Laboratory parameters of cardiac and kidney dysfunction in cardio-renal syndromes

Proactive Measures to Combat a SARS-CoV-2 Transmission Among High Risk Patients and Health Care Workers in an Outpatient Dialysis Facility

Background: End-stage-renal-failure (ESRF) patients attending clustered out-patient dialysis are susceptible to SARS-CoV-2 infection. Comorbidities render them vulnerable to severe COVID-19. Although preventative and mitigation strategies are recommended, the effect of these are unknown. A period of “potential-high-infectivity” results if a health-care-worker (HCWs) or a patient becomes infected.

Aim: We describe and analyze early, universal SARS-CoV-2 real time reverse transcription polymerase chain reaction (RT-PCR) tests, biomarker monitoring and SARS-CoV-2 preventative strategies, in a single dialysis center, after a positive patient was identified.

Methodology: The setting was a single outpatient dialysis center in Johannesburg, South Africa which had already implemented preventative strategies. We describe the management of 57 patients and 11 HCWs, after one of the patients tested positive for SARS-CoV-2. All individuals were subjected to RT-PCR tests and biomarkers (Neutrophil-Lymphocyte Ratio, C-reactive protein, and D-Dimer) within 72 h (initial-tests). Individuals with initial negative RT-PCR and abnormal biomarkers (one or more) were subjected to repeat RT-PCR and biomarkers (retest subgroup) during the second week. Additional stringent measures (awareness of viral transmission, dialysis distancing and screening) were implemented during the period of “potential high infectivity.” The patient retest subgroup also underwent clustered dialysis until retest results became available.

Results: A second positive-patient was identified as a result of early universal RT-PCR tests. In the two positive-patients, biomarker improvement coincided with RT-PCR negative tests. We identified 13 individuals for retesting. None of these retested individuals tested positive for SARS-CoV-2 and there was no deterioration in median biomarker values between initial and retests. Collectively, none of the negative individuals developed COVID-19 symptoms during the period “potential high infectivity.”

Conclusion: A SARS-CoV-2 outbreak may necessitate additional proactive steps to counteract spread of infection. This includes early universal RT-PCR testing and creating further awareness of the risk of transmission and modifying preventative strategies. Abnormal biomarkers may be poorly predictive of SARS-CoV-2 infection in ESRF patients due to underlying illnesses. Observing dynamic changes in biomarkers in RT-PCR positive and negative-patients may provide insights into general state of health.

The evaluation of acute kidney injury due to ischemia by urinary neutrophil gelatinase-induced lipocalin (uNGAL) measurement in patients who underwent partial nephrectomy

PURPOSE

To investigate the role of urinary neutrophil gelatinase-induced lipocalin (uNGAL) measurement in the early diagnosis of acute kidney injury that may occur after intraoperative ischemia in patients undergoing partial nephrectomy (PN).

METHODS

This prospective study included 86 patients who underwent open laparoscopic or robotic partial nephrectomy between May 2017 and May 2019. During the surgery, whether the patients had ischemia or not, type of vascular clamping and the ischemia time were noted. The definition of acute kidney injury (AKI) was classified according to Acute Kidney Injury Network (AKIN) criteria. Urine samples were collected preoperatively and 3 h after renal pedicle clamp removal and uNGAL was measured.

RESULTS

AKI was recorded in 34 (39.5%) of 86 patients after PN. Of the 34 patients, 26 (76.4%) had level 1 and 8 (23.6%) had level 2 AKI. uNGAL levels increased significantly as an early reflection of AKI in patients who underwent intraoperative total or renal artery clamping (p = 0.024). There was no significant postoperative increase in uNGAL in the non-ischemic group (p = 0.163). uNGAL expression was detected well before serum creatinine increase. Patients with AKI after PN had higher uNGAL expression (p = 0.008) However, there was no correlation between the level of AKI and uNGAL expression (r = 0.201, p = 0.066).

CONCLUSION

Ischemic acute kidney injury after nephron-sparing surgery can be detected early by uNGAL measurement. In future studies comparing outcomes of different surgical techniques on renal functions after PN, uNGAL levels may be used.

Neutrophil gelatinase-associated lipocalin: An early biomarker for predicting acute kidney injury and severity in patients with acute pancreatitis

Background and Aim

Acute kidney injury (AKI) in severe acute pancreatitis (SAP) has a high mortality rate. Traditionally used serum creatinine is an insensitive biomarker for the early detection of AKI. We aimed to study the role of plasma and urinary neutrophil gelatinase‐associated lipocalin (NGAL) in predicting AKI and a severe course in patients with acute pancreatitis (AP).

Methods

Consecutive patients of AP who presented within 72 h of symptom onset and age‐ and gender‐matched healthy controls were included. Urinary and serum NGAL levels [enzyme‐linked immunosorbent assay (ELISA)] were evaluated within 24 h of and 72 h after admission and once in controls. Urine and serum NGAL levels were correlated with development of AKI, severity, and outcomes of AP.

Results

Fifty patients with AP and 30 controls were enrolled. The mean serum and urine NGAL levels in patients on day 1 were significantly higher than the serum and urine NGAL levels in controls (P < 0.001). After excluding patients with AKI on day 1 (n = 10), both serum and urinary NGAL levels on days 1 and 3 were significantly higher in patients who subsequently developed AKI (n = 11) compared to those who did not (n = 29) (P = 0.02, 0.01 and P < 0.001, 0.03). A urinary NGAL level of 221.03 ng/mL on day 1 predicted AKI with a sensitivity and specificity of 82 and 80%, respectively (AUC = 0.9). Mean serum and urinary NGAL levels on day 1 were significantly elevated in patients with SAP compared to those without SAP (P = 0.04 and <0.001).

Conclusion

NGAL levels in urine and serum can predict severity of AP and development of AKI.

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.

Type 4 cardiorenal syndrome

The Acute Dialysis Quality Initiative consensus conference proposed a classification of cardiorenal syndrome (CRS), aiming for a better delineation of each subtype. Although the exact pathophysiology of type 4 CRS is not completely understood, the mechanisms involved are probably multifactorial. There is growing evidence that oxidative stress is a major connector in the development and progression of type 4 CRS. Giving its complexity, poor prognosis and increasing incidence, type 4 CRS is becoming a significant public health problem. Patients with chronic kidney disease are particularly predisposed to cardiac dysfunction, due to the high prevalence of traditional cardiovascular risk factors in this population, but the contribution of risk factors specific to chronic kidney disease should also be taken into account. Much remains to be elucidated about type 4 CRS: despite progress over the last decade, there are still significant questions regarding its pathophysiology and there is as yet no specific therapy. A better understanding of the mechanisms involved may provide potential targets for intervention. The present review will provide a brief description of the definition, epidemiology, diagnosis, prognosis, biomarkers and management strategies of type 4 CRS, and the pathophysiological mechanisms and risk factors presumably involved in its development will be particularly highlighted.

Plasma levels of neutrophil gelatinase-associated lipocalin in children with heart failure

INTRODUCTION

Data about plasma levels of neutrophil gelatinase-associated lipocalin (NGAL) in children with heart failure (HF) are very limited. NGAL is used widely as a biomarker for the diagnosis of renal injury in numerous clinical studies. The aim of this study is to investigate the plasma NGAL in children with HF caused by idiopathic dilated cardiomyopathy (IDCM) and its relation to the severity of HF.

MATERIAL AND METHODS

In a case-control study, 30 nondiabetic children, aged -16 years (all have IDCM) recruited from the pediatric department of our institute together with 30 healthy children were prospectively enrolled in this study. Patients underwent a detailed history taking, clinical examination, New York Heart Association (NYHA) class assessment and echocardiographic evaluation. Plasma levels of NGAL were measured by enzyme-linked immunosorbent assay.

RESULTS

Plasma levels of NGAL were significantly higher in children with HF compared with healthy controls (mean: 290.97 versus 144.33, p < 0.0001). The relationship between NGAL and the severity of HF was investigated. However, we did not find any statistically significant relationship between plasma NGAL levels and indices of myocardial function.

CONCLUSIONS

NGAL levels were significantly increased in children with HF caused by IDCM. However, there was no significant relationship between plasma NGAL levels and indices of myocardial function. Future multicenter clinical studies in a large population addressing the natural course of NGAL in HF and its potential as a treatment target are needed in the near future.

Kidney disease in heart failure: the importance of novel biomarkers for type 1 cardio-renal syndrome detection

Chronic kidney disease (CKD) in heart failure (HF) has been recognized as an independent risk factor for adverse outcome, although the most important clinical trials tend to exclude patients with moderate and severe renal insufficiency. Despite this common association, the precise pathophysiological connection and liaison between heart and kidney is partially understood. Moreover, is it not enough considering how much cardio-renal syndrome type 1 is attributable to previous CKD, and how much to new-onset acute kidney injury (AKI). Neither development of AKI, its progression and time nor duration is related to an adverse outcome. An AKI definition is not universally recognized, and many confounding terms have been used in literature: "worsening renal function", "renal impairment", "renal dysfunction", etc., are all names that contribute to misunderstanding, and do not facilitate an universal classification. Therefore, AKI development should be the consequence of the basal clinical characteristics of patients, different primitive kidney disease and hemodynamic status. AKI could also be the mirror of several underlying associated diseases poorly controlled. Finally, it is not clear which is the optimal laboratory tool for identifying patients with an increased risk of AKI. In the current report, we review the different kidney diseases' impact in HF, and we analyze the modalities for AKI recognition during HF focusing our attention about some new biomarkers with potential application in the current setting.

NGAL, L-FABP, and KIM-1 in comparison to established markers of renal dysfunction

BACKGROUND

New urinary biomarkers like neutrophil gelatinase-associated lipocalin (NGAL), liver-type fatty acid binding protein (L-FABP), and kidney injury molecule-1 (KIM-1) open the opportunity to detect kidney injuries in early stages. Our study aimed at evaluating NGAL, L-FABP, and KIM-1 in comparison to established markers of urine protein differentiation for detection of renal dysfunction.

METHODS

On the basis of the PROTIS expert system (for differentiation of glomerulo-/tubulopathy) urine and plasma samples of 263 randomly selected patients were routinely examined (urine: total protein, albumin, IgG, α1-microglobulin, creatinine, and dip stick results for leukocytes, blood, protein, glucose, pH, and nitrite; plasma: creatinine and cystatin C) followed by the analysis of the new urine biomarkers NGAL (CMIA), L-FABP (ECLIA), and KIM-1 (ELISA).

RESULTS

Of the three new markers L-FABP showed the highest correlation with α1-microglobulin (r=0.76, p<0.01) and was closest associated with the degree of tubular proteinuria assessed by the PROTIS system. NGAL distinguished the PROTIS proteinuria groups with distinctive tubular proteinurias from the controls as well, but revealed a marked diagnostic influence by leukocyturia. Urinary KIM-1 revealed only a weak diagnostic value for the detection of renal injury.

CONCLUSIONS

Urinary NGAL and L-FABP proved to be promising candidates for detecting injuries of the renal tubular system over a broad range of clinical conditions. L-FABP showed a better diagnostic performance and a lower interference by leukocyturia and hematuria than NGAL. Both markers may serve as sensitive tissue injury markers in addition to the established markers of renal functional impairment.

Patients with cardiorenal syndrome revealed increased neurohormonal activity, tubular and myocardial damage compared to heart failure patients with preserved renal function

BACKGROUND

Cardiorenal syndrome (CRS) is associated with increased cardiovascular morbidity and mortality; still, its biomarker pattern has been poorly evaluated so far. The aim of this study was to measure the inflammatory activation, neurohormonal status and kidney and myocardial damage in patients with CRS compared to patients with heart failure (HF) without renal impairment (RI).

METHODS

We analyzed 246 patients on the basis of renal function (group 1: 120 HF patients without RI; group 2: 126 CRS patients). In each group, interleukin-6, tumor necrosis factor-α, B-type natriuretic peptide (BNP), neutrophil gelatinase-associated lipocalin (NGAL), troponin T (TnT), osteoprotegerin and blood urea nitrogen (BUN) were measured. The diagnostic power of all laboratory parameters to detect CRS was evaluated by the receiver operating characteristic (ROC) curve and logistic regression analysis.

RESULTS

A significant increase in BNP [626.4 pg/ml, confidence interval (CI) 518-749 vs. 487.8 pg/ml, CI 411-578; p < 0.05], NGAL (156 ng/ml, CI 129-186 vs. 89.1 ng/ml, CI 72-109; p < 0.0001), BUN (108.9 mg/dl, CI 98-120 vs. 51 mg/dl, CI 46-55; p < 0,0001) and TnT (0.62 ng/ml, CI 0.51-0.75 vs. 0.21 ng/ml, CI 0.15-0.28; p < 0.001) was seen in CRS patients compared to HF patients without RI. ROC curve analysis showed that only NGAL, BUN, BUN/creatinine ratio and TnT can discriminate patients with CRS from patients without RI.

CONCLUSIONS

In CRS patients, renal tubular damage and neurohormonal and cardiac injury activation are increased compared to patients without RI. The current biomarker pattern could be used for an early diagnosis of RI in acute and chronic HF.

Clinical relevance of biomarkers in heart failure and cardiorenal syndrome: the role of natriuretic peptides and troponin

In recent years, numerous biomarkers have been studied in heart failure to improve diagnostic accuracy and identify patients at higher risk. The overall outcome remains fairish despite improvements in therapy, with mean survival after first hospitalization, around 5 years. We therefore need surrogate end points to better understand the pathogenetic mechanisms of the disease, including interplays with other organs. The kidney plays an important role in the initiation and progression of HF, and around one-third of patients with HF show some degree of renal dysfunction. In addition, treatment for HF often worsens renal function, consequently to hemodynamic and clinical improvement do not correspond an effective improvement in HF prognosis. Association between HF and renal impairment (RI) is now classified as cardiorenal syndrome (CRS) pointing out the bidirectional nature of this vicious circle leading to a mutual and progressive damage of both organs. The clinicians can rely on circulating biomarkers that give insights into the underlying pathogenetic mechanisms and help in risk stratification. Recently, a multimarker strategy including biomarker tool to traditional risk scores has been purposed and applied: Although each biomarker provided incremental outcome benefit, the combination of multiple biomarkers should offer the greatest improvement in risk prediction. Natriuretic peptides (NP) and cardiac troponins (TN) are the two biomarkers most studied in this setting, probably because of their organ-specific nature. However, both NP and TN cutoffs in presence of renal dysfunction need to be revised and discussed in relation to age, gender and stage of RI. In this context, the biomarkers are a unique opportunity to elucidate pathophysiological mechanisms, tailor clinical management to the single patient and improve outcomes. Specific studies about the exact role of biomarkers as in HF as in CRS should be planned and considered for future trials.

Role of neutrophil gelatinase-associated lipocalin for early detection of acute kidney injury

Acute kidney injury (AKI) is characterized by abrupt or rapid decline of renal function and is usually associated with the development of serious complications as well as an independent risk of mortality in hospitalized patients. Emergency physicians play a critical role in recognizing early AKI, preventing iatrogenic injury, and reversing the course of AKI. Among the various available biomarkers for AKI, reliable and automated assay methods are commercially available for only cystatin-C and neutrophil gelatinase-associated lipocalin (NGAL). NGAL appears to be a promising marker for early detection of AKI and is likely to be adapted for wide-scale clinical use in patient management as a point-of-care test. Use of NGAL along with panel of other renal biomarkers can improve the rate of early detection of AKI. Large, multicenter studies demonstrate the association between biomarkers and hard end points such as need for renal replacement therapy (RRT), cardiovascular events, hospital stay, and death, independent of serum creatinine concentrations.

The role of natriuretic peptides for the diagnosis of left ventricular dysfunction

Natriuretic peptides (NPs) are entered in current guidelines for heart failure (HF) diagnosis and management because of their high specificity and sensibility in screening patients with acute dyspnea. Due to their availability and relatively low cost, they became the first step examinations in HF patients evaluation at hospital admission together with clinical and chest radiography examination. NPs are released following any cardiac haemodynamic stress due to volume or pressure overload and should be considered as a mirror of cardiac condition helping in recognizing patients with poor outcome. Moreover, the exact role of NPs in early HF stages, in isolated diastolic dysfunction, and in general population is questioned. Several promising reports described their potential role; however, the wide cut-off definition, inclusion criteria, and intrinsic measurement biases do not actually consent to their clinical application in these settings. A multimodality strategy including both NPs and imaging studies appears to be the best strategy to define the cardiac dysfunction etiology and its severity as well as to identify patients with higher risk. In this review, we describe the current and potential role of NPs in patients with asymptomatic cardiac insufficiency, evaluating the requirement to obtain a better standardization for imaging as for laboratory criteria.

Neutrophil gelatinase-associated lipocalin: pathophysiology and clinical applications

Neutrophil gelatinase-associated lipocalin (NGAL), a 25 kDa protein produced by injured nephron epithelia, is one of the most promising new markers of renal epithelial injury. In contrast to serum creatinine and urinary output, which are the measures of kidney function, NGAL is specifically induced in the damaged nephron and then released into blood and urine, where it can be readily measured. Careful proof-of-concept studies using defined animal models have uncovered the sources and trafficking of NGAL in acute kidney injury (AKI) and have addressed the contributions of renal and non-renal sources. Clinical studies indicate that NGAL, unlike creatinine, is a marker responsive to tissue stress and nephron injury, but less so to adaptive hemodynamic responses. In certain clinical settings, NGAL is an earlier marker compared with serum creatinine. In addition, clinical studies have shown that NGAL is a powerful predictor of poor clinical outcomes, which can be used to risk stratify patients when combined with serum creatinine. NGAL has important limitations, including its responsiveness in systemic inflammation, which is partially uncoupled from its response to kidney injury and which needs to be considered when interpreting NGAL results clinically. This review covers the biology and pathophysiology of NGAL and summarizes the results of the growing body of clinical studies that have addressed the utility of NGAL in the early diagnosis of AKI, in the distinction of intrinsic AKI and in the prognostic assessment of broad patient populations.

Neutrophil gelatinase-associated lipocalin as a biomarker of cardiovascular disease: a systematic review

BACKGROUND

Neutrophil gelatinase-associated lipocalin (NGAL) is a biomarker of acute kidney injury (AKI). Recently, elevated NGAL levels have also been reported in heart failure, coronary heart disease, and stroke. Other studies demonstrate that NGAL is upregulated in failing myocardium and in atherosclerotic plaque. Our aim was to synthesize the current evidence on NGAL and cardiovascular disease (CVD), and to clarify the prognostic significance of systemic NGAL levels in CVD.

METHODS

We performed a systematic review to identify experimental and human studies on NGAL and CVD. We excluded articles which specifically dealt with AKI or renal endpoints.

RESULTS

We identified 22 studies, including both animal and human data. NGAL is highly expressed in the heart, both in failing myocardium and myocarditis, and is also expressed in atherosclerotic plaques. Areas of co-localization of NGAL and matrix metalloproteinase (MMP)-9 exhibited increased MMP-9 proteolytic activity. Systemic NGAL levels correlated with renal function and severity of CVD in several, but not all, studies. An association between elevated systemic NGAL levels and clinical outcomes (e.g., death, hospital readmissions) were reported in six CVD studies, but these had limited adjustment for potential confounders.

CONCLUSIONS

There is ample literature to support a putative role of NGAL in the pathophysiology of CVD, but at present there is insufficient data regarding the clinical utility of systemic NGAL levels in the management of CVD. Available evidence regarding NGAL as a predictor of outcomes in CVD is very limited.

Natriuretic peptides and NGAL in heart failure: does a link exist?

In recent years there has been growing interest in the development of new diagnostic tools and particularly in laboratory tests for the identification of heart failure (HF) patients. Because of the rise in HF occurrence, it is necessary to use simple and reliable method to recognize those patients at risk before the onset of the clinical symptoms. To date HF diagnosis remains difficult: its symptoms and signs are often non specific as well as being poor sensitive indicators for HF severity. Throughout the last 10 years published literature has highlighted a boom in the use of biomarkers for HF. Both B-type and N-terminal pro-B-type natriuretic peptides have demonstrated specific role in heart failure diagnosis, as well as risk assessment. A single determination of BNP at any time during the development of chronic heart failure (CHF) provides a clinically useful tool to establish the outcome. Renal dysfunction is often associated with heart failure and predicts adverse clinical outcomes. Many studies have recently suggested the clinical use of serum neutrophil gelatinase-associated lipocalin (NGAL) levels in patients admitted to the hospital for acute HF can be used to estimate the risk of early worsening renal function. This could be potentially applied in clinical practice for early identification of renal dysfunction development in patients with HF. NGAL levels appear also to predict renal dysfunction in patients with chronic HF and preserved renal function. For all these reasons, BNP and NGAL are two emerging tools useful for diagnosis and prognosis in HF. The combination of two laboratory biomarkers could potentially identify patients with more elevated risks of both cardiac hemodynamic impairment and kidney dysfunction.

Neutrophil gelatinase-associated lipocalin (NGAL) as biomarker of acute kidney injury: a review of the laboratory characteristics and clinical evidences

Acute kidney injury (AKI) is a common and serious condition, currently diagnosed by functional biomarkers, such as serum creatinine measurements. Unfortunately, creatinine increase is a delayed and unreliable indicator of AKI. The lack of early biomarkers of structural kidney injury has hampered our ability to translate promising experimental therapies to human AKI. The recent discovery, translation and validation of neutrophil gelatinase-associated lipocalin (NGAL), possibly the most promising novel AKI biomarker, is reviewed here. NGAL may be measured by several methods both in plasma and urine for the early diagnosis of AKI and for the prediction of clinical outcomes, such as dialysis requirement and mortality, in several common clinical scenarios, including in the intensive care unit, cardiac surgery and renal damage due the exposition to toxic agent and drugs, and renal transplantation. Furthermore, the predictive properties of NGAL, may play a critical role in expediting the drug development process. A systematic review of literature data indicates that further studies are necessary to establish accurate reference population values according to age, gender and ethnicity, as well as reliable and specific decisional values concerning the more common clinical settings related to AKI. Furthermore, proper randomized clinical trials on renal and systemic outcomes comparing the use of NGAL vs. standard clinical practice are still lacking and accurate cost-benefit and/or cost-utility analyses for NGAL as biomarker of AKI are also needed. However, it is important to note that NGAL, in the absence of diagnostic increases in serum creatinine, is able to detect some patients affected by subclinical AKI who have an increased risk of adverse outcomes. These results also suggest that the concept and definition of AKI might need to be reassessed.