Acute decompensated heart failure and the cardiorenal syndrome:

The Need to Identify Novel Markers for Early Renal Injury in Cardiorenal Syndrome

The term "Cardiorenal Syndrome" (CRS) refers to the complex interplay between heart and kidney dysfunction. First described by Robert Bright in 1836, CRS was brought to its modern view by Ronco et al. in 2008, who defined it as one organ's primary dysfunction leading to secondary dysfunction in the other, a view that led to the distinction of five different types depending on the organ of primary dysfunction and the temporal pattern (acute vs. chronic). Their pathophysiology is intricate, involving various hemodynamic, neurohormonal, and inflammatory processes that result in damage to both organs. While traditional biomarkers have been utilized for diagnosing and prognosticating CRS, they are inadequate for the early detection of acute renal damage. Hence, there is a pressing need to discover new biomarkers to enhance clinical outcomes and treatment approaches.

Could Endothelin-1 Be a Promising Neurohormonal Biomarker in Acute Heart Failure?

Acute heart failure (AHF) is a life-threatening condition with high morbidity and mortality. Even though this pathology has been extensively researched, there are still challenges in establishing an accurate and early diagnosis, determining the long- and short-term prognosis and choosing a targeted therapeutic strategy. The use of reliable biomarkers to support clinical judgment has been shown to improve the management of AHF patients. Despite a large pool of interesting candidate biomarkers, endothelin-1 (ET-1) appears to be involved in multiple aspects of AHF pathogenesis that include neurohormonal activation, cardiac remodeling, endothelial dysfunction, inflammation, atherosclerosis and alteration of the renal function. Since its discovery, numerous studies have shown that the level of ET-1 is associated with the severity of symptoms and cardiac dysfunction in this pathology. The purpose of this paper is to review the existing information on ET-1 and answer the question of whether this neurohormone could be a promising biomarker in AHF.

The trajectory of renal function following mechanical circulatory support and subsequent heart transplantation

Aim

Patients with advanced heart failure (HF) frequently suffer from renal insufficiency. The impact of durable mechanical circulatory support (MCS) and subsequent heart transplantation (HTx) on kidney function is not well described.

Methods and results

We studied patients with advanced HF who received durable MCS as bridge to transplantation (BTT) and underwent subsequent HTx at our centre between 1996 and 2018. Glomerular filtration rate (GFR) was measured by ⁵¹Cr‐EDTA or iohexol clearance during heart failure work‐up; 3–6 months after MCS; and 1 year after HTx. Chronic kidney disease (CKD) was classified according to KDIGO criteria based on estimated GFR. A total of 88 patients (46 ± 15 years, 84% male) were included, 63% with non‐ischaemic heart disease. The median duration of MCS‐treatment was 172 (IQR 116–311) days, and 81 subjects were alive 1 year after HTx. Measured GFR increased from 54 ± 19 during HF work‐up to 60 ± 16 mL/min/1.73 m² after MCS (P < 0.001) and displayed a slight but nonsignificant decrease to 57 ± 22 mL/min/1.73 m² 1 year after HTx (P = 0.38). The trajectory of measured GFR did not differ between pulsatile and continuous flow (CF) pumps. Among patients 35–49 years and those who were treated in the most recent era (2012–2018), measured GFR increased following MCS implantation and subsequent HTx. Estimated GFR displayed a similar course as did measured GFR.

Conclusions

In patients with advanced heart failure, measured GFR improved after MCS with no difference between pulsatile and CF‐pumps. The total study group showed no further increase in GFR following HTx, but in certain subgroups, including patients aged 35–54 years and those treated during the latest era (2012–2018), renal function appeared to improve after transplant.

Extracellular Vesicles and Their Relationship with the Heart-Kidney Axis, Uremia and Peritoneal Dialysis

Cardiorenal syndrome (CRS) is described as primary dysfunction in the heart culminating in renal injury or vice versa. CRS can be classified into five groups, and uremic toxin (UT) accumulation is observed in all types of CRS. Protein-bound uremic toxin (PBUT) accumulation is responsible for permanent damage to the renal tissue, and mainly occurs in CRS types 3 and 4, thus compromising renal function directly leading to a reduction in the glomerular filtration rate (GFR) and/or subsequent proteinuria. With this decrease in GFR, patients may need renal replacement therapy (RRT), such as peritoneal dialysis (PD). PD is a high-quality and home-based dialysis therapy for patients with end-stage renal disease (ESRD) and is based on the semi-permeable characteristics of the peritoneum. These patients are exposed to factors which may cause several modifications on the peritoneal membrane. The presence of UT may harm the peritoneum membrane, which in turn can lead to the formation of extracellular vesicles (EVs). EVs are released by almost all cell types and contain lipids, nucleic acids, metabolites, membrane proteins, and cytosolic components from their cell origin. Our research group previously demonstrated that the EVs can be related to endothelial dysfunction and are formed when UTs are in contact with the endothelial monolayer. In this scenario, this review explores the mechanisms of EV formation in CRS, uremia, the peritoneum, and as potential biomarkers in peritoneal dialysis.

Echocardiography is a good way to diagnose and monitor type 1 cardiorenal syndrome in ICU

BACKGROUND

Type one Cardiorenal syndrome (CRS) is defined by acute decompensated heart failure leading to secondary acute kidney injury. No studies evaluates the reliability of transthoracic echocardiography as an help tool for diagnosis and optimization of CRS. Therefore, the aim of this study was to assess echocardiographic parameters in patients with CRS in the Intensive Care Unit.

METHODS

We conducted an observational, prospective, single-center study in the ICU department of a general hospital. Patients admitted in the ICU and presenting with type 1 CRS were included. Transthoracic echocardiography was performed at baseline and at day end after treatment by the same trained operator for the same patients. We report various echocardiographic indices at these two timepoints.

RESULTS

27 patients were included. At baseline 96.3% of patients had signs of congestion (IVC dilation > 2 cm), 76 % had an altered S-wave (< 11.5 cm/s), 72.73% had an altered TAPSE (< 17 mm), 85.19% had an elevated RV/LV diameter ratio (> 0.6). Between baseline and D end, IVC size and, the number of patients with an elevated RV/LV diameter ratio significantly decreased. Weight decreased, whereas natriuresis significantly increased, and the amount of vasopressors support decreased. Diuresis, and S-wave velocity showed non-significant changes.

CONCLUSIONS

Main echocardiographic findings at baseline in patients with type 1 CRS consist of a right ventricular dysfunction associated an IVC dilation. We report that weight, RV/LV diameter ratio, and IVC diameter might constitute good follow-up parameters to monitor treatment response.

Predictors of acute kidney injury in patients with acute decompensated heart failure in emergency departments in China

Objective

This retrospective multicentre observational study was performed to assess the predictors of acute kidney injury (AKI) in patients with acute decompensated heart failure (ADHF) in emergency departments in China.

Methods

In total, 1743 consecutive patients with ADHF were recruited from August 2017 to January 2018. Clinical characteristics and outcomes were compared between patients with and without AKI. Predictors of AKI occurrence and underdiagnosis were assessed in multivariate regression analyses.

Results

Of the 1743 patients, 593 (34.0%) had AKI. AKI was partly associated with short-term all-cause mortality and cost. Cardiovascular comorbidities such as coronary heart disease, diabetes mellitus, and hypertension remained significant predictors of AKI in the univariate analysis. AKI was significantly more likely to occur in patients with a lower arterial pH, lower albumin concentration, higher creatinine concentration, and higher N-terminal pro-brain natriuretic peptide (NT-proBNP) concentration. Patients treated with inotropic agents were significantly more likely to develop AKI during their hospital stay.

Conclusion

This study suggests that cardiovascular comorbidities, arterial pH, the albumin concentration, the creatinine concentration, the NT-proBNP concentration, and use of inotropic agents are predictors of AKI in patients with ADHF.

Feature and impact of guideline-directed medication prescriptions for heart failure with reduced ejection fraction accompanied by chronic kidney disease

Background: With respect to total mortality and cardiovascular mortality, the feature and impact of guideline-directed medication (GDM) prescriptions for heart failure with reduced ejection fraction (HFrEF) with chronic kidney disease (CKD) are unknown. Therefore, we aimed to determine these aspects. Methods: GDM prescriptions and their impact on discharged patients with and without CKD were analyzed. To analyze differences in one-year clinical outcomes, propensity score matching was conducted on a cohort of patients with concomitant HFrEF and CKD who received more and fewer GDM prescriptions. Results: A total of 1509 patients were enrolled in Taiwan's HFrEF registry from May 2013 to October 2014, and 1275 discharged patients with complete one-year follow-up were further analyzed. Of these patients, 468 (36.7%) had moderate CKD, whereas 249 (19.5%) had advanced CKD. Patients with advanced CKD received fewer prescribed GDMs than other patients. Multivariate analysis revealed that peripheral arterial occlusive disease, thyroid disorder, advanced HF at discharge, diastolic blood pressure, digoxin use, and fewer prescribed GDMs were independent predictors of one-year total mortality. After propensity score matching, patients with fewer prescribed GDMs had higher one-year total mortality rate than those with more prescribed GDMs (P=0.036). Conclusions: CKD at discharge from HF hospitalization was associated with fewer GDM prescriptions, particularly in patients with more advanced CKD. The propensity-matched analysis indicated that more GDM prescriptions led to better clinical outcomes in HFrEF patients with CKD. Careful interpretation of changes in renal function during HF hospitalization may improve GDM prescriptions.

Predictors of Survival to Discharge After Successful Weaning From Venoarterial Extracorporeal Membrane Oxygenation in Patients With Cardiogenic Shock

BACKGROUND

This study identified predictors of hospital mortality after successful weaning of patients with cardiogenic shock off venoarterial (VA) extracorporeal membrane oxygenation (ECMO) support.Methods and Results:Adult patients who received peripheral VA ECMO from January 2012 to April 2017 were reviewed retrospectively. After excluding patients who died on ECMO support, predictors for survival to discharge were investigated in patients who were successfully weaned off ECMO. Of 191 patients successfully weaned off ECMO, 143 (74.9%) survived to discharge. The prevalence of a history of stroke and coronary artery disease, as well as ECMO-related complications, including newly developed stroke and sepsis, was a higher in patients who did not survive to discharge than in those who did. On the day of ECMO weaning, Sequential Organ Failure Assessment score and serum lactate were higher in patients who did not survive to discharge, although there was no significant difference in blood pressure and the use of vasoactive drugs between the 2 groups. On multivariable analysis, stroke and sepsis during ECMO support, a lower Glasgow Coma Scale and acute kidney injury requiring continuous renal replacement therapy after weaning were significant predictors for in-hospital mortality.

CONCLUSIONS

Complications that occurred during ECMO and the presence of extracardiac organ dysfunction after weaning were associated with in-hospital mortality in patients with cardiogenic shock who were successfully weaned off ECMO.

Natriuretic peptide analogues with distinct vasodilatory or renal activity: integrated effects in health and experimental heart failure

AIMS

Management of acute decompensated heart failure (ADHF) requires disparate treatments depending on the state of systemic/peripheral perfusion and the presence/absence of expanded body-fluid volumes. There is an unmet need for therapeutics that differentially treat each aspect. Atrial natriuretic peptide (ANP) plays an important role in blood pressure and volume regulation. We investigate for the first time the integrated haemodynamic, endocrine and renal effects of human ANP analogues, modified for exclusive vasodilatory (ANP-DRD) or diuretic (ANP-DGD) activities, in normal health and experimental ADHF.

METHODS AND RESULTS

We compared the effects of incremental infusions of ANP analogues ANP-DRD and ANP-DGD with native ANP, in normal (n = 8) and ADHF (n = 8) sheep. ANP-DRD administration increased plasma cyclic guanosine monophosphate (cGMP) in association with dose-dependent reductions in arterial pressure in normal and heart failure (HF) sheep similarly to ANP responses. In contrast to ANP, which in HF produced a diuresis/natriuresis, this analogue was without significant renal effect. Conversely, ANP-DGD induced marked stepwise increases in urinary cGMP, urine volume, and sodium excretion in HF comparable to ANP, but without accompanying vasodilatory effects. All peptides increased packed cell volume relative to control in both states, and in HF, decreased left atrial pressure. In response to ANP-DRD-induced blood pressure reductions, plasma renin activity rose compared to control only during the high dose in normals, and not at all in HF-suggesting relative renin inhibition, with no increase in aldosterone in either state, whereas renin and aldosterone were both significantly reduced by ANP-DGD in HF.

CONCLUSION

These ANP analogues exhibit distinct vasodilatory (ANP-DRD) and diuretic/natriuretic (ANP-DGD) activities, and therefore have the potential to provide precision therapy for ADHF patients with differing pathophysiological derangement of pressure-volume homeostasis.

Wnt/β-catenin signaling mediates both heart and kidney injury in type 2 cardiorenal syndrome

In type 2 cardiorenal syndrome, chronic heart failure is thought to cause or promote chronic kidney disease; however, the underlying mechanisms remain poorly understood. We investigated the role of Wnt signaling in heart and kidney injury in a mouse model of cardiac hypertrophy and heart failure induced by transverse aortic constriction (TAC). At 8 weeks after TAC, cardiac hypertrophy, inflammation, and fibrosis were prominent, and echocardiography confirmed impaired cardiac function. The cardiac lesions were accompanied by upregulation of multiple Wnt ligands and activation of β-catenin, as well as activation of the renin-angiotensin system (RAS). Wnt3a induced multiple components of the RAS in primary cardiomyocytes and cardiac fibroblasts in vitro. TAC also caused proteinuria and kidney fibrosis, accompanied by klotho depletion and β-catenin activation in the kidney. Pharmacologic blockade of β-catenin with a small molecule inhibitor or the RAS with losartan ameliorated cardiac injury, restored heart function, and mitigated the renal lesions. Serum from TAC mice was sufficient to activate β-catenin and trigger tubular cell injury in vitro, indicating a role for circulating factors. Multiple inflammatory cytokines were upregulated in the circulation of TAC mice, and tumor necrosis factor-α was able to inhibit klotho, induce β-catenin activation, and cause tubular cell injury in vitro. These studies identify Wnt/β-catenin signaling as a common pathogenic mediator of heart and kidney injury in type 2 cardiorenal syndrome after TAC. Targeting this pathway could be a promising therapeutic strategy to protect both organs in cardiorenal syndrome.

Utility of Novel Cardiorenal Biomarkers in the Prediction and Early Detection of Congestive Kidney Injury Following Cardiac Surgery

Acute Kidney Injury (AKI) in the context of right ventricular failure (RVF) is thought to be largely congestive in nature. This study assessed the utility of biomarkers high sensitivity cardiac troponin T (hs-cTnT), N-Terminal Pro-B-Type Natriuretic Peptide (NT-proBNP), and neutrophil gelatinase-associated lipocalin (NGAL) for prediction and early detection of congestive AKI (c-AKI) following cardiac surgery. This prospective nested case-control study recruited 350 consecutive patients undergoing elective cardiac surgery requiring cardiopulmonary bypass. Cases were patients who developed (1) AKI (2) new or worsening RVF, or (3) c-AKI. Controls were patients free of these complications. Biomarker levels were measured at baseline after anesthesia induction and immediately postoperatively. Patients with c-AKI had increased mean duration of mechanical ventilation and length of stay in hospital and in the intensive care unit (p < 0.01). For prediction of c-AKI, baseline NT-proBNP yielded an area under the curve (AUC) of 0.74 (95% CI, 0.60–0.89). For early detection of c-AKI, postoperative NT-proBNP yielded an AUC of 0.78 (0.66–0.91), postoperative hs-cTnT yielded an AUC of 0.75 (0.58–0.92), and ∆hs-cTnT yielded an AUC of 0.80 (0.64–0.96). The addition of baseline creatinine to ∆hs-cTnT improved the AUC to 0.87 (0.76–0.99), and addition of diabetes improved the AUC to 0.93 (0.88–0.99). Δhs-cTnT alone, or in combination with baseline creatinine or diabetes, detects c-AKI with high accuracy following cardiac surgery.

Levels of Proinflammatory Cytokines, Oxidative Stress, and Tissue Damage Markers in Patients with Acute Heart Failure with and without Cardiorenal Syndrome Type 1

BACKGROUND

Cardiorenal syndrome type 1 (CRS type 1) is characterized by a rapid worsening of cardiac function leading to acute kidney injury (AKI). Inflammation and oxidative stress seem to play a pivotal role in its pathophysiology. In this in vivo study, we examined the putative role of inflammation and humoral markers in the pathogenesis of the CRS type 1.

METHODS

We enrolled 53 patients with acute heart failure (AHF); 17 of them developed AKI (CRS type 1). The cause of AKI was presumed to be related to cardiac dysfunction after having excluded other causes. We assessed the plasma levels of proinflammatory cytokines (TNF-α, IL-6, IL-18, sICAM, RANTES, GMCSF), oxidative stress marker (myeloperoxidase, MPO), brain natriuretic peptide (BNP), and neutrophil gelatinase-associated lipocalin (NGAL) in AHF and CRS type 1 patients.

RESULTS

We observed a significant increase in IL-6, IL-18, and MPO levels in CRS type 1 group compared to AHF (p < 0.001). We found higher NGAL at admission in the CRS type 1 group compared to the AHF group (p = 0.008) and a positive correlation between NGAL and IL-6 (Spearman's rho = 0.45, p = 0.003) and between IL-6 and BNP (Spearman's rho = 0.43, p = 0.004). We observed lower hemoglobin levels in CRS type 1 patients compared to AHF patients (p < 0.05) and inverse correlation between hemoglobin and cytokines (IL-6: Spearman's rho = -0.38, p = 0.005; IL-18: Spearman's rho = -0.32, p = 0.02).

CONCLUSION

Patients affected by CRS type 1 present increased levels of proinflammatory cytokines and oxidative stress markers, increased levels of tissue damage markers, and lower hemoglobin levels. All these factors may be implicated in the pathophysiology of CRS type 1 syndrome.

Heart-Kidney Interactions in Cardiorenal Syndrome Type 1

The exact significance of kidney function deterioration during acute decompensated heart failure (ADHF) episodes is still under debate. Several studies reported a wide percentage of worsening renal function (WRF) in ADHF patients ranging from 20% to 40%. This is probably because of different populations enrolled with different baseline kidney and cardiac function, varying definition of acute kidney injury (AKI), etiology of kidney dysfunction (KD), and occurrence of transient or permanent KD over the observational period. Current cardiorenal syndrome classification does not distinguish among the mechanisms leading to cardiac and renal deterioration. Cardiorenal syndrome type 1 (CRS-1) is the result of a combination of neurohormonal activation, fluid imbalance, arterial underfilling, increased renal and abdominal pressure, and aggressive decongestive treatment. A more complete mechanistic approach to CRS-1 should include evaluation of baseline kidney function, timing, course and magnitude of KD, and introduction of specific biomarkers able to identify early kidney damage. Therefore, clinical and laboratory parameters may yield a different combination among predisposing, precipitating, and amplifying factors that may influence cardiorenal syndrome development. Thus, CRS-1 is a heterogeneous syndrome that needs to be better defined and categorized taking into account clinical status, renal condition, and treatment. The application of universal definitions for WRF/AKI definition would be the first step to achieve a clear classification.

Effectiveness and Safety of Peritoneal Dialysis Treatment in Patients with Refractory Congestive Heart Failure due to Chronic Cardiorenal Syndrome

Aims

To evaluate the effectiveness and safety of peritoneal dialysis (PD) in treating refractory congestive heart failure (RCHF) with cardiorenal syndrome (CRS).

Methods

A total of 36 patients with RCHF were divided into type 2 CRS group (group A) and non-type 2 CRS group (group B) according to the patients' clinical presentations and the ratio of serum urea to creatinine and urinary analyses in this prospective study. All patients were followed up till death or discontinuation of PD. Data were collected for analysis, including patient survival time on PD, technique failure, changes of heart function, and complications associated with PD treatment and hospitalization.

Results

There were 27 deaths and 9 patients quitting PD program after a follow-up for 73 months with an average PD time of 22.8 ± 18.2 months. A significant longer PD time was found in group B as compared with that in group A (29.0 ± 19.4 versus 13.1 ± 10.6 months, p = 0.003). Kaplan–Meier curves showed a higher survival probability in group B than that in group A (p < 0.001). Multivariate regression demonstrated that type 2 CRS was an independent risk factor for short survival time on PD. The benefit of PD on the improvement of survival and LVEF was limited to group B patients, but absent from group A patients. The impairment of exercise tolerance indicated by NYHA classification was markedly improved by PD for both groups. The technique survival was high, and the hospital readmission was evidently decreased for both group A and group B patients.

Conclusions

Our data suggest that PD is a safe and feasible palliative treatment for RCHF with type 2 CRS, though the long-term survival could not be expected for patients with the type 2 CRS. Registration ID Number is ChiCTR1800015910.

A Call to Action to Develop Integrated Curricula in Cardiorenal Medicine

With the adoption of the new definition and classification of cardiorenal syndrome (CRS) and its relevant subtypes, much attention has been placed on elucidating the mechanisms of heart and kidney interactions. Of great interest are the pathophysiological pathways by which acute heart failure may result in acute kidney injury (AKI; type 1), chronic heart failure accelerating the progression of chronic kidney disease (CKD; type 2), AKI provoking cardiac events (type 3), and CKD increasing the risk and severity of cardiovascular disease (type 4). A remarkable interest has also been placed on the acute and chronic systemic conditions, such as sepsis and diabetes, which simultaneously affect heart and kidney function (type 5). Furthermore, the physiology of acute and chronic heart-kidney cross talk is drawing attention to hemodynamics (fluids, pressures, flows, resistances, perfusion), physiochemical (electrolytes, pH, and toxins), and biological (inflammation, immune system activation, neurohormonal signals) processes. Common clinical scenarios call for recognition, knowledge, and skill in managing CRS. There is a clear need for medical and surgical specialists that are well versed in the pathophysiology and the clinical manifestations that arise in the setting of CRS. With this editorial, we are making a call to action to stimulate universities, medical schools, and teaching hospitals to create a core curriculum for cardiorenal medicine to better equip the physicians of the future for these common, serious, and frequently fatal syndromes.

Cardiorenal Syndrome: Diagnosis and Management

Cardiorenal syndrome (CRS) has not been well characterized in veterinary medicine, yet an accurate appreciation of the kidney and the cardiovascular system and their interactions may have practical clinical implications. A consensus for cardiovascular-renal axis disorders of dogs and cats was recently attempted. The outcome of patients with CRS is likely to improve with the increasing awareness and ability to identify and understand the pathophysiologic characteristics of CRS. The utilization of existing and emerging organ-specific biomarkers with greater sensitivities than conventional diagnostics forecast new opportunities to diagnose and manage cardiac disease.

Right Ventricular Function, Peripheral Edema, and Acute Kidney Injury in Critical Illness

Introduction

The cardiorenal syndrome generally focuses on left ventricular function, and the importance of the right ventricle as a determinant of renal function is described less frequently. In a cohort of critically ill patients with echocardiographic measurements obtained within 24 hours of admission to the intensive care unit, we examined the association of right ventricular function with acute kidney injury (AKI) and AKI-associated mortality. We also examined whether clinical measurement of volume overload modified the association between ventricular function and AKI in a subpopulation with documented admission physical examinations.

Methods

Among 1879 critically ill patients with echocardiographic ventricular measurements, 43% (n = 807) had ventricular dysfunction—21% (n = 388), 9% (n = 167), and 13% (n = 252) with isolated left ventricular dysfunction, isolated right ventricular dysfunction, and biventricular dysfunction, respectively. Overall, ventricular dysfunction was associated with a 43% higher adjusted risk of AKI (95% confidence interval [CI] 1.14–1.80; P = 0.002) compared with those with normal biventricular function, whereas isolated left ventricular dysfunction, isolated right ventricular dysfunction, and biventricular dysfunction were associated with a 1.34 (95% CI 1.00-1.77, P = 0.05), 1.35 (95% CI 0.90–2.10, P = 0.14) and 1.67 (95% CI 1.23–2.31, P = 0.002) higher adjusted risk. Although an episode of AKI was associated with an approximately 2-fold greater risk of hospital mortality in those with isolated left ventricular dysfunction and biventricular dysfunction, in those with isolated right ventricular dysfunction, AKI was associated with a 7.85-fold greater risk of death (95% CI 2.89–21.3, P < 0.001). Independent of ventricular function, peripheral edema was an important determinant of AKI.

Discussion

Like left ventricular function, right ventricular function is an important determinant of AKI and AKI-associated mortality. Volume overload, independently of ventricular function, is a risk factor for AKI. Whether establishment of euvolemia might mitigate AKI risk will require further study.

Urinary [TIMP-2] × [IGFBP7] for risk prediction of acute kidney injury in decompensated heart failure

BACKGROUND

In acute decompensated heart failure (ADHF) the risk of acute kidney injury (AKI) is high. Early detection of patients at risk for AKI is important. We tested urinary [TIMP-2] × [IGFBP7], a new US Food and Drug Administration-cleared test to assess AKI risk, in a cohort of hospitalized ADHF patients.

HYPOTHESIS

In patients with ADHF, urinary [TIMP-2] × [IGFBP7] is associated with moderate to severe AKI and related to increased mortality.

METHODS

We enrolled 400 patients in the emergency department at Robert-Bosch Hospital, Stuttgart, Germany. We examined the predictive ability of urinary [TIMP-2] × [IGFBP7] (units: [ng/mL]² /1000) for development of AKI stage 2 or 3 within 24 hours of sample collection in patients with ADHF. Operating characteristics were determined for the validated cutoffs of 0.3 and 2.0.

RESULTS

Forty patients had ADHF upon presentation and sufficient data for AKI staging. 27.5% developed AKI stage 2-3 within 7 days. Urinary [TIMP-2] × [IGFBP7] discriminated for AKI stage 2-3 over the first day with an area under the ROC curve of 0.84 (95% confidence interval: 0.72-0.93) and over 7 days with an AUC of 0.77 (95% confidence interval: 0.65-0.88). For the first day, sensitivity was 86% at the 0.3 cutoff and specificity was 95% at the 2.0 cutoff for prediction of AKI stage 2-3. There was a trend (P = 0.08) for higher mortality in patients with urinary [TIMP-2] × [IGFBP7] >2.0 and AKI 2-3.

CONCLUSIONS

Urinary [TIMP-2] × [IGFBP7] is a promising marker for AKI risk assessment in patients with ADHF.

Advances in the Management of Acute Cardiorenal Syndrome in China: Biomarkers for Predicting Development and Outcomes

BACKGROUND

Acute cardiorenal syndrome (CRS) is a common clinical condition associated with adverse outcomes. Early identification of acute kidney injury in this setting remains challenging given that serum creatinine level is a marker of renal function and not kidney injury.

SUMMARY

Several renal injury-related molecules are now available, which may help elucidate the complexities of the organ crosstalk, enabling more accurate risk stratification and effective interventions.

KEY MESSAGES

This review highlights the major studies that have characterized the diagnostic and prognostic predictive power of these biomarkers with reference to acute CRS. Although more research is needed, the current results are very promising.

Development and Validation of a Risk Score for Prediction of Acute Kidney Injury in Patients With Acute Decompensated Heart Failure: A Prospective Cohort Study in China

Background

Although several risk factors for acute kidney injury (AKI) have been identified, early detection of AKI in acute decompensated heart failure patients remains a challenge. The aim of this study was to develop and validate a risk score for early prediction of AKI in acute decompensated heart failure patients.

Methods and Results

A total of 676 consecutive acute decompensated heart failure participants were prospectively enrolled from 6 regional central hospitals. Data from 507 participants were analyzed. Participants from 4 of the 6 hospitals (n=321) were used to develop a risk score and conduct internal validation. External validation of the developed risk score was conducted in participants from the other 2 hospitals (n=186). Sequential logistic regression was used to develop and validate the risk score. The c statistic and calibration plot were used to assess the discrimination and calibration of the proposed risk score. The overall occurrence of AKI was 33.1% (168/507). The risk score, ranging from 0 to 55, demonstrated good discriminative power with an optimism‐corrected c statistic of 0.859. Similar results were obtained from external validation with c statistic of 0.847 (95% CI 0.819‐0.927). The risk score had good calibration with no apparent over‐ or under‐prediction observed from calibration plots.

Conclusions

The novel risk score is a simple and accurate tool that can help clinicians assess the risk of AKI in acute decompensated heart failure patients, which in turn helps them plan and initiate the most appropriate disease management for patients in time.

Association of anemia and renal dysfunction with in-hospital mortality among patients hospitalized for acute heart failure syndromes with preserved or reduced ejection fraction

BACKGROUND

The aim of this study was to evaluate the association of anemia and renal dysfunction with in-hospital outcomes in acute heart failure syndromes patients with preserved or reduced ejection fraction.

METHODS AND RESULTS

Of the 4842 patients enrolled in the Acute Decompensated Heart Failure Syndromes (ATTEND) registry, 4693 patients were evaluated to investigate the association among anemia, renal dysfunction, a preserved or reduced ejection fraction and in-hospital mortality. They were divided into four groups based on hemoglobin and estimated glomerular filtration rate at admission. The in-hospital mortality rate was 5.9% and 6.9% of the preserved and reduced ejection fraction groups, respectively. After adjustment for multiple comorbidities, there was no association of either anemia or renal dysfunction alone with in-hospital mortality in preserved ejection fraction patients, but the combination of anemia and renal dysfunction was associated with a somewhat higher risk of in-hospital mortality than that without either condition (odds ratio (OR), 2.75; 95% confidence interval (CI), 0.72-10.41; p=0.137). In reduced ejection fraction patients, adjusted analysis showed that a significantly higher risk of in-hospital mortality was associated with anemia alone (OR, 2.56; 95% CI, 1.10 -5.94; p=0.029) and with anemia plus renal dysfunction (OR, 2.34; 95% CI, 1.09-5.03; p=0.029) relative to the risk without either condition.

CONCLUSIONS

Our findings demonstrate that anemia combined with renal dysfunction is not a risk factor for in-hospital mortality in patients with a preserved ejection fraction, whereas anemia is an independent predictor of in-hospital mortality risk in reduced ejection fraction patients regardless of renal dysfunction.

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).

Urinary Biomarkers at the Time of AKI Diagnosis as Predictors of Progression of AKI among Patients with Acute Cardiorenal Syndrome

BACKGROUND AND OBJECTIVES

A major challenge in early treatment of acute cardiorenal syndrome (CRS) is the lack of predictors for progression of AKI. We aim to investigate the utility of urinary angiotensinogen and other renal injury biomarkers in predicting AKI progression in CRS.

DESIGN, SETTINGS, PARTICIPANTS, & MEASUREMENTS

In this prospective, multicenter study, we screened 732 adults who admitted for acute decompensated heart failure from September 2011 to December 2014, and evaluated whether renal injury biomarkers measured at time of AKI diagnosis can predict worsening of AKI. In 213 patients who developed Kidney Disease Improving Global Outcomes stage 1 or 2 AKI, six renal injury biomarkers, including urinary angiotensinogen (uAGT), urinary neutrophil gelatinase-associated lipocalin (uNGAL), plasma neutrophil gelatinase-associated lipocalin, urinary IL-18 (uIL-18), urinary kidney injury molecule-1, and urinary albumin-to-creatinine ratio, were measured at time of AKI diagnosis. The primary outcome was AKI progression defined by worsening of AKI stage (50 patients). The secondary outcome was AKI progression with subsequent death (18 patients).

RESULTS

After multivariable adjustment, the highest tertile of three urinary biomarkers remained associated with AKI progression compared with the lowest tertile: uAGT (odds ratio [OR], 10.8; 95% confidence interval [95% CI], 3.4 to 34.7), uNGAL (OR, 4.7; 95% CI, 1.7 to 13.4), and uIL-18 (OR, 3.6; 95% CI, 1.4 to 9.5). uAGT was the best predictor for both primary and secondary outcomes with area under the receiver operating curve of 0.78 and 0.85. These three biomarkers improved risk reclassification compared with the clinical model alone, with uAGT performing the best (category-free net reclassification improvement for primary and secondary outcomes of 0.76 [95% CI, 0.46 to 1.06] and 0.93 [95% CI, 0.50 to 1.36]; P<0.001). Excellent performance of uAGT was further confirmed with bootstrap internal validation.

CONCLUSIONS

uAGT, uNGAL, and uIL-18 measured at time of AKI diagnosis improved risk stratification and identified CRS patients at highest risk of adverse outcomes.

Fabry's disease: an example of cardiorenal syndrome type 5

Cardiorenal syndrome type 5 (CRS-5) includes conditions where there is a simultaneous involvement of the heart and kidney from a systemic disorder. This is a bilateral organ cross talk. Fabry's disease (FD) is a devastating progressive inborn error of metabolism with lysosomal glycosphingolipid deposition in variety of cell types, capillary endothelial cells, renal, cardiac and nerve cells. Basic effect is absent or deficient activity of lysosomal exoglycohydrolase a-galactosidase A. Renal involvement consists of proteinuria, isosthenuria, altered tubular function, presenting in second or third decade leading to azotemia and end-stage renal disease in third to fifth decade mainly due to irreversible changes to glomerular, tubular and vascular structures, especially highlighted by podocytes foot process effacement. Cardiac involvement consists of left ventricular hypertrophy, right ventricular hypertrophy, arrhythmias (sinus node and conduction system impairment), diastolic dysfunction, myocardial ischemia, infarction, transmural replacement fibrosis, congestive heart failure and cardiac death. Management of FD is based on enzymatic replacement therapy and control of renal (with anti-proteinuric agents such as angiotensin-converting enzyme inhibitors-and/or angiotensin II receptor blockers), brain (coated aspirin, clopidogrel and statin to prevent strokes) and heart complications (calcium channel blockers for ischemic cardiomyopathy, warfarin and amiodarone or cardioverter device for arrhythmias).

Degeneration of Dopaminergic Neurons Due to Metabolic Alterations and Parkinson's Disease

The rates of metabolic diseases, such as type 2 diabetes mellitus (T2DM), obesity, and cardiovascular disease (CVD), markedly increase with age. In recent years, studies have reported an association between metabolic changes and various pathophysiological mechanisms in the central nervous system (CNS) in patients with metabolic diseases. Oxidative stress and hyperglycemia in metabolic diseases lead to adverse neurophysiological phenomena, including neuronal loss, synaptic dysfunction, and improper insulin signaling, resulting in Parkinson’s disease (PD). In addition, several lines of evidence suggest that alterations of CNS environments by metabolic changes influence the dopamine neuronal loss, eventually affecting the pathogenesis of PD. Thus, we reviewed recent findings relating to degeneration of dopaminergic neurons during metabolic diseases. We highlight the fact that using a metabolic approach to manipulate degeneration of dopaminergic neurons can serve as a therapeutic strategy to attenuate pathology of PD.

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.

Single baseline serum creatinine measurements predict mortality in critically ill patients hospitalized for acute heart failure

Background

Acute heart failure (AHF) is a leading cause of death in critically ill patients and is often accompanied by significant renal dysfunction. Few data exist on the predictive value of measures of renal dysfunction in large cohorts of patients hospitalized for AHF.

Methods

Six hundred and eighteen patients hospitalized for AHF (300 male, aged 73.3 ± 10.3 years, 73% New York Heart Association Class 4, mean hospital length of stay 12.9 ± 7.7 days, 97% non‐ischaemic AHF) were included in a retrospective single‐centre data analysis. Echocardiographic data, serum creatinine/urea levels, estimated glomerular filtration rate (eGFR), and clinical/laboratory markers were recorded. Mean follow‐up time was 2.9 ± 2.1 years. All‐cause mortality was recorded, and univariate/multivariate analyses were performed.

Results

Normal renal function defined as eGFR > 90 mL/min/1.73 m² was noted in only 3% of AHF patients at baseline. A significant correlation of left ventricular ejection fraction with serum creatinine levels and eGFR (all P < 0.002) was noted. All‐cause mortality rates were 12% (90 days) and 40% (at 2 years), respectively. In a multivariate model, increased age, higher New York Heart Association class at admission, higher total cholesterol levels, and lower eGFR independently predicted death. Patients with baseline eGFR < 30 mL/min/1.73 m² had an exceptionally high risk of death (odds ratio 2.80, 95% confidence interval 1.52–5.15, P = 0.001).

Conclusions

In a large cohort of patients with mostly non‐ischaemic AHF, enhanced serum creatinine levels and reduced eGFR independently predict death. It appears that patients with eGFR < 30 mL/min/1.73 m² have poorest survival rates. Our data add to mounting data indicating that impaired renal function is an important risk factor for non‐survival in patients hospitalized for AHF.

Cardiovascular-renal axis disorders in the domestic dog and cat: a veterinary consensus statement

OBJECTIVES

There is a growing understanding of the complexity of interplay between renal and cardiovascular systems in both health and disease. The medical profession has adopted the term "cardiorenal syndrome" (CRS) to describe the pathophysiological relationship between the kidney and heart in disease. CRS has yet to be formally defined and described by the veterinary profession and its existence and importance in dogs and cats warrant investigation. The CRS Consensus Group, comprising nine veterinary cardiologists and seven nephrologists from Europe and North America, sought to achieve consensus around the definition, pathophysiology, diagnosis and management of dogs and cats with "cardiovascular-renal disorders" (CvRD). To this end, the Delphi formal methodology for defining/building consensus and defining guidelines was utilised.

METHODS

Following a literature review, 13 candidate statements regarding CvRD in dogs and cats were tested for consensus, using a modified Delphi method. As a new area of interest, well-designed studies, specific to CRS/CvRD, are lacking, particularly in dogs and cats. Hence, while scientific justification of all the recommendations was sought and used when available, recommendations were largely reliant on theory, expert opinion, small clinical studies and extrapolation from data derived from other species.

RESULTS

Of the 13 statements, 11 achieved consensus and 2 did not. The modified Delphi approach worked well to achieve consensus in an objective manner and to develop initial guidelines for CvRD.

DISCUSSION

The resultant manuscript describes consensus statements for the definition, classification, diagnosis and management strategies for veterinary patients with CvRD, with an emphasis on the pathological interplay between the two organ systems. By formulating consensus statements regarding CvRD in veterinary medicine, the authors hope to stimulate interest in and advancement of the understanding and management of CvRD in dogs and cats. The use of a formalised method for consensus and guideline development should be considered for other topics in veterinary medicine.

Prevalence, implication, and determinants of worsening renal function after surgery for congenital heart disease

Accumulating data in adults indicate the prognostic importance of worsening renal function (WRF) during treatment of acute heart failure. Venous congestion appears to play a dominant role in WRF; however, data regarding WRF in children with congenital heart disease (CHD) are limited. The present study was conducted to elucidate the prevalence and characteristics of WRF after surgery for CHD in children. We also tested our hypothesis that, similar to adult heart failure, venous congestion is an important determinant of WRF independent of cardiac output in this population. Fifty-five consecutive pediatric patients who underwent cardiovascular surgery for CHD were studied (median age 0.7 years; range 3 days to 17 years). The degree of WRF was assessed by the difference between the maximum levels of postoperative serum creatinine (Cr) and preoperative serum Cr. There was a high prevalence of WRF in the present cohort: an increase in Cr level was observed in 47 patients (85 %) and a Cr increase ≥0.3 mg/dL was seen in 23 (42 %). Importantly, WRF was significantly associated with a worse clinical outcome of a longer stay in the intensive care unit and hospital (both p < 0.05), even after controlling for age and operative factors. In addition, multivariate regression analysis revealed that central venous pressure, rather than cardiac output, was an independent determinant of WRF. Postoperative management to relieve venous congestion may help ameliorate or prevent WRF and thereby improve outcomes in patients with CHD.

Comparison of Neutrophil Gelatinase-Associated Lipocalin Versus B-Type Natriuretic Peptide and Cystatin C to Predict Early Acute Kidney Injury and Outcome in Patients With Acute Heart Failure

Neutrophil gelatinase-associated lipocalin (NGAL) has been described in chronic heart failure (HF) as marker of tubular damage and renal dysfunction; however, less data are available in patients with acute HF. Because of high rate of acute kidney injury (AKI) development, we aimed to investigate the role of NGAL in predicting early AKI development; second, we compared NGAL with respect to cystatin C, B-type natriuretic peptide (BNP), renal function, and blood urea nitrogen (BUN) for outcome prediction. We measured admission serum NGAL, cystatin C, and BNP in 231 patients affected to acute HF; all patients were submitted to daily creatinine, estimated glomerular filtration rate, and measurement to identify inhospital AKI defined by Risk, Injury, Failure, Loss, End-Stage Kidney Disease and Acute Kidney Injury Network criteria. We also measured admission and discharge estimated glomerular filtration rate, creatinine, and BUN to evaluate their prognostic role during a 6-month follow-up period; 78 patients developed AKI during hospitalization. In these subjects, NGAL levels were significantly increased respect to patients without AKI (295 ± 228 vs 129 ± 108 ng/ml, p <0.001). A cutoff of 134 ng/ml has been related to AKI with good sensibility and specificity (85% and 80%, respectively; area under the curve 0.81, p <0.001). BNP was also mildly increased (1,000 ± 906 vs 746 ± 580 pg/ml, p = 0.03) but not cystatin C. Patients with chronic kidney disease demonstrated higher NGAL levels compared with subjects with preserved renal function (258 ± 249 and 120 ± 77 ng/ml, p <0.001). The receiver-operating characteristic curve analysis demonstrated that increased NGAL values were associated with increased mortality (cutoff 170 ng/ml, sensibility 60%, specificity 82%, accuracy 71%, area under the curve 0.77, p <0.001). The same significant correlation was also found for BUN at discharge (cutoff 100 mg/dl, sensibility 65%, specificity 85%, accuracy 71%, area under the curve 0.77, p <0.001). Multivariable Cox regression analysis showed that cutoff 170 ng/ml was related with adverse outcome (hazard ratio 1.77, confidence interval 1.24 to 2.83, p = 0.01). In conclusion, NGAL measurement is a sensible tool to predict AKI during hospitalization. Elevated NGAL levels appear to be related to BUN increase and post-discharge outcome. This suggests a prognostic role of tubular damage beyond renal dysfunction.

Oxidative stress: dual pathway induction in cardiorenal syndrome type 1 pathogenesis

Cardiorenal Syndrome Type 1 (Type 1) is a specific condition which is characterized by a rapid worsening of cardiac function leading to acute kidney injury (AKI). Even though its pathophysiology is complex and not still completely understood, oxidative stress seems to play a pivotal role. In this study, we examined the putative role of oxidative stress in the pathogenesis of CRS Type 1. Twenty-three patients with acute heart failure (AHF) were included in the study. Subsequently, 11 patients who developed AKI due to AHF were classified as CRS Type 1. Quantitative determinations for IL-6, myeloperoxidase (MPO), nitric oxide (NO), copper/zinc superoxide dismutase (Cu/ZnSOD), and endogenous peroxidase activity (EPA) were performed. CRS Type 1 patients displayed significant augmentation in circulating ROS and RNS, as well as expression of IL-6. Quantitative analysis of all oxidative stress markers showed significantly lower oxidative stress levels in controls and AHF compared to CRS Type 1 patients (P < 0.05). This pilot study demonstrates the significantly heightened presence of dual oxidative stress pathway induction in CRS Type 1 compared to AHF patients. Our findings indicate that oxidative stress is a potential therapeutic target, as it promotes inflammation by ROS/RNS-linked pathogenesis.

Direct evidence of podocyte damage in cardiorenal syndrome type 2: preliminary evidence

BACKGROUND

Renal structural alterations have been partially uncovered in cardiorenal syndrome (CRS). Patients with CRS may have evidence of tubular damage, but markers of glomerular damage other than proteinuria have not been thoroughly investigated. The nature of renal damage in CRS may have therapeutic implications, as glomerular damage requires tight blood pressure control and renin-angiotensin-aldosterone system (RAAS) inhibition. The present investigation evaluates patients with CRS type 2 (CRS-2) for direct evidence of glomerular damage as evidenced by the presence of urinary podocin.

METHODS

The presence of glomerular damage was assessed in acutely decompensated patients with CRS-2 and healthy controls. Urinary podocin was determined by quantification of a tryptic peptide of podocin with high-performance liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS). Morning urine samples were collected for podocin, creatinine (Cr), and protein. Urinary podocin was expressed in femtomoles of podocin/milligram of Cr.

RESULTS

The urinary podocin/Cr ratio was greater in patients than in controls (0.37 ± 0.77 vs. 0.06 ± 0.05 fmol podocin/mg Cr, p = 0.04). A total of 40% of the patients had a urinary podocin/Cr ratio greater than the upper limit of normal (>0.2 fmol podocin/mg Cr). Patients with an elevated podocin/Cr ratio were more likely to have received ≤50% of the maximum dose of angiotensin-converting enzyme inhibitors or angiotensin receptor blockers (p = 0.04) than patients with a podocin/Cr ratio in the normal range.

CONCLUSIONS

CRS-2 may be associated with glomerular damage as evidenced by an elevated urinary podocin/Cr ratio. Modulators of RAAS may have a protective effect on urinary podocin loss.

Urinary Angiotensinogen Level Predicts AKI in Acute Decompensated Heart Failure: A Prospective, Two-Stage Study

A major challenge in prevention and early treatment of acute cardiorenal syndrome (CRS) is the lack of high-performance predictors. To test the hypothesis that urinary angiotensinogen (uAGT) is an early predictor for acute CRS and 1-year prognosis in patients with acute decompensated heart failure (ADHF), we performed a prospective, two-stage, multicenter cohort study in patients with ADHF. In stage I (test set), 317 patients were recruited from four centers. In stage II (validation set), 119 patients were enrolled from two other centers. Daily uAGT levels were analyzed consecutively. AKI was defined according to Kidney Disease Improving Global Outcomes (KDIGO) Clinical Practice Guidelines. In stage I, 104 (32.8%) patients developed AKI during hospitalization. Daily uAGT peaked on the first hospital day in patients who subsequently developed AKI. After multivariable adjustment, the highest quartile of uAGT on admission was associated with a 50-fold increased risk of AKI compared with the lowest quartile. For predicting AKI, uAGT (area under the receiver-operating characteristic curve [AUC]=0.84) outperformed urinary neutrophil gelatinase-associated lipocalin (AUC=0.78), the urinary albumin/creatinine ratio (AUC=0.71), and the clinical model (AUC=0.77). Survivors in stage I were followed prospectively for 1 year after hospital discharge. The uAGT level independently predicted the risk of 1-year mortality (adjusted odds ratio, 4.5; 95% confidence interval, 2.1 to 9.5) and rehospitalization (adjusted odds ratio, 3.6; 95% confidence interval, 1.6 to 5.7). The ability of uAGT in predicting AKI was validated in stage II (AUC=0.79). In conclusion, uAGT is a strong predictor for acute CRS and 1-year prognosis in ADHF.

Cardiorenal syndrome type 1: a defective regulation of monocyte apoptosis induced by proinflammatory and proapoptotic factors

In this study, we examined the possible immune-mediated mechanisms in cardiorenal syndrome (CRS) type 1 pathogenesis. We enrolled 40 patients with acute heart failure (AHF), 11 patients with CRS type 1 and 15 controls. Plasma from the different groups was incubated with monocytes; subsequently, cell apoptosis was evaluated by DNA fragmentation, caspase activity and cytofluorometric assay. Cytokine quantification in plasma and supernatant was performed by ELISA. Monocytes treated with CRS type 1 plasma showed significantly higher apoptosis compared with those treated with AHF and the controls (p < 0.05). Caspase-3 (CRS type 1: 2.20 ng/ml, IQR 2.06-2.33; AHF: 1.48 ng/ml, IQR 1.31-1.56; controls: 0.71 ng/ml, IQR 0.67-0.81) and caspase-8 levels (CRS type 1: 1.49 ng/ml, IQR 1.42-1.57; AHF: 0.94 ng/ml, IQR 0.84-0.98; controls: 0.56 ng/ml, IQR 0.51-0.58) in cells incubated with plasma from these patients demonstrated a significantly higher concentration. We observed a strong upregulation of plasma IL-6 and IL-18 in CRS type 1 compared with AHF and the controls (p < 0.05). Interestingly, we observed a similar concentration of TNF-α in CRS type 1 and AHF. In CRS type 1 patients, IL-6 (52.13 ng/ml, IQR 47.29-66.83) and IL-18 levels (197.75 ng/ml, IQR 120.80-265.49) in supernatant were significantly higher than in AHF patients (IL-6: 28.79 ng/ml, IQR 19.90-36.10; IL-18: 21.98 ng/ml, IQR 15.98-29.85) and controls (IL-6: 5.02 ng/ml, IQR 4.56-6.44; IL-18: 7.91 ng/ml, IQR 5.57-10.62). These findings suggest the presence of a defective regulation of monocyte apoptosis in CRS type 1 patients and the involvement of an immune-mediated mechanism in the pathophysiology of this syndrome.

Cardiorenal syndrome type 2: from diagnosis to optimal management

The deterioration of renal function, which is linked to chronic heart failure by a chronological and causal relationship (ie, the so-called cardiorenal syndrome [CRS] type 2), has recently become a matter of growing debate. This debate has concerned the efficacy, safety, and cost effectiveness of the therapies that have been implemented thus far for this syndrome (for example, the intravenous [IV] loop diuretics, such as repeated IV boluses or slow IV infusions, as well as mechanical fluid removal, particularly by means of isolated ultrafiltration [IUF]). Further controversies have also emerged concerning the optimal dosage and timing of some evidence-based drugs, such as angiotensin-converting-enzyme inhibitors. The present review summarizes the currently used diagnostic tools for detecting renal damage in CRS type 2. Subsequently, the meaning of worsening renal function is outlined, as well as the sometimes inconsistent therapeutic schemes that have been implemented in order to prevent or counteract worsening renal function. The need to elaborate upon more detailed and comprehensive scientific recommendations for targeted prevention and/or therapy of CRS type 2 is also underlined. The measures usually adopted (such as the more accurate modulation of loop diuretic dose, combined with the exploitation of other diuretics that are able to achieve a sequential blockade of the nephron, as well as the use of IV administration for loop diuretics) are briefly presented. The concept of diuretic resistance is illustrated, along with the paramount operational principles of IUF in diuretic-resistant patients. Some controversies regarding the comparison of IUF with stepped diuretic therapy in patients with CRS type 2 are also addressed.

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.