Association of Volume Overload With Kidney Function Outcomes Among Patients With Heart Failure With Reduced Ejection Fraction

Diagnostic value and utility of commonly used biomarkers of cardiac and renal function in cardiorenal syndromes: a narrative review

Cardiorenal syndrome (CRS), first defined in 2004 as a consequence of the interactions between the kidneys and other circulatory departments leading to acute heart failure, has since been recognized as a complex clinical entity that is hard to define, diagnose and classify. The framework for the classification of CRS according to pathophysiologic background was laid out in 2008, dividing CRS into five distinct phenotypes. However, determining the timing of individual organ injuries and making a diagnosis of either renal or cardiac failure remains an elusive task. In clinical practice, the diagnosis and phenotyping of CRS is mostly based on using laboratory biomarkers in order to directly or indirectly estimate the degree of end-organ functional decline. Therefore, a well-educated clinician should be aware of the effects that the reduction of renal and cardiac function has on the diagnostic and predictive value and properties of the most commonly used biomarkers (e.g. troponins, N-terminal pro-brain natriuretic peptide, serum creatinine etc). They should also be acquainted, on a basic level, with emerging biomarkers that are specific to either the degree of glomerular integrity (cystatin C) or tubular injury (neutrophil gelatinase-associated lipocalin). This narrative review aims to provide a scoping overview of the different roles that biomarkers play in both the diagnosis of CRS and the prognosis of the disease in patients who have been diagnosed with it, along with highlighting the most important pitfalls in their interpretation in the context of impaired renal and/or cardiac function.

Updates in Cardiorenal Syndrome

Cardiorenal syndrome is a term that refers to a collection of disorders involving both the heart and kidneys, encompassing multi-directional pathways between the 2 organs mediated through low arterial perfusion, venous congestion, and neurohormonal activation. The pathophysiology is complex and includes hemodynamic and neurohormonal changes, but inconsistent findings from recent studies suggest this is very heterogenous disorder. Management for ADHF remains focused on decongestion and neurohormonal blockade to overcome the intense sodium and fluid avidity of the CRS.

Association of serum N-terminal pro-brain natriuretic peptide levels with survival and renal outcomes among elderly patients with acute kidney injury in chronic heart failure

Background

Elderly patients exhibit a higher incidence of chronic heart failure (CHF). Patients with CHF can develop acute kidney injury (AKI) during follow-up, which can result in poor prognosis. This relationship between kidney dysfunction and levels of N-terminal pro-brain natriuretic peptides (NT-proBNP), with regard to prognosis, is complicated and has rarely been analyzed in elderly patients with CHF.

Method

We conducted a retrospective cohort study involving patients with a CHF history aged ≥ 65 years, who experienced an episode of AKI. Kaplan-Meier curves and Cox or logistic proportional hazards regression models were used to evaluate the association between serum NT-proBNP concentrations and mortality or renal recovery by day 90.

Results

A total of 1,160 eligible patients with AKI were available for the study. Of this sample, 41.5% of patients died within 90 days of the onset of AKI. Patients with a decreased change in NT-proBNP accompanying the episode of AKI had a lower risk (adjusted OR = 0.56, 95% CI = 0.34-0.91) of more severe AKI (stage 2 and 3 vs. stage 1). The more severe AKI were associated with higher mortality and non-recovery of renal function in elderly patients with CHF, independent of NT-proBNP levels. Elevated levels of baseline lnNT-proBNP (adjusted HR = 1.27, 95% CI = 1.17-1.38) predicted mortality in elderly patients with CHF within 90 days of AKI onset. Patients with a decrease in NT-proBNP accompanying AKI had a lower risk of mortality (adjusted HR = 0.62, 95% CI = 0.48-0.79). However, a decrease in NT-proBNP is a risk factor (adjusted OR = 1.59, 95% CI = 1.02-2.48) for the non-recovery of renal function following AKI-especially in elderly survivors with low baseline NT-proBNP levels.

Conclusion

A decreased change in NT-proBNP maybe protective for elderly patients with CHF by improving survival outcomes and preventing severe AKI. However, an excessive decrease in NT-proBNP is a risk factor for the non-recovery of renal function following AKI. Avoiding excessive changes in NT-proBNP may be protective for survival and renal injury prognosis.

Rates of In-Hospital Decongestion and Association with Mortality and Cardiovascular Outcomes Among Patients Admitted for Acute Heart Failure

BACKGROUND

Decongestion is an important goal in the management of acute heart failure. Whether the rate of decongestion is associated with mortality and cardiovascular outcomes is unknown.

METHODS

Using data from 4133 patients from the Efficacy of Vasopressin Antagonism in Heart Failure Outcome Study With Tolvaptan (EVEREST) trial, we used multivariable Cox regression models to evaluate the association between rates of in-hospital change in assessments of volume overload, including b-type natriuretic peptide (BNP), N-terminal pro b-type natriuretic peptide (NT-proBNP), as well as change in hemoconcentration, with risk of all-cause mortality and a composite outcome of cardiovascular mortality or heart failure hospitalization.

RESULTS

More rapid rates of in-hospital decongestion were associated with decreased risk of mortality and the composite outcome over a median 10-month follow-up. In reference to the quartile of slowest decline, the quartile with the fastest BNP and NT-proBNP decline had lower hazards of mortality (hazard rate [HR] = 0.43 [0.31, 0.59] and HR = 0.27 [0.19, 0.40], respectively) and composite outcome (HR = 0.49 [0.39, 0.60] and HR = 0.54 [0.42, 0.71], respectively). In reference to the quartile of slowest increase, the quartile with the fastest hematocrit increase had lower hazards of mortality (HR = 0.77 [0.62, 0.95]) and composite outcome (HR = 0.75 [0.64, 0.88]). Results were also consistent when models were repeated using propensity-score matching.

CONCLUSIONS

Faster rates of decongestion are associated with reduced risk of mortality and a composite of cardiovascular mortality and heart failure hospitalization. It remains unknown whether more rapid decongestion provides cardiovascular benefit or whether it serves as a proxy for less treatment resistant heart failure.

Rates of Reversal of Volume Overload in Hospitalized Acute Heart Failure: Association With Long-term Kidney Function

RATIONALE & OBJECTIVE

Achievement of decongestion in acute heart failure (AHF) is associated with improved survival and cardiovascular outcomes but can be associated with acute declines in estimated glomerular filtration rate (eGFR). We examined whether the rate of in-hospital decongestion is associated with longer term kidney function decline.

STUDY DESIGN

Post hoc analysis of trial data.

SETTINGS & PARTICIPANTS

Patients with ≥2 measures of kidney function (n = 3,500) from the Efficacy of Vasopressin Antagonism in Heart Failure Outcome Study With Tolvaptan (EVEREST) trial.

EXPOSURE

In-hospital rate of change in assessments of volume overload, including B-type natriuretic peptide (BNP), N-terminal pro-B-type natriuretic peptide (NT-proBNP), and clinical congestion score (0-12); and rate of change in hemoconcentration including measures of hematocrit, albumin, and total protein.

OUTCOME

Incident chronic kidney disease GFR category 4 or worse (chronic kidney disease [CKD] categories G4-G5; defined by a new eGFR of <30 mL/min/1.73 m²) and eGFR decline of >40%.

ANALYTICAL APPROACH

Multivariable cause-specific hazards models.

RESULTS

Over median 10-month follow-up period, faster decreases in volume overload and more rapid increases in hemoconcentration were associated with a decreased risk of incident CKD G4-G5 and eGFR decline of >40%. In adjusted analyses, for every 6% faster decline in BNP per week, there was a 32% lower risk of both incident CKD G4-G5 (HR, 0.68 [95% CI, 0.58-0.79]) and eGFR decline of >40% (HR, 0.68 [95% CI, 0.57-0.80]). For every 1% faster increase per week in absolute hematocrit, there was a lower risk for both incident CKD G4-G5 (HR, 0.73 [95% CI, 0.64-0.84]) and eGFR decline of >40% (HR, 0.82 [95% CI, 0.71-0.95]), with results consistent for other biomarkers.

LIMITATIONS

Possibility of residual confounding.

CONCLUSIONS

These results provide reassurance that more rapid decongestion in patients with AHF does not increase the risk of adverse kidney outcomes in patients with heart failure.

The impact of diabetes on heart failure development: The cardio-renal-metabolic connection

Heart failure (HF) and chronic kidney disease (CKD) are often associated in type 2 diabetes (T2D), aggravate each other and exert synergistic effects to increase the risk of cardiac and renal events. The risks of renal worsening in HF patients and HF in CKD patients need to be evaluated to tailor preventive therapy. The recent CV and renal trials enriched our knowledge about the natural history of HF and CKD in T2D and provided evidence for the benefit of sodium-glucose cotransporter 2 inhibitors (SGLT2is) in HF and renal decline prevention. SGLT-2is are the best choice in patients with HFrEF to improve CV prognosis and HF-related outcomes and also to prevent kidney-related outcomes, and in CKD patients to slow down renal failure and also reduce hospitalization for HF and CV death. In both situations the number of patients to treat in order to prevent such events in one patient is lower than in the general T2D population at high CV risk. GLP1-receptor agonists could be an alternative in a patient who is intolerant or has a contraindication to SGLT-2is. A tight collaboration between diabetologists, nephrologists and cardiologists should be encouraged for a holistic and effective strategy to reduce the burden of cardio-renal-metabolic interaction.