Renal dysfunction is a stronger determinant of systemic neutrophil gelatinase-associated lipocalin levels than myocardial dysfunction in systolic heart failure

Association between echocardiographic indexes and urinary Neutrophil Gelatinase-Associated Lipocalin (uNGAL) in dogs with myxomatous mitral valve disease

Neutrophil gelatinase-associated lipocalin (NGAL) is a biomarker of tubular damage, and its elevation has been described in human and canine cardiorenal syndrome. The aim was to evaluate the association between echocardiographic indexes and urine NGAL (uNGAL) and uNGAL normalized to urine creatinine (uNGALC) in dogs with MMVD. This is a multicentric prospective cross-sectional study. A total of 77 dogs with MMVD at different ACVIM stages were included. All dogs underwent echocardiography, serum chemistry, and urinalysis. Echocardiographic data analyzed were shortening fraction (SF), left ventricular diastolic (LVIDDn) and systolic (LVIDSn) diameters normalized for body weight, left atrium to aortic root ratio (LA/Ao), maximal (LAVMax) and minimal (LAVMin) left atrial volumes, LA stroke volume (LASV), early diastolic mitral peak velocity (EVmax), EVmax to tissue Doppler E' wave (E/E'), aortic (VTIAo) and mitralic (VTIMit) velocity time integrals and their ratio (VTIMit/VTIAo), and tricuspid regurgitation velocity (TRVmax). In the univariate analysis LASV, TRVmax, LAVMax, LVIDDn, and VTIMit/VTIAo were independent predictors of increased uNGAL and uNGALC; however, only LASV [(OR: 1.96, 95% CI: 1.16 to 3.31) P = 0.01 for NGAL, and (OR: 2.79, 95% CI: 1.50 to 5.17) P < 0.001 for NGALC] and TRVmax [(OR: 1.73, 95% CI: 1.20-2.51) P = 0.002 for NGAL, and (OR: 1.50, 95% CI: 10.07-2.10) P = 0.015 for NGALC] remained statistically significant in the multivariable analysis. Based on our results, LASV and TRVmax are associated with increased uNGAL and uNGALC. These parameters might detect dogs with MMVD at higher risk of developing kidney damage.

Neutrophil-Enriched Biomarkers and Long-Term Prognosis in Acute Coronary Syndrome: a Systematic Review and Meta-analysis

Activated neutrophils release a range of inflammatory products that represent potential biomarkers, and there is interest in the prognostic value of these in acute coronary syndrome (ACS) patients. We conducted a systematic review to examine neutrophil-enriched biomarkers and the occurrence of major adverse cardiovascular events (MACE) in patients with ACS. We identified twenty-seven studies including 17,831 patients with ACS. The most studied biomarkers were neutrophil gelatinase-associated lipocalin (NGAL) and myeloperoxidase (MPO). Meta-analyses showed that elevated NGAL was associated with higher MACE rates (unadjusted risk ratio (RR) 1.52, 95% CI 1.12-2.06, p = 0.006) as were elevated MPO levels (unadjusted RR 1.61, 95% CI 1.22-2.13, p = 0.01). There was limited data suggesting that increased levels of calprotectin, proteinase-3 and double-stranded DNA were also associated with MACE. These results suggest that higher levels of neutrophil-enriched biomarkers may be predictive of MACE in patients with ACS, although higher-quality studies are needed to confirm these observations.

Upregulation of Myocardial Neutrophil Gelatinase-Associated Lipocalin during Development of Heart Failure Caused by Volume-Overload and the Effect in Regulating Activity of Matrix Metalloproteinase-9

BACKGROUND

In patients with heart failure (HF), circulating neutrophil gelatinase-associated lipocalin (NGAL) level is increased, which is considered to be a predictor of mortality or renal outcomes. The expression of NGAL in the heart and kidney and its role in HF remain unclear.

METHODS

Aortocaval fistula was created in rats as a model of volume overload (VO)-induced HF.

RESULTS

During the development of HF, NGAL expression was upregulated in the heart but not in the kidney at both transcriptional and translational levels in the compensatory and HF phases, with a similar level in both phases. Cardiomyocytes were identified as the cell type responsible for NGAL expression. Consistent with the myocardial NGAL expression pattern, the plasma NGAL level was increased in both phases, and the level was not significantly different between both phases. We demonstrated the presence of a matrix metalloproteinase (MMP)-9/NGAL complex in cultured medium of cardiomyocytes isolated from volume-overloaded hearts by gelatin zymography. Formation of MMP-9/NGAL complex was shown to enhance the enzymatic activity of MMP-9. We found that early growth response (Egr)-1 was upregulated in the heart in both compensatory and HF phases. In neonatal cardiomyocytes, Egr-1 overexpression induced the gene expression of NGAL, which was dose-dependently suppressed by an interleukin-1 receptor antagonist.

CONCLUSIONS

During the development of HF due to VO, NGAL was upregulated in the heart but not in the kidney in both compensatory and HF phases, with a similar expression level. Myocardial NGAL upregulation enhanced MMP-9 activity through formation of the MMP-9/NGAL complex. The expression of myocardial NGAL was regulated by Egr-1.

Low Level Of Neutrophil Gelatinase-Associated Lipocalin (NGAL) In Patients With Chronic Heart Failure And Multivessel Coronary Atherosclerosis

Rationale — Several biomarkers are used to determine the prognosis of patients with heart failure (HF), including neutrophil gelatinase-associated lipocalin (NGAL, Lipocalin-2). We investigated NGAL serum levels in patients with HF and coronary artery disease (CAD). Methods — Fifty-three patients with chronic HF and stable multivessel CAD were included in the study. Patients were grouped on the basis of the NGAL level: low NGAL group (NGAL<37 ng/mL, n=19) and normal NGAL group (NGAL ≥37 ng/mL, n=34). Results and Discussion — The main findings from our study of patients with HF and multivessel CAD were: 1) Plasma NGAL levels were below reference values in 35.8% of cases. 2) We detected a strong positive correlation between neutrophil count and NGAL level (0.573, р<0.001). 3) Neutropenia was present in 15.8% of patients in the low NGAL group and in none in the group with a normal NGAL level (p=0.041). 4) Postinfarction left ventricular aneurysms were more often diagnosed in patients of the first group (15.8%) and in none of patients in the second group (p=0.041). Conclusion — Low NGAL has been associated with neutropenia in patients with heart failure and multivessel atherosclerotic CAD. Left ventricular aneurysms were diagnosed in 15.8% (n=3) patients with low NGAL and in none with normal NGAL levels. These changes may be due to maladaptive remodeling of the heart after myocardial infarction, but further research is needed.

Circulating heart failure biomarkers beyond natriuretic peptides: review from the Biomarker Study Group of the Heart Failure Association (HFA), European Society of Cardiology (ESC)

New biomarkers are being evaluated for their ability to advance the management of patients with heart failure. Despite a large pool of interesting candidate biomarkers, besides natriuretic peptides virtually none have succeeded in being applied into the clinical setting. In this review, we examine the most promising emerging candidates for clinical assessment and management of patients with heart failure. We discuss high-sensitivity cardiac troponins (Tn), procalcitonin, novel kidney markers, soluble suppression of tumorigenicity 2 (sST2), galectin-3, growth differentiation factor-15 (GDF-15), cluster of differentiation 146 (CD146), neprilysin, adrenomedullin (ADM), and also discuss proteomics and genetic-based risk scores. We focused on guidance and assistance with daily clinical care decision-making. For each biomarker, analytical considerations are discussed, as well as performance regarding diagnosis and prognosis. Furthermore, we discuss potential implementation in clinical algorithms and in ongoing clinical trials.

Prognostic role of plasma galectin-3 levels in acute coronary syndrome

Aim:

Cystatin C, neutrophil gelatinase-associated lipocalin and galectin-3 have emerged as biomarker candidates to predict cardiovascular outcomes and mortality in the general population as well as in patients with coronary artery or renal disease. However, their predictive role and clinical utility in patients with acute coronary syndromes alone or in combination beyond currently used risk scores remains to be determined.

Methods and results:

Cystatin C, neutrophil gelatinase-associated lipocalin, and galectin-3 were measured in plasmas of 1832 patients at the time of presentation with acute coronary syndromes requiring percutaneous coronary intervention or coronary artery bypass grafting. The primary outcomes were major adverse cardiac and cerebrovascular events (defined as the composite of all-cause mortality, cerebrovascular events, any repeat revascularization or myocardial infarction) and all-cause mortality after 1 year and occurred in 192 (10.5%) and 78 (4.3%) of patients, respectively. All three biomarkers were increased in those with major adverse cardiac and cerebrovascular events compared with those without (p&lt;0.001). However, only galectin-3 (all-cause mortality: hazard ratio=1.027 (95% confidence interval (1.011–1.043); p=0.001), major adverse cardiac and cerebrovascular events: hazard ratio=1.025 (95% confidence interval (1.012–1.037); p&lt;0.001)) but not cystatin C nor neutrophil gelatinase-associated lipocalin emerged as independent predictors of both major adverse cardiac and cerebrovascular events and death. The risks were particularly high in the highest quartile of galectin-3. The integration of galectin-3 into the global registry of acute coronary events (GRACE) score improved the prediction of major adverse cardiac and cerebrovascular events and all-cause mortality significantly. The areas under the receiver operator characteristics curves increased from 0.6701 to 0.6932 for major adverse cardiac and cerebrovascular events (p=0.0474) and from 0.804 to 0.8199 for all-cause mortality (p=0.0197). Finally, we applied net reclassification improvement index using different cut-offs for major adverse cardiac and cerebrovascular events which showed negative results (for the cut-offs of 5% and 15%, net reclassification improvement index 0.028, p=0.586, for the cut-offs of 10% and 20%, net reclassification improvement index 0.072, p=0.1132 and for the cut-offs of 10% and 30% the net reclassification improvement index is 0.0843, p=0.077).

Conclusion:

In acute coronary syndromes patients, galectin-3 has moderate prognostic accuracy, provides statistically significant incremental value in some, but not all models, and that the magnitude of any improvement would seem of questionable clinical value.

Community-Acquired Acute Kidney Injury as a Risk Factor of de novo Heart Failure Hospitalization

Objectives: Because patients with hospital-acquired acute kidney injury (AKI) are at risk for subsequent development of heart failure (HF) and little is known about the relation between community-acquired AKI (CA-AKI) and HF, we sought to determine if CA-AKI is a risk factor for incident HF hospitalization. Methods: We utilized Baylor Scott &amp; White Health databases at the primary care and inpatient hospitalization levels to identify adults without a prior history of HF who had 2 or more serum creatinine measurements within 13 months in the primary care setting. We defined CA-AKI as a serum creatinine increase ≥0.3 mg/dL or ≥1.5 times the baseline for consecutive values within a 13-month period. We created a flag for de novo HF hospitalization at 90, 180, and 365 days following CA-AKI evaluation. Results: In the analyses, 210,895 unique adults were included, of whom 5,358 (2.5%) had CA-AKI. Those with CA-AKI had higher rates of comorbidities, higher rate of males (48 vs. 42%, p < 0.001), and were older (61.5 [50.3, 73.1] vs. 54.1 [42.8, 64.7] years, p < 0.001) than those who did not have CA-AKI. In total, 607 (0.3%), 833 (0.4%), and 1,089 (0.5%) individuals had an incident HF hospitalization in the 90, 180, and 365 days following the CA-AKI evaluation, respectively. After adjusting for demographic and clinical characteristics, patients with CA-AKI had >2 times the risk of de novo HF hospitalization compared with patients who did not have CA-AKI (90 days: 2.35 [1.83–3.02], p < 0.001; 180 days: 2.52 [2.04–3.13], p < 0.001; 365 days: 2.16 [1.77–2.64], p < 0.001). These multivariable models yielded strong predictive abilities, with the areas under the receiver-operating characteristic curve >0.90. Conclusion: After controlling for baseline and clinical characteristics, patients with CA-AKI were at approximately twofold the risk of de novo HF hospitalization (within 90, 180, and 365 days) compared with those who did not have CA-AKI. Hence, detecting CA-AKI may provide an opportunity for early intervention at the primary care level to possibly delay HF development.

Redefining biomarkers in heart failure

Heart failure (HF) is the end result of many different cardiac and non-cardiac abnormalities leading to a complex clinical entity. In this view, the use of biomarkers in HF should be deeply reconsidered; indeed, the same biomarker may carry a different significance in patients with preserved or reduced EF. The aim of this review is to reconsider the role of biomarkers in HF, based on the different clinical characteristics of this syndrome. The role of cardiac and non-cardiac biomarkers will be reviewed with respect of the different clinical manifestations of this syndrome.

Plasma neutrophil gelatinase-associated lipocalin is independently associated with left ventricular hypertrophy and diastolic dysfunction in patients with chronic kidney disease

Background

Cardiovascular disease (CVD) is a leading cause of death in patients with chronic kidney disease (CKD). Left ventricular hypertrophy (LVH) and left ventricular diastolic dysfunction (LVDD) are known as predictors of CVD in these patients. Neutrophil gelatinase-associated lipocalin (NGAL) is a biomarker of acute kidney injury. Recently, elevated NGAL levels have been reported in patients with CVD. This study aimed to evaluate the association between plasma NGAL levels and LVH/LVDD in patients with CKD.

Methods

This study included 332 patients with pre-dialysis CKD (estimated glomerular filtration rate (eGFR) < 60 ml/min/1.73m²). Two-dimensional echocardiography was performed to measure the left ventricular mass index (LVMI). Tissue Doppler imaging was used to measure early mitral inflow velocity (E) and the peak early mitral annular velocity (E'). Diastolic function was estimated using E' and the ratio of E to E' (E/E'). The associations of echocardiographic index with clinical and laboratory variables (age, sex, diabetes, hypertension, eGFR, albumin, uric acid, calcium, phosphate, total cholesterol, hemoglobin, C-reactive protein, intact parathyroid hormone (PTH), the inferior vena cava collapse index (IVCCI) < 50%, and plasma NGAL) were investigated using univariate and multivariate analyses.

Results

In multivariate logistic regression analysis, plasma NGAL was an independent predictor of LVH (OR: 1.02, 95% CI: 1.01–1.02), P < 0.001). In addition, hypertension, intact PTH, and IVCCI < 50% were independent predictors of LVH. Plasma NGAL (OR: 1.02, 95% CI: 1.01–1.02, P < 0.001) was also an independent factor of LVDD. Furthermore, hypertension, intact PTH, and IVCCI < 50% were independent predictors of LVDD. Receiver operating characteristic curve analysis (area under the curve: 0.835, 95% CI: 0.792–0.879) showed the best cutoff value of plasma NGAL for identifying LVDD was ≥ 258 ng/ml with an associated sensitivity of 77.6% and a specificity of 87.6%.

Conclusion

Plasma NGAL levels were independent predictors of LVH and LVDD in patients with pre-dialysis CKD, suggesting that plasma NGAL could be a biomarker for LVH and LVDD in these patients.

Cardiorenal Syndrome Type 1: Definition, Etiopathogenesis, Diagnostics and Treatment

Cardiorenal Syndrome Type 1 (CRS-1) is defined as an acute worsening of heart function leading to acute kidney injury and/or dysfunction. It is an important cause of hospitalization which affects the diagnosis as well as the prognosis and treatment of patients. The purpose of this paper is to analyze causes that lead to the development of cardiorenal syndrome type 1 and its clinical consequences, as well as to emphasize the clinical importance of its early detection. The clinical studies and professional papers dealing with etiopathogenesis, diagnosis and treatment of cardiorenal syndrome type 1, have been analyzed. The most important role in the occurrence of cardio renal syndrome type 1 is played by hemodynamic mechanisms, activation of neurohumoral systems, inflammation and imbalance between the production of reactive oxygen species (ROS) and nitric oxide (NO). Diagnosis of cardiorenal syndrome type 1 involves biomarkers of acute renal injury among which the most important are: neutrophil gelatinaseassociated lipocalin (NGAL), cystatin C, kidney injury molecule 1 (KIM-1), liver-type fatty acid binding protein (L-FABP), IL-18 and the values of nitrogen compounds in serum. In addition to a pharmacological therapy, various modalities of extracorporeal ultrafiltration are applied in treatment of CRS-1, particularly if there is resistance to the use of diuretic therapy. As opposed to the experimental models, in clinical practice acute renal injury is often diagnosed late so that the measures taken do not give the expected results and the protective role shown in experimental conditions do not give the same results. For all these reasons, it is necessary to analyze the pathophysiology of renal impairment in cardiorenal syndrome as well as detect early indicators of kidney injury that could have clinical benefit and positive impact on reducing the cost of treatment.

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.

Circulating trimethylamine N-oxide and the risk of cardiovascular diseases: a systematic review and meta-analysis of 11 prospective cohort studies

Circulating trimethylamine N-oxide (TMAO), a canonical metabolite from gut flora, has been related to the risk of cardiovascular disorders. However, the association between circulating TMAO and the risk of cardiovascular events has not been quantitatively evaluated. We performed a systematic review and meta-analysis of all available cohort studies regarding the association between baseline circulating TMAO and subsequent cardiovascular events. Embase and PubMed databases were searched for relevant cohort studies. The overall hazard ratios for the developing of cardiovascular events (CVEs) and mortality were extracted. Heterogeneity among the included studies was evaluated with Cochran's Q Test and I² statistics. A random-effect model or a fixed-effect model was applied depending on the heterogeneity. Subgroup analysis and meta-regression were used to evaluate the source of heterogeneity. Among the 11 eligible studies, three reported both CVE and mortality outcome, one reported only CVEs and the other seven provided mortality data only. Higher circulating TMAO was associated with a 23% higher risk of CVEs (HR = 1.23, 95% CI: 1.07-1.42, I² = 31.4%) and a 55% higher risk of all-cause mortality (HR = 1.55, 95% CI: 1.19-2.02, I² = 80.8%). Notably, the latter association may be blunted by potential publication bias, although sensitivity analysis by omitting one study at a time did not significantly change the results. Further subgroup analysis and meta-regression did not support that the location of the study, follow-up duration, publication year, population characteristics or the samples of TMAO affect the results significantly. Higher circulating TMAO may independently predict the risk of subsequent cardiovascular events and mortality.

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.

Biomarkers in cardiovascular disease: Statistical assessment and section on key novel heart failure biomarkers

Cardiovascular disease (CVD) is a leading cause of death worldwide and continues to increase in prevalence compared to previous decades, in part because of the aging of the world population. Atherosclerotic CVD starts at a very young age and progresses over time allowing sufficient time for screening and early detection of the condition. Advances in biomarker research and developments related to CVD over the past 30 years have led to more sensitive screening methods, a greater emphasis on its early detection and diagnosis, and improved treatments resulting in more favorable clinical outcomes in the community. However, the use of biomarkers for different purposes in CVD remains an important area of research that has been explored by scientists over the years and many new developments are still underway. Therefore, a detailed description of all CVD biomarkers that are currently been used or investigated for future use in the field of cardiovascular medicine is out of scope for any review article. In the present review, we do not intend to replicate the information from previous exhaustive review on biomarkers, but highlight key statistical and clinical issues with an emphasis on methods to evaluate the incremental yield of biomarkers, including their clinical utility, a prerequisite before any putative novel biomarker is utilized in clinical practice. In addition, we will summarize information regarding recent novel heart failure biomarkers in current practice, which are undergoing scrutiny before they can be available for clinical use, and their impact on clinical outcomes.

Biomarkers of acute kidney injury and associations with short- and long-term outcomes

Acute kidney injury is strongly associated with increased mortality and other adverse outcomes. Medical researchers have intensively investigated novel biomarkers to predict short- and long-term outcomes of acute kidney injury in many patient care settings, such as cardiac surgery, intensive care units, heart failure, and transplant. Future research should focus on leveraging this relationship to improve enrollment for clinical trials of acute kidney injury.

Plasma Neutrophil Gelatinase-Associated Lipocalin as a Predictor of Cardiovascular Events in Patients with Chronic Kidney Disease

Background. Our aim was to assess plasma neutrophil gelatinase-associated lipocalin (NGAL) as a predictor of cardiovascular (CV) events in patients with chronic kidney disease (CKD) and no history of CV events. Methods. This was a prospective observational cohort study of 252 patients with predialysis CKD. CV events were defined as CV death, acute coronary syndrome, and hospitalization for worsening heart failure, stroke, and aortic dissection. Results. During a median follow-up period of 63 months, 36 CV events occurred. On Cox stepwise multivariate analysis, plasma NGAL and B-type natriuretic peptide (BNP) were significant predictors of CV events. Kaplan-Meier incidence rates of CV event-free survival at 5 years were 96.6%, 92.9%, 85.9%, and 61.3%, respectively, among quartiles of plasma NGAL (P < 0.0001). The C-index for the receiver-operating characteristic curves for CV events was greater when plasma NGAL was added to an established risk model (0.801, 95% CI 0.717–0.885), compared to the model without plasma NGAL (0.746, 95% CI 0.653–0.840, P = 0.021). Conclusion. Elevated plasma NGAL could predict future CV events in CKD patients with no history of CV events and add incremental value to the established risk model.

Plasma Neutrophil Gelatinase-Associated Lipocalin Reflects Both Inflammation and Kidney Function in Patients with Myocardial Infarction

BACKGROUND/AIMS

Neutrophil gelatinase-associated lipocalin (NGAL) has emerged as a marker for acute kidney injury and cardiovascular outcome. However, the relative importance of inflammation versus kidney function on plasma NGAL levels is uncertain, making the interpretation of plasma NGAL unclear. Accordingly, we investigated the relationship between plasma NGAL, inflammation and kidney function in patients with myocardial infarction (MI).

METHODS

We prospectively included 584 patients with acute ST-segment elevation MI (STEMI) treated with primary percutaneous coronary intervention (PCI) from 2006 to 2008. Blood samples were drawn immediately before PCI. Additionally, we included 42 patients who had 4 blood samples drawn before and after PCI. Plasma NGAL was measured using a time-resolved immunofluorometric assay. Cross-sectional analyses were performed in these two single-center, prospective study cohorts.

RESULTS

Estimated glomerular filtration rate (eGFR) was associated significantly more strongly with plasma NGAL when eGFR was abnormal compared to normal eGFR: a decrease in eGFR of 10 ml/min was associated with an increase in NGAL of 27% (18-36%) versus 4% (1-7%), respectively (p < 0.001). Leukocyte count and C-reactive protein were the main determinants of plasma NGAL in patients with normal eGFR, whereas eGFR was the main determinant at reduced kidney function.

CONCLUSIONS

eGFR determines the association of NGAL with either inflammation or kidney function; in patients with normal eGFR, plasma NGAL reflects inflammation but when eGFR is reduced, plasma NGAL reflects kidney function, highlighting the dual perception of plasma NGAL. From a clinical perspective, eGFR may be used to guide the interpretation of elevated NGAL levels in patients with STEMI.

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.

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.

Serum neutrophil gelatinase-associated lipocalin is associated with cardiovascular events in patients with chronic kidney disease

BACKGROUND

Neutrophil gelatinase-associated lipocalin (NGAL) is a member of the lipocalin family best known as a novel and early marker of acute kidney injury (AKI). Recent data suggest that NGQueryAL is not only a marker of AKI, but also an important player in the vascular remodeling, atherosclerotic plaque stability and thrombus formation. We conducted this study to investigate the association of serum NGAL levels with fatal and composite (fatal and non-fatal) cardiovascular events (CVE) in a cohort of patients with stage 1-5 CKD.

METHODS

This was an observational cohort study in which serum NGAL was obtained from 298 CKD (stages 1-5) patients. Fatal and composite CVE were recorded for a median 41 months. We examined alteration of serum NGAL through CKD groups as well as association with inflammatory markers. We also performed a Cox regression analysis to determine the association of NGAL with predefined clinical outcomes.

RESULTS

The median value of NGAL was 50.5 ng/mL (IR 47.6-54.9 ng/mL), and higher NGAL values were recorded in diabetic patients. In a multiple linear regression model, including all univariate associates of NGAL, only log eGFR, log hs-CRP and log HDL cholesterol maintained an independent association with log NGAL. During the observational period, 30 patients died due to cardiovascular causes and 69 non-fatal CVE were registered. In the fully adjusted model, we observed a 2.08-fold increase in the risk of fatal CVE and a 1.50-fold increase in the risk of fatal and non-fatal CVE for each increment of 1 SD in log NGAL values.

CONCLUSIONS

This is the first study that shows that serum NGAL is associated with cardiovascular events (fatal and non-fatal) in patients with CKD, independently of traditional risk factors, renal function and inflammation.

Biomarkers in Acute Heart Failure - Cardiac And Kidney

Natriuretic peptides (NP) are well-validated aids in the diagnosis of acute decompensated heart failure (ADHF). In acute presentations, both brain natriuretic peptide (BNP) and N-terminal of the prohormone brain natriuretic peptide (NT-proBNP) offer high sensitivity (>90 %) and negative predictive values (>95 %) for ruling out ADHF at thresholds of 100 and 300 pg/ml, respectively. Plasma NP rise with age. For added rule-in performance age-adjusted thresholds (450 pg/ml for under 50 years, 900 pg/ml for 50-75 years and 1,800 pg/ml for those >75 years) can be applied to NT-proBNP results. Test performance (specificity and accuracy but not sensitivity) is clearly reduced by renal dysfunction and atrial fibrillation. Obesity offsets the threshold downwards (to ~50 pg/ml for BNP), but overall discrimination is preserved. Reliable markers for impending acute kidney injury in ADHF constitute an unmet need, with candidates, such as kidney injury molecule-1 and neutrophil gelatinase-associated lipocalin, failing to perform sufficiently well, and new possibilities, including the cell cycle markers insulin growth factor binding protein 7 and tissue inhibitor of metalloproteinases type 2, remain the subject of research.

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.

NGAL and ST2 levels in ambulatory patients with chronic heart failure. Clinical and echocardiographic correlates

AIM

Neutrophil gelatinase-associated lipocalin (NGAL) and ST2 receptor, a member of the interleukin-1 receptor family, are novel biomarkers with a potential role in the diagnosis and risk stratification of patients with chronic heart failure (CHF). There is however scarce data on their relation with clinical characteristics and cardiac function in patients with CHF.

METHODS

Consecutive ambulatory patients with CHF were studied. All patients underwent clinical and echocardiographic assessment, and blood samples were collected for the estimation of ST2 and NGAL serum levels during the same assessment.

RESULTS

A total of 76 patients (79% male, mean age: 63 ± 14 years), with CHF and left ventricular ejection fraction of 28 ± 7% were included. Median NGAL was 0.16 (0.09-0.275) mg/L and median ST2 was 0.0125 (0.0071-0.0176) mg/L. No association between NGAL and ST2 was observed. Multivariate analysis revealed tissue Doppler-derived right ventricular systolic velocity as an independent predictor of ST2, and the duration of HF and serum creatinine levels as independent predictors of NGAL.

CONCLUSIONS

NGAL levels depend on the renal function and the duration of HF, while ST2 levels are affected by the right but not the left ventricular function and show no association with clinical indices of HF.

Novel renal biomarkers to assess cardiorenal syndrome

Renal dysfunction (RD) in heart failure portends adverse outcomes and often limits aggressive medical and decongestive therapies. Despite the high prevalence in this population, not all forms of RD are prognostically or mechanistically equivalent: RD can result from irreversible nephron loss secondary to diabetic or hypertensive kidney disease or it can develop secondary to heart failure (HF) itself, i.e., the cardiorenal syndrome. Furthermore, filtration is only one aspect of renal performance such that significant renal impairment secondary to cardiorenal syndrome can exist despite a normal glomerular filtration rate. Renal biomarkers have the potential to inform some of the intricacies involved in accurately assessing cardiorenal interactions. This article discusses novel biomarkers for cardiorenal syndrome and their utility in the prognosis, diagnosis, and targeted treatment of heart failure-induced RD.

Admission plasma neutrophil gelatinase associated lipocalin (NGAL) predicts worsening renal function during hospitalization and post discharge outcome in patients with acute heart failure

Abstract Background: The role of neutrophil gelatinase-associated lipocalin (NGAL) has been described in chronic heart failure (HF), however less data are available in patients admitted for acute HF.

METHODS

We evaluated the role of NGAL in predicting in-hospital worsening renal function (WRF) and post-discharge follow-up during six months period in patients with acute HF. All patients were submitted to creatinine, estimated glomerular filtration rate (eGFR), blood urea nitrogen (BUN) and B-type natriuretic peptide (BNP) measurement during hospitalization and before discharge.

RESULTS

Patients with chronic kidney dysfunction (CKD) demonstrated higher NGAL respect to subject with preserved renal function (241 ± 218 and 130 ± 80 ng/ml; P = 0.0001). In subgroup that developed WRF during hospitalization, NGAL levels were significantly increased respect to patients without WRF (272 ± 205 versus 136 ± 127 ng/ml; P = 0.0001). A cut off of 134 ng/ml has been related to WRF with good sensibility and specificity (92% and 71% AUC 0.83; P = 0.001). Multivariable Cox regression analysis showed that cut-off of 134 ng/ml was the only marker related to death (HR: 1.75; 95% CI: 1.24-2.45; P < 0.001). Follow-up analysis confirmed that NGAL > 130 ng/ml was associated with adverse events during a six-month period.

CONCLUSION

Admission NGAL measurement appears a sensible tool for in-hospital WRF prediction as well as an early marker for adverse outcome during post discharge vulnerable phase.

Cardiorenal syndrome

Cardiorenal syndrome (CRS) includes a broad spectrum of diseases within which both the heart and kidneys are involved, acutely or chronically. An effective classification of CRS in 2008 essentially divides CRS in two main groups, cardiorenal and renocardiac CRS, based on primum movens of disease (cardiac or renal); both cardiorenal and renocardiac CRS are then divided into acute and chronic, according to onset of disease. The fifth type of CRS integrates all cardiorenal involvement induced by systemic disease. This article addresses the pathophysiology, diagnosis, treatment, and outcomes of the 5 distinct types of CRS.

Acute decompensated heart failure: update on new and emerging evidence and directions for future research

Acute decompensated heart failure (ADHF) is a complex clinical event associated with excess morbidity and mortality. Managing ADHF patients is challenging because of the lack of effective treatments that both reduce symptoms and improve clinical outcomes. Existing guideline recommendations are largely based on expert opinion, but several recently published trials have yielded important data to inform both current clinical practice and future research directions. New insight has been gained regarding volume management, including dosing strategies for intravenous loop diuretics and the role of ultrafiltration in patients with heart failure and renal dysfunction. Although the largest ADHF trial to date (ASCEND-HF, using nesiritide) was neutral, promising results with other investigational agents have been reported. If these findings are confirmed in phase III trials, novel compounds, such as relaxin, omecamtiv mecarbil, and ularitide, among others, may become therapeutic options. Translation of research findings into quality clinical care can not be overemphasized. Although many gaps in knowledge exist, ongoing studies will address issues around delivery of evidence-based care to achieve the goal of improving the health status and clinical outcomes of patients with ADHF.

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.

The association between neutrophil gelatinase-associated lipocalin and clinical outcome in chronic heart failure: results from CORONA*

OBJECTIVE

To study the prognostic value of neutrophil gelatinase-associated lipocalin (NGAL) in chronic heart failure (HF) of ischaemic aetiology.

BACKGROUND

Neutrophil gelatinase-associated lipocalin is a marker of kidney injury as well as matrix degradation and inflammation and has previously been shown to be increased in HF. We investigated whether serum NGAL levels could provide prognostic information in chronic HF.

METHODS

We assessed NGAL as a predictor of primary outcomes (cardiovascular death, nonfatal stroke and nonfatal myocardial infarction, n = 307) and all-cause mortality (n = 321), cardiovascular mortality (n = 259) and hospitalization (n = 647) as well as the number of hospitalizations during follow-up for all (n = 1934) and CV causes (n = 1204) in 1415 patients with chronic HF (≥60 years, New York Heart Association class II-IV, ischaemic systolic HF) in the CORONA population, randomly assigned to 10 mg rosuvastatin or placebo. Results.  Multivariate analysis revealed that NGAL added significant information when adjusting for clinical variables, but was no longer significant when further adjusting for apolipoprotein A-1 (ApoA-1), glomerular filtration rate (GFR), C-reactive protein (CRP) and N-terminal pro-brain natriuretic peptide (NT-proBNP). However, belonging to the highest NGAL tertile was associated with more frequent hospitalization, even after adjusting for clinical variables, GFR and ApoA-1, but not after adjusting for CRP and NT-proBNP. There was no interaction between rosuvastatin treatment and NGAL. Conclusion.  Neutrophil gelatinase-associated lipocalin added no significant information to NT-proBNP and GFR in a multivariate model for primary and secondary end-points.

Lack of significant renal tubular injury despite acute kidney injury in acute decompensated heart failure

AIMS

Acute kidney injury (AKI) is a strong predictor of adverse events with an incompletely understood pathophysiology. Neutrophil gelatinase-associated lipocalin (NGAL) is proposed as an early marker of renal tubular injury. Our aim is to determine whether AKI during treatment of acute decompensated heart failure (ADHF) is accompanied by renal tubular injury.

METHODS AND RESULTS

Urinary NGAL (uNGAL) and urinary creatinine (uCreat) levels were measured in 141 consecutive patients hospitalized for ADHF and followed for 180 days for death or re-hospitalization. AKI was defined as a rise in serum creatinine ≥0.3 mg/dl in a 48 h period. Median uNGAL/uCreat levels on Day 1 (baseline) were similar between patients who did and did not develop AKI [22.8 (12.5-106.8) μg/g vs. 20.6 (12.4-52.0) μg/g, P = 0.55]. On Day 2 and beyond, the difference between the AKI and no AKI cohorts increased, but was only significant on Day 3 [36.2 (21.7-131.8) μg/g vs. 29.4 (11.4-54.6) μg/g, P = 0.02]. The area under the receiver operating characteristic curve for Day 2 uNGAL/uCreat (≥ or <32 µg/g) to predict AKI was 0.61. There was no difference in diuretic response between 'uNGAL/uCreat + ' (≥ 27 µg/g) and 'uNGAL/uCreat-' (<27 µg/g) patients. However 'uNGAL/uCreat + ' patients had more adverse events after 180 days (66% vs. 52%, P = 0.02).

CONCLUSIONS

In patients with ADHF who develop AKI following diuretic therapy, a minor rise in uNGAL precedes AKI. However, the degree of renal tubular insult was much lower than that observed in other forms of AKI.

Neutrophil Gelatinase-Associated Lipocalin (NGAL) predicts renal injury in acute decompensated cardiac failure: a prospective observational study

Background

Acute Decompensated Cardiac Failure (ADCF) is frequently associated with deterioration in renal function. Neutrophil gelatinase-associated lipocalin (NGAL) is an early marker of kidney injury. We aimed to determine if NGAL measured at admission predicts in-hospital acute kidney injury (AKI) in ADCF.

Methods

A prospective observational study measured NGAL and B-natriuretic peptide (BNP) from patients with ADCF presenting to two tertiary hospitals. Patients received standard care and were followed up daily as inpatients. ADCF was defined by PRIDE score ≥ 6 and AKI by RIFLE criteria.

Results

One hundred and two patients (median age 80, IQR 69-84 years, 52% male) were enrolled. AKI developed in 22 (25%) of 90 for whom outcome data was available. Seven patients died. NGAL was significantly elevated in those who developed AKI versus those who did not (median 130 ng/ml vs 69 ng/ml, p = 0.002). NGAL was also higher in those who died (median 136 ng/ml vs 68 ng/ml, p = 0.005). AKI was significantly associated with risk of death (5/22 (23%) vs 1/68 (1.5%), p = 0.001), but not length of hospital stay. NGAL significantly correlated with admission eGFR but not BNP. For prediction of AKI, NGAL > 89 ng/ml had sensitivity of 68% and specificity of 70% with area under the receiver operator characteristic (ROC) curve of 0.71 (0.58-0.84). After adjustment for baseline renal function, the odds ratio (OR) for AKI was 3.73 (1.26-11.01) if admission NGAL > 89 ng/ml.

Conclusions

Elevated NGAL at admission is associated with in-hospital AKI and mortality in patients with ADCF. However, it has only moderate diagnostic accuracy in this setting.

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.

Comparison of Serum Neutrophil Gelatinase-associated Lipocalin (NGAL) with Serum Creatinine in Prediction of Kidney Recovery after Renal Transplantation

BACKGROUND

Because of some insult to kidney during transplantation, assessment of kidney function after the procedure is essential. It would be ideal to find a marker better than creatinine to early predict the acute kidney injury.

OBJECTIVE

To compare with creatinine the predictive value of serum neutrophil gelatinase-associated lipocalin (NGAL) in detecting kidney recovery after renal transplantation.

METHODS

We studied 33 patients who received kidney transplantation (deceased [n=20] and live [n=13]) during a 6-month period in 2010. Serum NGAL and creatinine, hemoglobin, and blood glucose were measured at 0, 12, 24, 48, and 72 hours after transplantation. The need for dialysis and kidney function in one week were studied.

RESULTS

There were 16 men and 17 women with the mean±SD age of 36.3±12.2 (range: 14-58) years. Of the studied patients, 6 had delayed graft function (DGF; hemodialysis within the first week of transplant); 9 had slow graft function (SGF; serum creatinine reduction from transplantation to day 7 <70%), and 23 had immediate graft function (IGF; reduction in serum creatinine ≥70%). At any time, serum NGAL, and creatinine levels were significantly higher among patients with DGF (p=0.024) and SGF (p=0.026) compared with those with IGF. However, in those who got IGF vs non-IGF, serum creatinine levels were not significantly different (p=0.59) but serum NGAL levels differed significantly(p=0.020). Receiver-operating characteristic (ROC) curve and area under curves (AUCs) of serum NGAL and serum creatinine levels on the first post-transplantation day had similar significance in predicting the patient's need to dialysis in the first week. However, using AUC of serum creatinine was not helpful in predicting non-IGF, compared to serum NGAL. The AUCs of the serum NGAL were 0.70 (95% CI: 0.52-0.89) and 0.76 (95% CI: 0.59-0.93) after 12 and 24 hours, respectively (p<0.05). The highest AUC (0.82) was attributed to serum NGAL of 24 hour (p=0.002).

CONCLUSION

Serum NGAL level especially 24 hours post-transplantation, seems to be an early accurate predictor of both the need to dialysis and slow graft function within the first week of kidney transplantation.

Emerging biomarkers in heart failure

BACKGROUND

Until recently, biomarker testing in heart failure (HF) syndromes has been viewed as an elective supplement to diagnostic evaluation of patients suspected to suffer from this condition. This approach to the use of biomarker testing contrasts with other cardiovascular diagnoses such as acute myocardial infarction, for which biomarkers are integral to disease process definition, risk stratification, and in some cases treatment decision making.

CONTENT

In this review we consider various perspectives on the evaluation of biomarkers in HF. In addition, we examine recent advances in the understanding of established biomarkers in HF (such as the natriuretic peptides), the elucidation of novel biomarkers potentially useful for the evaluation and management of patients with HF, and the growing understanding of important and relevant comorbidities in HF. We also review candidate biomarkers from a number of classes: (a) myocyte stretch, (b) myocyte necrosis, (c) systemic inflammation, (d) oxidative stress, (e) extracellular matrix turnover, (f) neurohormones, and (g) biomarkers of extracardiac processes, such as renal function.

SUMMARY

Novel applications of established biomarkers of HF as well as elucidation and validation of emerging assays for HF syndromes have collectively led to a growing interest in the more widespread use of such testing in patients affected by the diagnosis.