kidney clearances of secretory solutes and cardiovascular events among patients with chronic kidney disease (CKD) remains uncertain.

STUDY DESIGN

A multicenter, prospective, cohort study.

SETTING & PARTICIPANTS

We evaluated 3,407 participants from the Chronic Renal Insufficiency Cohort (CRIC) study.

EXPOSURES

Baseline kidney clearances of 8 secretory solutes. We measured concentrations of secretory solutes in plasma and paired 24-hour urine specimens using liquid chromatography-tandem mass spectrometry (LC-MS/MS).

OUTCOMES

Incident heart failure, myocardial infarction, and stroke events.

ANALYTICAL APPROACH

We used Cox regression to evaluate associations of baseline secretory solute clearances with incident study outcomes adjusting for estimated GFR (eGFR) and other confounders.

RESULTS

Participants had a mean age of 56 years; 45% were women; 41% were Black; and the median estimated glomerular filtration rate (eGFR) was 43 mL/min/1.73 m². Lower 24-hour kidney clearance of secretory solutes were associated with incident heart failure and myocardial infarction but not incident stroke over long-term follow-up after controlling for demographics and traditional risk factors. However, these associations were attenuated and not statistically significant after adjustment for eGFR.

LIMITATIONS

Exclusion of patients with severely reduced eGFR at baseline; measurement variability in secretory solutes clearances.

CONCLUSIONS

In a national cohort study of CKD, no clinically or statistically relevant associations were observed between the kidney clearances of endogenous secretory solutes and incident heart failure, myocardial infarction, or stroke after adjustment for eGFR. These findings suggest that tubular secretory clearance provides little additional information about the development of cardiovascular disease events beyond glomerular measures of GFR and albuminuria among patients with mild-to-moderate CKD.

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.

Is the true clinical value of high-sensitivity troponins as a biomarker of risk? The concept that detection of high-sensitivity troponin 'never means nothing'

INTRODUCTION

High-sensitivity troponin (hs-cTn) assays are central to the diagnosis of myocardial infarction (MI). Their increased sensitivity has facilitated rapid pathways for the exclusion of MI. However, hs-cTn is now more readily detectable in patients without symptoms typical of MI, in whom a degree of myocardial injury is assumed. Recently, the practice of using the 99^th centile of hs-cTn as a working 'upper reference limit' has been challenged. There is increasing evidence that hs-cTn may provide useful prognostic information, regardless of any suspicion of MI, and as such these assays may have potential as a general biomarker for mortality. This raises the concept that detection of hs-cTn 'never means nothing.'

AREAS COVERED

In this review, we will evaluate the evidence for the use of hs-cTn assays outside their common clinical indication to rule out or diagnose acute MI.

EXPERT OPINION

The data presented suggest that hs-cTn testing may in the future have a generalized role as a biomarker of mortality risk and may be used less as a test for ruling in acute MI, but will remain a frontline test to exclude that diagnosis in ED. Further, the data suggest that the detection of hs-cTn 'never means nothing.'

Cardiac Biomarkers and Risk of Mortality in CKD (the CRIC Study)

Introduction

Cardiovascular disease (CVD) is the leading cause of mortality among individuals with chronic kidney disease (CKD). Cardiac biomarkers of myocardial distention, injury, and inflammation may signal unique pathways underlying CVD in CKD. In this analysis, we studied the association of baseline levels and changes in 4 traditional and novel cardiac biomarkers with risk of all-cause, CV, and non-CV mortality in a large cohort of patients with CKD.

Methods

Among 3664 adults with CKD enrolled in the Chronic Renal Insufficiency Cohort Study, we conducted a cohort study to examine the associations of baseline levels of N-terminal pro-B-type natriuretic peptide (NT-proBNP), cardiac high-sensitivity troponin T (hsTnT), growth differentiation factor−15 (GDF-15), and soluble ST-2 (sST-2) with risks of all-cause and cardiovascular (CV) mortality. Among a subcohort of 842 participants, we further examined the associations between change in biomarker levels over 2 years with risk of all-cause mortality. We used Cox proportional hazards regression models and adjusted for demographics, kidney function measures, cardiovascular risk factors, and medication use.

Results

After adjustment, elevated baseline levels of each cardiac biomarker were associated with increased risk of all-cause mortality: NT-proBNP (hazard ratio [HR] = 1.92, 95% confidence interval [CI] = 1.73−2.12); hsTnT (HR = 1.62, 95% CI = 1.48, 1.78]); GDF-15 (HR = 1.61, 95% CI = 1.46−1.78]); and sST-2 (HR = 1.26, CI = 1.16−1.37). Higher baseline levels of all 4 cardiac biomarkers were also associated with increased risk of CV. Declines in NT-proBNP (adjusted HR = 0.55, 95% CI = 0.36−0.86) and sST2 (HR = 0.55, 95% CI = 0.36−0.86]) over 2 years were associated with lower risk of all-cause mortality.

Conclusion

In a large cohort of CKD participants, elevations of NT-proBNP, hsTnT, GDF-15, and sST-2 were independently associated with greater risks of all-cause and CV mortality.

Novel Risk Factors for Progression of Diabetic and Nondiabetic CKD: Findings From the Chronic Renal Insufficiency Cohort (CRIC) Study

RATIONALE & OBJECTIVE

Identification of novel risk factors for chronic kidney disease (CKD) progression may inform mechanistic investigations and improve identification of high-risk subgroups. The current study aimed to characterize CKD progression across levels of numerous risk factors and identify independent risk factors for CKD progression among those with and without diabetes.

STUDY DESIGN

The Chronic Renal Insufficiency Cohort (CRIC) Study is a prospective cohort study of adults with CKD conducted at 7 US clinical centers.

SETTING & PARTICIPANTS

Participants (N=3,379) had up to 12.3 years of follow-up; 47% had diabetes.

PREDICTORS

30 risk factors for CKD progression across sociodemographic, behavioral, clinical, and biochemical domains at baseline.

OUTCOMES

Study outcomes were estimated glomerular filtration rate (eGFR) slope and the composite of halving of eGFR or initiation of kidney replacement therapy.

ANALYTICAL APPROACH

Stepwise selection of independent risk factors was performed stratified by diabetes status using linear mixed-effects and Cox proportional hazards models.

RESULTS

Among those without and with diabetes, respectively, mean eGFR slope was-1.4±3.3 and-2.7±4.7mL/min/1.73m² per year. Among participants with diabetes, multivariable-adjusted hazard of the composite outcome was approximately 2-fold or greater with higher levels of the inflammatory chemokine CXCL12, the cardiac marker N-terminal pro-B-type natriuretic peptide (NT-proBNP), and the kidney injury marker urinary neutrophil gelatinase-associated lipocalin (NGAL). Among those without diabetes, low serum bicarbonate and higher high-sensitivity troponin T, NT-proBNP, and urinary NGAL levels were all significantly associated with a 1.5-fold or greater rate of the composite outcome.

LIMITATIONS

The observational study design precludes causal inference.

CONCLUSIONS

Strong associations for cardiac markers, plasma CXCL12, and urinary NGAL are comparable to that of systolic blood pressure≥140mm Hg, a well-established risk factor for CKD progression. This warrants further investigation into the potential mechanisms that these markers indicate and opportunities to use them to improve risk stratification.

Cardiovascular outcome trials in patients with chronic kidney disease: challenges associated with selection of patients and endpoints

Although cardiovascular disease is a major health burden for patients with chronic kidney disease, most cardiovascular outcome trials have excluded patients with advanced chronic kidney disease. Moreover, the major cardiovascular outcome trials that have been conducted in patients with end-stage renal disease have not demonstrated a treatment benefit. Thus, clinicians have limited evidence to guide the management of cardiovascular disease in patients with chronic kidney disease, particularly those on dialysis. Several factors contribute to both the paucity of trials and the apparent lack of observed treatment effect in completed studies. Challenges associated with conducting trials in this population include patient heterogeneity, complexity of renal pathophysiology and its interaction with cardiovascular disease, and competing risks for death. The Investigator Network Initiative Cardiovascular and Renal Clinical Trialists (INI-CRCT), an international organization of academic cardiovascular and renal clinical trialists, held a meeting of regulators and experts in nephrology, cardiology, and clinical trial methodology. The group identified several research priorities, summarized in this paper, that should be pursued to advance the field towards achieving improved cardiovascular outcomes for these patients. Cardiovascular and renal clinical trialists must partner to address the uncertainties in the field through collaborative research and design clinical trials that reflect the specific needs of the chronic and end-stage kidney disease populations, with the shared goal of generating robust evidence to guide the management of cardiovascular disease in patients with kidney disease.

The Cardiorenal Syndrome: Mechanistic Insights and Prognostication with Soluble Biomarkers

PURPOSE OF REVIEW

To characterize and interpret recent studies of biomarkers of cardiorenal syndrome.

RECENT FINDINGS

Recent studies have questioned the mechanisms and significance of moderate worsening renal function (WRF) in patients with acute heart failure. In the setting of successful decongestion, WRF may not predict cardiorenal morbidity. Cardiac-specific biomarkers including cardiac troponins and natriuretic peptides are highly prognostic in acute and chronic HF patients with kidney impairment, and serial changes in these markers during hospitalization are also predictive of longer-term adverse outcomes. These markers also predict new HF in patients with established chronic kidney disease (CKD). The role of kidney tubular injury markers in acute HF remains controversial, with inconsistent associations with short- and long-term cardiorenal outcomes. Many cases of WRF in acute HF are not characterized by a clear pattern of renal tubular injury. Cardiac-specific and renal-specific biomarkers may provide mechanistic and prognostic information in cardiorenal syndromes.

Association of Cardiac Biomarkers With the Kansas City Cardiomyopathy Questionnaire in Patients With Chronic Kidney Disease Without Heart Failure

Background The Kansas City Cardiomyopathy Questionnaire (KCCQ) is a measure of heart failure (HF) health status. Worse KCCQ scores are common in patients with chronic kidney disease (CKD), even without diagnosed heart failure (HF). Elevations in the cardiac biomarkers GDF-15 (growth differentiation factor-15), galectin-3, sST2 (soluble suppression of tumorigenesis-2), hsTnT (high-sensitivity troponin T), and NT-proBNP (N-terminal pro-B-type natriuretic peptide) likely reflect subclinical HF in CKD. Whether cardiac biomarkers are associated with low KCCQ scores is not known. Methods and Results We studied participants with CKD without HF in the multicenter prospective CRIC (Chronic Renal Insufficiency Cohort) Study. Outcomes included (1) low KCCQ score <75 at year 1 and (2) incident decline in KCCQ score to <75. We used multivariable logistic regression and Cox regression models to evaluate the associations between baseline cardiac biomarkers and cross-sectional and longitudinal KCCQ scores. Among 2873 participants, GDF-15 (adjusted odds ratio 1.42 per SD; 99% CI, 1.19-1.68) and galectin-3 (1.28; 1.12-1.48) were significantly associated with KCCQ scores <75, whereas sST2, hsTnT, and NT-proBNP were not significantly associated with KCCQ scores <75 after multivariable adjustment. Of the 2132 participants with KCCQ ≥75 at year 1, GDF-15 (adjusted hazard ratio, 1.36 per SD; 99% CI, 1.12-1.65), hsTnT (1.20; 1.01-1.44), and NT-proBNP (1.30; 1.08-1.56) were associated with incident decline in KCCQ to <75 after multivariable adjustment, whereas galectin-3 and sST2 did not have significant associations with KCCQ decline. Conclusions Among participants with CKD without clinical HF, GDF-15, galectin-3, NT-proBNP, and hsTnT were associated with low KCCQ either at baseline or during follow-up. Our findings show that elevations in cardiac biomarkers reflect early symptomatic changes in HF health status in CKD patients.

Associations Between Cardiac Biomarkers and Cardiac Structure and Function in CKD

Introduction

Subclinical changes to cardiac structure and function detected with echocardiography precede the development of clinical heart failure (HF) in persons with chronic kidney disease (CKD). Circulating cardiac biomarkers may reflect these pathophysiological changes. This study investigated associations between established biomarkers (N-terminal pro-B-type natriuretic peptide [NT-proBNP] and high-sensitivity troponin T [hsTnT]) and novel biomarkers (growth differentiation factor 15 [GDF-15], galectin-3 [Gal-3], and soluble ST-2 [sST-2]), using echocardiographic measurements in persons with CKD.

Methods

In cross-sectional analyses among 2101 participants with mild to moderate CKD in the Chronic Renal Insufficiency Cohort (CRIC), biomarker levels measured at baseline were evaluated with echocardiographic measurements 1 year later. These included left ventricular mass index (LVMI), left ventricular end-systolic volume (LVESV), left ventricular end-diastolic volume (LVEDV), left ventricular ejection fraction (LVEF), and left atrial diameter (LAD). Multivariable linear regression analyses tested associations of each biomarker with echocardiographic measurements, adjusting for covariates.

Results

GDF-15 was significantly associated with higher LVMI (1.0 g/m^2.7; 95% CI, 0.4–1.7), LVESV (0.4 ml/m^2.7; 95% CI, 0.0–0.7), and LVEDV (0.6 ml/m^2.7; 95% CI, 0.1–1.1), but not with LVEF or LAD. These findings were not significant when adjusting for NT-proBNP and hsTnT. Gal-3 and sST-2 had no significant associations. Higher levels of NT-proBNP and hsTnT were associated with all echocardiographic measurements.

Conclusion

In patients with CKD, the novel biomarker GDF-15, a marker of inflammation and tissue injury, and clinical biomarkers NT-proBNP and hsTnT, were associated with echocardiographic measurements of subclinical cardiovascular disease. Collectively, these biomarkers may highlight biological pathways that contribute to the development of clinical HF.

High-sensitivity Troponin I Predicts Galectin-3 in Chronic Kidney Disease Patients

PURPOSE

Plasma galectin-3 (pG3) regulates inflammation. B-type natriuretic peptide (BNP), high-sensitivity Troponin I (hsTnI), and pG3 concentrations are elevated in chronic kidney disease (CKD) patients. The associations of pG3 with hsTnI/BNP are unclear. We explored the relationship of hsTnI and BNP with pG3 in Asian CKD patients and healthy controls.

METHODS

We retrieved prospectively collected frozen plasma samples from 163 stable CKD patients and 105 healthy controls. BNP, hsTnI and pG3 were assayed. pG3 was assessed for associations with age, gender, ethnicity, blood pressures; height, weight, body mass index (BMI), previously diagnosed CKD, diabetes, hypertension, coronary artery disease, estimated glomerular filtration rate (eGFR); C-reactive protein, beta-trace protein, 24 h urine protein, serum albumin, uric acid and cystatin C. We created two models predicting pG3 using multiple linear regression. Akaike Information Criterion (AIC) was used for comparison. Significance was taken at P < 0.05.

RESULTS

CKD versus healthy participants: mean BMI (28.2 vs. 24.9 kg/m²), median serum creatinine (159 vs. 69 µmol/L; 1.8 vs. 0.78 mg/dL), median eGFR (49 vs. 104 mL/min/1.73m²), median pG3 (29.4 vs. 15.4 ng/mL), median BNP (136 vs. 23 pg/mL), and median hsTnI (12.5 vs. 2.6 pg/mL). By univariate analysis, all variables are associated with pG3 except weight, gender and diagnosis of cerebrovascular or peripheral vascular diseases. A parsimonious model selected for hsTnI, BMI, serum albumin, cystatin C and eGFR (AIC = 77.6).

CONCLUSION

BNP and hsTnI are associated with pG3 in Asian CKD patients. hsTnI is a better predictor of pG3.

Association of Machine Learning-Derived Phenogroupings of Echocardiographic Variables with Heart Failure in Stable Coronary Artery Disease: The Heart and Soul Study

BACKGROUND

Many individual echocardiographic variables have been associated with heart failure (HF) in patients with stable coronary artery disease (CAD), but their combined utility for prediction has not been well studied.

METHODS

Unsupervised model-based cluster analysis was performed by researchers blinded to the study outcome in 1,000 patients with stable CAD on 15 transthoracic echocardiographic variables. We evaluated associations of cluster membership with HF hospitalization using Cox proportional hazards regression analysis.

RESULTS

The echo-derived clusters partitioned subjects into four phenogroupings: phenogroup 1 (n = 85) had the highest levels, phenogroups 2 (n = 314) and 3 (n = 205) displayed intermediate levels, and phenogroup 4 (n = 396) had the lowest levels of cardiopulmonary structural and functional abnormalities. Over 7.1 ± 3.2 years of follow-up, there were 198 HF hospitalizations. After multivariable adjustment for traditional cardiovascular risk factors, phenogroup 1 was associated with a nearly fivefold increased risk (hazard ratio [HR] = 4.8; 95% CI, 2.4-9.5), phenogroup 2 was associated with a nearly threefold increased risk (HR = 2.7; 95% CI, 1.4-5.0), and phenogroup 3 was associated with a nearly twofold increased risk (HR = 1.9; 95% CI, 1.0-3.8) of HF hospitalization, relative to phenogroup 4.

CONCLUSIONS

Transthoracic echocardiographic variables can be used to classify stable CAD patients into separate phenogroupings that differentiate cardiopulmonary structural and functional abnormalities and can predict HF hospitalization, independent of traditional cardiovascular risk factors.

Meta-analysis of preoperative high-sensitivity cardiac troponin measurement in non-cardiac surgical patients at risk of cardiovascular complications

Background

Patients undergoing major non-cardiac surgery are at risk of cardiovascular complications. Raised levels of high-sensitivity troponin are frequently detected before operation among these patients. However, the prognostic value of high-sensitivity troponin in predicting postoperative outcomes remains unclear.

Methods

A systematic search of PubMed, Embase and Science Citation Index Expanded was undertaken for observational studies published before March 2018 that reported associations between raised preoperative levels of high-sensitivity troponin and postoperative major adverse cardiac events and/or mortality after non-cardiac surgery. Meta-analyses were performed, where possible, using random-effects models.

Results

Seven cohort studies with a total of 4836 patients were included. A raised preoperative high-sensitivity troponin level was associated with a higher risk of short-term major adverse cardiac events (risk ratio (RR) 2·92, 95 per cent c.i. 1·96 to 4·37; I2 = 82·6 per cent), short-term mortality (RR 5·39, 3·21 to 9·06; I2 = 0 per cent) and long-term mortality (RR 2·90, 1·83 to 4·59, I2 = 74·2 per cent). The addition of preoperative high-sensitivity troponin measurement provided improvements in cardiovascular risk discrimination (increase in C-index ranged from 0·058 to 0·109) and classification (quantified by continuous net reclassification improvement) compared with Lee's Revised Cardiac Risk Index alone. There was substantial heterogeneity and inadequate risk stratification analysis in the included studies.

Conclusion

Raised preoperative levels of high-sensitivity troponin appear to represent a risk for postoperative major adverse cardiac events and mortality. Further study is required before high-sensitivity troponin can be used to predict risk stratification in routine clinical practice.

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.

Association Between Renal Function and Troponin T Over Time in Stable Chronic Kidney Disease Patients

Background People with reduced glomerular filtration rate (GFR) often have elevated cardiac troponin T (cTnT) levels. It remains unclear how cTnT levels develop over time in those with chronic kidney disease (CKD). The aim of this study was to prospectively study the association between cTnT and GFR over time in older advanced-stage CKD patients not on dialysis. Methods and Results The EQUAL (European Quality Study) study is an observational prospective cohort study in stage 4 to 5 CKD patients aged ≥65 years not on dialysis (incident estimated GFR, <20 mL/min/1.73 m²). The EQUAL cohort used for the purpose of this study includes 171 patients followed in Sweden between April 2012 and December 2018. We used linear mixed models, adjusted for important groups of confounders, to investigate the effect of both measured GFR and estimated GFR on high-sensitivity cTnT (hs-cTnT) trajectory over 4 years. Almost all patients had at least 1 hs-cTnT measurement elevated above the 99th percentile of the general reference population (≤14 ng/L). On average, hs-cTnT increased by 16%/year (95% CI, 13-19; P<0.0001). Each 15 mL/min/1.73 m2 lower mean estimated GFR was associated with a 23% (95% CI, 14-31; P<0.0001) higher baseline hs-cTnT and 9% (95% CI, 5-13%; P<0.0001) steeper increase in hs-cTnT. The effect of estimated GFR on hs-cTnT trajectory was somewhat lower than a previous myocardial infarction (15%), but higher than presence of diabetes mellitus (4%) and male sex (5%). Conclusions In CKD patients, hs-cTnT increases over time as renal function decreases. Lower CKD stage (each 15 mL/min/1.73 m2 lower) is independently associated with a steeper hs-cTnT increase over time in the same range as other established cardiovascular risk factors.

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.

Cardiac Biomarkers and Risk of Incident Heart Failure in Chronic Kidney Disease: The CRIC (Chronic Renal Insufficiency Cohort) Study

Background

Cardiac biomarkers may signal mechanistic pathways involved in heart failure (HF), a leading complication in chronic kidney disease. We tested the associations of NT‐proBNP (N‐terminal pro‐B‐type natriuretic peptide), high‐sensitivity troponin T (hsTnT), galectin‐3, growth differentiation factor‐15 (GDF‐15), and soluble ST2 (sST2) with incident HF in chronic kidney disease.

Methods and Results

We examined adults with chronic kidney disease enrolled in a prospective, multicenter study. All biomarkers were measured at baseline. The primary outcome was incident HF. Secondary outcomes included HF with preserved ejection fraction (EF≥50%) and reduced ejection fraction (EF<50%). Cox models were used to test the association of each cardiac biomarker with HF, adjusting for demographics, kidney function, cardiovascular risk factors, and medication use. Among 3314 participants, all biomarkers, with the exception of galectin‐3, were significantly associated with increased risk of incident HF (hazard ratio per SD higher concentration of log‐transformed biomarker): NT‐proBNP (hazard ratio, 2.07; 95% CI, 1.79–2.39); hsTnT (hazard ratio, 1.38; 95% CI, 1.21–1.56); GDF‐15 (hazard ratio, 1.44; 95% CI, 1.26–1.66) and sST2 (hazard ratio, 1.19; 95% CI, 1.05–1.35). Higher NT‐proBNP, hsTnT, and GDF‐15 were also associated with a greater risk of HF with reduced EF; while higher NT‐proBNP GDF‐15 and sST2 were associated with HF with preserved EF. Galectin‐3 was not associated with either HF with reduced EF or HF with preserved EF.

Conclusions

In chronic kidney disease, elevations of NT‐proBNP, hsTnT, GDF‐15, sST2 were associated with incident HF. There was a borderline association of galectin‐3 with incident HF. NT‐proBNP and hsTnT were more strongly associated with HF with reduced EF, while the associations of the newer biomarkers GDF‐15 and sST2 were stronger for HF with preserved EF.

Association Between High-Sensitivity Cardiac Troponin T and Echocardiographic Parameters in Chronic Kidney Disease: Results From the KNOW-CKD Cohort Study

Background

It is unclear whether high‐sensitivity troponin T (hs‐TnT) is associated with subclinical cardiac changes in chronic kidney disease (CKD). We evaluated the relationship between hs‐TnT and left ventricular structure and function in a CKD population, according to estimated glomerular filtration rate.

Methods and Results

We analyzed 2017 patients with CKD stages 1 to 5 (predialysis) in the KNOW‐CKD (Korean Cohort Study for Outcome in Patients With Chronic Kidney Disease) cohort. The predictor was hs‐TnT level measured at baseline, and the outcomes were left ventricular hypertrophy (LVH) and systolic and diastolic dysfunction shown by echocardiography at baseline and after 4 years. Participants were categorized into quartiles according to hs‐TnT levels. The associations between quartiles of hs‐TnT and outcomes were assessed using multivariable logistic regression analysis with confounders including demographics, medical history, and laboratory findings. A receiver operating characteristic curve was used to assess the diagnostic power of hs‐TnT for the outcomes as a continuous variable. For subgroup analysis, patients were stratified based on an estimated glomerular filtration rate of 60 mL/min per 1.73 m². Elevated hs‐TnT was associated with LVH and diastolic dysfunction at baseline in an adjusted model but was not associated with systolic dysfunction. These associations remained significant for both estimated glomerular filtration rate subgroups. Receiver operating characteristic curve analysis showed that hs‐TnT as a continuous variable exhibited fair significance for detection of LVH (area under the curve: 0.689) and diastolic dysfunction (area under the curve: 0.744). Multivariable analysis showed that higher hs‐TnT levels at baseline were related to development of LVH but not diastolic dysfunction (n=864).

Conclusions

In CKD patients, hs‐TnT is strongly associated with alterations of left ventricular structure and diastolic dysfunction for both estimated glomerular filtration rate strata. Baseline hs‐TnT levels are predictive of new LVH on follow‐up.

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.