High prevalence of microalbuminuria in chronic heart failure patients

Renal Assessment in Acute Cardiorenal Syndrome

Cardiorenal syndrome (CRS) is a complex, heterogeneous spectrum of symptoms that has kept cardiologists awake for decades. The heart failure (HF) population being burdened with multimorbidity poses diagnostic and therapeutic challenges even for experienced clinicians. Adding deteriorated renal function to the equation, which is one of the strongest predictors of adverse outcome, we measure ourselves against possibly the biggest problem in modern cardiology. With the rapid development of new renal assessment methods, we can treat CRS more effectively than ever. The presented review focuses on explaining the pathophysiology, recent advances and current practices of monitoring renal function in patients with acute CRS. Understanding the dynamic interaction between the heart and the kidney may improve patient care and support the selection of an effective and nephroprotective treatment strategy.

Right Heart Function in Cardiorenal Syndrome

Purpose of Review

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

Recent Findings

Cardiorenal syndrome (CRS) in patients with heart failure is associated with poor outcome. Although systemic venous congestion and elevated central venous pressure have been recognized as main contributors to CRS, they are often neglected in clinical practice. The delicate hemodynamic balance in CRS is particularly determined by the respective status of the right heart.

Summary

The consideration of hemodynamic and CRS profiles is advantageous in tailoring treatment for better preservation of renal function. Assessment and monitoring of right heart and renal function by known and emerging tools like renal Doppler ultrasonography or new biomarkers may have direct clinical implications.

Heart failure in type 2 diabetes: current perspectives on screening, diagnosis and management

Type 2 diabetes is one of the most relevant risk factors for heart failure, the prevalence of which is increasing worldwide. The aim of the review is to highlight the current perspectives of the pathophysiology of heart failure as it pertains to type 2 diabetes. This review summarizes the proposed mechanistic bases, explaining the myocardial damage induced by diabetes-related stressors and other risk factors, i.e., cardiomyopathy in type 2 diabetes. We highlight the complex pathology of individuals with type 2 diabetes, including the relationship with chronic kidney disease, metabolic alterations, and heart failure. We also discuss the current criteria used for heart failure diagnosis and the gold standard screening tools for individuals with type 2 diabetes. Currently approved pharmacological therapies with primary use in type 2 diabetes and heart failure, and the treatment-guiding role of NT-proBNP are also presented. Finally, the influence of the presence of type 2 diabetes as well as heart failure on COVID-19 severity is briefly discussed.

Biomarkers in Cardiorenal Syndrome

Cardiorenal syndrome is a clinical manifestation of the bidirectional interaction between the heart and kidney diseases. Over the last years, in patients with cardiovascular diseases, several biomarkers have been studied in order to better assess renal function as well as to identify patients prone to experiencing chronic or acute worsening of renal function. The aim of this review is to focus on the possible clinical usefulness of the most recent biomarkers in the setting of cardiorenal syndrome.

Elevated urinary albumin concentration predicts worse clinical outcomes in hospitalized acute decompensated heart failure patients

Objective

To investigate the prognostic value of elevated urinary albumin concentration (UAC) in hospitalized acute decompensated heart failure (ADHF) patients.

Methods

We measured UAC at baseline in 1818 hospitalized ADHF patients who were admitted to our Heart Failure Center. All patients were followed up for a median period of 937.5 days. The primary endpoint was a composite of all‐cause death or heart transplantation (HTx) or left ventricular assist device (LVAD) implantation.

Results

In total, 41.5% of ADHF patients had albuminuria (UAC ≥ 20 mg/L). The median value of UAC was 15.5 mg/L. A total of 679 patients died or underwent HTx/LVAD during follow‐up. The median UAC was significantly lower in non‐HTx/LVAD survivors (14.3 mg/L) than in those who died or underwent HTx/LVAD (18.0 mg/L, P < 0.001). Compared with patients without albuminuria (reference, n = 1064), those with albuminuria had a 1.47‐fold higher risk of all‐cause death or HTx/LVAD (95% confidence interval [CI]:1.26–1.71, P < 0.001), with hazard ratios (HRs) of 1.42 (95% CI: 1.21–1.66) and 1.74 (95% CI: 1.33–2.26) in patients with microalbuminuria (20 mg/L ≤ UAC < 200 mg/L, n = 617) and macroalbuminuria (UAC ≥ 200 mg/L, n = 137), respectively (both P < 0.001). After adjustment for significant clinical risk factors, the albuminuria group had a higher risk of primary adverse events than the non‐albuminuria group (HR = 1.28, 95% CI: 1.09–1.50, P = 0.003), with HRs of 1.27 [95% CI: 1.07–1.49] and 1.36 [95% CI: 1.01–1.84] in patients with microalbuminuria and macroalbuminuria, respectively (P = 0.006 and P = 0.041). The adjusted risk of primary adverse events also increased with the degree of albuminuria in the test for trend (HR = 1.21, 95% CI: 1.06–1.37, P for trend = 0.004). In the subgroup analysis, albuminuria had a significantly greater prognostic value for patients with left ventricular ejection fraction ≥ 40%, eGFR ≥ 60 mL/min/1.73 m², BUN/creatinine ratio ≥ 20 or NT‐proBNP < 2098 pg/mL.

Conclusion

The presence of albuminuria evaluated by UAC predicts adverse clinical outcomes in hospitalized ADHF patients.

Right Heart Failure and Cardiorenal Syndrome

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

Low-grade albuminuria in pulmonary arterial hypertension

Low-grade albuminuria, determined by the urinary albumin to creatinine ratio, has been linked to systemic vascular dysfunction and is associated with cardiovascular mortality. Pulmonary arterial hypertension is related to mutations in the bone morphogenetic protein receptor type 2, pulmonary vascular dysfunction and is increasingly recognized as a systemic disease. In a total of 283 patients (two independent cohorts) diagnosed with pulmonary arterial hypertension, 18 unaffected BMPR2 mutation carriers and 68 healthy controls, spot urinary albumin to creatinine ratio and its relationship to demographic, functional, hemodynamic and outcome data were analyzed. Pulmonary arterial hypertension patients and unaffected BMPR2 mutation carriers had significantly elevated urinary albumin to creatinine ratios compared with healthy controls ( P < 0.01; P = 0.04). In pulmonary arterial hypertension patients, the urinary albumin to creatinine ratio was associated with older age, lower six-minute walking distance, elevated levels of C-reactive protein and hemoglobin A1c, but there was no correlation between the urinary albumin to creatinine ratio and hemodynamic variables. Pulmonary arterial hypertension patients with a urinary albumin to creatinine ratio above 10 µg/mg had significantly higher rates of poor outcome ( P < 0.001). This study shows that low-grade albuminuria is prevalent in pulmonary arterial hypertension patients and is associated with poor outcome. This study shows that albuminuria in pulmonary arterial hypertension is associated with systemic inflammation and insulin resistance.

Heart Failure and Kidney Disease

Kidney disease is commonly found in heart failure (HF) patients. They share many risk factors and common pathophysiological pathways which often lead to mutual dysfunction. Both haemodynamic and non-haemodynamic mechanisms are involved in the development of renal impairment in heart failure patients. Moreover, the presence of a chronic kidney disease is a significant independent predictor of worse outcome in chronic as well as in acute decompensated HF. As a consequence, an accurate evaluation of renal function plays a key role in the management of HF patients. Serum creatinine levels and glomerular filtration rate (GFR) estimates are the corner stones of renal function evaluation in clinical practice. However, to overcome their limits, several emerging glomerular and tubular biomarkers have been proposed over the last years. Alongside the renal biomarkers, imaging techniques could complement the laboratory data exploring different pathophysiological pathways. In particular, Doppler evaluation of renal circulation is a highly feasible technique that can effectively identify HF patients prone to develop renal dysfunction and with a worse outcome. Finally, some classes of drugs currently used in heart failure treatment can affect renal function and their use can be influenced by the presence of chronic kidney disease.

Prevalence of Albuminuria in a General Population Cohort of Patients With Established Chronic Heart Failure

BACKGROUND

Numerous studies have reported an association between albuminuria and adverse outcomes in adults with chronic heart failure (CHF). However, the prevalence of albuminuria in adults with established CHF remains unclear.

METHODS AND RESULTS

This study was a cross-sectional analysis of the National Health and Nutrition Examination Survey (NHANES) 1999-2012. Adults aged ≥18 years were included, and diagnosis of CHF was based on participant self-report. The primary outcome was the prevalence of microalbuminuria (albumin-to-creatinine ratio 30-300 mg/g) and macroalbuminuria (albumin-to-creatinine ratio >300 mg/g) in adults with CHF. The secondary outcome was the adjusted odds ratio of any albuminuria in adults with and without CHF. During the study period, 37,961 adults did not have CHF and 1,214 adults had CHF. In adults with CHF, 22.1% (95% confidence interval [CI] 19.6%-24.7%) had microalbuminuria and 10.4% (95% CI 8.1%-12.7%) macroalbuminuria. In adjusted analyses, the odds of albuminuria in adults with CHF was 1.89-fold higher (95% CI 1.59-2.26; P < .001) than in adults without CHF.

CONCLUSIONS

Taken together, albuminuria is more common in adults with CHF than in those without CHF, even after adjustment for important demographic and clinical confounders.

Effect of exercise training on renal function and renal aquaporin-2 expression in rats with chronic heart failure

1. Chronic heart failure (CHF) is often accompanied by renal dysfunction. Exercise training may relieve the symptomatic burden and improve the overall prognosis of CHF. In the present study, the effects of exercise training on renal function and renal aquaporin (AQP)-2 expression in CHF rats were examined to determine whether exercise training could relieve renal dysfunction in CHF rats. 2. Male Sprague-Dawley rats were divided into three groups: sham, sedentary CHF (Sed-CHF) and exercise training CHF (Ex-CHF) groups. Cardiorenal function was assessed in each group by haemodynamic measurement and ultraviolet spectrophotometry. Pathological changes in cardiac and renal tissues were evaluated histologically and the collagen volume fraction (CVF) was calculated. The expressions of AQP-2 and β-tubulin were determined by western blotting and immunohistochemistry. 3. The Sed-CHF rats were found to have increased left ventricular end-diastolic pressure (LVEDP) and CVF in the heart compared with sham rats. Exercise training decreased LVEDP and CVF values in Ex-CHF rats. The Sed-CHF rats were found to have increased serum levels of creatinine (sCr), blood urea nitrogen (BUN) and arginine vasopressin (AVP), as well as increased CVF in the kidney, compared with sham rats. Exercise training decreased levels of sCr, BUN, AVP and CVF in Ex-CHF rats. Moreover, exercise training decreased AQP-2 and β-tubulin protein expression in the kidney of CHF rats. 4. The results suggest that exercise training can significantly improve the renal dysfunction in CHF rats and that the underlying mechanism may be related to water reabsorption and preventing changes to the cytoskeleton.

Evaluation of chronic kidney disease in chronic heart failure: From biomarkers to arterial renal resistances

Chronic kidney disease and its worsening are recurring conditions in chronic heart failure (CHF) which are independently associated with poor patient outcome. The heart and kidney share many pathophysiological mechanisms which can determine dysfunction in each organ. Cardiorenal syndrome is the condition in which these two organs negatively affect each other, therefore an accurate evaluation of renal function in the clinical setting of CHF is essential. This review aims to revise the parameters currently used to evaluate renal dysfunction in CHF with particular reference to the usefulness and the limitations of biomarkers in evaluating glomerular dysfunction and tubular damage. Moreover, it is reported the possible utility of renal arterial resistance index (a parameter associated with abnormalities in renal vascular bed) for a better assesment of kidney disfunction.

Association between renal function and cardiovascular structure and function in heart failure with preserved ejection fraction

AIM

Renal dysfunction is a common comorbidity in patients with heart failure and preserved ejection fraction (HFpEF). We sought to determine whether renal dysfunction was associated with measures of cardiovascular structure/function in patients with HFpEF.

METHODS

We studied 217 participants from the PARAMOUNT study with HFpEF who had echocardiography and measures of kidney function. We evaluated the relationships between renal dysfunction [estimated glomerular filtration rate (eGFR) >30 and <60 mL/min/1.73 m(2) and/or albuminuria] and cardiovascular structure/function.

RESULTS

The mean age of the study population was 71 years, 55% were women, 94% hypertensive, and 40% diabetic. Impairment of at least one parameter of kidney function was present in 62% of patients (16% only albuminuria, 23% only low eGFR, 23% both). Renal dysfunction was associated with abnormal LV geometry (defined as concentric hypertrophy, or eccentric hypertrophy, or concentric remodelling) (adjusted P = 0.048), lower midwall fractional shortening (MWFS) (P = 0.009), and higher NT-proBNP (P = 0.006). Compared with patients without renal dysfunction, those with low eGFR and no albuminuria had a higher prevalence of abnormal LV geometry (P = 0.032) and lower MWFS (P < 0.01), as opposed to those with only albuminuria. Conversely, albuminuria alone was associated with greater LV dimensions (P < 0.05). Patients with combined renal impairment had mixed abnormalities (higher LV wall thicknesses, NT-proBNP; lower MWFS).

CONCLUSION

Renal dysfunction, as determined by both eGFR and albuminuria, is highly prevalent in HFpEF, and associated with cardiac remodelling and subtle systolic dysfunction. The observed differences in cardiac structure/function between each type of renal damage suggest that both parameters of kidney function might play a distinct role in HFpEF.

Novel renal biomarkers to assess cardiorenal syndrome

Renal dysfunction (RD) in heart failure portends adverse outcomes and often limits aggressive medical and decongestive therapies. Despite the high prevalence in this population, not all forms of RD are prognostically or mechanistically equivalent: RD can result from irreversible nephron loss secondary to diabetic or hypertensive kidney disease or it can develop secondary to heart failure (HF) itself, i.e., the cardiorenal syndrome. Furthermore, filtration is only one aspect of renal performance such that significant renal impairment secondary to cardiorenal syndrome can exist despite a normal glomerular filtration rate. Renal biomarkers have the potential to inform some of the intricacies involved in accurately assessing cardiorenal interactions. This article discusses novel biomarkers for cardiorenal syndrome and their utility in the prognosis, diagnosis, and targeted treatment of heart failure-induced RD.

The role of albuminuria as a non-invasive marker for congestive acutely decompensated chronic heart failure and the spironolactone effect in elderly Portuguese: a non-randomized trial

BACKGROUND/OBJECTIVES

Albuminuria is a robust, validated cardiovascular risk factor. It is a simple and widely available test that was shown to be a powerful and independent predictor of prognosis in chronic heart failure. Mineralocorticoid receptor antagonists may reduce the acute and chronic harmful effects of mineralocorticoid receptor activation on the kidney. The objectives of the trial were to compare the effect of spironolactone versus standard acutely decompensated heart failure (ADHF) therapy on albuminuria and to investigate the role of albuminuria as a prognostic marker in patients with ADHF.

METHODS

Secondary analysis of a prospective, interventional study including 100 patients with ADHF. Fifty patients were non-randomly assigned to spironolactone 100 mg/day plus standard ADHF therapy (intervention group) or standard ADHF therapy alone (control group).

RESULTS

Patients in control group were older, had higher creatinine and urea levels, and had higher proportion of microalbuminuria (all, P < 0.05). Paired comparison of baseline and day 3 log albuminuria within each group, showed a more pronounced decrease in the intervention group (1.79 ± 0.75 to 1.59 ± 0.67, P = 0.003 vs 1.89 ± 0.70 to 1.79 ± 0.74, P = 0.096). In addition, the proportion of patients with normoalbuminuria increased from baseline to day 3 in spironolactone group (20 (40%) to 27 (54%), P < 001), accordingly the number of patients in the micro and macroalbuminuria groups was reduced. Day 1 albuminuria was positively correlated with day 1 N-terminal pro-brain natriuretic peptide (0.260 [0.105-0.758], P = 0.009).

CONCLUSIONS

High-dose spironolactone added to standard ADHF therapy is likely to induce a more pronounced albuminuria decrease and a significant reduction in the proportion of micro and macroalbuminuria.

Proteinuria and its relation to cardiovascular disease

Chronic kidney disease (CKD) and its associated morbidity pose a worldwide health problem. As well as risk of endstage renal disease requiring renal replacement therapy, cardiovascular disease is the leading cause of premature death among the CKD population. Proteinuria is a marker of renal injury that can often be detected earlier than any tangible decline in glomerular filtration rate. As well as being a risk marker for decline in renal function, proteinuria is now widely accepted as an independent risk factor for cardiovascular morbidity and mortality. This review will address the prognostic implications of proteinuria in the general population as well as other specific disease states including diabetes, hypertension and heart failure. A variety of pathophysiological mechanisms that may underlie the relationship between renal and cardiovascular disease have been proposed, including insulin resistance, inflammation, and endothelial dysfunction. As proteinuria has evolved into a therapeutic target for cardiovascular risk reduction in the clinical setting we will also review therapeutic strategies that should be considered for patients with persistent proteinuria.

Renal dysfunction, restrictive left ventricular filling pattern and mortality risk in patients admitted with heart failure: a 7-year follow-up study

Background

Renal dysfunction is associated with a variety of cardiac alterations including left ventricular (LV) hypertrophy, LV dilation, and reduction in systolic and diastolic function. It is common and associated with an increased mortality risk in heart failure (HF) patients. This study was designed to evaluate whether severe diastolic dysfunction contribute to the increased mortality risk observed in HF patients with renal dysfunction.

Methods

Using Cox Proportional Hazard Models on data (N = 669) from the EchoCardiography and Heart Outcome Study (ECHOS) study we evaluated whether estimated glomerular filtration rate (eGFR) was associated with mortality risk before and after adjustment for severe diastolic dysfunction. Severe diastolic dysfunction was defined by a restrictive left ventricular filling pattern (RF) (=deceleration time < 140 ms) by Doppler echocardiography.

Results

Median eGFR was 58 ml/min/1.73 m², left ventricular ejection fraction was 33% and RF was observed in 48%. During the 7 year follow up period 432 patients died. Multivariable adjusted eGFR was associated with similar mortality risk before (Hazard Ratio(HR)_{eGFR 10 ml increase}: 0.94 (95% CI: 0.89-0.99, P = 0.024) and after (HR_{eGFR 10 ml increase}: 0.93 (0.89-0.99), P = 0.012) adjustment for RF (HR: 1.57 (1.28-1.93), P < 0.001).

Conclusions

In patients admitted with HF RF does not contribute to the increased mortality risk observed in patients with a decreased eGFR. Factors other than severe diastolic dysfunction may explain the association between renal function and mortality risk in HF patients.

Usefulness of albuminuria as a prognostic indicator in patients with chronic heart failure secondary to ischemic or idiopathic dilated cardiomyopathy

Albuminuria is an established risk factor for mortality and cardiovascular events in the general population. Albuminuria might be a marker of the various pathophysiologic changes, such as diffuse vascular injury and systemic inflammation, that arise in patients with chronic heart failure (CHF). However, the relation between albuminuria and CHF has not yet been fully elucidated. Therefore, the purpose of the present study was to assess the prevalence and prognostic significance of albuminuria in patients with CHF secondary to ischemic or idiopathic dilated cardiomyopathy. Of the 712 patients with CHF, 311 had normoalbuminuria, 304 had microalbuminuria, and 97 had macroalbuminuria. The patients with albuminuria had more cardiovascular co-morbidity and worse renal function than those with normoalbuminuria. A total of 152 cardiac events occurred during the follow-up period. Kaplan-Meier analysis demonstrated that patients with albuminuria had a greater incidence of cardiac events than those without albuminuria. Furthermore, albuminuria was significantly associated with an increased risk of cardiac events, even after adjustment for other prognostic variables. In conclusion, albuminuria is a powerful and independent predictor of adverse prognosis in patients with CHF and could be useful for risk stratification of patients with CHF.

Current and novel renal biomarkers in heart failure

Renal function is the most important predictor of clinical outcome in heart failure (HF). It is therefore essential to have accurate and reliable measurement of renal function and early specific markers of renal impairment in patients with HF. Several renal functional entities exist, including glomerular filtration (GFR), glomerular permeability, tubulointerstitial damage, and endocrine function. Different markers have been studied that can be used to determine changes and the effect of treatment in these entities. In the present review, we summarize current and novel markers that give an assessment of renal function and prognosis in the setting of acute and chronic HF.

Adding thiazide to a rennin-angiotensin blocker regimen to improve left ventricular relaxation in diabetes and nondiabetes patients with hypertension

The urinary albumin to creatinine ratio (UACR) is an independent predictor of outcomes in patients with diastolic dysfunction. Thus, we investigated the relationship between diastolic dysfunction, UACR, and diabetes mellitus (DM) in the EDEN study. We investigated the effect of switching from an angiotensin-converting enzyme inhibitor (ACEi) or angiotensin receptor blocker (ARB) to a combination of losartan and hydrochlorothiazide on left ventricular (LV) relaxation in patients with hypertension and diastolic dysfunction. We enrolled 106 patients with and 265 patients without DM. All patients had diastolic dysfunction and had not achieved their treatment goals with an ACEi or ARB. The measurements of e′ velocity and E/e′ ratio was performed with echocardiography as markers of LV diastolic function. We switched the ACEi or ARB to losartan/hydrochlorothiazide and followed these patients for 24 weeks. UACR was decreased in patients with DM (123.4 ± 288.4 to 66.5 ± 169.2 mg/g creatinine; P = 0.0024), but not in patients without DM (51.2 ± 181.8 to 39.2 ± 247.9 mg/g creatinine; P = 0.1051). Among DM patients, there was a significant relationship between changes in UACR and changes in e′ velocity (r = −0.144; P = 0.0257) and between changes in estimated glomerular filtration rate and changes in the E/e′ ratio (r = −0.130; P = 0.0436). Among patients without DM, there was a significant relationship between changes in high-sensitivity C-reactive protein (hs-CRP) and changes in E/e′ (r = 0.205; P = 0.0010). Multivariate analysis demonstrated changes in hemoglobin A_1c levels as one of the determinants of change of e′ and E/e′ in patients with DM, whereas hs-CRP was the determinant of change of e′ among patients without DM. These data suggest that improvement in LV diastolic function is associated with an improvement of DM and a concomitant reduction in UACR among DM patients, and with a reduction of hs-CRP in patients without DM when thiazide is added to a renin–angiotensin blocker treatment regimen.

Renal dysfunction in heart failure

Renal dysfunction is a common, important comorbidity in patients with both chronic and acute heart failure (HF). Chronic kidney disease and worsening renal function (WRF) are associated with worse outcomes, but our understanding of the complex bidirectional interactions between the heart and kidney remains poor. When addressing these interactions, one must consider the impact of intrinsic renal disease resulting from medical comorbidities on HF outcomes. WRF may result from any number of important processes. Understanding the role of each of these factors and their interplay are essential in understanding how to improve outcomes in patients with renal dysfunction and HF.

The role of the kidney in heart failure

Renal dysfunction is common in patients with heart failure and is associated with high morbidity and mortality. Cardiac and renal dysfunction may worsen each other through multiple mechanisms such as fluid overload and increased venous pressure, hypo-perfusion, neurohormonal and inflammatory activation, and concomitant treatment. The interaction between cardiac and renal dysfunction may be critical for disease progression and prognosis. Renal dysfunction is conventionally defined by a reduced glomerular filtration rate, calculated from serum creatinine levels. This definition has limitations as serum creatinine is dependent on age, gender, muscle mass, volume status, and renal haemodynamics. Changes in serum creatinine related to treatment with diuretics or angiotensin-converting enzyme inhibitors are not necessarily associated with worse outcomes. New biomarkers might be of additional value to detect an early deterioration in renal function and to improve the prognostic assessment, but they need further validation. Thus, the evaluation of renal function in patients with heart failure is important as it may reflect their haemodynamic status and provide a better prognostic assessment. The prevention of renal dysfunction with new therapies might also improve outcomes although strong evidence is still lacking.

Biomarkers: optimizing treatment guidance in heart failure

Heart failure is a frequent and life-threatening syndrome which is not only the result of myocardial injury or hemodynamic overload as commonly perceived, but appears to be the result of an interplay among genetic, neurohormonal, inflammatory, and biochemical factors, collectively referred to as biomarkers. Biomarkers can become risk factors in case their therapeutic modification results in an improvement of clinical outcomes. Among those markers identified in patients with heart failure, a number appears to have direct clinical relevance in aiding diagnosis, risk stratification, monitoring therapy, and treating to targets in order to improve clinical outcomes. These include brain natriuretic peptides (e.g., BNP, NT-proBNP), inflammatory markers (e.g., hsCRP), neurohormones (e.g., aldosterone), cardiorenal markers (e.g., cycstatin C), and novel markers (e.g., galectin-3). While their utility to indicate risk is mostly well established, there are less data to establish that a treatment using biomarkers as a guidance results in better outcomes than a more generalized intensified treatment of patients with heart failure. Future directions may involve larger platforms that facilitate to simultaneously analyze hundreds of biomarkers and may help to tailor heart failure therapy on a single patient basis, considering the specific pathogenesis and prognosis. Also from a therapeutic perspective there are data that a single intervention such as aldosterone blockade may affect multiple biomarkers at the same time. Taken together the data indicate that biomarkers are evolving into a valuable addendum to the diagnostic and therapeutic armamentarium.

Diminished renal function and the incidence of heart failure

Heart failure is one of the most common, costly, disabling and deadly diseases. During the last decade, several different indices reflecting renal function such as creatinine-based glomerular filtration rate, circulating levels of cystatin C and low-grade albuminuria have been demonstrated to be independent risk factors for heart failure. This review summarizes our current knowledge of the relationship between diminished renal function and the incidence of heart failure in the community, and also in individuals with increased risk of heart failure such as patients with overt cardiovascular disease, hypertension or diabetes. This review will also put forward important areas of future research in this field.

The effects of heart failure on renal function

Heart-kidney interactions have been increasingly recognized by clinicians and researchers who study and treat heart failure and kidney disease. A classification system has been developed to categorize the different manifestations of cardiac and renal dysfunction. Work has highlighted the significant negative prognostic effect of worsening renal function on outcomes for individuals with heart failure. The etiology of concomitant cardiac and renal dysfunction remains unclear; however, evidence supports alternatives to the established theory of underfilling, including effects of venous congestion and changes in intra-abdominal pressure. Conventional therapy focuses on blockade of the renin-angiotensin-aldosterone system with expanding use of direct renin and aldosterone antagonists. Novel therapeutic interventions using extracorporeal therapy and antagonists of the adenosine pathway show promise and require further investigation.

Proteinuria, Chronic Kidney Disease, and the Effect of an Angiotensin Receptor Blocker in Addition to an Angiotensin-Converting Enzyme Inhibitor in Patients With Moderate to Severe Heart Failure

Background— Chronic kidney disease (CKD) is an established risk factor for poor outcomes in heart failure (HF). Whether proteinuria provides additional prognostic information is not known. Renin-angiotensin blockade medications improve outcomes in HF but are underutilized in HF patients with renal dysfunction because of safety concerns and a lack of evidence of their effectiveness.

Methods and Results— In the Valsartan in Heart Failure Trial (Val-HeFT), 5010 patients with class II, III, or IV heart failure were randomly assigned to receive valsartan or placebo. The 2 primary outcomes were death and first morbid event, defined as death, sudden death with resuscitation, hospitalization for HF, or administration of intravenous inotropic or vasodilator drugs for 4 hours or more without hospitalization. The study cohort was divided into subgroups according to the presence of CKD (estimated glomerular filtration rate <60 mL · min −1 · 1.73 m −2 ) and proteinuria (positive dipstick). Multivariable Cox proportional hazards regression models were used to examine the relationships between study outcomes and proteinuria, including its interaction with CKD. The interaction between valsartan and CKD was also tested. The effect of valsartan on estimated glomerular filtration rate was estimated by generalized linear models, including tests of interactions between treatment and CKD. At baseline, CKD was found in 58% and dipstick-positive proteinuria in 8% of patients. Dipstick-positive proteinuria was independently associated with mortality (hazard ratio [HR] 1.28, 95% confidence interval [CI] 1.01 to 1.62, P =0.05) and first morbid event (HR 1.28, 95% CI 1.06 to 1.55, P =0.01). The increased risk of death associated with dipstick-positive proteinuria was similar for those with and without CKD (HR 1.26, 95% CI 0.96 to 1.66 versus HR 1.37, 95% CI 0.83 to 2.26; P =0.94), as was the hazard for first morbid event (HR 1.26, 95% CI 1.01 to 1.57 versus HR 1.42, 95% CI 0.98 to 2.07; P =0.71). Valsartan reduced estimated glomerular filtration rate compared with placebo to a similar extent ( P =0.52) in the subgroups with CKD (mean reduction −3.6 mL · min −1 · 1.73 m −2 ) and without CKD (mean reduction −4.0 mL · min −1 · 1.73 m −2 ) and by −3.8 mL · min −1 · 1.73 m −2 in both groups combined. The beneficial effect of valsartan on first morbid events was similar in those with and without CKD (HR 0.86, 95% CI 0.74 to 0.99 versus HR 0.91, 95% CI 0.73 to 1.12; P =0.23) and was significant in the subgroup with CKD. The effect of valsartan on mortality did not differ in patients with and without CKD (HR 1.01, 95% CI 0.85 to 1.20 versus HR 0.91, 95% CI 0.69 to 1.25; P =0.08).

Conclusions— CKD was common and dipstick-positive proteinuria was infrequent in this sample of patients with HF. After controlling for other risk factors, including CKD, the relatively small subgroup with dipstick-positive proteinuria did have worse outcomes. Valsartan reduced the estimated glomerular filtration rate by the same amount in patients with and without CKD and reduced the risk of the first morbid event in patients with CKD, which suggests its beneficial effects in patients with HF and CKD.

Albuminuria in heart failure: what do we really know?

PURPOSE OF THE REVIEW

To describe the role of albuminuria as a risk marker for heart failure and a predictor for treatment effect on heart failure prognosis.

RECENT FINDINGS

The level of albumin in the urine is a predictor of heart failure in the general population and in patients with cardiovascular risk, such as those with diabetes. Mild elevations of albuminuria, in the microalbuminuria range, appear to be associated with impaired systemic endothelial function. This increases the chance of developing hypertension, diabetes and cardiovascular disease, ultimately leading to heart failure. Higher levels of albuminuria, in the proteinuric range, reflect marked renal pathology, which increases cardiovascular risk due to renal function decline. In patients with established heart failure, microalbuminuria is highly prevalent (30%). Although more frequent in diastolic than systolic dysfunction, it appears to indicate a worse prognosis in the latter class. Diabetes is a multiplier of risk, probably due to bidirectional relationship between diabetes and heart failure. Treatment with drugs that intervene in the renin-angiotensin-aldosterone system (RAAS) lowers albuminuria and is associated with prevention of the onset and worsening of heart failure and other cardiovascular disorders.

SUMMARY

Albuminuria is associated with increased heart failure risk. Lowering of albuminuria using RAAS inhibitors appears to lower the risk for heart failure.

Albuminuria in chronic heart failure: prevalence and prognostic importance

BACKGROUND

Increased excretion of albumin in urine might be a marker of the various pathophysiological changes that arise in patients with heart failure. Therefore our aim was to assess the prevalence and prognostic value of a spot urinary albumin to creatinine ratio (UACR) in patients with heart failure.

METHODS

UACR was measured at baseline and during follow-up of 2310 patients in the Candesartan in Heart failure: Assessment of Reduction in Mortality and morbidity (CHARM) Programme. The prevalence of microalbuminuria and macroalbuminuria, and the predictive value of UACR for the primary composite outcome of each CHARM study--ie, death from cardiovascular causes or admission to hospital with worsening heart failure--and death from any cause were assessed.

FINDINGS

1349 (58%) patients had a normal UACR, 704 (30%) had microalbuminuria, and 257 (11%) had macroalbuminuria. The prevalence of increased UACR was similar in patients with reduced and preserved left ventricular ejection fractions. Patients with an increased UACR were older, had more cardiovascular comorbidity, worse renal function, and a higher prevalence of diabetes mellitus than did those with normoalbuminuria. However, a high prevalence of increased UACR was still noted among patients without diabetes, hypertension, or renal dysfunction. Elevated UACR was associated with increased risk of the composite outcome and death even after adjustment for other prognostic variables including renal function, diabetes, and haemoglobin A1c. The adjusted hazard ratio (HR) for the composite outcome in patients with microalbuminuria versus normoalbuminuria was 1.43 (95% CI 1.21-1.69; p<0.0001) and for macroalbuminuria versus normoalbuminuria was 1.75 (1.39-2.20; p<0.0001). The adjusted values for death were 1.62 (1.32-1.99; p<0.0001) for microalbuminuria versus normoalbuminuria, and 1.76 (1.32-2.35; p=0.0001) for macroalbuminuria versus normoalbuminuria. Treatment with candesartan did not reduce or prevent the development of excessive excretion of urinary albumin.

INTERPRETATION

Increased UACR is a powerful and independent predictor of prognosis in heart failure.

FUNDING

AstraZeneca.

Causes and consequences of systemic venous hypertension

The causes of systemic venous hypertension (SVHT) include cardiac- and circulatory-related factors, whereas its consequences include the congestion of hepatic, splanchnic, and peripheral circulations, which contribute significantly to the clinical congestive heart failure syndrome. Based on a disequilibrium in hydrostatic and oncotic pressures, the increased filtration and formation of interstitial fluid at these sites with an accompanying increase in lymph flow mandates an increment in lymphatic drainage to protect against such congestion and the appearance of edema and ascites. However, lymph flow via the thoracic duct into systemic veins is opposed by elevations in central venous pressure. Various management strategies have the potential to prevent and/or correct SVHT. The case of a 54-year-old man with a dilated cardiomyopathy who presented with decompensated biventricular failure, expressed as anasarca and ascites, is used to illustrate the importance of SVHT.

Microalbuminuria in nondiabetic and nonhypertensive systolic heart failure patients

The American Diabetes Association and the National Kidney Foundation define microalbuminuria as an albumin (microg)/creatinine (mg) ratio (ACR) between 30 and 300 microg/mg regardless of sex. Microalbuminuria is associated with increased cardiovascular risk. The authors evaluated the prevalence of microalbuminuria in nondiabetic and nonhypertensive systolic heart failure (SHF) patients. Twenty-seven SHF patients, 18 years and older, with New York Heart Association functional classes II through IV and left ventricular ejection fraction < or =40%, who were nondiabetic and nonhypertensive and not receiving angiotensin-converting enzyme inhibitors, were selected. Twenty-seven healthy individuals, paired according to sex, ethnicity, and age, were used as controls. Early-morning midstream urine was used. Data are expressed as medians. Excretion of albumin in SHF patients (39 microg/mL urine) was significantly higher than in controls (26 microg/mL urine). Creatinine excretion was not significantly different between patients and controls. ACR was significantly higher in patients (54 microg/mg) than in controls (24 microg/mg). The results indicate that microalbuminuria was significantly present in nondiabetic and nonhypertensive SHF patients.

Differential associations between renal function and "modifiable" risk factors in patients with chronic heart failure

BACKGROUND

Reduced glomerular filtration rate (GFR) is strongly associated with reduced survival in patients with chronic heart failure (CHF). Our aim was to determine different pathophysiologic markers that are associated with reduced renal function in CHF.

METHODS AND RESULTS

We studied 86 patients with CHF (58+/-12 years, 78% male). GFR and renal blood flow (RBF) were determined by (125)I-Iothalamate and (131)I-Hippuran clearances. Filtration fraction (FF) was calculated. We determined haemoglobin levels, endothelial function, inflammatory status, plasma renin activity (PRA) and N-terminal pro brain natriuretic peptide (NT-proBNP). Urinary albumin excretion (UAE) was measured in 24 h urine. Mean GFR was 74+/-28 ml/min/1.73 m(2). GFR was strongly related to RBF (r=0.915, P<0.001), FF (r=0.546, P<0.001), but only weakly to endothelial function and PRA. In multivariate analysis, RBF (r=0.938, P < 0.001), FF (r=0.786, P < 0.001) and haemoglobin levels (r= -0.520, P<0.001) were independently associated with GFR. UAE was mainly dependent on RBF (r= -0.401, P < 0.001) and increased exponentially with decreasing RBF. RBF was mainly associated with NT-proBNP (r= -0.561, P<0.001) and PRA (r= -0.422, P<0.001).

CONCLUSION

Reduced GFR is mainly dependent of decreased RBF in patients with CHF. Endothelial function and neurohormonal activation showed only mild associations with GFR. NT-proBNP showed a strong relationship with RBF, and may be used as a marker of reduced renal perfusion.

Urinary neutrophil gelatinase associated lipocalin (NGAL), a marker of tubular damage, is increased in patients with chronic heart failure

Renal impairment, as measured by reduced glomerular filtration rate (GFR) and increased urinary albumin excretion (UAE), is prevalent in patients with chronic heart failure (CHF) and is associated with reduced survival. The prevalence of structural tubular damage in CHF is unknown. We investigated 90 CHF patients and 20 age and sex matched healthy controls, and determined estimated GFR, UAE, N terminal-pro brain natriuretic peptide (NT-proBNP) and urinary neutrophil gelatinase associated lipocalin (NGAL) as a marker for tubular damage. CHF patients had significantly lower averaged estimated GFR (64+/-17 vs 90+/-12 mL/min/1.73 m(2), P<0.0001), but higher NT-proBNP and UAE levels (both P<0.0001). Median urinary NGAL levels were markedly increased in CHF patients compared to controls (175 (70-346) vs 37 (6-58) microg/gCr, P<0.0001). Both serum creatinine (r=0.26, P=0.006) and eGFR (r=-0.29, P=0.002) were significantly associated with urinary NGAL levels as were NT-proBNP and UAE but to a lesser extent. In conclusion, renal impairment in CHF patients is not only characterised by decreased eGFR and increased UAE, but also by the presence of tubular damage, as measured by increased urinary NGAL concentrations.