Novel urinary biomarkers in detecting acute kidney injury, persistent renal impairment, and all-cause mortality following decongestive therapy in acute decompensated heart failure

Definition, Staging, and Role of Biomarkers in Acute Kidney Injury in the Context of Cardiovascular Interventions

Acute kidney injury (AKI) is a frequently occurring complication of cardiovascular interventions, and associated with adverse outcomes. Therefore, a clear definition of AKI is of paramount importance to enable timely recognition and treatment. Historically, changes in the serum creatinine and urine output have been used to define AKI, and the criteria have evolved over time with better understanding of the impact of AKI on the outcomes. However, the reliance on serum creatinine for these AKI definitions carries numerous limitations including delayed rise, inability to differentiate between hemodynamics versus structural injury and assay variability to name a few.

Renal Biomarkers in Cardiovascular Patients with Acute Kidney Injury: A Case Report and Literature Review

Biomarkers have become important tools in the diagnosis and management of cardiorenal syndrome (CRS), a complex condition characterized by dysfunction in both the cardiovascular and renal systems. Biomarkers can help identify the presence and severity of CRS, predict its progression and outcomes, and facilitate personalized treatment options. Several biomarkers, including natriuretic peptides, troponins, and inflammatory markers, have been extensively studied in CRS, and have shown promising results in improving diagnosis and prognosis. In addition, emerging biomarkers, such as kidney injury molecule-1 and neutrophil gelatinase-associated lipocalin, offer potential for early detection and intervention of CRS. However, the use of biomarkers in CRS is still in its infancy, and further research is needed to establish their utility in routine clinical practice. This review highlights the role of biomarkers in the diagnosis, prognosis, and management of CRS, and discusses their potential as valuable clinical tools for personalized medicine in the future.

Predictive Value of N-Terminal Pro B-Type Natriuretic Peptide for Contrast-Induced Nephropathy Non-Recovery and Poor Outcomes Among Patients Undergoing Percutaneous Coronary Intervention

BACKGROUND

Contrast-induced nephropathy (CIN) is a frequent complication in patients undergoing percutaneous coronary intervention (PCI). The degree of recovery of renal function from CIN may affect long-term prognosis. N-terminal pro B-type natriuretic peptide (NT-proBNP) is a simple but useful biomarker for predicting CIN. However, the predictive value of preprocedural NT-proBNP for CIN non-recovery and long-term outcomes in patients undergoing PCI remains unclear.Methods and Results: This study prospectively enrolled 550 patients with CIN after PCI between January 2012 and December 2018. CIN non-recovery was defined as persistent serum creatinine >25% or 0.5 mg/dL over baseline from 1 week to 12 months after PCI in patients who developed CIN. CIN non-recovery was observed in 40 (7.3%) patients. Receiver operating characteristic analysis indicated that the best NT-proBNP cut-off value for detecting CIN non-recovery was 876.1 pg/mL (area under the curve 0.768; 95% confidence interval [CI] 0.731-0.803). After adjusting for potential confounders, multivariable analysis indicated that NT-proBNP >876.1 pg/mL was an independent predictor of CIN non-recovery (odds ratio 1.94; 95% CI 1.03-3.75; P=0.0042). Kaplan-Meier curves showed higher rates of long-term mortality among patients with CIN non-recovery than those with CIN recovery (Chi-squared=14.183, log-rank P=0.0002).

CONCLUSIONS

Preprocedural NT-proBNP was associated with CIN non-recovery among patients undergoing PCI. The optimal cut-off value for NT-proBNP to predict CIN non-recovery was 876.1 pg/mL.

Urine N-terminal pro-B-type natriuretic peptide and plasma proenkephalin are promising biomarkers for early diagnosis of cardiorenal syndrome type 1 in acute decompensated heart failure: a prospective, double-center, observational study in real-world

Background

Patients with acute decompensated heart failure (ADHF) show cardiorenal syndrome type 1 (CRS-1) are more likely to have a poor outcome. However, the current criteria often lead to delayed CRS-1 diagnosis. Therefore, we evaluated the predictive value of plasma proenkephalin (pPENK) and urine NT-proBNP (uNT-proBNP) for early diagnosis of CRS-1 and vulnerable-phase prognosis in ADHF patients.

Methods

The plasma NT-proBNP (pNT-proBNP), pPENK, and uNT-proBNP were measured in 121 ADHF patients on admission. The plasma neutrophil gelatinase-associated lipocalin (pNGAL) was chosen as the reference. Logistic regression was used to determine the predictors of CRS-1. The area under the receiver operating curves (ROCs) was calculated to assess the early diagnostic value of pNGAL, pPENK, and uNT-proBNP/uCr for CRS-1. To evaluate the prognostic risk of factors for the 90-d outcomes of all ADHF patients, the Cox regression was performed and the cumulative risk curve was plotted.

Results

We found that pPENK [OR 1.093 (95% CI 1.022–1.169), p = 0.010; AUROC = 0.899 (95% CI 0.831–0.946)] and uNT-proBNP/uCr ratio [OR 1.015 (95% CI 1.003–1.028), p = 0.012; AUROC = 0.934 (95% CI 0.874–0.971)] could independently predict the occurrence of CRS-1 in hospitalized patients with ADHF. The pPENK [HR 1.014 (95% CI 1.000–1.042), p = 0.044] and uNT-proBNP/uCr ration [HR 0.998 (95% CI 0.997–1.000), p = 0.045] were also independent predictors of the risk of HF readmission or all-cause death 90 d after discharge in ADHF patients.

Conclusions

The newly found pPENK and noninvasive test of uNT-proBNP/uCr ratio (pg/nmol) on admission may be two promising novel predictive biomarkers for early diagnosis of CRS-1 occurrence and vulnerable-phase outcomes in ADHF patients.

Vitamin D Binding Protein and Renal Injury in Acute Decompensated Heart Failure

Background

Renal function in acute decompensated heart faiulre (ADHF) is a strong predictor of disease evolution and poor outcome. Current biomarkers for early diagnostic of renal injury in the setting of ADHF are still controversial, and their association to early pathological changes needs to be established. By applying a proteomic approach, we aimed to identify early changes in the differential urine protein signature associated with development of renal injury in patients hospitalised due to ADHF.

Materials and Methods

Patients (71 [64–77] years old) admitted at the emergency room with ADHF and hospitalised were investigated (N = 64). Samples (urine/serum) were collected at hospital admission (day 0) and 72 h later (day 3). Differential serum proteome was analysed by two-dimensional electrophoresis and matrix-assisted laser desorption/ionisation-time of flight (MALDI-ToF/ToF). Validation studies were performed using ELISA.

Results

Proteomic analysis depicted urinary vitamin D binding protein (uVDBP) as a two spots protein with increased intensity in ADHF and significant differences depending on the glomerular filtration rate (GFR). Urinary VDBP in patients with ADHF at hospitalisation was > threefold higher than in healthy subjects, with the highest levels in those patients with ADHF already presenting renal dysfunction. At day 3, urine VDBP levels in patients maintaining normal renal function dropped to normal values (P = 0.03 vs. day 0). In contrast, urine VDBP levels remained elevated in the group developing renal injury, with values twofold above the normal range (P < 0.05), while serum creatinine and GF levels were within the physiological range in this group. Urinary VDBP in ADHF positively correlated with markers of renal injury such as cystatin C and Kidney Injury Molecule 1 (KIM-1). By ROC analysis, urinary VDBP, when added to cystatin C and KIM-1, improved the prediction of renal injury in patients with ADHF.

Conclusion

We showed increased urine VDBP in patients with ADHF at hospital admission and a differential uVDBP evolution pattern at early stage of renal dysfunction, before pathological worsening of GFR is evidenced.

Biomarkers in Cardiorenal Syndrome and Potential Insights Into Novel Therapeutics

Heart and kidney failure often co-exist and confer high morbidity and mortality. The complex bi-directional nature of heart and kidney dysfunction is referred to as cardiorenal syndrome, and can be induced by acute or chronic dysfunction of either organ or secondary to systemic diseases. The five clinical subtypes of cardiorenal syndrome are categorized by the perceived primary precipitant of organ injury but lack precision. Traditional biomarkers such as serum creatinine are also limited in their ability to provide an early and accurate diagnosis of cardiorenal syndrome. Novel biomarkers have the potential to assist in the diagnosis of cardiorenal syndrome and guide treatment by evaluating the relative roles of implicated pathophysiological pathways such as hemodynamic dysfunction, neurohormonal activation, endothelial dysfunction, inflammation and oxidative stress, and fibrosis. In this review, we assess the utility of biomarkers that correlate with kidney and cardiac (dys)function, inflammation/oxidative stress, fibrosis, and cell cycle arrest, as well as emerging novel biomarkers (thrombospondin-1/CD47, glycocalyx and interleukin-1β) that may provide prediction and prognostication of cardiorenal syndrome, and guide potential development of targeted therapeutics.

MicroRNA-423-5p as a biomarker for early diagnosis and outcome prediction of acute kidney injury in patients with acute decompensated heart failure

OBJECTIVE

To evaluate the clinical significance of serum and urinary microRNA-423-5p in the prediction of acute kidney injury onset and survival in patients with acute decompensated heart failure.

METHODS

A total of 180 acute decompensated heart failure patients, including 57 acute kidney injury cases and 123 non-acute kidney injury cases, were included in this study. Serum and urinary neutrophil gelatinase-associated lipocalin, a biomarker of renal injury of acute kidney injury, was detected using an enzyme-linked immunosorbent assay. Expression of microRNA-423-5p in serum and urine samples was examined using quantitative real-time polymerase chain reaction. The clinical significance of microRNA-423-5p was evaluated using receiver operating characteristic curve and Kaplan-Meier survival analysis.

RESULTS

The levels of neutrophil gelatinase-associated lipocalin and microRNA-423-5p in serum and urine samples were elevated in patients with acute kidney injury compared with the non-acute kidney injury cases (all P < 0.05). Serum and urinary microRNA-423-5p had relatively high predictive performance for acute kidney injury onset in acute decompensated heart failure patients, and this predictive value was more significant when combined with urinary neutrophil gelatinase-associated lipocalin. In addition, serum and urinary elevated levels of microRNA-423-5p predicted a poor 180-day survival in the acute kidney injury group.

CONCLUSION

Increased serum and urinary microRNA-423-5p can predict the occurrence of acute kidney injury in acute decompensated heart failure patients, and is associated with poor survival of acute kidney injury patients. In addition, the diagnostic value of urine neutrophil gelatinase-associated lipocalin for the early screening of acute kidney injury from acute decompensated heart failure patients might be improved by considering the changes in urinary microRNA-423-5p.

Diagnostic accuracy of fibroblast growth factor 23 for predicting acute kidney injury in patients with acute decompensated heart failure

BACKGROUND

Elevated plasma levels of fibroblast growth factor 23 (FGF23) have emerged as a predictor for the development of acute kidney injury (AKI) in patients undergoing cardiac surgery and those with critical illnesses. However, accurate data in cases involving acute decompensated heart failure (ADHF) remains limited.

METHODS

Single centre cohort study was performed in patients admitted for ADHF. Plasma c-terminal FGF23 (c-FGF23) was measured at baseline and 24 hours after being diagnosed with ADHF. AKI was defined by KDIGO 2012 criteria.

RESULTS

The study enrolled 62 patients diagnosed with ADHF. The incidence of AKI was 45% and significantly increased the risk of death. Patients developing AKI had significantly higher levels of plasma c-FGF23 at baseline in comparison with those not developing AKI [median value 1258.5 (57.2, 15 850) vs 230.2 (68.515 850) RU/mL, P = .005]. During the first 24 hours, plasma c-FGF23 levels decreased in both groups, and the levels of c-FGF23 at 24 hours were consistent with the baseline [861.8 (75.7, 15 850) vs 226.3 (56, 5450.8) RU/mL, P = .006]. Receiver operating characteristic analysis of both first time and second time for plasma c-FGF23 collection yielded an area under curve of 0.71 for the prediction of AKI incidence. With the cut-off point at 450 RU/mL, the sensitivity and specificity of plasma c-FGF23 at the baseline for predicting AKI were 71.4% and 61.8% respectively.

CONCLUSION

Plasma c-FGF23 may serve as a novel biomarker for development of AKI in patients with ADHF. These results should be revalidated in larger-scale, cohort studies.

Utility of Urine Biomarkers and Electrolytes for the Management of Heart Failure

PURPOSE OF REVIEW

To provide insight into the role of urine biomarkers and electrolytes for the management of heart failure.

RECENT FINDINGS

The age-dependent decrease in glomerular filtration rate due to loss of functional nephrons occurs at a faster pace in heart failure, potentially exacerbated by episodes of acute kidney injury. Urine biomarkers have not convincingly demonstrated to improve detection of irreversible renal damage and predict long-term renal trajectories, compared with serial creatinine measurements. Recent data show that natriuresis and diuretic response track poorly with glomerular filtration, but strongly with prognosis. Urine sodium concentration > 50-70 mmol/L was recently put forward through expert consensus as an adequate diuretic response. The value of urine biomarkers to detect structural renal damage in heart failure remains unsure and the latter is probably uncommon, especially over short-term follow-up. Urine electrolytes on the other hand predict diuretic response accurately and may allow better diuretic titration.

Natural history and profile of selective cytokines in patients of acute pancreatitis with acute kidney injury

OBJECTIVES

To study the natural course of patients with acute pancreatitis (AP) with acute kidney injury (AKI) and their cytokine profile.

METHODS

Natural course of patients with AP and AKI was studied in 97 individuals. Levels of TNFα, IL-6, IL-10, IL-8 and IL-1β were measured at presentation and at 72 h in patients who developed AKI.

RESULTS

Amongst the entire cohort, 16.4% patients developed AKI (persistent AKI - 11 patients, transient AKI - 5 patients). Mortality rate was 25% amongst patients with AKI. Levels of IL-6 (p = 0.035) and IL-8 (p = 0.002) were found to be significantly higher in the AKI group. On multivariate analysis, IL-8 levels at baseline were found to be an independent predictor of AKI. AKI group had significant rise of TNF-α (P < 0.001), IL-6 (P < 0.001) and IL- 1β (P < 0.001) on day 3 whereas persistent-AKI group had significant rise of TNF-α (p = 0.031), IL-6 (p = 0.001) and IL-1β on day 3 and significant decline of IL-10 (p = 0.015). Using a cut-off of 105 pg/ml, IL-8 levels at baseline could predict AKI with a sensitivity of 87.5% and specificity of 59.2%, with area under the curve being 0.744 (p = 0.002).

CONCLUSION

AP patients developing AKI have poor prognosis. IL-8 levels can predict AKI in patients with AP.

Short-term prognostic implications of serum and urine neutrophil gelatinase-associated lipocalin in acute heart failure: findings from the AKINESIS study

AIMS

Kidney impairment has been associated with worse outcomes in acute heart failure (AHF), although recent studies challenge this association. Neutrophil gelatinase-associated lipocalin (NGAL) is a novel biomarker of kidney tubular injury. Its prognostic role in AHF has not been evaluated in large cohorts. The present study aimed to determine if serum NGAL (sNGAL) or urine NGAL (uNGAL) is superior to creatinine for predicting short-term outcomes in AHF.

METHODS AND RESULTS

The study was conducted in an international, multicentre, prospective cohort consisting of 927 patients with AHF. Admission and peak values of sNGAL, uNGAL and uNGAL/urine creatinine (uCr) ratio were compared to admission and peak serum creatinine (sCr). The composite endpoints were death, initiation of renal replacement therapy, heart failure (HF) readmission and any emergent HF-related outpatient visit within 30 and 60 days, respectively. The mean age of the cohort was 69 years and 62% were male. The median length of stay was 6 days. The composite endpoint occurred in 106 patients and 154 patients within 30 and 60 days, respectively. Serum NGAL was more predictive than uNGAL and the uNGAL/uCr ratio but was not superior to sCr [area under the curve: admission sNGAL 0.61, 95% confidence interval (CI) 0.55-0.67, and 0.59, 95% CI 0.54-0.65; peak sNGAL: 0.60, 95% CI 0.54-0.66, and 0.57, 95% CI 0.52-0.63; admission sCr: 0.60, 95% CI 0.54-0.64, and 0.59, 95% CI 0.53-0.64; peak sCr: 0.61, 95% CI 0.55-0.67, and 0.59, 95% CI 0.54-0.64, at 30 and 60 days, respectively]. NGAL was not predictive of the composite endpoint in multivariate analysis.

CONCLUSIONS

Serum NGAL outperformed uNGAL but neither was superior to admission or peak sCr for predicting adverse events.

Cardiorenal Syndrome Revisited

Cardiorenal syndromes have been categorized into 5 clinical subtypes based on which organ is perceived to be the primary precipitant of the vicious and interrelated cycle of declining function in both organs. This clinical classification has broadened interest in cardiorenal interactions, but it is merely descriptive, does not rely on or inform predominant pathophysiology, and has produced little change in either practice or the research agenda. In contrast, recent scientific work identifies common pathophysiological pathways for several categories of cardiorenal syndromes, suggesting a unifying pathogenesis. Fibrosis is a common consequence of inflammation- and oxidative stress-related endothelial dysfunction in aging, hypertension, diabetes mellitus, obesity, ischemia, and organ injury. It is a common feature in heart failure and chronic kidney disease. Therefore, we suggest that fibrosis may be not only a marker but also the primary driver of pathophysiology in several cardiorenal syndromes. Interstitial fibrosis in the heart, large arteries, and kidneys may play a key role in the pathophysiology of the cardiorenal syndrome continuum. Focusing on fibrosis as a disease mediator might enable the identification of fibrosis-related biotargets that could potentially be modulated with renin-angiotensin-aldosterone system inhibitors, mineralocorticoid receptor antagonists, or other novel antifibrotic agents in development. This conceptual approach may be an effective new strategy for the prevention and treatment of fibrosis within the cardiorenal syndrome continuum.

Renal Effects of Intensive Volume Removal in Heart Failure Patients With Preexisting Worsening Renal Function

Background The relationship between intensive volume removal in acute decompensated heart failure patients with preexisting worsening renal function (WRF) and renal tubular injury, postdischarge renal function, and clinical outcomes is unknown. Methods and Results We used data from the multicenter CARRESS-HF trial (Cardiorenal Rescue Study in Acute Decompensated Heart Failure) that randomized patients with acute decompensated heart failure and preexisting WRF to intensive volume removal with stepped pharmacological therapy or fixed rate ultrafiltration. Patients in the urinary renal tubular injury biomarker substudy (NAG [N-acetyl-b-D-glucosaminidase], KIM-1 [kidney injury molecule-1], and NGAL [neutrophil gelatinase-associated lipocalin]) were evaluated (N=105). The severity of prerandomization WRF was unrelated to baseline renal tubular injury biomarkers ( r=0.14; P=0.17). During randomized intensive volume removal, creatinine further worsened in 53% of patients. Despite a small to moderate magnitude increase in creatinine in most of these patients, postrandomization WRF was strongly associated with worsening in renal tubular injury biomarkers (odds ratio, 12.6; P=0.004). This observation did not differ by mode of volume removal (stepped pharmacological therapy versus ultrafiltration, P_interaction=0.46). Increase in renal tubular injury biomarkers was associated with a higher incidence of hemoconcentration (odds ratio, 3.1; P=0.015), and paradoxically, better recovery of creatinine at 60 days ( P=0.01). Conclusions In acute decompensated heart failure patients with preexisting WRF, intensive volume removal resulted in a further worsening of creatinine approximately half of the time, a finding associated with a rise in tubular injury biomarkers. However, decongestion and renal function recovery at 60 days were superior in patients with increased tubular injury markers. These data suggest that the benefits of decongestion may outweigh any modest or transient increases in serum creatinine or tubular injury markers that occur during intensive volume removal. Clinical Trial Registration URL: https://www.clinicaltrials.gov . Unique identifier: NCT00608491.

Practical management of concomitant acute heart failure and worsening renal function in the emergency department

Worsening renal function (i.e. any increase in creatinine or decrease in the estimated glomerular filtration rate) is common in patients admitted for acute heart failure in the emergency department. Although worsening renal function (WRF) has been associated with the occurrence of dismal outcomes, this only appears to be the case when associated with clinical deterioration. However, if the clinical status of the patient is improving, a certain increase in serum creatinine may be acceptable. This WRF, which is not associated with clinical deterioration or adverse outcomes (e.g. during treatment up-titration), has been referred to as 'pseudo-WRF' and should not detract clinicians from targeting 'guideline-recommended' therapies. This is an important message for emergency physicians to pursue diuretics as long as signs of pulmonary congestion persist to improve the clinical status of the patient. In the present review, we aim to provide clinicians in acute settings with an integrative and comprehensive approach to cardiorenal interactions in acute heart failure.

Editor's Choice-Diuretic resistance in acute heart failure

Diuretic resistance is a powerful predictor of adverse outcome in acute heart failure (AHF), irrespectively of underlying glomerular filtration rate. Metrics of diuretic efficacy such as natriuresis, urine output, weight loss, net fluid balance, or fractional sodium excretion, differ in their risk for measurement error, convenience, and biological plausibility, which should be taken into account when interpreting their results. Loop diuretic resistance in AHF has multiple causes including altered drug pharmacokinetics, impaired renal perfusion and effective circulatory volume, neurohumoral activation, post-diuretic sodium retention, the braking phenomenon and functional as well as structural adaptations in the nephron. Ideally, these mechanisms should guide specific treatment decisions with the goal of achieving complete decongestion. Therefore, volume overload needs to be identified correctly to avoid poor diuretic response due to electrolyte depletion or dehydration. Next, renal perfusion should be optimised if possible and loop diuretics should be prescribed above their threshold dose. Addition of thiazide-type diuretics should be considered when a progressive decrease in loop diuretic efficacy is observed with prolonged use (i.e., the braking phenomenon). Furthermore, thiazide-type diuretics are a useful addition in patients with low glomerular filtration rate. However, they limit free water excretion and are relatively contraindicated in cases of hypotonic hyponatremia, where acetazolamide is the better option. Finally, ultrafiltration should be considered in patients with refractory diuretic resistance as persistent volume overload after decongestive treatment is associated with worse outcomes. Whether more upfront use of any of these individually tailored decongestion strategies is superior to monotherapy with loop diuretics remains to be shown by adequately powered randomised clinical trials.

Toward Precision Medicine in the Cardiorenal Syndrome

Although the field of oncology has made significant steps toward individualized precision medicine, cardiology and nephrology still often use a "one size fits all" approach. This applies to the intersection of the heart-kidney interaction and the cardiorenal syndrome as well. Recent studies have shown that the prognostic implications of worsening renal function (WRF) in acute heart failure are variable; thus, there is a need to differentiate the implications of WRF to better guide precise care. This may best be performed with biomarkers that can give the clinician a real-time evaluation of the physiologic state at the time of developing WRF. This review will summarize current cardiac and renal biomarkers and their status in the evaluation of cardiorenal syndrome. Although we have made progress in our understanding of this syndrome, further investigation is needed to bring precision medicine into routine clinical practice for the care of patients with cardiorenal syndrome.

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.

Worsening Renal Function in Patients With Acute Heart Failure Undergoing Aggressive Diuresis Is Not Associated With Tubular Injury

BACKGROUND

Worsening renal function (WRF) in the setting of aggressive diuresis for acute heart failure treatment may reflect renal tubular injury or simply indicate a hemodynamic or functional change in glomerular filtration. Well-validated tubular injury biomarkers, N-acetyl-β-d-glucosaminidase, neutrophil gelatinase-associated lipocalin, and kidney injury molecule 1, are now available that can quantify the degree of renal tubular injury. The ROSE-AHF trial (Renal Optimization Strategies Evaluation-Acute Heart Failure) provides an experimental platform for the study of mechanisms of WRF during aggressive diuresis for acute heart failure because the ROSE-AHF protocol dictated high-dose loop diuretic therapy in all patients. We sought to determine whether tubular injury biomarkers are associated with WRF in the setting of aggressive diuresis and its association with prognosis.

METHODS

Patients in the multicenter ROSE-AHF trial with baseline and 72-hour urine tubular injury biomarkers were analyzed (n=283). WRF was defined as a ≥20% decrease in glomerular filtration rate estimated with cystatin C.

RESULTS

Consistent with protocol-driven aggressive dosing of loop diuretics, participants received a median 560 mg IV furosemide equivalents (interquartile range, 300-815 mg), which induced a urine output of 8425 mL (interquartile range, 6341-10 528 mL) over the 72-hour intervention period. Levels of N-acetyl-β-d-glucosaminidase and kidney injury molecule 1 did not change with aggressive diuresis (both P>0.59), whereas levels of neutrophil gelatinase-associated lipocalin decreased slightly (-8.7 ng/mg; interquartile range, -169 to 35 ng/mg; P<0.001). WRF occurred in 21.2% of the population and was not associated with an increase in any marker of renal tubular injury: neutrophil gelatinase-associated lipocalin (P=0.21), N-acetyl-β-d-glucosaminidase (P=0.46), or kidney injury molecule 1 (P=0.22). Increases in neutrophil gelatinase-associated lipocalin, N-acetyl-β-d-glucosaminidase, and kidney injury molecule 1 were paradoxically associated with improved survival (adjusted hazard ratio, 0.80 per 10 percentile increase; 95% confidence interval, 0.69-0.91; P=0.001).

CONCLUSIONS

Kidney tubular injury does not appear to have an association with WRF in the context of aggressive diuresis of patients with acute heart failure. These findings reinforce the notion that the small to moderate deteriorations in renal function commonly encountered with aggressive diuresis are dissimilar from traditional causes of acute kidney injury.

Relationships of kidney injury molecule-1 with renal function and cardiovascular risk factors in the general population

BACKGROUND

Kidney injury molecule-1 (KIM-1) has been associated with kidney damage in patients with preexisting renal disease. However, little is known about the relationships of KIM-1 with renal function and cardiovascular risk factors in healthy individuals from the general population.

METHODS

Healthy individuals aged 25-41years were enrolled in a population-based study. Main exclusion criteria were a BMI >35kg/m², preexisting kidney disease or established cardiovascular disease. KIM-1 was measured from frozen plasma samples using a high-sensitivity assay. Multivariable linear regression models were constructed to assess the relationships of KIM-1 with renal function and various cardiovascular risk factors.

RESULTS

We included 2060 individuals (47% men, median (interquartile range) age: 37 (31-40) years) in this analysis. Median KIM-1 levels were 82.5 (IQR 59.4-112.7) pg/ml. We found no significant relationship of KIM-1 with creatinine (adjusted β-coefficient (95% confidence interval) 0.0005 (-0.002; 0.003), p=0.61) and cystatin C (-0.02 (-0.21; 0.17), p=0.84). There were significant linear relationships of log-transformed KIM-1 with systolic blood pressure (adjusted β-coefficient (95% confidence interval) 0.07 (0.04; 0.09), p<0.0001), diastolic blood pressure (0.04 (0.02; 0.07), p=0.001), low-density lipoprotein cholesterol (0.09 (0.06; 0.11), p<0.0001), high-density lipoprotein cholesterol (0.07 (0.05; 0.1), p<0.0001), high-sensitivity C-reactive protein (0.05 (0.03; 0.07), p<0.0001), age (0.09 (0.07; 0.11), p<0.0001), BMI (0.04 (0.01; 0.06), p=0.005) and current smoking (0.12 (0.07; 0.17), p<0.0001).

CONCLUSION

Among healthy adults from the general population, plasma levels of KIM-1 were not associated with renal function but were independently related to multiple cardiovascular risk factors.

Serum Cystatin C Predicts AKI and the Prognosis of Patients in Coronary Care Unit: a Prospective, Observational Study

BACKGROUND/AIMS

Acute Kidney Injury (AKI) is a serious clinical state associated with high morbidity and mortality, particularly in critical ill patients. We investigated the hypothesis that serum Cystatin C (sCysC) is a good predictor for AKI and may affect the short-term prognosis of coronary care unit (CCU) patients.

METHODS

In this prospective, observational study, we screened 412 adults admitted to the CCU from January 1, 2014 to June 1, 2015 at Zhongnan Hospital of Wuhan University. Serum samples were obtained at the time of admission, and sCysC was quantified through nephelometry. AKI was defined based on KDIGO-AKI criteria. After the patients' hospital discharge, the survivors in this study were followed up for up to 2 years. The primary endpoint was the incidence of AKI stratified by severity stage, while the second endpoints included 2-year mortality, rehospitalization and failure in renal recovery rates, as well as the progression of AKI to CKD.

RESULTS

According to the KDIGO-AKI criteria, AKI occurred in 130 (31.6%) patients. After multivariate adjustments, the highest quartile of sCysC was associated with a 9-fold increased risk of incident AKI compared with the lowest quartile. For predicting AKI, sCysC [area under the receiver operating characteristic curve (AUC=0.842)] outperformed β2-micro globulin (AUC=0.813) and the clinical model (AUC=0.777), and a cutoff of 1.255 mg/L yielded good sensitivity and specificity. After a median 19.8-month follow-up, 112 (27.2%) patients died within 2 years after admission. The sCysC independently predicted the risk of 2-year mortality [adjusted odds ratio (OR), 4.955; 95% confidence interval (95% CI), 2.853 to 8.603] and rehospitalization (OR, 3.128; 95% CI, 2.011 to 4.867), as well as renal recovery failure (OR, 3.618, 95% CI, 1.753 to 7.463).

CONCLUSIONS

Serum CysC is a strong predictor of AKI and the short-term prognosis of CCU patients.

Urinary neutrophil gelatinase-associated lipocalin and cystatin C compared to the estimated glomerular filtration rate to predict risk in patients with suspected acute myocardial infarction

INTRODUCTION

Impaired renal function, reflected by estimated glomerular filtration rate (eGFR) or cystatin C, is a strong risk predictor in the presence of acute myocardial infarction (AMI). Urinary neutrophil gelatinase-associated lipocalin (uNGAL) is an early marker of acute kidney injury. uNGAL might also be a good predictor of outcome in patients with cardiovascular disease. Aim of the present study was to evaluate the prognostic value of uNGAL compared to eGFR and cystatin C in patients with suspected AMI.

METHODS

1818 patients were enrolled with suspected AMI. Follow-up information on the combined endpoint of death or non-fatal myocardial infarction was obtained 6months after enrolment and was available in 1804 patients. 63 events (3.5%) were registered.

RESULTS

While cystatin C and eGFR were strong risk predictors for the primary endpoint even adjusted for several variables, uNGAL was not independently associated with outcome: When applied continuously uNGAL was associated with outcome but did not remain a statistically significant predictor after several adjustments (i.e. eGFR). By adding cystatin C or uNGAL to GRACE risk score variables, only cystatin C could improve the predictive value while uNGAL showed no improvement.

CONCLUSION

We could show that cystatin C is an independent risk predictor in patients with suspected AMI and cystatin C can add improvement to the commonly used GRACE risk score. In contrast uNGAL is not independently associated with outcome and seems not to add further prognostic information to GRACE risk score.

[Value of N-terminal pro brain natriuretic peptide in predicting acute kidney injury in patients with acute decompensated chronic heart failure]

AIM

To investigate the prognostic value of serum N-terminal pro-brain natriuretic peptide (NT-proBNP) in the development of acute kidney injury (AKI) in patients with acute decompensated chronic heart failure (ADCHF).

SUBJECTS AND METHODS

Eighty-three patients (55 (66%) men and 28 (34%) women; mean age, 65±11 years) with ADCHF were examined. AKI was diagnosed and classified according to the 2012 Kidney Disease Improving Global Outcomes Clinical Practice guidelines. To rule out contrast-induced AKI, the investigation enrolled only patients in whom radiopague agents had not been injected 7 days before and during hospitalization. Enzyme immunoassay was used to determine serum NT-proBNP concentrations in all the patients upon hospital admission.

RESULTS

AKI was diagnosed in 18 (22%) patients, 13 (16%) had Stage I, 4 (5%) had Stage II, and 1 (1%) had Stage III. The serum concentration of NT-proBNP was significantly higher in patients with AKI than that in the other patients [1512.1 (981.0; 2246.2) and 861.8 (499.0; 1383.6) pg/ml (p=0.008). The rise in NT-proBNP concentrations of more than 942 pg/ml was established to be associated with a considerable increase in the risk of AKI (relative risk (RR) was 4.3; 95% confidence interval (CI), 1.27-14.90; p=0.02). RОС analysis indicated that a NT-proBNP level of >942 pg/ml allows prediction of AKI with a sensitivity of 78% (52; 94) and a specificity of 55% (44; 69) (AUC=0.70; p=0.006). Four (5%) patients died in hospital. NT-proBNP levels in all the dead were greater than 942 pg/ml. Two of the 4 deceased patients had AKI.

CONCLUSION

A high level of NT-proBNP in a patient with ADCHF during hospitalization can serve as a biomarker for high risk of AKI and for high mortality rates.

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.

Renal function assessment in heart failure

Renal function is one of the most consistent prognostic determinants in heart failure. The prognostic information it provides is independent of the ejection fraction and functional status. This article reviews the various renal function assessment measures, with special emphasis on the fact that the patient's clinical situation and response to the heart failure treatment should be considered for the correct interpretation of the results. Finally, we review the literature on the performance of tubular damage biomarkers.

N-acteyl-ß-D-glucosaminidase and kidney injury molecule-1: New predictors for long-term progression of chronic kidney disease in patients with heart failure

AIM

Patients with chronic heart failure (CHF) are often characterized by the cardiorenal syndrome (CRS). The aim of the present study was to assess whether novel markers of kidney injury are able to predict progression of chronic kidney disease (CKD) in patients with CHF.

METHODS

New renal biomarkers, N-acteyl-ß-D-glucosaminidase (NAG), kidney injury molecule-1 (KIM-1) and Neutrophil Gelatinase-Associated Lipocalin (NGAL), were assessed from urine samples of 149 patients with chronic heart failure. During a 5-year-follow-up, renal function was assessed by creatinine and estimated glomerular filtration rate (eGFR CKD EPI) and was available for 138 patients. Further, data regarding all-cause mortality was obtained.

RESULTS

Twenty-six patients (18.8%) developed a progression of CKD during the follow-up period, as defined by decline in eGFR category accompanied by a ≥25% drop in eGFR form baseline. No difference regarding age, sex, body mass index, hypertension, diabetes or EF was present between patients with and without CKD progression (each P = n.s.). At baseline, creatinine concentrations and eGFR were significantly different between both groups (sCr: 1.50 ± 0.67 vs 1.04 ± 0.37, P = < 0.001; eGFR: 47.8 ± 12.3 vs. 77.3 ± 23.5 mL/min per 1.73m(2) , each P < 0.001). In a Kaplan-Meier-analysis, KIM-1 and NAG were significant predictors for CKD progression (both P < 0.05). In Cox regression analysis, NAG > median (OR 3.25,P = 0.013), initial eGFR (OR 0.94, P < 0.001) and diuretic use (OR 3.92, P = 0.001) were independent predictors of CKD progression. Further, KIM-1 and NAG were also independent predictors of a combined endpoint of CKD progression and all-cause mortality by Cox regression analysis (each P < 0.05). The combination of both markers showed additive value regarding both endpoints. NGAL showed no association with CKD progression.

CONCLUSIONS

During long-term follow-up chronic heart failure patients with CKD show a relevant disease progression. The current study emphasizes a strong association of the tubular biomarkers NAG and KIM-1 with CKD progression in chronic heart failure and suggests their usefulness as cardiorenal markers.

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.

Urinary levels of novel kidney biomarkers and risk of true worsening renal function and mortality in patients with acute heart failure

AIMS

Recent studies indicate the need to redefine worsening renal function (WRF) in acute heart failure (AHF), linking a rise in creatinine with clinical status to identify patients who develop 'true WRF'. We evaluated the usefulness of serial assessment of urinary levels of neutrophil gelatinase-associated lipocalin (uNGAL), kidney injury molecule-1 (uKIM-1), and cystatin C (uCysC) for prediction of 'true WRF'.

METHODS AND RESULTS

In 132 patients with AHF, uNGAL, uKIM-1, and uCysC were measured using a highly sensitive immunoassay based on a single-molecule counting technology (Singulex, Alameda, CA, USA) at baseline, day 2, and day 3. Patients who developed WRF (a ≥0.3 mg/dL increase in serum creatinine or a >25% decrease in the estimated glomerular filtration rate from the baseline value) were differentiated into those 'true WRF' (presence of deterioration/no improvement in clinical status during hospitalization) vs. 'pseudo-WRF' (uneventful clinical course). 'True WRF' occurred in 13 (10%), 'pseudo-WRF' in 15 (11%), whereas the remaining 104 (79%) patients did not develop WRF. Patients with 'true WRF' were more often females, had higher levels of NT-proBNP, creatinine, and urea on admission, higher urine albumin to creatinine ratio at day 2, higher uNGAL at baseline, day 2, and day 3, and higher KIM-1 at day 2 (vs. pseudo-WRF vs. without WRF, all P < 0.05). Patients with pseudo-WRF did not differ from those without WRF. In the multivariable model, elevated uNGAL at all time points and uKIM-1 at day 2 remained independent predictors of 'true WRF'.

CONCLUSION

Elevated levels of uNGAL and uKIM-1 may predict development of 'true WRF' in AHF.

Biomarkers for the Early Detection and Prognosis of Acute Kidney Injury

AKI is an increasingly common disorder that is strongly linked to short- and long-term morbidity and mortality. Despite a growing heterogeneity in its causes, providing a timely and certain diagnosis of AKI remains challenging. In this review, we summarize the evolution of AKI biomarker studies over the past few years, focusing on two major areas of investigation: the early detection and prognosis of AKI. We highlight some of the lessons learned in conducting AKI biomarker studies, including ongoing attempts to address the limitations of creatinine as a reference standard and the recent shift toward evaluating the prognostic potential of these markers. Lastly, we suggest current gaps in knowledge and barriers that may be hindering their incorporation into care and a full ascertainment of their value.

Novel Biomarkers of Heart Failure

Although substantial improvements have been made in majority of cardiac disorders, heart failure (HF) remains a major health problem, with both increasing incidence and prevalence over the past decades. For that reason, the number of potential biomarkers that could contribute to diagnosis and treatment of HF patients is, almost exponentially, increasing over the recent years. The biomarkers that are, at the moment, more or less ready for use in everyday clinical practice, reflect different pathophysiological processes present in HF. In this review, seven groups of biomarkers associated to myocardial stretch (mid-regional proatrial natriuretic peptide, MR-proANP), myocyte injury (high-sensitive troponins, hs-cTn; heart-type fatty acid-binding protein, H-FABP; glutathione transferase P1, GSTP1), matrix remodeling (galectin-3; soluble isoform of suppression of tumorigenicity 2, sST2), inflammation (growth differentiation factor-15, GDF-15), renal dysfunction (neutrophil gelatinase-associated lipocalin, NGAL; kidney injury molecule-1, KIM-1), neurohumoral activation (adrenomedullin, MR-proADM; copeptin), and oxidative stress (ceruloplasmin; myeloperoxidase, MPO; 8-hydroxy-2'-deoxyguanosine, 8-OHdG; thioredoxin 1, Trx1) in HF will be overviewed. It is important to note that clinical value of individual biomarkers within the single time points in both diagnosis and outcome prediction in HF is limited. Hence, the future of biomarker application in HF lies in the multimarker panel strategy, which would include specific combination of biomarkers that reflect different pathophysiological processes underlying HF.

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.

Combination of Urinary Biomarkers Improves Early Detection of Acute Kidney Injury in Patients With Heart Failure

BACKGROUND

Acute kidney injury (AKI) is associated with morality and repeated hospitalization, and is frequently encountered in patients with acute decompensated heart failure (ADHF). However, few effective tools exist for early AKI identification and risk stratification.

METHODS AND RESULTS

This was a prospective observational study conducted in the coronary care unit (CCU) of a tertiary care university hospital. Patients with a diagnosis of ADHF and who were using diuretics were enrolled.Samples collected between December 2013 and February 2015 were tested for serum cystatin C (Cys-C), urinary neutrophil gelatinase-associated lipocalin, and kidney injury molecule-1 (KIM-1). Demographic, clinical, and laboratory data were evaluated. A total of 103 adult patients with a mean age of 68 years were investigated. AKI was diagnosed in 49 patients (47.6%). For predicting intrinsic AKI on the first day of CCU admission, a combination of Cys-C and urine KIM-1 yielded an excellent area under the receiver operating characteristic curve of 0.828, a sensitivity of 71.0%, and specificity of 43.0%, for an overall accuracy of 78%.

CONCLUSIONS

In this study, we found that combinations of the biomarker (Cys-C and KIM-1) were an effective clinical model for predicting AKI in patients with ADHF. The biomarker was also useful for differentiating subclinical AKI in patients with ADHF.

Measurement of neutrophil gelatinase-associated lipocalin (NGAL) in patients with non-communicable diseases: any additional benefit?

AIM

Chronic kidney disease (CKD) is one of the major complication from non-communicable diseases (NCD), such as diabetes or hypertension. We aimed to determine if routine measurement of neutrophil gelatinase-associated lipocalin (NGAL) in NCD patients could provide additional benefit for diagnosing kidney disease.

METHODS

Fasting serum NGAL, urea, creatinine, uric acid and albumin were measured in 298 NCD patients. Estimated glomerular filtration rate (e-GFR) was calculated using the CKD-EPI equation. Multiple linear regression modeling was used for analysis.

RESULTS

CKD patients have the highest levels of NGAL than the other NCD patients (p < 0.001). Although NGAL was significantly related to e-GFR, creatinine, urea and albumin in CKD-patients (p < 0.001) and not in the other NCD patients (p > 0.05), only serum creatinine predicted NGAL levels in CKD-patients (p < 0.001).

CONCLUSION

NGAL level is best associated with serum creatinine only in patients with CKD and NGAL measurement may not be cost effective as a routine kidney function test in NCD patients in under-resourced economies.

Biomarkers of renal injury and function: diagnostic, prognostic and therapeutic implications in heart failure

Heart failure guidelines suggest evaluating renal function as a routine work-up in every patient with heart failure. Specifically, it is advised to calculate glomerular filtration rate and determine blood urea nitrogen. The reason for this is that renal impairment and worsening renal function (WRF) are common in heart failure, and strongly associate with poor outcome. Renal function, however, consists of more than glomerular filtration alone, and includes tubulointerstitial damage and albuminuria. For each of these renal entities, different biomarkers exist that have been investigated in heart failure. Hypothetically, and in parallel to data in nephrology, these markers may aid in the diagnosis of renal dysfunction, or for risk stratification, or could help in therapeutic decision-making. However, as reviewed in the present manuscript, while these markers may carry prognostic information (although not always additive to established markers of renal function), their role in predicting WRF is limited at best. More importantly, none of these markers have been evaluated as a therapeutic target nor have their serial values been used to guide therapy. The evidence is most compelling for the oldest-serum creatinine (in combination with glomerular filtration rate)-but even for this biomarker, evidence to guide therapy to improve outcome is circumstantial at best. Although many new renal biomarkers have emerged at the horizon, they have only limited usefulness in clinical practice until thoroughly and prospectively studied. For now, routine measurement of (novel) renal biomarkers can help to determine cardiovascular risk, but there is no role for these biomarkers to change therapy to improve clinical outcome in heart failure.

Cardiorenal Syndrome Type 1: Renal Dysfunction in Acute Decompensated Heart Failure

OBJECTIVE

To present a review of cardiorenal syndrome type 1 (CRS1).

METHODS

Review of the literature.

RESULTS

Acute kidney injury occurs in approximately one-third of patients with acute decompensated heart failure (ADHF) and the resultant condition was named CRS1. A growing body of literature shows CRS1 patients are at high risk for poor outcomes, and thus there is an urgent need to understand the pathophysiology and subsequently develop effective treatments. In this review we discuss prevalence, proposed pathophysiology including hemodynamic and nonhemodynamic factors, prognosticating variables, data for different treatment strategies, and ongoing clinical trials and highlight questions and problems physicians will face moving forward with this common and challenging condition.

CONCLUSION

Further research is needed to understand the pathophysiology of this complex clinical entity and to develop effective treatments.

Plasma neutrophil gelatinase-associated lipocalin predicts major adverse cardiovascular events after cardiac care unit discharge

BACKGROUND

Emerging acute kidney injury biomarkers, including neutrophil gelatinase-associated lipocalin (NGAL), have a high potential for predicting worsening renal function. Acute exacerbation of renal dysfunction has a great impact on the outcomes of cardiovascular patients in critical conditions. This study aimed to evaluate whether plasma NGAL can predict the mortality and major adverse cardiovascular events (MACEs) after discharge from the cardiac care unit (CCU).

METHODS

Patients who were admitted to the CCU of the Tokyo University Hospital were prospectively enrolled (101 patients). Blood and urinary markers, including the blood NGAL, brain natriuretic peptide, creatinine, cystatin C, urinary albumin, N-acetyl-β-d-glucosaminidase, and L-type fatty acid-binding protein, were measured at CCU discharge. The primary outcome was MACEs until at least 6 months after CCU discharge.

RESULTS

Thirty-five patients experienced MACEs (35%). Multivariate logistic analysis revealed that the plasma NGAL, length of CCU stay, and existence of diabetes and heart failure were independent predicting factors for MACEs. Patients with the highest NGAL at discharge (>75th percentile) showed a significantly higher risk of MACEs than those with the lowest NGAL (<25th percentile) (log-rank test; hazard ratio, 5.15; 95% confidence interval 1.84-18.20; p<0.01).

CONCLUSION

Plasma NGAL at CCU discharge is a significant prognostic indicator of outcomes at 6 months in critically ill cardiac patients treated in a CCU.

The kidney in heart failure: an update

Heart and kidney are closely related in the clinical syndrome of heart failure (HF). It is now sufficiently clear that renal dysfunction occurs frequently in all phenotypes of HF, and when present, it is associated with higher mortality and morbidity. While the pathophysiology is multifactorial, the most important factors are a reduced renal perfusion and venous congestion. Recent interest has focused on worsening renal function (WRF), a situation strongly related to mortality, but seemingly only when HF status deteriorates. Unfortunately, to date clinicians are unable to identify specifically those patients with a grim prognosis following WRF. Although much has been learned on cardiorenal interaction in HF, still more questions have been left unanswered. The coming decade should provide us with more dedicated epidemiologic, mechanistic, and controlled trials in HF patients with reduced renal function. An updated classification of the cardiorenal syndrome that incorporates recent evidence and points towards areas of interest and uncertainties, and areas where progress is needed could facilitate this process. Ultimately, this should lead to preventive and treatment strategies that can preserve renal function and associated outcome in patients with HF.

Management of the cardiorenal syndrome in decompensated heart failure

BACKGROUND

The management of the cardiorenal syndrome (CRS) in decompensated heart failure (HF) is challenging, with high-quality evidence lacking.

SUMMARY

The pathophysiology of CRS in decompensated HF is complex, with glomerular filtration rate (GFR) and urine output representing different aspects of kidney function. GFR depends on structural factors (number of functional nephrons and integrity of the glomerular membrane) versus hemodynamic alterations (volume status, renal perfusion, arterial blood pressure, central venous pressure or intra-abdominal pressure) and neurohumoral activation. In contrast, urine output and volume homeostasis are mainly a function of the renal tubules. Treatment of CRS in decompensated HF patients should be individualized based on the underlying pathophysiological processes.

KEY MESSAGES

Congestion, defined as elevated cardiac filling pressures, is not a surrogate for volume overload. Transient decreases in GFR might be accepted during decongestion, but hypotension must be avoided. Paracentesis and compression therapy are essential to remove fluid overload from third spaces. Increasing the effective circulatory volume improves renal function when cardiac output is depressed. As mechanical support is invasive and inotropes are related to increased mortality, afterload reduction through vasodilator therapy remains the preferred strategy in patients who are normo- or hypertensive. Specific therapies to augment renal perfusion (rolofylline, dopamine or nesiritide) have rendered disappointing results, but recently, serelaxin has been shown to improve renal function, even with a trend towards reduced all-cause mortality in selected patients. Diuretic resistance is associated with worse outcomes, independent of the underlying GFR. Combinational diuretic therapy, with ultrafiltration as a bail-out strategy, is indicated in case of diuretic resistance.

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.

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.

CD4+ lymphocyte adenosine triphosphate--a new marker in sepsis with acute kidney injury?

BACKGROUND

AKI frequently develops in sepsis patients, significantly decreasing the overall prognosis. There are currently no diagnostic markers available which reliably predict the prognosis of sepsis-associated AKI. Recently, ATP content of CD4+ T cells (ATP_CD4) has been shown to correlate with survival in sepsis. The aim of the study was to determine ATP_CD4 in sepsis-associated AKI.

METHODS

Thirty-three patients with sepsis were prospectively analyzed for ATP_CD4 at three different time points. Results were related to survival, renal recovery, and further clinical/laboratory findings.

RESULTS

ATP_CD4 tended to lower in concentration at 48 h after onset of sepsis in those patients with complete renal recovery. There were no differences between patients with no AKI and those with AKI of different severity (AKIN 1-3). Urinary NGAL did not correlate with renal prognosis.

CONCLUSION

ATP_CD4 may serve as risk predictor in sepsis-associated AKI. Lower concentrations may indicate a higher chance of complete renal recovery in sepsis.