Markers of renal function and acute kidney injury in acute heart failure: definitions and impact on outcomes of the cardiorenal syndrome

Incidence, mortality, and predictors of acute kidney injury in patients with heart failure: a systematic review

Acute kidney injury (AKI) is common in patients with heart failure (HF), but studies have been inconsistent about the incidence of AKI in patients with HF. We conducted a meta-analysis to examine the incidence of AKI and its impact on mortality in patients with HF. We also looked at inpatient variables that could predict the development of AKI to identify potential risk factors, so that these can be used as a starting point for intervention and prevention in this group. The Embase, Medline, PubMed, Cochrane libraries, and Web of Science databases were used for searching articles from the inception of the database to October 2022. The EndNote software was used for screening. Meta-analysis was performed using Stata 16.0 software to combine effect sizes. A total of 37 studies were included. Of all the 3 533 583 patients with HF, 774 887 had AKI, with a pooled incidence of 33% [95% confidence interval (CI): 32-35%]. The incidence rate of AKI in acute HF and chronic HF was 36% (95% CI: 31-40%) and 30% (95% CI: 24-35%), respectively. Eleven studies found that AKI patients had higher in-hospital mortality than non-AKI patients [risk ratio (RR): 3.65; 95% CI: 3.04-4.39, P < 0.001]. Mortality was assessed in five studies, and it was found that mortality remained high at 1-year follow-up after onset of AKI (RR: 1.85, 95% CI: 1.54-2.22, P < 0.001). Fifteen admission variables were included and analysed in 13 studies. The combined results showed that diabetes, hypertension, history of chronic kidney disease, chronic HF systolic, age, N-terminal pro-B-type natriuretic peptide, creatinine > 1.0 mg/dL, index estimated glomerular filtration rate < 60 mL/min/1.73 m2 , blood urea nitrogen > 24 mg/dL, intravenous dobutamine, and serum albumin were predictor factors for HF patients with AKI (P < 0.05). In this meta-analysis, AKI occurred in approximately 33% of HF patients during hospitalization and the risk of dying in the hospital was tripled. Even during 1-year long-term follow-up, the risk of death remained high, and multiple inpatient variables showed that HF patients tended to have AKI. Early intervention and treatment are important to reduce the incidence of AKI and improve the prognosis.

Patient Selection and End Point Definitions for Decongestion Studies in Acute Decompensated Heart Failure: Part 1

Despite recent advances in the treatment of patients with chronic heart failure, acute decompensated heart failure remains associated with significant mortality and morbidity because many novel therapies have failed to demonstrate meaningful benefit. Persistent congestion in the setting of escalating diuretic therapy has been repeatedly shown to be a marker of poor prognosis and is currently being targeted by various emerging device-based therapies. Because these therapies inherently carry procedural risk, patient selection is key in the future trial design. However, it remains unclear which patients are at a higher risk of residual congestion or adverse outcomes despite maximally tolerated decongestive therapy. In the first part of this 2-part review, we aimed to outline patient risk factors and summarize current evidence for early recognition of high-risk profile for residual congestion and adverse outcomes. These factors are classified as relating to the following: (1) previous clinical course, (2) severity of congestion, (3) diuretic response, and (4) degree of renal impairment. We also aimed to provide an overview of key inclusion criteria in recent acute decompensated heart failure trials and investigational device studies and propose potential criteria for selection of high-risk patients in future trials.

The Association Between Intra-abdominal Pressure and Diuretic Response in Heart Failure

PURPOSE OF THE REVIEW

An efficient diuretic response is vital during cardiac decompensation in heart failure (HF) patients. The increase in intra-abdominal pressure (IAP) could be one of the keys for understanding cardiorenal syndrome and guiding diuretic treatment during hospitalization. In this review, we analyze the relationship between IAP and diuretic response in HF patients.

RECENT FINDINGS

Increased IAP is associated with worsening renal function (WRF) in patients with advanced HF. Furthermore, the persistence of a rise in IAP after the first 72 h of intravenous diuretic treatment has been correlated with a worse diuretic response, a higher degree of congestion, and an impaired prognosis. The rise in IAP in HF patients has been associated with impaired renal function and a lower diuretic response. Nonetheless, more studies are needed to elucidate the actual role of IAP in congestive nephropathy and whether it may help guide diuretic therapy during acute decompensations.

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

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

New Insight in Cardiorenal Syndrome: From Biomarkers to Therapy

Cardiorenal syndrome consists in the coexistence of acute or chronic dysfunction of heart and kidneys resulting in a cascade of feedback mechanisms and causing damage to both organs associated with high morbidity and mortality. In the last few years, different biomarkers have been investigated with the aim to achieve an early and accurate diagnosis of cardiorenal syndrome, to provide a prognostic role and to guide the development of targeted pharmacological and non-pharmacological therapies. In such a context, sodium-glucose cotransporter 2 (SGLT2) inhibitors, recommended as the first-line choice in the management of heart failure, might represent a promising strategy in the management of cardiorenal syndrome due to their efficacy in reducing both cardiac and renal outcomes. In this review, we will discuss the current knowledge on the pathophysiology of cardiorenal syndrome in adults, as well as the utility of biomarkers in cardiac and kidney dysfunction and potential insights into novel therapeutics.

Incidence, severity, risk factors and outcomes of acute kidney injury in older adults: systematic review and meta-analysis

OBJECTIVES

Old age was identified as a strong risk factor for acute kidney injury (AKI). Our objectives were to provide estimates of AKI, risk factors and outcomes in patients ≥ 75 years for whom data are scarce.

METHODS

Observational studies and randomized controlled trials between 2005 and 2021 with patients of mean or median age ≥ 75 years, reporting AKI according to current definitions. Data on AKI incidence, risk factors and mortality were analyzed separately in unselected (UC) and acute heart failure (AHF) cohorts.

RESULTS

Twenty-six observational studies and 4 randomized controlled trials with 51,111 UC and 25,414 AHF patients were included. Ages averaged 79.4 and 79.8 years, respectively. Pooled risk ratios (RRs) of AKI rates were 26.29% (95% confidence intervals (CI) 13.20-41.97) (UC) and 24.21% (95% CI 20.03-28.65) (AHF). In both cohorts, AKI was associated with decreased estimated glomerular filtration rate at baseline, chronic kidney disease (UC: RR 1.80 (95% CI 1.15-2.80), AHF: RR 1.51 (95% CI 1.26-1.95) and hypertension (UC: RR 1.30 (95% CI 1.09-1.56), AHF: RR 1.07 (95% CI 1.05-1.09). RRs of AKI in patients on renin-angiotensin-inhibitors were 0.87 (95% CI 0.78-0.97) and 0.88 (95% CI 0.78-0.98) in UC and AHF, respectively. AKI was consistently associated with increased risk of in-hospital mortality (UC: RR 3.15 (95% CI 2.28-4.35), AHF: RR 4.28 (95% CI 2.53-7.24).

CONCLUSION

AKI is frequent in patients ≥ 75 years. While reduced renal function at baseline, CKD and hypertension were associated with AKI development, renin-angiotensin-inhibitors may be protective. Older AKI patients showed higher short-term mortality rates.

New aspects in cardiorenal syndrome and HFpEF

Cardiorenal syndrome (CRS) is a complex disease in which the heart and kidneys are simultaneously affected, and subsequently, the malfunction of one organ promotes the deterioration of the other. Heart failure (HF) with preserved ejection fraction (HFpEF) is the most common form of HF. The pathophysiology of CRS is not well known and several mechanisms have been proposed. An elevation of central venous pressure seems to be one of the key points to consider, among others such as an increase in intraabdominal pressure. Several diagnostic tools have been identified to establish the diagnosis of CRS in patients with HFpEF. Currently, the availability of biomarkers of renal and cardiac injury, the use of pulmonary ultrasound, the monitoring of the size of the inferior vena cava and the study of the renal venous pattern offer a new dimension in accurately diagnosing and quantifying organ damage in CRS. Beyond the symptomatic treatment of congestion, until recently specific therapeutic tools for patients with CRS and HFpEF were not available. Interestingly, the development of new drugs such as the angiotensin/neprilysin inhibitors and sodium-glucose cotransporter-2 (SGLT-2) inhibitors offer new therapeutic strategies with potential benefits in reduction of cardiorenal adverse outcomes in this population. Randomized clinical trials that focus on patients with HFpEF are currently ongoing to delineate optimal new treatments that may be able to modify their prognosis. In addition, multidisciplinary teamwork (nephrologist, cardiologist and nurse) is expected to decrease the number of visits and the rate of hospitalizations, with a subsequent patient benefit.

Serum Myoglobin Is Associated With Postoperative Acute Kidney Injury in Stanford Type A Aortic Dissection

Background

The correlation between rhabdomyolysis and postoperative acute kidney injury has been reported in several surgical procedures. As a good predictor of rhabdomyolysis-related acute kidney injury, an elevated serum myoglobin level was often observed after total aortic arch replacement combined with frozen elephant trunk implantation. However, the correlation between serum myoglobin and acute kidney injury in such patients had not been established.

Methods

Totally 398 stanford type A aortic dissection patients who underwent total aortic arch replacement combined with frozen elephant trunk implantation were enrolled in this retrospective study. The correlations between serum myoglobin and acute kidney injury as well as the 30-day mortality were assessed.

Results

Overall, 268(67.3%) patients had acute kidney injury (KDIGO stage 1 or higher) and 75(18.8%) had severe acute kidney injury (KDIGO stage 2&3). Patients who developed acute kidney injury had higher level of perioperative serum myoglobin than patients without acute kidney injury. After adjusting for known acute kidney injury risk factors, logarithmically transformed preoperative serum myoglobin [OR = 1.58 (95% CI, 1.26–1.95), P < 0.001] and postoperative day 1 serum myoglobin [OR = 3.47 (95%CI, 2.27–5.29), P < 0.001] were associated with severe acute kidney injury. These correlation persisted after adjustment for decline in filtration via change in serum creatinine (ΔCr) and biomarkers of cardiac and kidney injury, including N-terminal prohormone of brain natriuretic peptide, cardiac troponin I, creatine kinase-MB, serum creatinine and Cystatin C. Compared with the clinical model, sMb considerably improved the risk discrimination and reclassification for AKI.

Conclusion

For stanford type A aortic dissection patients underwent total aortic arch replacement with frozen elephant trunk implantation, serum myoglobin can improve postoperative acute kidney injury risk classification. Rhabdomyolysis may be an important supplement to the existing knowledge on the mechanism of acute kidney injury.

Identifying patients with heart failure in susceptible to de novo acute kidney injury: a machine learning approach (Preprint)

Background

Studies have shown that more than half of patients with heart failure (HF) with acute kidney injury (AKI) have newonset AKI, and renal function evaluation markers such as estimated glomerular filtration rate are usually not repeatedly tested during the hospitalization. As an independent risk factor, delayed AKI recognition has been shown to be associated with the adverse events of patients with HF, such as chronic kidney disease and death.

Objective

The aim of this study is to develop and assess of an unsupervised machine learning model that identifies patients with HF and normal renal function but who are susceptible to de novo AKI.

Methods

We analyzed an electronic health record data set that included 5075 patients admitted for HF with normal renal function, from which 2 phenogroups were categorized using an unsupervised machine learning algorithm called K-means clustering. We then determined whether the inferred phenogroup index had the potential to be an essential risk indicator by conducting survival analysis, AKI prediction, and the hazard ratio test.

Results

The AKI incidence rate in the generated phenogroup 2 was significantly higher than that in phenogroup 1 (group 1: 106/2823, 3.75%; group 2: 259/2252, 11.50%; P<.001). The survival rate of phenogroup 2 was consistently lower than that of phenogroup 1 (P<.005). According to logistic regression, the univariate model using the phenogroup index achieved promising performance in AKI prediction (sensitivity 0.710). The generated phenogroup index was also significant in serving as a risk indicator for AKI (hazard ratio 3.20, 95% CI 2.55-4.01). Consistent results were yielded by applying the proposed model on an external validation data set extracted from Medical Information Mart for Intensive Care (MIMIC) III pertaining to 1006 patients with HF and normal renal function.

Conclusions

According to a machine learning analysis on electronic health record data, patients with HF who had normal renal function were clustered into separate phenogroups associated with different risk levels of de novo AKI. Our investigation suggests that using machine learning can facilitate patient phengrouping and stratification in clinical settings where the identification of high-risk patients has been challenging.

Insights of Worsening Renal Function in Type 1 Cardiorenal Syndrome: From the Pathogenesis, Biomarkers to Treatment

Type-1 cardiorenal syndrome refers to acute kidney injury induced by acute worsening cardiac function. Worsening renal function is a strong and independent predictive factor for poor prognosis. Currently, several problems of the type-1 cardiorenal syndrome have not been fully elucidated. The pathogenesis mechanism of renal dysfunction is unclear. Besides, the diagnostic efficiency, sensitivity, and specificity of the existing biomarkers are doubtful. Furthermore, the renal safety of the therapeutic strategies for acute heart failure (AHF) is still ambiguous. Based on these issues, we systematically summarized and depicted the research actualities and predicaments of the pathogenesis, diagnostic markers, and therapeutic strategies of worsening renal function in type-1 cardiorenal syndrome.

Comparison of renal impairment post-myocardial infarction with reduced and preserved left ventricular function in rats with normal renal function

This study aimed to compare the renal impairments in post-myocardial infarction (MI) rats with normal renal biochemical parameters at baseline with versus without cardiac dysfunction and explore the potential mechanisms involved in these differences. Sprague-Dawley rats with permanent ligation of coronary artery were used as MI models. Renal function, histological and molecular changes were compared between the reduced ejection fraction (EF) (EF < 40%) group and the preserved EF (EF ≥ 40%) group 3 or 9 weeks post-MI. The results revealed that blood cystatin C increased significantly at 9 but not 3 weeks, but it was not associated with cardiac dysfunction. Renal fibrosis and inflammatory cell infiltrations increased significantly in the reduced EF group than in the preserved EF group at 3 and 9 weeks. Glomerular podocyte injury, identified by increased immunostaining for desmin and decreased immunostaining for Wilms' tumor-1, was more significant in the reduced EF group than in the preserved EF group at 9, but not 3 weeks. The number of p16^ink4a-positive and 8-hydroxy-2'-deoxyguanosine-positive podocytes was greater in the reduced EF group than in the preserved EF group at both time points. These changes were associated with increased expression of angiotensin II type 1/2 receptors at both time points. In conclusion, our study demonstrated that cardiac dysfunction accounted for substantially severity in renal parenchymal impairment in a partially time-dependent manner, and local activation of angiotensin II receptors, increased cell senescence and oxidative stress, and enhanced inflammatory reaction may be potential modulators participated in the deterioration of renal parenchymal injury.

Value of Plasma NGAL and Creatinine on First Day of Admission in the Diagnosis of Cardiorenal Syndrome Type 1

Background

The presence of acute kidney injury in the setting of acute heart failure (AHF) or acute decompensated heart failure (ADHF) is a very common occurrence and was termed cardiorenal syndrome 1 (CRS1). Neutrophil gelatinase-associated lipocalin (NGAL) in the blood and urine is one of the earliest biomarkers of acute kidney injury due to ischemia or renal toxicity. This study was aimed to evaluate the diagnostic efficacy of plasma NGAL in the diagnosis of CRS1.

Methods

There were 139 patients with AHF or ADHF in the department of Cardiovascular Resuscitation and Interventional Cardiology at Ho Chi Minh City 115 People Hospital from September 2018 to March 2019. This was a prospective cohort study.

Results

There were 48 cases (rate 34.5%) with CRS1, mean age was 66.12 ± 15.77 and men accounted for 50.4%. There were no significant differences of vital signs at admission, diagnosis, and EF-based heart failure between CRS1 and non-CRS1 groups. The urea, creatinine on first day (creatinine D1) and third day (creatinine D3), NT-proBNP, and NGAL levels were higher in the CRS1 group than the non-CRS1 group, p < 0.05. The optimal cutoff plasma NGAL for diagnosing CRS1 was >353.23 ng/ml, area under curve (AUC) 0.732 (95% CI 0.65-0.80, p < 0.001), sensitivity 74.47%, specificity 68.48%, positive predictive value 54.7%, and negative predictive value 84%. Multivariable logistic regression analysis eGFR_CKDEPID1 remained the strongest independent predictor of CRS1. Building the optimal regression model (without eGFRCKDEPID1) by the BMA (Bayesian model average) method with two variables NGAL and Creatinine D1, we had the equation: odds ratio = e _y while y = -2.39 + 0.0037 × NGAL + 0.17 × Creatinine D1. The nomogram (without eGFR_CKDEPID1) was designed to predict the likelihood of CRS1 with AUC 0.79.

Conclusions

The combination of plasma NGAL and creatinine D1 on the first day at admission had a high accuracy of predictive model for CRS1.

New renal haemodynamic indices can predict worsening of renal function in acute decompensated heart failure

AIMS

Worsening of renal function (WRF) is a common complication in patients with acute decompensated heart failure (ADHF). We aimed to evaluate the role of intrarenal Doppler ultrasound (IRD) in the early prediction of WRF in this patient group.

METHODS AND RESULTS

Among 90 patients (age: 57.5 ± 11.1 years; 62% male) hospitalized with ADHF, resistivity index (RI), acceleration time (AT), and pulsatility index (PI) were measured on admission and at 24 and 72 h. WRF was defined as increased serum creatinine ≥0.3 mg/dL from baseline. Adverse clinical outcomes were defined as the composite of death, use of vasopressors, and need for ultrafiltration for refractory oedema. WRF developed in 40% of patients. Mean values of renal AT, RI, and PI on admission were 59.7 ± 15, 0.717 ± 0.08, and 1.5 ± 0.48 ms, respectively. At 24 h, there was significant decrease in AT (to 56.7 ± 10 ms, P = 0.02) and renal RI (to 0.732 ± 0.07; P < 0.001); these changes were maintained up to 72 h. Renal PI showed no significant changes. Independent predictors of WRF were renal AT at 24 h and admission values of renal RI, left ventricular ejection fraction, and plasma cystatin C. Renal AT at 24 h ≥ 57.8 ms had 89% sensitivity and 70% specificity for the prediction of WRF. Independent predictors for adverse clinical outcomes were left ventricular end systolic dimension and WRF.

CONCLUSIONS

Among ADHF patients receiving diuretic therapy, measurement of renal AT and RI by IRD can help identify patients at increased risk for WRF.

The future for diagnostic tests of acute kidney injury in critical care: evidence synthesis, care pathway analysis and research prioritisation

BACKGROUND

Acute kidney injury (AKI) is highly prevalent in hospital inpatient populations, leading to significant mortality and morbidity, reduced quality of life and high short- and long-term health-care costs for the NHS. New diagnostic tests may offer an earlier diagnosis or improved care, but evidence of benefit to patients and of value to the NHS is required before national adoption.

OBJECTIVES

To evaluate the potential for AKI in vitro diagnostic tests to enhance the NHS care of patients admitted to the intensive care unit (ICU) and identify an efficient supporting research strategy.

DATA SOURCES

We searched ClinicalTrials.gov, The Cochrane Library databases, Embase, Health Management Information Consortium, International Clinical Trials Registry Platform, MEDLINE, metaRegister of Current Controlled Trials, PubMed and Web of Science databases from their inception dates until September 2014 (review 1), November 2015 (review 2) and July 2015 (economic model). Details of databases used for each review and coverage dates are listed in the main report.

REVIEW METHODS

The AKI-Diagnostics project included horizon scanning, systematic reviewing, meta-analysis of sensitivity and specificity, appraisal of analytical validity, care pathway analysis, model-based lifetime economic evaluation from a UK NHS perspective and value of information (VOI) analysis.

RESULTS

The horizon-scanning search identified 152 potential tests and biomarkers. Three tests, Nephrocheck^® (Astute Medical, Inc., San Diego, CA, USA), NGAL and cystatin C, were subjected to detailed review. The meta-analysis was limited by variable reporting standards, study quality and heterogeneity, but sensitivity was between 0.54 and 0.92 and specificity was between 0.49 and 0.95 depending on the test. A bespoke critical appraisal framework demonstrated that analytical validity was also poorly reported in many instances. In the economic model the incremental cost-effectiveness ratios ranged from £11,476 to £19,324 per quality-adjusted life-year (QALY), with a probability of cost-effectiveness between 48% and 54% when tests were compared with current standard care.

LIMITATIONS

The major limitation in the evidence on tests was the heterogeneity between studies in the definitions of AKI and the timing of testing.

CONCLUSIONS

Diagnostic tests for AKI in the ICU offer the potential to improve patient care and add value to the NHS, but cost-effectiveness remains highly uncertain. Further research should focus on the mechanisms by which a new test might change current care processes in the ICU and the subsequent cost and QALY implications. The VOI analysis suggested that further observational research to better define the prevalence of AKI developing in the ICU would be worthwhile. A formal randomised controlled trial of biomarker use linked to a standardised AKI care pathway is necessary to provide definitive evidence on whether or not adoption of tests by the NHS would be of value.

STUDY REGISTRATION

The systematic review within this study is registered as PROSPERO CRD42014013919.

FUNDING

The National Institute for Health Research Health Technology Assessment programme.

Systemic inflammation in acute cardiorenal syndrome: an observational pilot study

AIMS

Acute cardiorenal syndrome (CRS) with and without consideration of the volume state was assessed with regard to inflammatory parameters.

METHODS AND RESULTS

Blood samples from patients with acute CRS (Ronco type 1 or 3, Group 1, n = 15), end-stage renal disease (Group 2, n = 12), hypertension (Group 3, n = 15), and, in a second cohort, with acute CRS and hypervolemia (Group 4, n = 9) and hypertension (Group 5, n = 10) were analysed with regard to lipopolysaccharide-binding protein (LBP), interleukins (ILs), and monocyte function (flow cytometry) both on admission (all groups) and on discharge (Groups 1 and 4). By discharge, one Group 1 patient died. LBP (ANOVA for Groups 1-3: P = 0.001) and IL-6 (Kruskal-Wallis for Groups 1-3: P < 0.0001) were higher in Group 1 (LBP: 11.7 ± 2.0 μg/mL; IL-6: 15.0 ± 6.1 pg/mL) and in Group 2 (LBP: 10.4 ± 1.4 μg/mL; IL-6: 14.6 ± 3.8 pg/mL) than in Group 3 (LBP: 5.8 ± 0.4 μg/mL; IL-6: 1.8 ± 0.4 pg/mL). In a direct comparison, the proportion of activated monocytes (CD14 and CD16 positive) was higher in Group 1 (6.9% ± 0.7%) vs. Group 3 (5.1% ± 0.6%; P = 0.018). Group 4 patients had higher IL-6 plasma levels (34.2 ± 10.1 pg/mL) than Group 1 patients (15.0 ± 6.1 pg/mL; P = 0.03). All other findings obtained in CRS groups (Groups 1 and 4) were comparable.

CONCLUSIONS

In acute CRS, a state of systemic inflammation was found, which is comparable with the end-stage renal disease situation. In comparison with hypertensive controls, a monocytic activation was found in acute CRS regardless of volume state.

Pathophysiology of acute heart failure syndrome: a knowledge gap

Although much remains unknown regarding the pathophysiology of acute heart failure (AHF), precipitating events are thought to involve a complex set of interactions between the heart, kidneys, and peripheral vasculature. In addition to these interactions, which are considered the primary abnormalities in patients with AHF, several other organ systems may also be affected and contribute to disease progression. Currently available scientific literature suggests that the natural history and pathophysiology of AHF consists of two phases: (1) an "initiation phase" involving a series of triggering events, and (2) an "amplification phase," in which multiple mechanisms contribute to worsening HF and exacerbate end-organ damage. Biomarkers of cardiac, renal, pulmonary, and other organ function have been identified during episodes of AHF, including brain natriuretic peptide, troponin I, and troponin T; biomarkers associated with AHF have proven to be useful tools for studying the pathophysiology of the syndrome, predicting clinical outcomes, and identifying patient management strategies. Despite considerable advances in recent years, AHF continues to be a leading cause of hospitalization and death in patients with chronic HF. Moreover, AHF remains a major healthcare issue exacting a considerable cost burden. Addressing this ongoing unmet need requires prioritizing efforts to better understand the natural history and pathophysiology of AHF; only then can targeted therapies be developed to prevent rehospitalization in patients with AHF, or at least alter the trajectory of disease progression toward improved clinical outcomes.

Development of biomarker combinations for postoperative acute kidney injury via Bayesian model selection in a multicenter cohort study

Background

Acute kidney injury (AKI) is a frequent complication of cardiac surgery. We sought prognostic combinations of postoperative biomarkers measured within 6 h of surgery, potentially in combination with cardiopulmonary bypass time (to account for the degree of insult to the kidney). We used data from a large cohort of patients and adapted methods for developing biomarker combinations to account for the multicenter design of the study.

Methods

The primary endpoint was sustained mild AKI, defined as an increase of 50% or more in serum creatinine over preoperative levels lasting at least 2 days during the hospital stay. Severe AKI (secondary endpoint) was defined as a serum creatinine increase of 100% or more or dialysis during hospitalization. Data were from a cohort of 1219 adults undergoing cardiac surgery at 6 medical centers; among these, 117 developed sustained mild AKI and 60 developed severe AKI. We considered cardiopulmonary bypass time and 22 biomarkers as candidate predictors. We adapted Bayesian model averaging methods to develop center-adjusted combinations for sustained mild AKI by (1) maximizing the posterior model probability and (2) retaining predictors with posterior variable probabilities above 0.5. We used resampling-based methods to avoid optimistic bias in evaluating the biomarker combinations.

Results

The maximum posterior model probability combination included plasma N-terminal-pro-B-type natriuretic peptide, plasma heart-type fatty acid binding protein, and change in serum creatinine from before to 0-6 h after surgery; the median probability combination additionally included plasma interleukin-6. The center-adjusted, optimism-corrected AUCs for these combinations were 0.80 (95% CI: 0.78, 0.87) and 0.81 (0.78, 0.87), respectively, for predicting sustained mild AKI, and 0.81 (0.76, 0.90) and 0.83 (0.76, 0.90), respectively, for predicting severe AKI. For these data, the Bayesian model averaging methods yielded combinations with prognostic capacity comparable to that achieved by standard frequentist methods but with more parsimonious models.

Conclusions

Pending external validation, the identified combinations could be used to identify individuals at high risk of AKI immediately after cardiac surgery and could facilitate clinical trials of renoprotective agents.

Diagnostic and prognostic value of cystatin C in acute heart failure

BACKGROUND

The accurate early diagnosis of acute kidney injury (AKI) in patients with acute heart failure (AHF) is an unmet clinical need. Cystatin C might improve the early detection of AKI.

METHODS

207 patients presenting to the emergency department with AHF were enrolled. Cystatin C was measured in plasma in a blinded fashion at presentation and serially thereafter. The potential of Cystatin C levels to predict AKI was assessed as the primary endpoint. Long-term mortality was assessed as a secondary endpoint.

RESULTS

At presentation, creatinine (140μmol/L [91-203] vs. 97μmol/L [76-132], p<0.01) and Cystatin C (2.00mg/L [1.30-3.08] vs. 1.45mg/L [1.00-1.90], p<0.01) levels were significantly higher in AKI compared to Non-AKI patients. The diagnostic accuracy for AKI quantified by the area under the receiver operating characteristic curve was mediocre and comparable for both markers (creatinine 0.68; 95%CI 0.58-78 vs. Cystatin C 0.67; 95%CI 0.58-0.76). Serial measurements of Cystatin C did not further increase the prognostic accuracy for AKI. Cystatin C levels were significantly higher in decedents than in survivors (1.90mg/L [1.30-2.70] vs. 1.30mg/L [1.0-1.6], p<0.001). The combination of Cystatin C and BNP levels significantly improved the prediction of mortality provided by either parameter alone. In multivariable regression analysis Cystatin C remained independently associated with mortality (HR 1.41; 95%CI 1.02-1.95).

CONCLUSION

Plasma Cystatin C levels do not adequately predict AKI in patients with AHF. However, in multivariable regression analysis Cystatin C predicted mortality after the adjustment for baseline renal function, AKI, BNP levels and heart failure risk factors.

Organ dysfunction, injury and failure in acute heart failure: from pathophysiology to diagnosis and management. A review on behalf of the Acute Heart Failure Committee of the Heart Failure Association (HFA) of the European Society of Cardiology (ESC)

Organ injury and impairment are commonly observed in patients with acute heart failure (AHF), and congestion is an essential pathophysiological mechanism of impaired organ function. Congestion is the predominant clinical profile in most patients with AHF; a smaller proportion presents with peripheral hypoperfusion or cardiogenic shock. Hypoperfusion further deteriorates organ function. The injury and dysfunction of target organs (i.e. heart, lungs, kidneys, liver, intestine, brain) in the setting of AHF are associated with increased risk for mortality. Improvement in organ function after decongestive therapies has been associated with a lower risk for post-discharge mortality. Thus, the prevention and correction of organ dysfunction represent a therapeutic target of interest in AHF and should be evaluated in clinical trials. Treatment strategies that specifically prevent, reduce or reverse organ dysfunction remain to be identified and evaluated to determine if such interventions impact mortality, morbidity and patient-centred outcomes. This paper reflects current understanding among experts of the presentation and management of organ impairment in AHF and suggests priorities for future research to advance the field.

Serelaxin in clinical development: past, present and future

The availability of highly purified recombinant human relaxin, serelaxin, has allowed clinical trials to be conducted in several indications and the elucidation of its pharmacology in human subjects. These studies have demonstrated that serelaxin has unique haemodynamic properties that are likely to contribute to organ protection and long-term outcome benefits in acute heart failure. Clinical observations support its consideration for therapeutic use in other patient populations, including those with chronic heart failure, coronary artery disease, portal hypertension and acute renal failure.

LINKED ARTICLES

This article is part of a themed section on Recent Progress in the Understanding of Relaxin Family Peptides and their Receptors. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v174.10/issuetoc.

Cardiorenal Syndrome in Western Countries: Epidemiology, Diagnosis and Management Approaches

BACKGROUND

It is well established that a large number of hospitalized patients present various degrees of heart and kidney dysfunction; primary disease of the heart or kidney often involves dysfunction or injury to the other.

SUMMARY

Based on above-cited organ cross-talk, the term cardiorenal syndrome (CRS) was proposed. Although CRS was usually referred to as abruption of kidney function following heart injury, it is now clearly established that it can describe negative effects of an impaired renal function on the heart and circulation. The historical lack of clear syndrome definition and complexity of diseases contributed to a waste of precious time especially concerning diagnosis and therapeutic strategies. The effective classification of CRS proposed in a Consensus Conference by the Acute Dialysis Quality Group essentially divides CRS into two main groups, cardiorenal and renocardiac CRS, on the basis of primum movens of disease (cardiac or renal); both cardiorenal and renocardiac CRS are then divided into acute and chronic according to disease onset. Type 5 CRS integrates all cardiorenal involvement induced by systemic disease.

KEY MESSAGES

Prevalence and incidence data show a widespread increase of CRS also due to an increasing incidence of acute and chronic cardiovascular disease, such as acute decompensated heart failure, arterial hypertension and valvular heart disease. Patients with chronic kidney disease present various degrees of cardiovascular involvement especially due to chronic inflammatory status, volume and pressure overload and secondary hyperparathyroidism leading to a higher incidence of calcific heart disease. The following review will focus on the main aspects (epidemiology, risk factors, diagnostic tools and protocols, therapeutic approaches) of CRS in Western countries (Europe and United States).

Right ventricular dysfunction as predictor of longer hospital stay in patients with acute decompensated heart failure: a prospective study in Indonesian population

BACKGROUND

Hospital length of stay (LOS) is a key determinant of heart failure hospitalization costs. Longer LOS is associated with lower quality of care measures and higher rates of readmission and mortality. Right ventricular (RV) dysfunction predicted poor outcomes in patients with stable chronic heart failure (CHF), however, its prognostic value in the acute decompensated heart failure (ADHF) patients has not been sufficiently clarified. This study investigated the prognostic value of RV dysfunction in predicting longer LOS in ADHF patients.

METHODS

A prospective cohort study was conducted in National Cardiovascular Center Harapan Kita to all patients admitted with ADHF. Clinical data and baseline RV function assessed by tricuspid annular plane systolic excursion (TAPSE) were collected. Clinical comorbidities including malnutrition, pneumonia and worsening renal function (WRF) were monitored during hospitalization. The primary outcome was hospital LOS. Cox regression analysis was used to identify independent predictors for longer LOS.

RESULTS

Two hundred and fifty-nine ADHF patients were included in this cohort study. On time-to-event analysis, diastolic blood pressure (HR = 1.011; 95 % CI = 1.004-1.018; p = 0.002), hemoglobin levels (HR = 1.102; 95 % CI = 1.045-1.162; p < 0.001), RV function (HR = 0.659; 95 % CI = 0.506-0.857; p = 0.002), WRF (HR = 2.015; 95 % CI = 1.520-2.670; p < 0.001) and malnutrition (HR = 5.965; 95 % CI = 4.402-8.082; p < 0.001) were associated with longer LOS. In a multivariate Cox regression model, RV function (HR = 0.466; 95 % CI = 0.238-0.915; p = 0.026), WRF (HR = 2.985; 95 % CI = 2.032-4.386; p < 0.001) and malnutrition (HR = 7.479; 95 % CI = 5.071-11.030; p < 0.001) were the independent predictors of longer hospital LOS. Based on the median TAPSE values, patients with TAPSE ≤ 16 mm had significantly longer LOS (HR = 2.227; 95 % CI = 1.103-4.494; p = 0.026) compared to those with TAPSE > 16 mm.

CONCLUSIONS

Right ventricular dysfunction, WRF and malnutrition are important predictors of longer LOS. This is the first study to describe that in ADHF patients, lower the TAPSE resulted in longer the LOS.

Crosstalk of Various Biomarkers That Might Provide Prompt Identification of Acute or Chronic Cardiorenal Syndromes

INTRODUCTION

Pathophysiological interaction between the heart and kidneys represents the basis for clinical entities called cardiorenal syndromes. The purpose of the study was to assess the relations between acute and chronic cardiorenal syndromes and biomarkers [advanced oxidation protein products, brain natriuretic peptide, malondialdehyde, xanthine oxidoreductase (XOD), xanthine oxidase, xanthine dehydrogenase, interleukin 8, cystatin C, plasminogen activator inhibitor-1, high-sensitive troponin T, C-reactive protein and glomerular filtration rate, measured by the Modification of Diet in Renal Disease (MDRD) formula], to hypothesize biomarkers that might provide a prompt identification of acute or chronic cardiorenal syndromes, and to distinguish acute versus chronic types of these syndromes.

METHODS

A total of 114 participants were enrolled in this study, i.e. 79 patients divided into subgroups of acute and chronic cardiorenal syndromes and 35 volunteers.

RESULTS

Nonadjusted odds ratio (OR) showed that there was a significant risk for acute cardiorenal syndrome with increased XOD activity (p = 0.037), elevated cystatin C concentration (p = 0.038) and MDRD (p = 0.028). Multivariable adjusted OR, on the other hand, revealed that only glomerular filtration rate measured by the MDRD formula had a significance for acute cardiorenal syndrome (p = 0.046). Nonadjusted OR showed a significant risk for chronic cardiorenal syndrome only in elderly (p = 0.002). Multivariable adjusted OR exhibited that age was the only risk factor for chronic cardiorenal syndrome (p = 0.012).

CONCLUSION

Cystatin C, glomerular filtration rate measured by the MDRD equation and XOD were independent risk factors for acute cardiorenal syndrome, while age remained an independent risk factor for chronic cardiorenal syndrome. When comparing ORs of evaluated parameters, the highest significance for acute cardiorenal syndrome was plasma concentration of cystatin C.

Serelaxin for the treatment of acute heart failure: a review with a focus on end-organ protection

Acute heart failure (AHF) is a complex clinical syndrome characterized by fluid overload and haemodynamic abnormalities (short-term clinical consequences) and the development of end-organ damage (long-term consequences). Current therapies for the treatment of AHF, such as loop diuretics and vasodilators, help to relieve haemodynamic imbalance and congestion, but have not been shown to prevent (and may even contribute to) end-organ damage, or to provide long-term clinical benefit. Serelaxin is the recombinant form of human relaxin-2, a naturally occurring hormone involved in mediating haemodynamic changes during pregnancy. Preclinical and clinical studies have investigated the effects mediated by serelaxin and the suitability of this agent for the treatment of patients with AHF. Data suggest that serelaxin acts via multiple pathways to improve haemodynamics at the vascular, cardiac, and renal level and provide effective congestion relief. In addition, this novel agent may protect the heart, kidneys, and liver from damage by inhibiting inflammation, oxidative stress, cell death, and tissue fibrosis, and stimulating angiogenesis. Serelaxin may therefore improve both short- and long-term outcomes in patients with AHF. In this review, we examine the unique mechanisms underlying the potential benefits of serelaxin for the treatment of AHF, in particular, those involved in mediating end-organ protection.

Prediction of mortality using quantification of renal function in acute heart failure

BACKGROUND

Renal function, as quantified by the estimated glomerular filtration rate (eGFR), is a predictor of death in acute heart failure (AHF). It is unknown whether one of the clinically-available serum creatinine-based formulas to calculate eGFR is superior to the others for predicting mortality.

METHODS AND RESULTS

We quantified renal function using five different formulas (Cockroft-Gault, MDRD-4, MDRD-6, CKD-EPI in patients<70 years, and BIS-1 in patients≥70 years) in 1104 unselected AHF patients presenting to the emergency department and enrolled in a multicenter study. Two independent cardiologists adjudicated the diagnosis of AHF. The primary endpoint was the accuracy of the five eGFR equations to predict death as quantified by the time-dependent area under the receiver-operating characteristics curve (AUC). The secondary endpoint was the accuracy to predict all-cause readmissions and readmissions due to AHF. In a median follow-up of 374 days (IQR: 221 to 687 days), 445 patients (40.3%) died. eGFR as calculated by all equations was an independent predictor of mortality. The Cockcroft-Gault formula showed the highest prognostic accuracy (AUC 0.70 versus 0.65 for MDRD-4, 0.55 for MDRD-6, and 0.67 for the combined formula CKD-EPI/BIS-1, p<0.05). These findings were confirmed in patients with varying degrees of renal function and in three vulnerable subgroups: women, patients with severe left ventricular dysfunction, and the elderly. The prognostic accuracy for readmission was poor for all equations, with an AUC around 0.5.

CONCLUSIONS

Calculating eGFR using the Cockcroft-Gault formula assesses the risk of mortality in patients with AHF more accurately than other commonly used formulas.

Combined biomarker analysis for risk of acute kidney injury in patients with ST-segment elevation myocardial infarction

BACKGROUND

Acute kidney injury (AKI) complicating ST-segment elevation myocardial infarction (STEMI) increases subsequent morbidity and mortality. We combined the biomarkers of heart failure (HF; B-type natriuretic peptide [BNP] and soluble ST2 [sST2]) and renal injury (NGAL [neutrophil gelatinase-associated lipocalin] and cystatin C) in predicting the development of AKI in patients with STEMI undergoing primary percutaneous coronary intervention (PCI).

METHODS AND RESULTS

From March 2010 to September 2013, 189 STEMI patients were sequentially enrolled and serum samples were collected at presentation for BNP, sST2, NGAL and cystatin C analysis. 37 patients (19.6%) developed AKI of varying severity within 48 hours of presentation. Univariate analysis showed age, Killip class ≥2, hypertension, white blood cell counts, hemoglobin, estimated glomerular filtration rate, blood urea nitrogen, creatinine, and all the four biomarkers were predictive of AKI. Serum levels of the biomarkers were correlated with risk of AKI and the Acute Kidney Injury Network (AKIN) stage and all significantly discriminated AKI (area under the receiver operating characteristic [ROC] curve: BNP: 0.86, sST2: 0.74, NGAL: 0.75, cystatin C: 0.73; all P < 0.05). Elevation of ≥2 of the biomarkers higher than the cutoff values derived from the ROC analysis improved AKI risk stratification, regardless of the creatine level (creatinine < 1.24 mg/dL: odds ratio [OR] 11.25, 95% confidence interval [CI] 1.63-77.92, P = 0.014; creatinine ≥ 1.24: OR 15.0, 95% CI 1.23-183.6, P = 0.034).

CONCLUSIONS

In this study of STEMI patients undergoing primary PCI, the biomarkers of heart failure (BNP and sST2) and renal injury (NGAL and cystatin C) at presentation were predictive of AKI. High serum levels of the biomarkers were associated with an elevated risk and more advanced stage of AKI. Regardless of the creatinine level, elevation of ≥2 of the biomarkers higher than the cutoff values indicated a further rise in AKI risk. Combined biomarker approach may assist in risk stratification of AKI in patients with STEMI.

Cystatin C in acute kidney injury diagnosis: early biomarker or alternative to serum creatinine?

BACKGROUND

Early acute kidney injury (AKI) diagnosis is needed to pursue treatment trials. We evaluated cystatin C (CysC) as an early biomarker of serum creatinine (SCr)-AKI and an alternative to define AKI.

METHODS

We studied 160 non-cardiac children in the intensive care unit (ICU). We measured daily CysC and SCr. AKI was staged by KDIGO (Kidney Disease: Improving Global Outcomes) guidelines using SCr and CysC (CysC-AKI). We calculated area under the curve (AUC) for (1) neutrophil gelatinase-associated lipocalin (NGAL), interleukin-18 (IL-18), kidney injury molecule-1 (KIM-1) and urine CysC to diagnose SCr- and CysC-AKI; and (2) for CysC to diagnose SCr-AKI. We evaluated AKI associations with length of stay and ventilation duration.

RESULTS

We found that 44 % of patients developed SCr-AKI; 32 % developed CysC-AKI. Early ICU NGAL was most diagnostic of CysC-AKI (AUC 0.69, 95% CI 0.54-0.84); IL-18 was most diagnostic for SCr-AKI (AUC 0.69 95% CI 0.55-0.82). Combining SCr and CysC-AKI definition led to higher biomarker diagnostic AUC's. CysC-AKI was not more strongly associated with clinical outcomes. Early ICU CysC predicted SCr-AKI development (AUC 0.70, 95 % CI 0.53-0.89).

CONCLUSIONS

Our findings do not support replacing SCr by CysC to define AKI. Early ICU CysC predicts SCr-AKI development and combined SCr-CysC-AKI definition leads to stronger AKI biomarker associations.

Cardiorenal Syndrome in Acute Heart Failure: Revisiting Paradigms

Cardiorenal syndrome has been defined as the simultaneous dysfunction of both the heart and the kidney. Worsening renal function that occurs in patients with acute heart failure has been classified as cardiorenal syndrome type 1. In this setting, worsening renal function is a common finding and is due to complex, multifactorial, and not fully understood processes involving hemodynamic (renal arterial hypoperfusion and renal venous congestion) and nonhemodynamic factors. Traditionally, worsening renal function has been associated with worse outcomes, but recent findings have revealed mixed and heterogeneous results, perhaps suggesting that the same phenotype represents a diversity of pathophysiological and clinical situations. Interpreting the magnitude and chronology of renal changes together with baseline renal function, fluid overload status, and clinical response to therapy might help clinicians to unravel the clinical meaning of renal function changes that occur during an episode of heart failure decompensation. In this article, we critically review the contemporary evidence on the pathophysiology and clinical aspects of worsening renal function in acute heart failure.

Novel markers and therapies for patients with acute heart failure and renal dysfunction

BACKGROUND

Acute kidney injury complicates decompensated heart failure in ∼33% of cases and is associated with morbidity and mortality; thus, we sought to systematically review this topic in order to summarize novel diagnostic and therapeutic approaches.

METHODS

Structured PubMed searches on these topics were conducted in February 2014 and relevant literature was identified. The PubMed search identified a total of 192 articles that were individually screened for inclusion in this analysis, and 58 were included.

RESULTS

Acute kidney injury, defined by substantial increases in serum creatinine, is associated consistently with prolonged length of stay, rehospitalization, and mortality. Biomarker studies suggested that natriuretic peptides are prognostic for shorter- and longer-term mortality. Novel proteins indicating kidney damage and albumin in the urine are associated with acute kidney injury. The most promising acute pharmacologic treatment appears to be serelaxin, which has been shown to improve acute heart failure symptoms, hemodynamic parameters, and renal function.

CONCLUSIONS

The presence of acute kidney injury results in worse clinical outcomes for patients with acute heart failure. Novel biomarkers and therapies hold the promise of improving both cardiac and renal outcomes in these patients.

Evidence of uncoupling between renal dysfunction and injury in cardiorenal syndrome: insights from the BIONICS study

OBJECTIVE

The objective of the study was to assess urinary biomarkers of renal injury for their individual or collective ability to predict Worsening renal function (WRF) in patients with acutely decompensated heart failure (ADHF).

METHODS

In a prospective, blinded international study, 87 emergency department (ED) patients with ADHF were evaluated with biomarkers of cardiac stretch (B type natriuretic peptide [BNP] and its amino terminal equivalent [NT-proBNP], ST2), biomarkers of renal function (creatinine, estimated glomerular filtration rate [eGFR]) and biomarkers of renal injury (plasma neutrophil gelatinase associated lipocalin [pNGAL], urine kidney injury molecule-1 [KIM-1], urine N-acetyl-beta-D-glucosaminidase [NAG], urine Cystatin C, urine fibrinogen). The primary endpoint was WRF.

RESULTS

26% developed WRF; baseline characteristics of subjects who developed WRF were generally comparable to those who did not. Biomarkers of renal function and urine biomarkers of renal injury were not correlated, while urine biomarkers of renal injury correlated between each other. Biomarker concentrations were similar between patients with and without WRF except for baseline BNP. Although plasma NGAL was associated with the combined endpoint, none of the biomarker showed predictive accuracy for WRF.

CONCLUSIONS

In ED patients with ADHF, urine biomarkers of renal injury did not predict WRF. Our data suggest that a weak association exists between renal dysfunction and renal injury in this setting (Clinicaltrials.gov NCT#0150153).

Biomarkers and physiopathology in the cardiorenal syndrome

Acute cardiorenal syndrome (CRS) corresponds to an association of acute heart failure and a worsening of renal function. The detection of acute kidney injury (AKI) unfortunately occurs at a late stage of CRS, leading to an increased mortality of the patients. In this review, we described the pathophysiology of CRS and discussed the potential interest of biochemical biomarkers (namely creatinine, cystatin C, NGAL, KIM-1, fatty acid binding protein, Nacetyl-β-D-glucosaminidase and IL-18) that could potentially help to detect AKI earlier and thus reduce the morbi-mortality of the patients suffering from CRS.

Heart failure mortality according to acute variations in N-terminal pro B-type natriuretic peptide and cystatin C levels

AIM

Changes in N-terminal pro B-type natriuretic peptide (NT-proBNP) levels and cystatin C (CysC) are predictors of adverse outcomes in acute heart failure. This study assess whether NT-proBNP variations might provide independent information in addition to that obtained from CysC levels.

METHODS

NT-proBNP levels were assessed in patients admitted due to acute heart failure using an observational study. Patients were classified as follows: group 1, those with a decrease in NT-proBNP levels of at least 30% from admission to 4 weeks after discharge; group 2, those with no significant changes in levels; and group 3, those who showed an increase in NT-proBNP of 30%. A multivariable Cox regression model and c-statistics were used. The primary end-point was all-cause mortality at 1-year follow-up.

RESULTS

A total of 195 patients completed the follow-up. The mortality rate reached 20.5% (40 patients); 14 out of the 32 in group 3. The cumulative incidence of death, according to the change in NT-proBNP and Kaplan-Meier analysis, showed a significant increase in group 3 (log-rank P = 0.004). In the multivariable analysis, NT-proBNP variation for group 3 (hazard ratio 4.27; P <0.001) and for group 2 (hazard ratio 2.19; P = 0.043) in comparison with group 1 were independently associated with all-cause mortality, as well as anemia, hyponatremia, and admission CysC levels. Patients in group 3, and those with levels of serum CysC above the median, were also associated with slight increase in mortality.

CONCLUSION

An increase of at least 30% in NT-proBNP levels after hospitalization is related to all-cause mortality in patients with acute heart failure and provides supplementary prognostic information in patients with high levels of CysC. A decrease in NT-proBNP of at least 30% is a desirable target to achieve.

When cardiac failure, kidney dysfunction, and kidney injury intersect in acute conditions: the case of cardiorenal syndrome

OBJECTIVE

To review and describe diagnostic and prognostic value of biomarkers of renal function and renal injury in the cardiorenal syndrome complicating acutely decompensated heart failure.

DATA SOURCES

PubMed search and review of relevant medical literature.

STUDY SELECTION

Two reviewers screened and selected studies in English with diagnostic or prognostic assessment of biomarkers of renal injury.

DATA EXTRACTION

Narrative review of the medical literature.

DATA SYNTHESIS

Cardiorenal syndrome has a complex pathophysiology and has a generally poor prognosis in patients with acutely decompensated heart failure. Among the methods to recognize risk for cardiorenal syndrome may be the use of circulating or urinary biomarkers, which may allow for more accurate early diagnosis and risk stratification; use of biomarkers may provide important pathophysiologic understanding beyond risk prediction. However, different phenotypes of patients with acute renal dysfunction may be present, which has ramifications with respect to response to treatment strategies. Addition of biomarkers of renal injury may provide additional prognostic value to biomarkers of renal or cardiac function, but more data are needed.

CONCLUSIONS

Biomarkers reflecting renal function and injury are likely to better phenotype subgroups of patients with cardiorenal syndrome and to provide unique prognostic information. Future studies are needed relative to strategies using such biomarkers to guide care of affected patients.

Contemporary strategies in the diagnosis and management of heart failure

Heart failure (HF) is an important public health problem, and strategies are needed to improve outcomes and decrease health care resource utilization and costs. Its prevalence has increased as the population ages, and HF continues to be associated with a high mortality rate and frequent need for hospitalization. The total cost of care for patients with HF was $30.7 billion in 2012, and it is estimated to more than double to $69.8 billion by 2030. Given this reality, there has been recent investigation into ways of identifying and preventing HF in patients at risk (stage A HF) and those with cardiac structural and functional abnormalities but no clinical HF symptoms (stage B). For patients who have symptoms of HF (stage C), there has been important research into the most effective ways to decongest patients hospitalized with acute decompensated HF and prevent future hospital readmissions. Successful strategies to treat patients with HF and preserved ejection fraction, which has increased in prevalence, continue to be sought. We are in the midst of a rapid evolution in our ability to care for patients with end-stage HF (stage D) because of the introduction of and improvements in mechanical circulatory support. Left ventricular assist devices used as destination therapy offer an important therapeutic option to patients who do not qualify for heart transplant because of advanced age or excessive comorbidity. This review provides a thorough update on contemporary strategies in the diagnosis and management of HF by stage (A to D) that have emerged during the past several years.

Acute Cardiorenal Syndrome Type 1 in Patients With Congestive Heart Failure Exacerbations Is Not an Indicator of Poor Outcome and Increased Mortality

Background

Over one million patients are hospitalized each year with acute decompensated heart failure (ADHF) in the US. Approximately 20% to 40% of them will develop acute cardiorenal syndrome type 1 (ACRS1) via multiple mechanisms.

Methods

From January 2010 to December 2010, 197 patients were diagnosed with ADHF. Initial N-terminal pro-brain natriuretic peptide (NT-pro BNP), creatinine levels throughout hospital stay, use of invasive mechanical ventilation, length of hospital stay and death were assessed for each patient. ACRS1 was diagnosed when an increase of creatinine > 0.3 mg/dL from baseline was noted during hospital stay. We sought to investigate whether presence of ACRS1 is associated with increased length of stay, need for mechanical ventilation and increased in-hospital mortality in patients admitted with ADHF.

Results

Total of 61 (31%) patients experienced ACRS1. Mean hospital stay for ACRS1 patients was 8.43 ± 6.28 days while for non-ACRS1 was 5.06 ± 4.19 (P < 0.0001). Twenty-eight (14%) patients required invasive mechanical ventilation (11 non-ACRS1 vs. 17 ACRS1). ACRS1 was associated with more frequent use of invasive ventilation (odd ratio 3.45, CI 1.52 - 7.79, P = 0.003). Fifteen (8%) patients expired (8 non-ACRS1 vs. 7 ACRS1). There was no difference in mortality between groups (odd ratio 2.07, CI 0.72 - 6.00, P = 0.18).

Conclusions

Development of ACRS1 was not associated with increased incidence of in-hospital mortality, but it prolonged hospital stay and need for mechanical ventilation.