Renal impairment and outcomes in heart failure: systematic review and meta-analysis

Routine laboratory results and thirty day and one-year mortality risk following hospitalization with acute decompensated heart failure

Introduction

Several blood tests are performed uniformly in patients hospitalized with acute decompensated heart failure and are predictive of the outcomes: complete blood count, electrolytes, renal function, glucose, albumin and uric acid. We sought to evaluate the relationship between routine admission laboratory tests results, patient characteristics and 30-day and one-year mortality of patients admitted for decompensated heart failure and to construct a simple mortality prediction tool.

Methods

A retrospective population based study. Data from seven tertiary hospitals on all admissions with a principal diagnosis of heart failure during the years 2002–2005 throughout Israel were captured.

Results

8,246 patients were included in the study cohort. Thirty day mortality rate was 8.5% (701 patients) and one-year mortality rate was 28.7% (2,365 patients). Addition of five routine laboratory tests results (albumin, sodium, blood urea, uric acid and WBC) to a set of clinical and demographic characteristics improved c-statistics from 0.76 to 0.81 for 30-days and from 0.72 to 0.76 for one-year mortality prediction (both p-values <0.0001). Three dichotomized abnormal laboratory results with highest odds ratio for one-year mortality (hypoalbuminaemia, hyponatremia and elevated blood urea) were used to construct a simple prediction score, capable of discriminating from 1.1% to 21.4% in 30-day and from 11.6% to 55.6% in one-year mortality rates between patients with a score of 0 (1,477 patients) vs. score of 3 (544 patients).

Discussion

A small set of abnormal routine laboratory results upon admission can risk-stratify and independently predict 30-day and one-year mortality in patients hospitalized with acute decompensated heart failure.

The cardiorenal syndrome in heart failure: an evolving paradigm

Heart failure constitutes a significant source of morbidity and mortality in the United States, and its incidence and prevalence continue to grow, increasing its burden on the healthcare system. Renal dysfunction in patients with heart failure is common and has been associated with adverse clinical outcomes. This interaction, termed the cardiorenal syndrome, is a complex phenomenon characterized by a pathophysiologic disequilibrium between the heart and the kidney, in which malfunction of 1 organ consequently promotes the impairment of the other. Multiple neurohumoral mechanisms are involved in this cardiorenal interaction, including the deficiency of and/or resistance to compensatory natriuretic peptides, leading to sodium retention, volume overload and organ remodeling. Management of patients with the cardiorenal syndrome can be challenging and should be individualized. Emerging therapies must address the function of both organs to secure better clinical outcomes. To this end, a multidisciplinary approach is recommended to achieve optimal results.

Impact of reduced kidney function on cardiopulmonary fitness in patients with systolic heart failure

BACKGROUND

Decreased renal function has been consistently associated with increased mortality among patients with systolic heart failure. The relationship between estimated glomerular filtration rate (eGFR) and other high-risk features including reduced cardiorespiratory fitness has not been previously reported in this patient population.

METHODS

The HF-ACTION trial was a prospective, randomized trial of exercise therapy versus usual care in patients with systolic heart failure. Patients with class 2-4 heart failure and a left ventricular ejection fraction of ≤ 35% were recruited. Serum creatinine was measured up to 1 year prior to entry. The 4-variable modified Modification of Diet in Renal Disease equation was used to calculate eGFR. Peak oxygen consumption (peak VO(2)) was directly measured using gas exchange analysis during progressive exercise testing to volitional fatigue or adverse signs/symptoms.

RESULTS

Of 2,091 subjects (mean age 59 ± 13 years, with serum creatinine available at baseline), 72% were men, and 61, 33, and 5% were Caucasians, African Americans, and others, respectively. Older age, diabetes, and hypertension were all more frequent with declining eGFR. The Pearson correlation between eGFR and peak VO(2) was 0.22 (p < 0.0001). Age was negatively correlated with both eGFR (r = -0.44, p < 0.0001) and peak VO(2) (r = -0.27, p < 0.0001). The peak VO(2) tended to decline across decreasing levels of eGFR. Individuals with an eGFR <30 ml/min/1.73 m(2) had, on average, 2.1 high-risk features including peak VO(2) <14 ml/kg/min, age >75 years, diabetes, and functional class 3-4 symptoms. Conversely, those with an eGFR >90 ml/min/1.73 m(2) had relatively few (1.0) high-risk characteristics.

CONCLUSIONS

Reduced renal filtration is associated with impaired cardiorespiratory fitness and a clustering of high-risk features in systolic heart failure patients which portend a more complicated course and higher all-cause mortality.

Worsening renal function in patients admitted with acute decompensated heart failure: incidence, risk factors and prognostic implications

INTRODUCTION AND OBJECTIVES

Acute decompensated heart failure (ADHF) is a common cause of hospital admission and is associated with an increased risk of worsening renal function (WRF). The aims of this study were to investigate the incidence and predictors of WRF in patients admitted for ADHF and to assess the prognostic significance of WRF at 1 year.

METHODS

A retrospective analysis of data on 200 consecutive patients admitted with ADHF was carried out. By definition, WRF occurred when the serum creatinine level increased during hospitalization by 0.3 mg/dL and by > or =25% from admission.

RESULTS

Overall, 23% of patients developed WRF. On multivariate analysis, age >80 years (odds ratio [OR]=2.72; 95% confidence interval [CI], 1.86-3.42), admission glomerular filtration rate <60 mL/min per 1.73 m2 (OR=2.05; 95% CI, 1.53-2.27) and admission systolic pressure <90 mmHg (OR=1.61, 95% CI, 1.17-3.22) were independently associated with WRF. The rate of mortality or readmission for heart failure (HF) at 1 year was higher in the WRF group (P< .01 by log-rank test). The median hospital stay was 9 days for patients with WRF and 4 days for those without (P< .05). On multivariate analysis, WRF remained independently associated with mortality or HF rehospitalization (hazard ratio=1.65; 95% CI, 1.12-2.67; P=.003).

CONCLUSIONS

In patients admitted for ADHF, WRF was a common complication and was associated with a longer hospital stay and an increased risk of mortality or HF hospitalization. Clinical characteristics at admission can help identify patients at an increased risk of WRF.

The significance of serum urea and renal function in patients with heart failure

Renal function and urea are frequently abnormal in patients with heart failure (HF) and are predictive of increased mortality. The relative importance of each parameter is less clear. We prospectively compared the predictive value of renal function and serum urea on clinical outcome in patients with HF. Patients hospitalized with definite clinical diagnosis of HF (n = 355) were followed for short-term (1 yr) and long-term (mean, 6.5 yr) survival and HF rehospitalization. Increasing tertiles of discharge estimated glomerular filtration rate (eGFR) were an independent predictor of increased long-term survival (hazard ratio [HR], 0.65; 95% confidence interval [CI], 0.47-0.91; p = 0.01) but not short-term survival. Admission and discharge serum urea and blood urea nitrogen (BUN)/creatinine ratio were predictors of reduced short- and long-term survival on multivariate Cox regression analysis. Increasing tertiles of discharge urea were a predictor of reduced 1-year survival (HR, 2.13; 95% CI, 1.21-3.73; p = 0.009) and long-term survival (HR, 1.93; 95% CI, 1.37-2.71; p < 0.0001). Multivariate analysis including discharge eGFR and serum urea demonstrated that only serum urea remained a significant predictor of long-term survival; however, eGFR and BUN/creatinine ratio were both independently predictive of survival. Urea was more discriminative than eGFR in predicting long-term survival by area under the receiver operating characteristic curve (0.803 vs. 0.787; p = 0.01). Increasing tertiles of discharge serum urea and BUN/creatinine were independent predictors of HF rehospitalization and combined death and HF rehospitalization. This study suggests that serum urea is a more powerful predictor of survival than eGFR in patients with HF. This may be due to urea's relation to key biological parameters including renal, hemodynamic, and neurohormonal parameters pertaining to the overall clinical status of the patient with chronic HF.

Therapeutic strategies for heart failure in cardiorenal syndromes

Cardiorenal syndromes are disorders of the heart and kidneys whereby acute or long-term dysfunction in one organ may induce acute or long-term dysfunction of the other. The management of cardiovascular diseases and risk factors may influence, in a beneficial or harmful way, kidney function and progression of kidney injury. In this review, we assess therapeutic strategies and discuss treatment options for the management of patients with heart failure with decreased kidney function and highlight the need for future high-quality studies in patients with coexisting heart and kidney disease.

Long-term outcomes of medicare beneficiaries with worsening renal function during hospitalization for heart failure

We examined whether worsening renal function (RF) was associated with long-term mortality, readmission, and inpatient costs in Medicare beneficiaries hospitalized with heart failure (HF). Baseline renal insufficiency in patients hospitalized for HF is associated with increased risk of morbidity and mortality. However, the relation between worsening RF and long-term clinical outcomes is unclear. We linked clinical registry data to Medicare inpatient claims to identify 1-year outcomes of patients > or =65 years of age hospitalized with HF. Worsening RF was defined as a change in serum creatinine > or =0.3 mg/dl. Relations between worsening RF and 1-year mortality and readmission were evaluated with multivariable Cox proportional hazards models with robust SEs; associations with inpatient costs were evaluated with generalized linear models with a log-link and Poisson distribution. Of 20,063 patients hospitalized with HF and discharged alive, 3,581 (17.8%) had worsening RF during the index hospitalization. One year after discharge, 35.4% of these patients died, 64.5% were readmitted, and average costs at 1 year were $14,829 (interquartile range 0 to 19,366). After adjustment for patient characteristics, baseline RF, and comorbid conditions, worsening RF was independently associated with 1-year mortality (hazard ratio 1.12, 95% confidence interval 1.04 to 1.20) but not readmission or total inpatient costs. In conclusion, worsening RF in patients hospitalized with HF was independently associated with long-term mortality.

Epidemiology of cardiorenal syndrome

The interdependence of cardiac and renal dysfunction has emerged as a focus of intense interest in heart failure management due to the substantial associated morbidity and mortality. Captured in the clinical entity known as cardiorenal syndrome, recent definitions afford discussion of the acute and longitudinal evaluation and management of these patients. This article discusses potential pathophysiologic mechanisms of cardiorenal syndrome, epidemiology, inpatient and long-term care (including investigational therapies and mechanical fluid removal), and end-of-life and palliative care.

Influence of renal function on the use of guideline-recommended therapies for patients with heart failure

Guidelines have been established for the treatment of patients with heart failure (HF) and left ventricular dysfunction, but renal dysfunction might limit adherence to these guidelines. Few data have characterized the use of guideline-recommended therapy for patients with HF, left ventricular dysfunction, and renal dysfunction who are treated in outpatient settings. The Registry to Improve the Use of Evidence-Based Heart Failure Therapies in the Outpatient Setting (IMPROVE HF) was a prospective study of patients receiving treatment as outpatients in cardiology practices in the United States. The rates of adherence to 7 guideline-recommended therapies were evaluated for patients with a left ventricular ejection fraction of < or = 35%. The estimated glomerular filtration rate was estimated using the Modification of Diet in Renal Disease formula for 13,164 patients who were categorized as having stage 1 through stage 4/5 chronic kidney disease (CKD). More than 1/2 (52.2%) of the patients had stage 3 or 4/5 CKD. Older patients and women were at increased risk of higher stage CKD, and the rates of co-morbid health conditions were significantly greater among patients with more severe CKD. The patients with more severe CKD were significantly less likely to receive all interventions except cardiac resynchronization therapy. However, multivariate analysis controlling for patient characteristics revealed that the severity of CKD was an independent predictor of adherence to angiotensin-converting enzyme inhibitor/angiotensin receptor blocker therapy but not to any of the 6 other guideline-recommended measures. In conclusion, these results confirm that CKD is common in patients with HF and left ventricular dysfunction but is not independently associated with adherence to guideline-recommended therapy in outpatient cardiology practices, with the exception of angiotensin-converting enzyme inhibitor/angiotensin receptor blocker therapy.

Managing anemia in patients with chronic heart failure: what do we know?

Anemia is common in patients with chronic heart failure (HF) with an incidence ranging from 4% to 55% depending on the studied population. Several studies have highlighted that the prevalence of anemia increases with worsening heart failure as reflected by New York Heart Association classification. Additionally, several epidemiological studies have highlighted its role as a prognostic marker, linking it to worse outcomes including; malnutrition, increased hospitalizations, refractory heart failure and death. The pathophysiology of anemia is multifactorial and related to various factors including; hemodilution, iron losses from anti-platelet drugs, activation of the inflammatory cascade, urinary losses of erythropoietin and associated renal insufficiency. There are a host of epidemiological studies examining HF outcomes and anemia, but only a few randomized trials addressing this issue. The purpose of this article is to review the literature that examines the interrelationship of anemia and congestive HF, analyzing its etiology, impact on outcomes and also the role of associated kidney disease as well as cardiorenal syndrome both as a marker of morbidity and mortality.

Hemodynamic predictors of survival in scleroderma-related pulmonary arterial hypertension

RATIONALE

Pulmonary arterial hypertension (PAH) related to systemic sclerosis (SSc) has a poorer prognosis compared with other forms of PAH for reasons that remain unexplained.

OBJECTIVES

To identify risk factors of mortality in a well-characterized cohort of patients with PAH related to systemic sclerosis (SSc-PAH).

METHODS

Seventy-six consecutive patients with SSc (64 women and 12 men; mean age 61 +/- 11 yr) were diagnosed with PAH by heart catheterization in a single center, starting in January 2000, and followed over time. Kaplan-Meier estimates were calculated and mortality risk factors were analyzed.

MEASUREMENTS AND MAIN RESULTS

Forty (53%) patients were in World Health Organization functional class III or IV. Mean pulmonary artery pressure was 41 +/- 11 mm Hg, pulmonary vascular resistance (PVR) was 8.6 +/- 5.6 Wood units, and cardiac index was 2.4 +/- 0.7 L/min/m(2). Median follow-up time was 36 months, with 42 deaths observed. Survival estimates were 85%, 72%, 67%, 50%, and 36% at 1, 2, 3, 4, and 5 years, respectively. Multivariate analysis identified PVR (hazard ratio [HR], 1.10; 95% confidence interval [CI], 1.03-1.18; P < 0.01), stroke volume index (HR, 0.94; 95% CI, 0.89-0.99; P = 0.02), and pulmonary arterial capacitance (HR, 0.43; 95% CI, 0.20-0.91; P = 0.03) as strong predictors of survival. An estimated glomerular filtration rate less than 60 ml/min/1.73 m(2) portended a threefold risk of mortality.

CONCLUSIONS

Our results suggest that specific components of right ventricular dysfunction and renal impairment contribute to increased mortality in SSc-PAH. Understanding the mechanisms of right ventricular dysfunction in response to increased afterload should lead to improved targeted therapy in these patients.

Clinical practice: heart failure in children. Part I: clinical evaluation, diagnostic testing, and initial medical management

Current evidence suggests that almost half of all children with cardiomyopathy and symptomatic heart failure will die or require a cardiac transplant within 5 years of diagnosis. The recognition, diagnostic assessment, and treatment of heart failure in children are therefore challenging undertakings, to say the least. It involves an assessment of cardiac appearance and function, adaptation of the child as a whole, and a diagnostic approach that evaluates many possible root causes. This review is intended to assist the practicing pediatrician and cardiologist by providing a framework for this diagnostic assessment and to give an overview of the treatment options available for children with heart failure. In this first part, we will focus on clinical evaluation, diagnostic testing, and initial medical management. In the second part of this series, the maintenance treatment and treatment options applicable when medical treatment is insufficient will be addressed.

Cardiorenal syndrome: still not a defined entity

Because of the increasing incidence of cardiac failure and chronic renal failure due to the progressive aging of the population, the extensive application of cardiac interventional techniques, the rising rates of obesity and diabetes mellitus, coexistence of heart failure and renal failure in the same patient are frequent. More than half of subjects with heart failure had renal impairment, and mortality worsened incrementally across the range of renal dysfunctions. In patients with heart failure, renal dysfunction can result from intrinsic renal disease, hemodynamic abnormalities, or their combination. Severe pump failure leads to low cardiac output and hypotension, and neurohormonal activation produces both fluid retention and vasoconstriction. However, the cardiorenal connection is more elaborate than the hemodynamic model alone; effects of the renin-angiotensin system, the balance between nitric oxide and reactive oxygen species, inflammation, anemia and the sympathetic nervous system should be taken into account. The management of cardiorenal patients requires a tailored therapy that prioritizes the preservation of the equilibrium of each individual patient. Intravascular volume, blood pressure, renal hemodynamic, anemia and intrinsic renal disease management are crucial for improving patients' survival. Complications should be foreseen and prevented, looking carefully at basic physical examination, weight and blood pressure monitoring, and blood, urine urea and electrolytes measurement.

Iothalamate quantification by tandem mass spectrometry to measure glomerular filtration rate

BACKGROUND

Glomerular filtration rate (GFR) can be determined by measuring renal clearance of the radiocontrast agent iothalamate. Current analytic methods for quantifying iothalamate concentrations in plasma and urine using liquid chromatography or capillary electrophoresis have limitations such as long analysis times and susceptibility to interferences. We developed a liquid chromatography-tandem mass spectrometry (LC-MS/MS) method to overcome these limitations.

METHODS

Urine and plasma samples were deproteinized using acetonitrile and centrifugation. The supernatant was diluted in water and analyzed by LC-MS/MS using a water:methanol gradient. We monitored 4 multiple reaction monitoring transitions: m/z 614.8-487.0, 614.8-456.0, 614.8-361.1, and 614.8-177.1. We compared the results to those obtained via our standard capillary electrophoresis (CE-UV) on samples from 53 patients undergoing clinical GFR testing.

RESULTS

Mean recovery was 90%-110% in both urine and plasma matrices. Imprecision was <or=15% for the m/z 614.8-487.0 and 614.8-456.0 transitions over a 10-day period at 1 mg/L. Method comparison for 159 patient samples (53 clearances) provided the following Passing-Bablok regressions: plasma iothalamate LC-MS/MS (y) vs CE-UV (x), y = 0.99x + 0.36; urine iothalamate LC-MS/MS vs CE-UV, y = 1.01x + 0.31; corrected GFR LC-MS/MS vs CE-UV, y = 1.00x + 0.00. Interfering substances prevented accurate iothalamate quantification by CE-UV in 2 patients, whereas these samples could be analyzed by LC-MS/MS.

CONCLUSIONS

Iothalamate can be quantified by LC-MS/MS for GFR measurement. This method circumvents potential problems with interfering substances that occasionally confound accurate GFR determinations.

Cardiorenal syndrome

Kidney dysfunction in patients with heart failure and cardiovascular disorders in patients with chronic kidney disease are common. A recently proposed consensus definition of cardiorenal syndrome stresses the bidirectional nature of these heart-kidney interactions. The treatment of cardiorenal syndrome is challenging, however, promising new therapeutic options are currently being investigated in recent and ongoing clinical trials.

Mechanisms of the cardiorenal syndromes

The kidney and heart have essential roles in maintaining blood volume homeostasis and in the regulation of systemic blood pressure. Acute or chronic dysfunction in either the heart or kidneys can induce dysfunction in the other organ, resulting in the so-called cardiorenal syndromes, which are classified into five different types. Abrupt worsening of cardiac function predisposes an individual to acute kidney injury from renal hypoperfusion or renal congestion. Progressive, sometimes permanent, chronic kidney impairment can result from chronic renal hypoperfusion or congestion. Heart failure is common in patients with acute kidney injury. Chronic kidney disease predisposes individuals to atherosclerotic, arteriosclerotic and cardiomyopathic disease. Finally, both cardiac and renal disease can also occur secondary to systemic conditions, such as diabetes or autoimmune disease. This Review examines the mechanisms presiding over the first four types of cardiorenal syndromes. These mechanisms provide a template that accounts for the heart-kidney interactions that occur in patients whose concomitant cardiac and renal conditions result from a third cause.

Detection and prognostic impact of renal dysfunction in patients with chronic heart failure and normal serum creatinine

BACKGROUND

Accurate identification of renal dysfunction (RD) is crucial to risk stratification in chronic heart failure (CHF). Patients with CHF are at special risk of having RD despite normal serum creatinine (SCr), owing to a decreased Cr generation. At low levels of SCr, the equations estimating renal function are less accurate. This study was aimed to assess and compare the prognostic value of formulas estimating renal function in CHF patients with normal SCr.

METHODS

We studied 462 patients with systolic CHF and normal SCr. Creatinine clearance was estimated by the Cockcroft-Gault (eCrCl) and glomerular filtration rate by the 4-variable MDRD equation (eGFR); eCrCl normalized for body-surface area (eCrCl(BSA)) was calculated. The primary outcome was all-cause mortality at 2 years.

RESULTS

Seventy five patients died. At multivariate Cox regression analysis, only eCrCl(BSA) was significantly associated with mortality (p = 0.006); eGFR (p = 0.24), eCrCl (p = 0.09) and BUN (p = 0.14) were not statistically significant predictors. The patients in the lowest eCrCl(BSA) quartile had an adjusted 2.1-fold (CI: 1.06-4.1) increased risk of mortality, compared with those in the referent quartile. Two-year survival was 70.4% in the lowest eCrCl(BSA) quartile and 89.7% in the referent quartile. Other independent predictors of mortality were ischemic etiology (RR: 2.16 [CI: 1.3-3.5], p = 0.0017), NYHA III/IV class (RR: 2.45 [CI: 1.51-3.97], p = 0.0003), LVEF <0.25 (RR: 3.38 [CI: 1.69-6.75], p = 0.014), and anemia (RR: 1.86 [CI: 1.16-2.99], p = 0.009).

CONCLUSIONS

A sizeable proportion of CHF patients have prognostically significant RD despite normal SCr. Such patients represent a high-risk subgroup and can more accurately be identified by the CG formula corrected for BSA than the MDRD.

Cystatin C in acute heart failure without advanced renal impairment

BACKGROUND

The prognostic value of cystatin C relative to glomerular filtration rate (GFR) estimated by the Modification of Diet in Renal Disease Study (MDRD) equation modified for Japan has not been investigated in acute heart failure patients with normal to moderately impaired renal function. More accurate detection of mild renal impairment might improve the risk stratification of heart failure patients, especially patients with normal to moderately impaired renal function.

METHODS

Cystatin C and creatinine levels were measured on admission in 328 consecutive patients hospitalized for worsening chronic heart failure with a GFR estimated by MDRD equation modified for Japan >or=30 mL/min/1.73 m(2).

RESULTS

During a median follow-up period of 915 days, there were 52 (16%) cardiac deaths. In stepwise Cox regression analyses including cystatin C and GFR estimated by MDRD equation modified for Japan (either as continuous variables or as variables categorized into quartiles), cystatin C (P <.0001), but not GFR estimated by MDRD equation modified for Japan, was independently associated with cardiac mortality. Adjusted relative risk according to the quartiles of these markers and Kaplan-Meier analyses revealed that the cystatin C was a better marker to separate low-risk from high-risk patients. Furthermore, receiver-operating characteristic curve analyses of these markers revealed that cystatin C showed a higher precision in predicting cardiac mortality.

CONCLUSION

Measurements of cystatin C might improve early risk stratification compared with GFR estimated by MDRD equation modified for Japan in acute heart failure patients with normal to moderately impaired renal function.

Elevated blood urea nitrogen-to-creatinine ratio increased the risk of hospitalization and all-cause death in patients with chronic heart failure

OBJECTIVES

To examine the relationship between blood urea nitrogen (BUN)-to-creatinine ratio and the prognosis of chronic heart failure (HF).

METHODS

We analyzed the data from the cohort of 243 adult patients with chronic HF followed at the HF clinic in a tertiary medical center between December 2003 and June 2006. Primary endpoints were the events of all-cause death and first hospitalization for HF.

RESULTS

During a median follow-up of 1.2 years, 72 events were recorded with an event rate of 25.7 events per 100 person-years. In multivariate-adjusted Cox regression models, elevated BUN-to-creatinine ratio was associated with a heightened risk of hospitalization and all-cause death [hazard ratio (HR), 1.24; 95% confidence interval (CI), 1.02-1.51]. The relationship remained after adjusting for glomerular filtration rate (GFR) (HR, 1.23; 95% CI, 1.01-1.51). There was a linear trend toward increasing risks of adverse outcomes across the tertiles of BUN-to-creatinine ratio (P = 0.02). The coexisting presence of the third tertile of BUN-to-creatinine ratio and GFR < 60 ml/min/1.73 m(2) tended to pose a synergistic risk for hospitalization and all-cause death (relative risk, 2.29), relative to those at the first and second tertiles who had GFR > or = 60 ml/min/1.73 m(2).

CONCLUSIONS

An elevated BUN-to-creatinine ratio, independent of GFR, confers an increased risk of hospitalization and all-cause death in patients with chronic HF.

Prognostic value of formulas estimating excretory renal function in the elderly with systolic heart failure

BACKGROUND

reduced renal excretory function (REF) is increasingly being appreciated as a potent prognostic factor in chronic heart failure (CHF). The Cockroft-Gault (CG) and the simplified Modification of Diet in Renal Disease (MDRD) equations have been recommended to estimate REF. However, limitations for both formulas have been reported in the elderly. Their prognostic performance in older CHF patients has not been investigated.

OBJECTIVES

to assess the factors independently associated with all-cause mortality and compare the prognostic value of formulas estimating REF in CHF patients aged > or =70 years.

DESIGN

a longitudinal study with a median follow-up of 859 days. The end-point was all-cause mortality.

SETTING

Division of Cardiology and Cardiac Rehabilitation.

SUBJECTS

two hundred and sixty-six patients aged > or =70 years with systolic CHF.

METHODS

REF was estimated using the CG (eCrCl(CG)) and the MDRD (eGFR(MDRD)) formulas. Cox proportional hazards model was used to assess the factors independently associated with mortality and compare the prognostic value of estimating formulas. Receiver-operating characteristic (ROC) curve analysis was also performed.

RESULTS

Kaplan-Meier estimates of the rates of death at 1 and 2 years were 85% and 73%, respectively At multivariate analysis, eCrCl(CG) <50 mL/min (P = 0.005), anaemia (P = 0.012), non-prescription of beta-blockers (P = 0.006) and left ventricular ejection fraction (P = 0.03) were the only independent predictors of mortality. On ROC analysis, the eCrCl(CG) was significantly more accurate than the eGFR(MDRD).

CONCLUSIONS

among CHF patients aged > or =70 years, reduced REF is the most powerful independent predictor of survival. The excess in risk conferred by reduced REF is better appraised by means of the CG than the MDRD equation.

Renal and cardiac function for long-term (10 year) risk stratification after myocardial infarction

Aims To determine whether combined renal and cardiac function after acute myocardial infarction (MI) predicts 10 year mortality and heart failure (HF). Methods and results Estimated glomerular filtration rate (eGFR), plasma amino terminal pro-brain natriuretic peptide (NT-proBNP), and radionuclide ventriculography were obtained in 1063 patients with MI between 24-96 h of symptom onset. Mortality and HF were documented over follow-up of 9.3 years. Estimated GFR, NT-proBNP, and left ventricular ejection fraction (LVEF) each independently predicted 10 year mortality. Reduced eGFR (below 60 mL/min/1.73 m(2)) combined with increased NT-proBNP (above 1000 pg/mL) was associated with higher mortality rate compared with preserved eGFR together with lower NT-proBNP (60 vs. 14%, P < 0.001). Similar results for mortality were identified for eGFR combined with LVEF (dichotomized about 50%) (58 vs. 17%, P < 0.001). Corresponding analysis combining eGFR and NT-proBNP to predict HF yielded rates of 34 and 7% for high- and low-risk groups, respectively (P < 0.001). Similar risk stratification for HF was observed when combining eGFR with LVEF (35 vs. 7%, P < 0.001). Conclusion Ten year rates of mortality and HF are 5-10 times higher when lower eGFR is present together with increased NT-proBNP or depressed LVEF.

Anemia: the point of convergence or divergence for kidney disease and heart failure?

Cardiorenal anemia syndrome refers to the simultaneous presence of anemia, heart failure (HF), and chronic kidney disease (CKD) that forms a pathologic triangle with an adverse impact on morbidity and mortality. The reciprocal relationships among these 3 components have been the subject of a number of trials with inconsistent and sometimes paradoxic results. In this paper, the pathophysiologic concepts underlying interactions among these 3 conditions are discussed. Then, the similarities and dissimilarities of the relationships between anemia and either HF or CKD are considered; explanations are provided for differences in the results of the currently available studies. Erythropoietin-stimulating agent protocols are usually based on the results of studies designed for the CKD population, and upper hemoglobin target levels are chosen to avoid cardiovascular complications. It is not yet clear whether those renal guidelines are optimal for patients with HF, especially because those patients may have reversible components of kidney dysfunction, both HF and renal parameters improving with anemia correction. We review these issues and suggest a pragmatic approach to the care of patients with HF until such time that controlled trials establish definitive anemia treatment goals that are dynamic and disease specific, rather than those that adopt a more simplistic hemoglobin-specific approach.

Renal dendritic cells: an update

Discovery into the role of renal dendritic cells (rDCs) in health and disease of the kidney is rapidly accelerating. Progress in deciphering DC precursors and the heterogeneity of monocyte subsets in mice and humans is providing insight into the biology of rDCs. Recent findings have extended knowledge of the origins, anatomy and function of the rDC network at steady state and during periods of injury to the renal parenchyma. This brief review highlights these new findings and provides an update on the study of rDCs.

Importance of venous congestion for worsening of renal function in advanced decompensated heart failure

OBJECTIVES

To determine whether venous congestion, rather than impairment of cardiac output, is primarily associated with the development of worsening renal function (WRF) in patients with advanced decompensated heart failure (ADHF).

BACKGROUND

Reduced cardiac output is traditionally believed to be the main determinant of WRF in patients with ADHF.

METHODS

A total of 145 consecutive patients admitted with ADHF treated with intensive medical therapy guided by pulmonary artery catheter were studied. We defined WRF as an increase of serum creatinine >/=0.3 mg/dl during hospitalization.

RESULTS

In the study cohort (age 57 +/- 14 years, cardiac index 1.9 +/- 0.6 l/min/m(2), left ventricular ejection fraction 20 +/- 8%, serum creatinine 1.7 +/- 0.9 mg/dl), 58 patients (40%) developed WRF. Patients who developed WRF had a greater central venous pressure (CVP) on admission (18 +/- 7 mm Hg vs. 12 +/- 6 mm Hg, p < 0.001) and after intensive medical therapy (11 +/- 8 mm Hg vs. 8 +/- 5 mm Hg, p = 0.04). The development of WRF occurred less frequently in patients who achieved a CVP <8 mm Hg (p = 0.01). Furthermore, the ability of CVP to stratify risk for development of WRF was apparent across the spectrum of systemic blood pressure, pulmonary capillary wedge pressure, cardiac index, and estimated glomerular filtration rates.

CONCLUSIONS

Venous congestion is the most important hemodynamic factor driving WRF in decompensated patients with advanced heart failure.

Cystatin C and NT-proBNP, a powerful combination of biomarkers for predicting cardiovascular mortality in elderly patients with heart failure: results from a 10-year study in primary care

AIMS

Heart failure (HF) is common among the elderly patients. It is essential to identify those at high risk in order to optimize the use of resources. We aimed to evaluate whether a combination of two biomarkers might give better prognostic information about the risk of cardiovascular (CV) mortality in patients with symptoms associated with HF, compared with only one biomarker.

METHODS AND RESULTS

Four hundred and sixty-four primary health-care patients (mean age 73 years, range 65-87) with symptoms of HF were examined. All patients were evaluated using Doppler echocardiography and blood samples, including measurement of cystatin C and NT-proBNP. The patients were followed over a 10-year period. Patients with serum cystatin C levels within the highest quartile had almost three times the risk (HR: 2.92; 95% CI: 1.23-4.90) of CV mortality compared with those patients who had levels within the first, second, or third quartiles. If, at the same time, the patient had a plasma concentration of NT-proBNP within the highest quartile, the risk increased to >13 times (HR: 13.61; 95% CI: 2.56-72.24) during 10 years of follow-up or >17 times (HR: 17.04; 95% CI: 1.80-163.39) after 5 years of follow-up.

CONCLUSION

Combined analysis of cystatin C and NT-proBNP could provide important prognostic information among elderly patients in the community with symptoms of HF.

High prevalence of stage 3 chronic kidney disease in older adults despite normal serum creatinine

BACKGROUND

Serum creatinine is commonly used to diagnose chronic kidney disease (CKD), but may underestimate CKD in older adults when compared with using glomerular filtration rates (eGFR). The magnitude of this underestimation is not clearly defined.

OBJECTIVE

Using the Modification of Diet in Renal Disease (MDRD) equation, to describe both the prevalence and the magnitude of underestimation of stage 3 CKD (GFR 30-59 ml/min/1.73 m(2)), as well as ideal serum creatinine cutoff values to diagnose stage 3 CKD among Americans > or =65 years of age.

DESIGN

Cross-sectional.

PARTICIPANTS

A total of 3,406 participants > or =65 years of age from the 1999-2004 National Health and Nutrition Examination Surveys (NHANES).

MEASUREMENTS

Serum creatinine levels were used to determine eGFR from the MDRD equation. Information on clinical conditions was self-reported.

RESULTS

Overall, 36.1% of older adults in the US have stage 3 or greater CKD as defined by eGFR values. Among older adults with stage 3 CKD, 80.6% had creatinine values < or =1.5 mg/dl, and 38.6% had creatinine values < or =1.2 mg/dl. Optimal cutoff values for serum creatinine in the diagnosis of stage 3 CKD in older adults were > or =1.3 mg/dl for men and > or =1.0 mg/dl for women, regardless of the presence or absence of hypertension, diabetes, or congestive heart failure.

CONCLUSION

Use of serum creatinine underestimates the presence of advanced (stage 3 or greater) CKD among older adults in the US. Automated eGFR reporting may improve the accuracy of risk stratification for older adults with CKD.

Predictive Value of Myocardial Perfusion Single-Photon Emission Computed Tomography and the Impact of Renal Function on Cardiac Death

Background— Patients with chronic kidney disease (CKD) have worse cardiovascular outcomes than those without CKD. The prognostic utility of myocardial perfusion single-photon emission CT (MPS) in patients with varying degrees of renal dysfunction and the impact of CKD on cardiac death prediction in patients undergoing MPS have not been investigated.

Methods and Results— We followed up 1652 consecutive patients who underwent stress MPS (32% exercise, 95% gated) for cardiac death for a mean of 2.15±0.8 years. MPS defects were defined with a summed stress score (normal summed stress score <4, abnormal summed stress score≥4). Ischemia was defined as a summed stress score ≥4 plus a summed difference score ≥2, and scar was defined as a summed difference score <2 plus a summed stress score ≥4. Renal function was calculated with the Modified Diet in Renal Disease equation. CKD (estimated glomerular filtration rate <60 mL · min −1 · 1.73 m −2 ) was present in 36%. Cardiac death increased with worsening levels of perfusion defects across the entire spectrum of renal function. Presence of ischemia was independently predictive of cardiac death, all-cause mortality, and nonfatal myocardial infarction. Patients with normal MPS and CKD had higher unadjusted cardiac death event rates than those with no CKD and normal MPS (2.7% versus 0.8%, P =0.001). Multivariate Cox proportional hazards models revealed that both perfusion defects (hazard ratio 1.90, 95% CI 1.47 to 2.46) and CKD (hazard ratio 1.96, 95% CI 1.29 to 2.95) were independent predictors of cardiac death after accounting for risk factors, left ventricular dysfunction, pharmacological stress, and symptom status. Both MPS and CKD had incremental power for cardiac death prediction over baseline risk factors and left ventricular dysfunction (global χ 2 207.5 versus 169.3, P <0.0001).

Conclusions— MPS provides effective risk stratification across the entire spectrum of renal function. Renal dysfunction is also an important independent predictor of cardiac death in patients undergoing MPS. Renal function and MPS have additive value in risk stratisfying patients with suspected coronary artery disease. Patients with CKD appear to have a relatively less benign prognosis than those without CKD, even in the presence of a normal scan.

Metformin use in decompensated heart failure

Metformin is associated with decreased mortality and morbidity in stable heart failure patients with diabetes mellitus type II. Diabetic heart failure patients with elevated systolic blood pressure are at increased risk for developing acute decompensated heart failure, which is often associated with decreased kidney function. Metformin-associated lactic acidosis is a rare but fatal side effect that may occur when kidney function is decreased. During acute decompensated heart failure, timely treatment may prevent the decrease in kidney function to the threshold associated with an increased risk of metformin-associated lactic acidosis. Metformin should not be withheld in diabetic patients with stable heart failure who do not have other risk factors for acute decompensated heart failure or lactic acidosis.