The Relevance of Implementing the Systematic Screening of Perioperative Myocardial Injury in Noncardiac Surgery Patients

Perioperative myocardial injury (PMI) is a common cardiac complication. Recent guidelines recommend its systematic screening using high-sensitivity cardiac troponin (hs-cTn). However, there is limited evidence of local screening programs. We conducted a prospective, single-center study aimed at assessing the feasibility and outcomes of implementing systematic PMI screening. Hs-cTn concentrations were measured before and after surgery. PMI was defined as a postoperative hs-cTnT of ≥14 ng/L, exceeding the preoperative value by 50%. All patients were followed-up during the hospitalization, at one month and one year after surgery. The primary outcome was the incidence of death and major cardiovascular and cerebrovascular events (MACCE). The secondary outcomes focused on the individual components of MACCE. We included two-thirds of all eligible high-risk patients and achieved almost complete compliance with follow-ups. The prevalence of PMI was 15.7%, suggesting a higher presence of cardiovascular (CV) antecedents, increased perioperative CV complications, and higher preoperative hs-cTnT values. The all-cause death rate was 1.7% in the first month, increasing up to 11.2% at one year. The incidence of MACCE was 9.5% and 8.6% at the same time points. Given the observed elevated frequencies of PMI and MACCE, implementing systematic PMI screening is recommendable, particularly in patients with increased cardiovascular risk. However, it is important to acknowledge that achieving optimal screening implementation comes with various challenges and complexities.

Non-invasive electromechanical assessment during atrial fibrillation identifies underlying atrial myopathy alterations with early prognostic value

Electromechanical characterization during atrial fibrillation (AF) remains a significant gap in the understanding of AF-related atrial myopathy. This study reports mechanistic insights into the electromechanical remodeling process associated with AF progression and further demonstrates its prognostic value in the clinic. In pigs, sequential electromechanical assessment during AF progression shows a progressive decrease in mechanical activity and early dissociation from its electrical counterpart. Atrial tissue samples from animals with AF reveal an abnormal increase in cardiomyocytes death and alterations in calcium handling proteins. High-throughput quantitative proteomics and immunoblotting analyses at different stages of AF progression identify downregulation of contractile proteins and progressive increase in atrial fibrosis. Moreover, advanced optical mapping techniques, applied to whole heart preparations during AF, demonstrate that AF-related remodeling decreases the frequency threshold for dissociation between transmembrane voltage signals and intracellular calcium transients compared to healthy controls. Single cell simulations of human atrial cardiomyocytes also confirm the experimental results. In patients, non-invasive assessment of the atrial electromechanical relationship further demonstrate that atrial electromechanical dissociation is an early prognostic indicator for acute and long-term rhythm control.

Antibody-mediated interferences affecting cardiac troponin assays: recommendations from the IFCC Committee on Clinical Applications of Cardiac Biomarkers

The International Federation of Clinical Chemistry Committee on Clinical Applications of Cardiac Biomarkers (IFCC C-CB) provides educational documents to facilitate the interpretation and use of cardiac biomarkers in clinical laboratories and practice. Our aim is to improve the understanding of certain key analytical and clinical aspects of cardiac biomarkers and how these may interplay. Measurements of cardiac troponin (cTn) have a prominent place in the clinical work-up of patients with suspected acute coronary syndrome. It is therefore important that clinical laboratories know how to recognize and assess analytical issues. Two emerging analytical issues resulting in falsely high cTn concentrations, often several fold higher than the upper reference limit (URL), are antibody-mediated assay interference due to long-lived cTn-antibody complexes, called macrotroponin, and crosslinking antibodies that are frequently referred to as heterophilic antibodies. We provide an overview of antibody-mediated cTn assay interference and provide recommendations on how to confirm the interference and interpret the results.

Single Troponin Measurement to Rule Out Myocardial Infarction: JACC Review Topic of the Week

The term "single-sample rule-out" refers to the ability of very low concentrations of high-sensitivity cardiac troponin (hs-cTn) on presentation to exclude acute myocardial infarction with high clinical sensitivity and negative predictive value. Observational and randomized studies have confirmed this ability. Some guidelines endorse use of a concentration of hs-cTn at the assay's limit of detection, while other studies have validated the use of higher concentrations, allowing this approach to identify a greater proportion of patients at low risk. In most studies, at least 30% of patients can be triaged with this approach. The concentration of hs-cTn varies according to the assay used and sometimes how regulations permit reporting. It is clear that patients need to be at least 2 hours from the onset of symptoms being evaluated. Caution is warranted, particularly with older patients, women, and patients with underlying cardiac comorbidities.

Myocardial injury after major non-cardiac surgery evaluated with advanced cardiac imaging: a pilot study

BACKGROUND

Myocardial injury after non-cardiac surgery (MINS) is a frequent complication caused by cardiac and non-cardiac pathophysiological mechanisms, but often it is subclinical. MINS is associated with increased morbidity and mortality, justifying the need to its diagnose and the investigation of their causes for its potential prevention.

METHODS

Prospective, observational, pilot study, aiming to detect MINS, its relationship with silent coronary artery disease and its effect on future adverse outcomes in patients undergoing major non-cardiac surgery and without postoperative signs or symptoms of myocardial ischemia. MINS was defined by a high-sensitive cardiac troponin T (hs-cTnT) concentration > 14 ng/L at 48-72 h after surgery and exceeding by 50% the preoperative value; controls were the operated patients without MINS. Within 1-month after discharge, cardiac computed tomography angiography (CCTA) and magnetic resonance imaging (MRI) studies were performed in MINS and control subjects. Significant coronary artery disease (CAD) was defined by a CAD-RADS category ≥ 3. The primary outcomes were prevalence of CAD among MINS and controls and incidence of major cardiovascular events (MACE) at 1-year after surgery. Secondary outcomes were the incidence of individual MACE components and mortality.

RESULTS

We included 52 MINS and 12 controls. The small number of included patients could be attributed to the study design complexity and the dates of later follow-ups (amid COVID-19 waves). Significant CAD by CCTA was equally found in 20 MINS and controls (30% vs 33%, respectively). Ischemic patterns (n = 5) and ischemic segments (n = 2) depicted by cardiac MRI were only observed in patients with MINS. One-year MACE were also only observed in MINS patients (15.4%).

CONCLUSION

This study with advanced imaging methods found a similar CAD frequency in MINS and control patients, but that cardiac ischemic findings by MRI and worse prognosis were only observed in MINS patients. Our results, obtained in a pilot study, suggest the need of further, extended studies that screened systematically MINS and evaluated its relationship with cardiac ischemia and poor outcomes. Trial registration Clinicaltrials.gov identifier: NCT03438448 (19/02/2018).

Growth differentiation factor 15 as mortality predictor in heart failure patients with non-reduced ejection fraction

Aims

The prognostic value of biomarkers in patients with heart failure (HF) and mid‐range (HFmrEF) or preserved ejection fraction (HFpEF) has not been widely addressed. The aim of this study was to assess whether the prognostic value of growth differentiation factor 15 (GDF‐15) is superior to that of N‐terminal pro‐brain natriuretic peptide (NT‐proBNP) in patients with HFmrEF or HFpEF.

Methods and results

Heart failure patients with either HFpEF or HFmrEF were included in the study. During their first visit to the HF unit, serum samples were obtained and stored for later assessment of GDF‐15 and NT‐proBNP concentrations. Patients were followed up by the HF unit. The main endpoint was all‐cause mortality. A total of 311 patients, 90 (29%) HFmrEF and 221 (71%) HFpEF, were included. Mean age was 72 ± 13 years, and 136 (44%) were women. No differences were found in GDF‐15 or NT‐proBNP concentrations between both HF groups. During a median follow‐up of 15 months (Q1–Q3: 9–30 months), 98 patients (32%) died, most (71%) of cardiovascular causes. Patients who died had higher median concentrations of GDF‐15 (4085 vs. 2270 ng/L, P < 0.0001) and NT‐proBNP (1984 vs. 1095 ng/L, P < 0.0001). A Cox multivariable model identified New York Heart Association Functional Class III (P = 0.04), systolic blood pressure (P = 0.01), left atrial diameter (P = 0.03), age >65 years (P < 0.0001), and GDF‐15 concentrations (P = 0.01) but not NT‐proBNP as independent predictors of all‐cause mortality. The area under the curve was 0.797 for the basic model including NT‐proBNP, and the area under the curve comparing the overall model was 0.819, P = 0.016 (DeLong's test). Integrated discrimination improvement index after the inclusion of GDF‐15 in the model with the mortality risk factors was 0.033; that is, the ability to predict death increased by 3.3% (P = 0.004). Net reclassification improvement was 0.548 (P < 0.001); that is, the capacity to improve the classification of the event (mortality) was 54.8%. GDF‐15 concentrations were divided in tertiles (<1625, 1625–4330, and >4330 ng/L), and survival curves were evaluated using the Kaplan–Meier technique. Patients in the highest tertile had the poorest 5 year survival, at 16%, whereas the lowest tertile had the best survival, of 78% (P < 0.001).

Conclusions

Growth differentiation factor 15 was superior to NT‐proBNP for assessing prognosis in patients with HFpEF and HFmrEF. GDF‐15 emerges as a strong, independent biomarker for identifying HFmrEF and HFpEF patients with worse prognosis.

Educational Recommendations on Selected Analytical and Clinical Aspects of Natriuretic Peptides with a Focus on Heart Failure: A Report from the IFCC Committee on Clinical Applications of Cardiac Bio-Markers

The IFCC Committee on Clinical Applications of Cardiac Bio-Markers (C-CB) has directives and initiatives focused on providing evidence-based educational resources to aid and improve understanding around key analytical and clinical aspects of cardiac biomarkers used in clinical practice and the research setting. As a task force, we have previously published position statements and recommendations focused on use and analytical aspects of high-sensitivity cardiac troponin assays. The current educational document is the first from the C-CB highlighting important biochemical, analytical, and clinical aspects as they relate to the natriuretic peptides (NPs), including B-type natriuretic peptide (BNP) and N-terminal pro–B-type natriuretic peptide (NT-proBNP), with a focus on heart failure.

P6437Growth differentiation factor-15 and stromal cell-derived factor-1 as long-term prognosis biomarkers in acute coronary syndrome

Introduction

After an acute coronary syn bdrome (ACS) patients are at high risk of cardiovascular morbidity and mortality. In this scenario, Growth differentiation factor-15 (GDF-15) and Stromal cell derived factor-1 (SDF-1) has been reported as potential biomarkers in ACS. However, there is limited data about their combined use in long-term prognosis.

Purpose

To study the long-term prognostic value of GDF-15 and SDF-1 in ACS.

Methods

We included patients with ACS who underwent coronary angiography. During angiography an arterial blood sample was collected. Plasma SDF-1 and GDF-15 were measured and clinical data and long-term events were obtained. The cut-off point of SDF-1 and GDF-15 was identified individually by receiver operating characteristic curves. Patients were classified into 3 groups: 1) both biomarkers below cut-off points; 2) only one biomarker above cut-off points; 3) both biomarkers above cut-off points.

Results

A total of 238 patients were included. The median (IQR) age was 64 (55–74) year and 27.3% were female. Of all patients, 60.9% were admitted with non-ST-elevation myocardial infarction, 22.7% with ST-elevation myocardial infarction and 16.4% with unstable angina. The cut-off point of SDF-1 was 3283.5pg/mL and GDF-15 was 1849ng/L. A total of 127 patients were in group 1, 64 in group 2 and 47 in group 3. Group 3 patients were associated with older age, hypertension, dyslipidemia, diabetes mellitus and history of myocardial infarction (MI), stroke, chronic kidney disease and peripheral artery disease. Besides, they were more likely to have left ventricular dysfunction (ejection fraction <40%) and significant three vessels stenosis. During 6.5 years of follow-up 8 patients died (6.3%) in group 1, 7 patients died (10.9%) in group 2 and 25 patients died (53.2%) in group 3 (Figure 1). Multivariate Cox analysis showed that high levels of SDF-1 and GDF-15 (group 3) were an independent predictor of all-cause death (HR 5.8; 95% CI 2.4 - 14.1; p<0.001) and the composite of major adverse cardiovascular events (MACE) which were identified as all-cause death, nonfatal MI and heart failure (HR 3.9; 95% CI 2.1 - 7.3; p<0.001). During follow-up 1 patient had heart failure in group 1 (0.8%), 3 patients (4.7%) in group 2 and 9 patients (19.1%) in group 3. Despite the low number of events of heart failure, the multivariate competing risks regression showed association between group 3 and heart failure during follow-up (HR 28.0; 95% CI 3.5 - 225.2; p=0.002). Higher levels of SDF-1 and GDF-15 (group 3) were not associated with new MI in multivariate competing risks regression. Regarding group 2, all multivariate analyses were non-significant.

Cumulative survival and incidence curves

Conclusions

Higher values of combined GDF-15 and SDF-1 are an excellent predictor of all-cause death, MACE and heart failure in long-term follow-up of patients with ACS. The combined use of SDF-1 and GDF-15 may be useful in long-term ACS prognosis.

Ultrasensitive quantification of cardiac troponin I by a Single Molecule Counting method: analytical validation and biological features

AIM

To evaluate analytical and biological characteristics of the Singulex Clarity® cTnI assay, based upon Single Molecule Counting technology.

METHODS

Assay's analytical sensitivity, precision, linearity, hook effect, cross-reactivity or interference by endogenous and exogenous substances, stability, 99th reference percentile [p99th] in EDTA plasma were evaluated in single or multi-site studies.

RESULTS

Detection limit was 0.12 ng/L. Sensitivity was 0.14 ng/L at 20% CV (functional sensitivity) and 0.53 ng/L at 10% CV. Imprecision was 3.16%-10.0% in a multi-lot, single-site study, and 5.5%-12.0% in a single-lot, multi-site study; assay was linear from 0.08 to 25,000 ng/L. No hook effect was observed; any cross-reactivity/interference exceeded the 10%. Healthy subjects were recruited using clinical history, normal NT-proBNP and eGFR (n = 560) or plasma creatinine (n = 535) as inclusion criteria. cTnI was detectable in 96.8% of healthy subjects. The p99th were 8.01 (eGFR used) and 8.15 ng/L (plasma creatinine); both were measured with ≤5.7% CV. Median cTnI were significantly higher in older and male than in young and female subjects.

CONCLUSIONS

The Singulex Clarity cTnI assay show analytical features and % detection in healthy subjects that improve the corresponding values of most of the existing high-sensitivity cTnI assays.

Clinical Laboratory Practice Recommendations for the Use of Cardiac Troponin in Acute Coronary Syndrome: Expert Opinion from the Academy of the American Association for Clinical Chemistry and the Task Force on Clinical Applications of Cardiac Bio-Markers of the International Federation of Clinical Chemistry and Laboratory Medicine

This document is an essential companion to the third iteration of the National Academy of Clinical Biochemistry [NACB,8 now the American Association for Clinical Chemistry (AACC) Academy] Laboratory Medicine Practice Guidelines (LMPG) on cardiac markers. The expert consensus recommendations were drafted in collaboration with the International Federation of Clinical Chemistry and Laboratory Medicine Task Force on Clinical Applications of Bio-Markers (IFCC TF-CB). We determined that there is sufficient clinical guidance on the use of cardiac troponin (cTn) testing from clinical practice groups. Thus, in this expert consensus document, we focused on clinical laboratory practice recommendations for high-sensitivity (hs)-cTn assays. This document utilized the expert opinion class of evidence to focus on the following 10 topics: (a) quality control (QC) utilization, (b) validation of the lower reportable analytical limits, (c) units to be used in reporting measurable concentrations for patients and QC materials, (d) 99th percentile sex-specific upper reference limits to define the reference interval; (e) criteria required to define hs-cTn assays, (f) communication with clinicians and the laboratory's role in educating clinicians regarding the influence of preanalytic and analytic problems that can confound assay results, (g) studies on hs-cTn assays and how authors need to document preanalytical and analytical variables, (h) harmonizing and standardizing assay results and the role of commutable materials, (i) time to reporting of results from sample receipt and sample collection, and (j) changes in hs-cTn concentrations over time and the role of both analytical and biological variabilities in interpreting results of serial blood collections.

High sensitivity cardiac troponin T in patients not having an acute coronary syndrome: results from the TRAPID-AMI study

PURPOSE

To describe the baseline, 1 hr and delta high sensitivity cardiac troponin (hs-cTnT) values in patients with suspected acute myocardial infarction (AMI) but without a final acute coronary syndrome (ACS) diagnosis.

MATERIALS AND METHODS

hs-cTnT assay for RAPID rule out of acute myocardial infarction (TRAPID-AMI) was a prospective diagnostic trial that enrolled emergency department (ED) patients with suspected AMI. Final patient diagnoses were adjudicated by a clinical events committee and subjects placed in different clinical groups: AMI, unstable angina, non-ACS cardiac, non-cardiac and unknown origin. The baseline, 1 hr and delta hs-cTnT values were analysed in the 902 non-ACS patients.

RESULTS

Amongst the 1282 studied the patient groups were 213 (17%) AMI, 167 (13%) unstable angina, 113 (9%) non-ACS cardiac, 288 (22%) non-cardiac and 501 (39%) unknown origin. The hs-cTnT values in the non-cardiac and unknown origin groups were combined. The median hs-cTnT values (ng/L) were higher (p < 0.001) in the non-ACS cardiac compared to the non-cardiac/unknown origin group at baseline (11.8, <5) and 1 hr (12.3, <5). Their negative predictive values were 0.955 (baseline) and 0.954 (1 hr) for predicting non-ACS cardiac versus non-cardiac/unknown origin diagnoses.

CONCLUSIONS

Hs-cTnT may help predict whether non-ACS ED patients have a final non-ACS cardiac or non-cardiac/unknown origin diagnoses.

Cardiac Troponin Assays: Guide to Understanding Analytical Characteristics and Their Impact on Clinical Care

BACKGROUND

Cardiac troponin I (cTnI) and cardiac troponin T (cTnT) determinations are fixtures in clinical practice and research. Cardiac troponin testing has been the standard of practice for the diagnosis of acute myocardial infarction (AMI), early rule-out, risk stratification, and outcomes assessment in patients presenting with acute coronary syndrome (ACS) and non-ACS myocardial injury. We recognize from reading the literature over the past several years how poorly understood the analytical characteristics are for cTnI and cTnT assays by laboratorians, clinicians, and scientists who use these assays.

CONTENT

The purposes of this mini-review are (a) to define limit of blank, limit of detection, limit of quantification, and imprecision, (b) overview the analytical characteristics of the existing cardiac troponin assays, (c) recommend approaches to define a healthy (normal) reference population for determining the 99th percentile and the appropriate statistic to use for this calculation, (d) clarify how an assay becomes designated as “high sensitivity,” and (e) provide guidance on determining delta (Δ) change values.

SUMMARY

This review raises important educational information regarding cTnI and cTnT assays, their 99th percentile upper reference limits (URL) differentiated by sex, and specifically addresses high-sensitivity (hs)-assays used to measure low concentrations. Recommendations are made to help clarify the nomenclature and analytical and clinical characteristics to define hs-assays. The review also identifies challenges for the evolving implementation of hs-assays into clinical practice. It is hoped that with the introduction of these concepts, laboratorians, clinicians and researchers can develop a more unified view of how these assays should be used worldwide.

Specificity of B-Type Natriuretic Peptide Assays: Cross-Reactivity with Different BNP, NT-proBNP, and proBNP Peptides

BACKGROUND

B-type natriuretic peptides (BNPs) are used clinically to diagnose and monitor heart failure and are present in the circulation as multiple proBNP-derived fragments. We investigated the specificity of BNP immunoassays with glycosylated and nonglycosylated BNP, N-terminal proBNP (NT-proBNP), and proBNP peptides to probe the cross-reactivity of each assay.

METHODS

Nine B-type natriuretic peptides were studied,including synthetic and recombinant BNP (Shionogi, Scios, Mayo), human and synthetic glycosylated and nonglycosylated NT-proBNP (HyTest, Roche Diagnostics), and human glycosylated and nonglycosylated proBNP (HyTest, Scios). Five BNP [Abbott, Abbott POC, Alere, Beckman Coulter, Siemens (Centaur)], 9 NT-proBNP [Ortho-Clinical Diagnostics, Roche, Response, bioMerieux, Siemens (Dimension, Immulite, Stratus CS), Mitsubishi] and 3 research-use-only proBNP immunoassays [Biosite (Alere), Bio-Rad, Goetze] were evaluated. Specificity was assessed by calculating the recovery between baseline and peptide-spiked human plasma pools at target concentrations of 100 ng/L BNP, 300 ng/L proBNP, or 450 ng/L NT-proBNP. All assays were performed in duplicate.

RESULTS

BNP and NT-proBNP assays demonstrated substantial cross-reactivity with proBNP peptides. NT-proBNP assays do not detect glycosylated forms of either NT-proBNP or proBNP. proBNP assays preferentially detect the BNP 1-32 peptide and have minimal cross-reactivity with BNP peptides and glycosylated proBNP.

CONCLUSIONS

BNP or NT-proBNP results are not transferable among the current existing immunoassays owing to their differences in cross-reactivity and ability to detect various glycosylated forms of proBNP-derived fragments. Opportunities remain to standardize and harmonize BNP and NT-proBNP assays, as well as to develop specific proBNP assays, to widen their clinical scope of use.

Cost-Effectiveness of Highly Sensitive Cardiac Troponin T to Rule Out Acute Rejection After Heart Transplantation

BACKGROUND

Endomyocardial biopsy (EMB) remains the gold standard for detecting acute rejection (AR) after heart transplantation (HTx). Non-invasive detection of AR thus far remains a challenge. Several studies have demonstrated that highly sensitive cardiac troponin T (hs-cTnT) concentrations have a low positive predictive value for diagnosing AR. Nevertheless, hs-cTnT proved to be useful for ruling out AR after HTx. An hs-cTnT concentration <17 ng/L, a value close to that used for rule-in or rule-out myocardial infarction, was associated with a 100% negative predictive value of AR. However, the cost-effectiveness of a strategy with the use of hs-cTnT for ruling out AR in HTx patients remains to be proven.

METHODS

The cost-effectiveness of hs-cTnT determination for ruling out AR was assessed, comparing the costs of hs-cTnT measurements in 305 blood samples obtained at the time of EMB. Eighteen samples were excluded because the EMB was not assessable.

RESULTS

Hs-cTnT determination cost 16.00€ per sample, whereas EMB cost 1752.00€ per biopsy; cost estimations included direct and indirect (30%) charges. Thirty-nine (13.6%) of the 287 blood samples presented hs-cTnT concentrations <17 ng/L; in none of them was an AR >2R degree found in the EMB. The cost of the assessment in the 287 blood samples and biopsies was of 4592.00€ for hs-cTnT and 502,824.00€ for EMB. Hs-cTnT systematic measurement would have avoided 39 EMB, with a saving of 68,328.00€, which represents the 13.5% of the total budget expended in these cases.

CONCLUSIONS

The use of hs-cTnT values to rule out the need of EMB for AR diagnosis after HTx appears to be a cost-effective procedure.

Use of B-type natriuretic peptides to detect the existence and severity of diastolic dysfunction in non-cardiac critically ill patients: a pilot study

BACKGROUND

This observational study was designed to evaluate and compare the usefulness of BNP and NT-proBNP concentrations to detect the existence and severity of left ventricular diastolic dysfunction (LVDD) in critically ill patients.

METHODS

A prospective, observational study in a university hospital. The sample included 86 consecutive adult patients. Based on echocardiography data, LVDD were classified into normal, impaired relaxation, pseudonormal or restrictive patterns. Patients were classified according to whether filling pressures were elevated or non-elevated in the echocardiography. Sampling for natriuretic peptides was performed immediately before echocardiography.

RESULTS

Fifty patients showed LVDD. The most frequently observed pattern was impaired relaxation (N.=35), followed by the restrictive (N.=9) and the pseudonormal (N.=6) patterns. BNP concentrations in restrictive and pseudonormal patterns were higher than in normal and impaired relaxation patterns, while NT-proBNP only showed differences between normal and pseudonormal or restrictive patterns. Cut-off values using ROC curve analyses to detect LVDD were 125 ng/L for BNP and 390 ng/L NT-proBNP. BNP and NT-proBNP concentrations were higher in the 15 patients with restrictive and pseudonormal patterns, suggesting elevated filling pressures. Cut-off values using ROC curve analyses to detect echocardiography signs of elevated filling pressures were 254 ng/L for BNP and 968 for NT-proBNP. Both natriopeptides performed in a similar way to detect LVDD and elevated filling pressures.

CONCLUSION

Both BNP and NT-proBNP are useful screening tools to detect the presence of advanced degrees of LVDD, and especially to rule out elevated filling pressures.

New York Heart Association class versus amino-terminal pro-B type natriuretic peptide for acute heart failure prognosis

BACKGROUND

The prognostic value of the New York Heart Association classification (NYHAC) in acutely decompensated heart failure (ADHF) is unknown.

OBJECTIVES

We sought to determine the relative value of NYHAC among patients with concomitantly measured amino-terminal pro-B type natriuretic peptide (NT-proBNP) at presentation with ADHF.

MATERIALS AND METHODS

NYHAC was determined for 720 patients with ADHF and 1-year mortality status was examined. Cox-proportional hazards analysis compared the prognostic accuracy of NYHAC with other ADHF risk measures.

RESULTS

NYHAC had a significant univariate association with 1-year mortality status (HR 1.41, 95% confidence interval (CI) 1.03-1.94; p = 0.03) but was not a significant predictor of death in a multivariable model that included NT-proBNP (HR 2.14; 95% CI 1.65-2.81, p < 0.001).

CONCLUSIONS

In contrast to objective measures such as NT-proBNP, the NYHAC appears to provide limited prognostic information among individuals with ADHF.

Electronegative LDL induces Fas and modifies gene expression in mononuclear cells

Electronegative LDL (LDL(-)) is a minor modified LDL subfraction that promotes cytokine release by human mononuclear cells. The aim of the current study was to evaluate changes in gene expression induced by LDL(-) versus native LDL in lymphocytes and monocytes. Therefore, mononuclear cells were incubated with these LDL subfractions and their effects on expression in human whole genome were analyzed by gene array. Differential expression of the genes was quantified by real-time RT-PCR. LDL(-) altered the gene expression pattern, particularly of inflammatory genes. LDL(-) down-regulated CD36 and colony-stimulating factor 1 receptor (CSF1R) genes and up-regulated Fas expression and Fas protein on cellular membrane. LDL(-) seemed to promote the alterations in these genes by activation of NF-kB and inhibition of AP1 and PPARG. In conclusion, LDL(-) induced changes in gene expression in monocytes and lymphocytes. Fas up-regulation suggests a proinflammatory action; however, CSF1R and CD36 down-regulation could decrease monocyte differentiation and activation. Therefore, LDL(-) promoted not only inflammatory effects but also counteracting actions in circulating mononuclear cells.

The MUSIC Risk score: a simple method for predicting mortality in ambulatory patients with chronic heart failure

AIMS

The prognosis of chronic heart failure (CHF) is extremely variable, although generally poor. The purpose of this study was to develop prognostic models for CHF patients.

METHODS AND RESULTS

A cohort of 992 consecutive ambulatory CHF patients was prospectively followed for a median of 44 months. Multivariable Cox models were developed to predict all-cause mortality (n = 267), cardiac mortality (primary end-point, n = 213), pump-failure death (n = 123), and sudden death (n = 90). The four final models included several combinations of the same 10 independent predictors: prior atherosclerotic vascular event, left atrial size >26 mm/m(2), ejection fraction < or =35%, atrial fibrillation, left bundle-branch block or intraventricular conduction delay, non-sustained ventricular tachycardia and frequent ventricular premature beats, estimated glomerular filtration rate <60 mL/min/1.73 m(2), hyponatremia < or =138 mEq/L, NT-proBNP >1.000 ng/L, and troponin-positive. On the basis of Cox models, the MUSIC Risk scores were calculated. A cardiac mortality score >20 points identified a high-risk subgroup with a four-fold cardiac mortality risk.

CONCLUSION

A simple score with a limited number of non-invasive variables successfully predicted cardiac mortality in a real-life cohort of CHF patients. The use of this model in clinical practice identifies a subgroup of high-risk patients that should be closely managed.

Multicentric evaluation of the homogeneous LDL-cholesterol Plus assay: comparison with beta-quantification and Friedewald formula

OBJECTIVES

To evaluate the analytical and clinical performance of a new version of the LDL-C Plus assay and compare it with the beta-quantification (BQ) method in a multicenter study.

DESIGN AND METHODS

Direct LDL-C was measured in 169 fresh pooled samples and in 830 clinical samples with known LDL-C by BQ. The reactivity of lipoproteins and the effect of hemoglobin, bilirubin and chylomicrons (CM) were studied.

RESULTS

Direct LDL-C total imprecision was <2.2%; inaccuracy <+/-2.5% (unaffected by triglycerides up to 9.5 mmol/L); and total error 9.8%. Direct assay reacted with 95%, 50% and 25% of the cholesterol in the LDL, intermediate (IDL) and VLDL fractions, respectively. A significant association was observed with BQ. Icteric samples showed a negative bias and the effect of CM was variable. A positive bias was observed when VLDL-cholesterol/triglyceride ratio was >0.57.

CONCLUSIONS

LDL-C Plus assay represents a valid alternative to BQ for clinical laboratories.

Amino-terminal pro-B-type natriuretic peptide: analytic considerations

Amino-terminal pro-B-type natriuretic peptide (NT-proBNP) is a convenient molecule to work with in clinical laboratories, with preanalytic and analytic advantages, such as excellent stability at different temperatures, flexibility in sample type, and strong harmony across all commercially available NT-proBNP assays (including recently released point-of-care methods). Another major advantage of NT-proBNP assays is that they show excellent analytic precision. Reference values for NT-proBNP testing are strongly affected by the population tested. Among nondiseased populations, lower values are expected, whereas in diseased populations, such as in patients with acute dyspnea, higher reference values are more useful. Also, the biologic variability of NT-proBNP should be taken into account to evaluate the significance of any change in its values. When analyzed in patients with stable heart failure, biologic variability was 25%-40%. This article reviews the laboratory aspects of NT-proBNP testing from the perspective of the clinical laboratorian.

Antiatherogenic role of high-density lipoproteins: insights from genetically engineered-mice

Plasma levels of high-density lipoprotein (HDL) cholesterol are inversely correlated with the incidence of atherosclerotic cardiovascular disease. The cardioprotective effects of HDL have been attributed to its role in reverse cholesterol transport (RCT) and especially the macrophage-dependent RCT, and also to the antioxidant properties of HDL as well as its direct effects on endothelial function. However, few of these effects have been verified in vivo in humans. With the creation and detailed analysis of genetically-engineered mice, a solid body of new information has emerged on the mechanisms controlling these key antiatherogenic functions of HDL and their effects on atherogenesis. This article provides a review of new insights into the molecular mechanisms underlying these three most studied antiatherogenic functions of HDL in vivo with a focus on genetically-engineered mice.

NT-proBNP testing for diagnosis and short-term prognosis in acute destabilized heart failure: an international pooled analysis of 1256 patients: the International Collaborative of NT-proBNP Study

AIMS

Experience with amino-terminal pro-brain natriuretic peptide (NT-proBNP) testing for evaluation of dyspnoeic patients with suspected acute heart failure (HF) is limited to single-centre studies. We wished to establish broader standards for NT-proBNP testing in a study involving four sites in three continents.

METHODS AND RESULTS

Differences in NT-proBNP levels among 1256 patients with and without acute HF and the relationship between NT-proBNP levels and HF symptoms were examined. Optimal cut-points for diagnosis and prognosis were identified and verified using bootstrapping and multi-variable logistic regression techniques. Seven hundred and twenty subjects (57.3%) had acute HF, whose median NT-proBNP was considerably higher than those without (4639 vs. 108 pg/mL, P<0.001), and levels of NT-proBNP correlated with HF symptom severity (P=0.008). An optimal strategy to identify acute HF was to use age-related cut-points of 450, 900, and 1800 pg/mL for ages <50, 50-75, and >75, which yielded 90% sensitivity and 84% specificity for acute HF. An age-independent cut-point of 300 pg/mL had 98% negative predictive value to exclude acute HF. Among those with acute HF, a presenting NT-proBNP concentration >5180 pg/mL was strongly predictive of death by 76 days [odds ratio=5.2, 95% confidence interval (CI)=2.2-8.1, P<0.001].

CONCLUSION

In this multi-centre, international study, NT-proBNP testing was valuable for diagnostic evaluation and short-term prognosis estimation in dyspnoeic subjects with suspected or confirmed acute HF and should establish broader standards for use of the NT-proBNP in dyspnoeic patients.

NT-ProBNP reduction percentage during admission for acutely decompensated heart failure predicts long-term cardiovascular mortality

BACKGROUND

N-terminal brain natriuretic peptide (NT-proBNP) improves emergency room diagnosis of acutely decompensated heart failure. Less evidence is available on the usefulness of NT-proBNP as a prognostic marker after hospitalization for acute heart failure. The percentage of NT-proBNP reduction during admission and its prognostic significance were studied.

METHODS AND RESULTS

This was a prospective study of 74 patients in the emergency department who were diagnosed with acute heart failure and who had follow-up evaluation for 6 and 12 months after admission. Plasma NT-proBNP concentrations were measured on admission, at 24 hours, at day 7, and at 6 and 12 months. Eighteen patients died during the 12-month follow-up; 12 deaths were from cardiovascular causes. NT-proBNP concentrations were significantly higher in the emergency department and at 24 hours than those concentrations that were found at day 7 and beyond (P < .001). During admission, the NT-proBNP concentration fell a mean of 15% in patients who died of cardiovascular causes during the 1-year follow-up evaluation, in 75% in those patients who died of non-cardiovascular causes, and in 50% in survivors (P = .004). The area under the receiver operator characteristic curve for NT-proBNP reduction percentage to predict cardiovascular death was 0.78 (95% CI, 0.66-0.90; P = .002). A 30% NT-proBNP reduction percentage cutoff value had 75% accuracy for the identification of high-risk patients and was the only variable that was associated with cardiovascular death in multivariate analysis (odds ratio, 4.4; 95% CI, 1.12-17.4; P = .03).

CONCLUSION

NT-proBNP reduction percentage during admission for acutely decompensated heart failure appeared to be the best predictor of cardiovascular death during the follow-up period. A <30% NT-proBNP reduction percentage identified a subgroup of high-risk patients.

Diabetes mellitus and cardiovascular disease

Diabetes is associated with a high incidence and poor prognosis of cardiovascular disease, and with high short- and long-term mortality. Adequate treatment of cardiovascular disorders and aggressive management of coexisting risk factors have proved to be at least as effective in diabetic as in nondiabetic patients in randomized, controlled studies. Indeed, treating diabetic patients with cardiovascular disease results in a larger absolute risk reduction than in nondiabetic subjects. Nevertheless, diabetic patients often receive inadequate therapy, which may, to a certain extent, explain their poor prognosis. Recommendations for the treatment of diabetic patients with acute myocardial infarction should include beta-blockers, aspirin, and ACE-inhibitors in all patients in whom no specific contraindications exist. Fibrinolysis should be administered when indicated, and the benefits of improving glycemic control should not be forgotten either. In patients with multi-vessel disease who need revascularization, when selecting the type of procedure, the superiority of surgical revascularization over angioplasty should be borne in mind. Even heart transplantation should be included as a therapeutic option since there are no data to support the exclusion of patients on account of their diabetes. Finally, coexisting risk factors should be intensively treated through lifestyle intervention, with or without drug therapy, in order to achieve secondary prevention goals.