Lower rather than higher levels of B-type natriuretic peptides (NT-pro-BNP and BNP) predict short-term mortality in end-stage heart failure patients treated with nesiritide

Natriuretic peptide testing strategies in heart failure: A 2023 update

Natriuretic peptides (NPs), including B-type natriuretic peptide (BNP) and N-terminal pro-BNP (NT-proBNP), have been recommended as standard biomarkers for diagnosing heart failure (HF), and one of the strongest risk predictors for mortality and HF hospitalization regardless of ejection fraction (EF) and etiology of HF. BNP is an active neurohormone opposing renin-angiotensin-aldosterone and sympathetic nervous system overactivated in HF, whereas NT-proBNP is an inactive prohormone released from cardiomyocytes in response to wall stress. Despite substantial advances in the development of guideline-directed medical therapy (GDMT) for HF with reduced EF, studies demonstrating direct benefits of NP-guided chronic HF therapy on mortality, HF hospitalization, and GDMT optimization have yielded conflicting results. However, accumulating evidence shows that achieving prespecified BNP or NT-proBNP target over time is significantly associated with favorable outcomes, suggesting that benefits of serially measured NPs may be limited to particular groups of HF patients, such as those with extreme levels of baseline BNP or NT-proBNP, which could represent severe phenotypes of HF associated with natriuretic peptide resistance or cardiorenal syndrome. Over the past decade, clinical utilization of BNP and NT-proBNP has been expanded, especially using serial NP measurements for guiding HF therapy, optimizing GDMT and identifying at-risk patients with HF phenotypes who may be minimally symptomatic or asymptomatic.

Vasostatin-1 as a potential novel circulating biomarker in patients with chronic systolic heart failure: A pilot study

BACKGROUND AND AIMS

Previous studies have shown that circulating chromogranin A (CgA) increases in patients with chronic systolic heart failure (HF). Aim of the present study is to evaluate the potential role of circulating vasostatin-1 (VS-1), a cardioregulatory fragment of CgA, as prognostic marker in patients with chronic HF.

MATERIALS AND METHODS

The plasma levels of CgA and VS-1 were determined in 80 patients with chronic systolic HF. Patients were followed-up to evaluate the occurrence of cardiovascular (CV) events.

RESULTS

CgA and VS-1 plasma levels were significantly higher in patients with CV events at follow-up. VS-1, but not CgA, was associated to NT-proBNP. No significant association of CgA and VS-1 with left ventricular ejection fraction (LVEF) was observed. CgA, NT-proBNP and age, but not VS-1, were independent predictors of CV events.

CONCLUSION

In patients with chronic systolic HF those who experienced CV events had higher levels of VS-1 and CgA. Given its established effect on cardiac cells, the association of VS-1 levels with NT-proBNP levels but not with LVEF, suggests that this fragment might provide complementary information to NT-proBNP and CgA in HF patients.

Relationship between duration of heart failure, patient characteristics, outcomes, and effect of therapy in PARADIGM-HF

Aims

Little is known about patient characteristics, outcomes, and the effect of treatment in relation to duration of heart failure (HF). We have investigated these questions in PARADIGM‐HF. The aim of the study was to compare patient characteristics, outcomes, and the effect of sacubitril/valsartan, compared with enalapril, in relation to time from HF diagnosis in PARADIGM‐HF.

Methods and results

HF duration was categorized as 0–1, >1–2, >2–5, and >5 years. Outcomes were adjusted for prognostic variables, including N‐terminal pro‐brain natriuretic peptide (NT‐proBNP). The primary endpoint was the composite of HF hospitalization or cardiovascular death. The number of patients in each group was as follows: 0–1 year, 2523 (30%); >1–2 years, 1178 (14%); >2–5 years, 2054 (24.5%); and >5 years, 2644 (31.5%). Patients with longer‐duration HF were older, more often male, and had worse New York Heart Association class and quality of life, more co‐morbidity, and higher troponin‐T but similar NT‐proBNP levels. The primary outcome rate (per 100 person‐years) increased with HF duration: 0–1 year, 8.4 [95% confidence interval (CI) 7.6–9.2]; >1–2 years, 11.2 (10.0–12.7); >2–5 years, 13.4 (12.4–14.6); and >5 years, 14.2 (13.2–15.2); P < 0.001. The hazard ratio was 1.26 (95% CI 1.07–1.48), 1.52 (1.33–1.74), and 1.53 (1.33–1.75), respectively, for >1–2, >2–5, and >5 years, compared with 0–1 year. The benefit of sacubitril/valsartan was consistent across HF duration for all outcomes, with the primary endpoint hazard ratio 0.80 (95% CI 0.67–0.97) for 0–1 year and 0.73 (0.63–0.84) in the >5 year group. For the primary outcome, the number needed to treat for >5 years was 18, compared with 29 for 0–1 year.

Conclusions

Patients with longer‐duration HF had more co‐morbidity, worse quality of life, and higher rates of HF hospitalization and death. The benefit of a neprilysin inhibitor was consistent, irrespective of HF duration. Switching to sacubitril/valsartan had substantial benefits, even in patients with long‐standing HF.

A prospective, randomized, double-blind, placebo-controlled pilot study of sacubitril/valsartan (Entresto) in dogs with cardiomegaly secondary to myxomatous mitral valve disease

Background

The effects of sacubitril/valsartan (S/V) on the renin‐angiotensin‐aldosterone system (RAAS) in dogs with cardiomegaly secondary to myxomatous mitral valve disease (MMVD) are currently unknown.

Objectives

To determine the pharmacodynamic effects of S/V on the RAAS, natriuretic peptide concentrations, systolic arterial pressure (SAP), tests of renal function, and serum electrolyte concentrations in dogs with cardiomegaly secondary to MMVD.

Animals

Thirteen client‐owned dogs weighing 4‐15 kg with American College of Veterinary Internal Medicine (ACVIM) Stage B2 MMVD.

Methods

Prospective, randomized, double‐blind, placebo‐controlled pilot study of S/V in dogs with ACVIM Stage B2 MMVD.

Results

Thirteen dogs were recruited: S/V (n = 7) and placebo (n = 6). The median percentage increase in urinary aldosterone to creatinine ratio (UAldo : C) between day 0 and day 30 was significantly lower in the S/V group (12%; P = .032) as compared with the placebo group (195%). The median percentage decrease of NT‐proBNP concentration from day 0 to day 30 was not statistically different between groups (P = .68). No statistical differences were seen in echocardiographic, thoracic radiographic, SAP, or serum biochemical test results measured at any time point between groups. No adverse events were observed for dogs in either group.

Conclusion and Clinical Importance

Sacubitril/valsartan may provide a new pharmaceutical method to effectively inhibit the RAAS in dogs with ACVIM Stage B2 MMVD.

Interleukin-1β levels predict long-term mortality and need for heart transplantation in ambulatory patients affected by idiopathic dilated cardiomyopathy

Aims

The prognostic stratification of patients with Idiopathic Dilated Cardiomyopathy (iDCM) is a difficult task. Here, we assessed the additive value of the evaluation of biomarkers of inflammasome activation and systemic inflammation for the long-term risk stratification of iDCM patients.

Methods and Results

We studied 156 ambulatory iDCM patients (mean age 58 years, 77% men, 79% in NYHA class 1-2, median Left Ventricular Ejection Fraction (LVEF) 35%, mean sodium 139 mEq/L, median BNP 189 pg/mL, median IL-1 beta (IL-1β) 1.08 pg/mL, median IL-6 1.7 pg/mL and median IL-10 2.7 pg/mL).

During the follow-up period of 89.6 months, 35 patients (22%) died/underwent heart transplantation. Patients who died/underwent heart transplantation were more likely to be male, to be in NYHA class III, to have atrial fibrillation, to have lower LVEF and higher BNP levels. IL-1β, IL-6 and IL-10 levels did not differ significantly between the groups of patients with good or bad prognosis. IL-1β levels did not vary significantly among either the different NYHA classes or the quartiles of LVEF. In a multivariable model, however, IL-1β was a strong and independent predictor of all-cause mortality (HR 1.193, 95% CI 1.056 – 1.349, p=0.005 for log squared transformed values). Other factors associated with the outcome were: male gender, presence of atrial fibrillation and sodium concentration. The estimated time-dependent ROC curve of the multivariable model showed an AUC 0.74 (95% CI 0.65-0.86).

Conclusions

Serum levels of IL-1β could be useful to predict the long-term outcome of patients with iDCM.

B-type brain natriuretic peptide as a measure of the severity of hand-foot-mouth disease: a case-control study

BACKGROUND

Hand-foot-mouth disease (HFMD) is an acute infectious disease caused by enteroviruses, and HFMD complicated by cardiopulmonary failure has a high mortality. B type natriuretic peptide (BNP) is widely applied in monitoring cardiovascular disorders, and thus, we investigated whether this index was associated with the severity of HFMD and the outcome in severe HFMD.

METHODS

Serum BNP, lactate, and glucose levels as well as white blood cell (WBC) count, PaO2/FiO2, and cardiac output (CO) were analyzed in the 83 enrolled HFMD patients according to different conditions (common, severe, and critical; with and without complication; and survivors and non-survivors). The control group consisted of 29 patients with respiratory tract infections.

RESULTS

No significant differences in CO were observed between the groups. Serum lactate, glucose, BNP, and WBC levels in the critical group were significantly higher than those in the severe, common, and control groups (p < 0.01 or 0.05). The PaO2/FiO2 ratio was significantly lower in the critical group (214.286 ± 154.346) than in the other groups. According to logistic regression analysis, the areas under the curve for serum BNP, glucose, and PaO2/FiO2 of the patients with complications were 0.774, 0.738, and 0.75, respectively. Moreover, the BNP level was significantly higher in HFMD patients with complications and non-survivors.

CONCLUSION

Our findings indicate that BNP could be a biochemical indicator for severe (critical) HFMD and used for prognosis in terms of complications and death. Combined with Glu and PaO2/FiO2 and clinical symptoms of HFMD, the value of BNP as an indicator became more precise and specific. Our results may provide another valuable, objective biochemical indicator for severe HFMD.

TRIAL REGISTRATION NUMBER

ChiCTR-DDT-14004576 . Name of registry: Chinese Clinical Trial Registry. Date of registration: 2014-09-21.

Prognostic prediction in acute heart failure patients with extreme BNP values

BACKGROUND

Some patients have good prognosis despite elevated B-type natriuretic peptide (BNP), while others have ominous outcome with low BNP. We aimed at characterising these groups of patients.

METHODS

We analysed patients prospectively included in an acute HF registry. Vital status within 1-year post discharge was ascertained. A receiver-operating characteristic curve was used to define discharge BNP cut-offs for 1-year death prediction. Among survivors, we compared patients with low and not-low BNP (cut-off 400 pg/mL); and among non-survivors those with high vs not-high BNP (cut-off 2000 pg/mL). In the specific subgroups of patients with low and high BNP, mortality predictors were assessed with multivariate Cox-regression analysis.

RESULTS

We studied 584 patients, median age 78 years, 62.5% had HF with reduced ejection fraction; and 199 (34.1%) died during the first year. Non-survivors were very homogeneous irrespective of BNP, survivors were substantially different. In patients discharged with BNP <400 pg/mL, increasing age independently predicted death; when BNP ≥2000 pg/mL death predictors were higher NYHA class, and non-use of evidence-based therapy. BNP was outcome associated in both groups.

CONCLUSIONS

Different prognostic predictors may play a role in different BNP levels. We suggest that risk stratification in HF would probably be more accurate if made on top of BNP knowledge.

Effect of B-Type Natriuretic Peptide Level on Long-Term Outcome in Patients With End-Stage Heart Failure

Previous studies have demonstrated elevated B-type natriuretic peptide (BNP) level indicates a poor outcome in patients with heart failure (HF). However, some patients with end-stage HF presented with low BNP level and the impact of the nearly "normal" BNP level on long-term outcome is not well understood. Our study aimed to evaluate the association of BNP level with long-term outcome in 218 consecutive patients with dilated cardiomyopathy and end-stage HF. Sixty-two patients (28%) presented with admission BNP level ≤400 pg/ml. During a median follow-up period of 20 months (4 to 26 months), the all-cause mortality rate in patients with BNP ≤400 pg/ml was higher than in patients with BNP >400 pg/ml (76% vs 48%, p <0.001). Patients were then divided into 5 groups according to the BNP level (≤400, 401 to 1,000, 1,001 to 2,000, 2,001 to 3,000, and >3,000 pg/ml), the all-cause mortality were 76%, 41%, 40%, 49%, and 75%, respectively (p <0.001). After multivariate adjustment, both BNP ≤400 and >3,000 pg/ml were independently associated with increased risk of all-cause mortality (hazard ratios 1.87, 95% CI 1.02 to 3.42, p = 0.043 and hazard ratio 2.31, 95% CI 1.16 to 4.60, p = 0.018, respectively). In conclusion, our present study demonstrated a "U-like" shape between BNP level and all-cause mortality in end-stage HF, and the seemingly "normal" BNP level might also be a risk factor for poor outcome. Low BNP level may be a reflection of impaired neurohormonal response or altered metabolism of BNP and is associated with increased risk of poor outcome.

Biomarkers in heart failure: the importance of inconvenient details

The proliferation of cardiac-related biomarkers and advocacy for their use has often come without adequate discussion of limitations in the interpretation of values and their best use in heart failure (HF) patients to provide a balanced assessment of how cardiac biomarkers are advocated for use in HF and areas where we would argue there are no gaps in knowledge. We include suggestions to address these issues. We have focused on peer-reviewed publications over the period 2000 to present. Most studies have used samples at one or at most two points in time to define risk. Although biomarkers might add to the magnitude of risk, it is unclear how often they lead to changes in treatment. We suggest that defining the use of serial biomarker testing over time would be more helpful. To do this, it is necessary to take into account the biomarker's analytical and biological variability in addition to its ability to define and monitor therapy. These factors are often overlooked leading to conclusions that may be statistically significant but not clinically or analytically robust. An appreciation of the value and limitations of biomarker use is important to all clinicians who manage HF patients. If the proper studies are done so that biomarkers are used optimally, they will likely be helpful in defining when and how to intervene. If we continue as we have, we will continue to have ambiguity about the use of these valuable probes in the assessment and management of HF.

Clinical implications of normal B-type natriuretic peptide levels in patients with severe chronic heart failure

Background: High plasma B-type natriuretic peptide (BNP) levels in patients with severe chronic heart failure (CHF) often indicate poor ventricular function and poor prognosis. However, in some such patients plasma BNP levels are normal.

Objective: To investigate the clinical implications of BNP levels in patients with severe CHF.

Methods: Fifty-seven patients with severe CHF were divided into group A (13 normal plasma BNP level) and 44 patients (high plasma BNP levels) group B. Diuretics, angiotensin-converting enzyme inhibitors (or angiotensin II receptor antagonist, e.g., metoprolol) and digitalis were used as conventional treatment. The clinical characteristics of all patients in two groups were analyzed and compared.

Results: At the first admission, left ventricular end diastolic diameter in group B was significantly lower than group A (p < 0.05), and the plasma BNP level in group B was significantly higher than group A (p < 0.05). When metoprolol was used, 6 and 5 patients in group A and B could not tolerate the initial dose. In other cases using metoprolol at average maximum tolerance dose of metoprolol 12.5-6.25 and 24.20-11.22 mg/day in group A and B, respectively, there was a significant difference between them (p < 0.05). There were no significant differences in plasma BNP levels between two groups during stable period. The plasma BNP level in group B during acute worsening stage was significantly higher than in the remission stage (962.73-165.00 ng/L vs 876.24-167.70 ng/L, p < 0.05). However, there was no significant difference between group A (74.03-11.18 ng/L) and group B (71.38-11.68 ng/L) (p > 0.05). The mobility of group A was higher than group B (11/12 vs 6/44, p < 0.05). Logistic regression analysis showed that, the plasma BNP level was the independent risk factor for predicting cardiac death (regression coefficient, 3.817; OR, 45.488; 95% CI, 5.322ʺ388.791).

Conclusion: In patients with severe CHF, normal plasma BNP level suggests depletion of BNP secretion and further deterioration of cardiac function, indicating a poor prognosis.

Serum miR-210 and miR-30a expressions tend to revert to fetal levels in Chinese adult patients with chronic heart failure

BACKGROUND

MicroRNAs (miRNAs) are widely involved in the process of chronic heart failure (HF), which is characterized by reactivation of the fetal gene program. Here, we examined whether the serum expression levels of some HF-related miRNAs in adult HF patients would tend to revert to fetal levels.

METHODS AND RESULTS

Serum was obtained from the peripheral venous blood of 22 HF patients, 18 asymptomatic controls, and the umbilical venous blood of 9 fetuses from 9 independent parturitions. Serum pools of the three groups were initially screened against 40 known HF-associated miRNAs via quantitative reverse transcriptase polymerase chain reaction. Twenty-seven miRNAs were stably expressed in the serum pools. Nine miRNAs showed similar expression levels in the HF and fetus groups compared to the controls, two of which (miR-210, miR-30a) were significantly up-regulated in both groups. These miRNAs showed high diagnostic accuracy and correlations with blood N-terminal prohormone of brain natriuretic peptide, identifying them as potential biomarkers for HF. Putative targets of the miRNAs were predicted with online software programs, and the Kyoto Encyclopedia of Genes and Genomes pathway analysis was employed to identify miRNA-regulated functional modules. In particular, miR-210 seemed to be more closely related than miR-30a to the pathological mechanisms of HF, including the calcium signaling, vascular smooth muscle contraction, transforming growth factor-β signaling, and aldosterone-regulated sodium reabsorption pathways.

CONCLUSION

The serum expression levels of some HF-related miRNAs in HF patients tended towards fetal levels. Among them, miR-210 and miR-30a were elevated in the HF and fetus groups.

Readmissions after implantation of axial flow left ventricular assist device

OBJECTIVES

The purpose of this study was to determine the occurrence and causes of readmissions after implantation of axial flow left ventricular assist device (LVAD).

BACKGROUND

Based on the REMATCH (Randomized Evaluation of Mechanical Assistance for the Treatment of Congestive Heart Failure) study experience, readmissions after LVAD implantation are thought to be frequent.

METHODS

We retrospectively analyzed admissions to our facility in a cohort of 115 patients implanted between January 2008 and July 2011 with the HeartMate II axial flow LVAD, of whom 42 were bridged to transplant. To account for repeated events, Andersen-Gill models were used to determine possible predictors.

RESULTS

The patients were followed for 1.4 ± 0.9 years. There were 224 readmissions in 83 patients. The overall readmission rate was 1.64 ± 1.97 per patient-year of follow-up. The readmission rate for the first 6 months was 2.0 ± 2.3 and decreased to 1.2 ± 2.1 during subsequent follow-up. Leading causes were bleeding (66 readmissions in 34 patients), mostly gastrointestinal bleed (51 in 27 patients), cardiac (51 in 36 patients, most for HF or arrhythmia), infections (32 in 25 patients) of which 6 were pump related, and thrombosis (20 in 15 patients) including 13 readmissions due to hemolysis. Preoperative variables associated with (fewer) readmissions in a multivariate model include residence within our hospital-extended referral zone of Minnesota and the neighboring states (hazard ratio: 0.66; 95% confidence interval: 0.48 to 0.91; p = 0.011), hemoglobin (hazard ratio: 0.91, 95% confidence interval: 0.84 to 0.99; p = 0.027) and N-terminal pro-B-type natriuretic peptide (hazard ratio: 0.98; 95% confidence interval: 0.96 to 1.0 per 1,000-unit increase, p = 0.022). C-statistic for the model: 0.63.

CONCLUSIONS

Readmission rates after axial flow LVAD implantation decrease during the first 6 months and then stabilize. The leading causes are bleeding, cardiac (heart failure and arrhythmia), infections, and thrombosis.

Who has advanced heart failure?: definition and epidemiology

Summarizing current guidelines and advanced heart failure (AHF) clinical trials/registries, this review focuses on the current definition of AHF and emphasizes the secular trends in this definition over the last two decades. Further, clinical, imaging, hemodynamic, functional capacity and biomarker parameters that may aid clinicians to better recognize patients with AHF are reviewed. Finally, we review the limited data concerning the epidemiology of AHF which to date has been poorly characterized.

Molecular risk stratification in advanced heart failure patients

Risk stratification in advanced heart failure (HF) is crucial for the individualization of therapeutic strategy, in particular for heart transplantation and ventricular assist device implantation. We tested the hypothesis that cardiac gene expression profiling can distinguish between HF patients with different disease severity. We obtained tissue samples from both left (LV) and right (RV) ventricle of explanted hearts of 44 patients undergoing cardiac transplantation or ventricular assist device placement. Gene expression profiles were obtained using an in-house microarray containing 4217 muscular organ-relevant genes. Based on their clinical status, patients were classified into three HF-severity groups: deteriorating (n= 12), intermediate (n= 19) and stable (n= 13). Two-class statistical analysis of gene expression profiles of deteriorating and stable patients identified a 170-gene and a 129-gene predictor for LV and RV samples, respectively. The LV molecular predictor identified patients with stable and deteriorating status with a sensitivity of 88% and 92%, and a specificity of 100% and 96%, respectively. The RV molecular predictor identified patients with stable and deteriorating status with a sensitivity of 100% and 96%, and a specificity of 100% and 100%, respectively. The molecular prediction was reproducible across biological replicates in LV and RV samples. Gene expression profiling has the potential to reproducibly detect HF patients with highest HF severity with high sensitivity and specificity. In addition, not only LV but also RV samples could be used for molecular risk stratification with similar predictive power.

Role for precursor Pro-B type natriuretic peptide in assessing response to therapy and prognosis in patients with decompensated heart failure treated with nesiritide

BACKGROUND

ProBNP, the precursor peptide to BNP and NT-proBNP (NP), circulates in patients with chronic heart failure (HF) and appears to be the predominant form of NP. This heterogeneity may confound interpretation of NP concentrations. The aim of this study was to evaluate the response to therapy and prognostic influence of proBNP in a cohort of patients admitted to hospital for decompensated HF.

METHODS

We prospectively evaluated 40 Class III-IV patients who received clinically-indicated nesiritide infusions as part of their care. Blood was drawn before, during, and post-infusion, and assayed for proBNP, BNP, and NT-proBNP.

RESULTS

All biomarkers were increased at baseline consistent with HF. ProBNP and NT-proBNP demonstrated significant reductions in response to therapy (42% and 18% post-infusion, respectively). In the patients who experienced post-hospital mortality (40% at 6 months), baseline proBNP and BNP concentrations were significantly lower than in survivors. This paradoxical finding may be explained by the end-stage nature of this patient cohort possibly experiencing exhaustion of their NP systems.

CONCLUSIONS

Circulating concentrations of proBNP are increased in decompensated HF and similar to NT-proBNP are reduced in response to acute therapy. Paradoxically and similar to BNP, baseline proBNP concentrations were lower in post-hospital non-survivors. While hypothesis generating, the results of this study support a role for proBNP in monitoring therapy and predicting short-term outcome. These findings need to be confirmed in a patient cohort without nesiritide therapy and more moderate HF.

Recent advances in atherosclerosis-based proteomics: new biomarkers and a future perspective

Vascular proteomics is providing two main types of data: proteins that actively participate in vascular pathophysiological processes and novel protein candidates that can potentially serve as useful clinical biomarkers. Although both types of proteins can be identified by similar proteomic strategies and methods, it is important to clearly distinguish biomarkers from mediators of disease. A particular protein, or group of proteins, may participate in a pathogenic process but not serve as an effective biomarker. Alternatively, a useful biomarker may not mediate pathogenic pathways associated with disease (i.e., C-reactive protein). To date, there are no clear successful examples in which discovery proteomics has led to a novel useful clinical biomarker in cardiovascular diseases. Nevertheless, new sources of biomarkers are being explored (i.e., secretomes, circulating cells, exosomes and microparticles), an increasing number of novel proteins involved in atherogenesis are constantly described, and new technologies and analytical strategies (i.e., quantitative proteomics) are being developed to access low abundant proteins. Therefore, this presages a new era of discovery and a further step in the practical application to diagnosis, prognosis and early action by medical treatment of cardiovascular diseases.

Only Large Reductions in Concentrations of Natriuretic Peptides (BNP and NT-proBNP) Are Associated with Improved Outcome in Ambulatory Patients with Chronic Heart Failure

Background: Concentrations of B-type natriuretic peptides (BNPs), including N-terminal pro-B-type natriuretic peptide (NT-proBNP), can be used to estimate prognosis in chronic heart failure. Large biologic variability, however, limits the usefulness of serial measurements in individual patients. As a result, the magnitude of change in peptide concentrations that is clinically meaningful remains to be established.

Methods: We studied 172 New York Heart Association class III–IV outpatients. Primary endpoints were death/transplantation or heart failure hospitalization. The magnitude of peptide changes was categorized as no change (&lt;20% increase or decrease from enrollment), ≥20% to ≤80% increase or decrease; and &gt;80% increase or decrease. Changes were also assessed using cutpoints (500 ng/L for BNP and 1000 ng/L for NT-proBNP).

Results: Fifty-two patients died or received transplants during the course of the study. Risk reduction for heart failure hospitalization was demonstrated only for BNP decreases of &gt;80% from enrollment [hazard ratio (HR) 0.318, P = 0.0315]. BNP increases from less than to more than the prespecified cutpoint of 500 ng/L were associated with increased mortality risk (HR 2.101, P = 0.0069), whereas decreases from more than to less than the cutpoint did not reduce risk. NT-proBNP decreases from more than to less than the cutpoint of 1000 ng/L were associated with reduced risk of death/transplantation (HR 0.119, P = 0.0354).

Conclusions: BNP increases from less than to more than the cutpoint were associated with increased risk of events, whereas further increases did not add to risk. In contrast, only substantial natriuretic peptide decreases (&gt;80%) reduced risk. These data suggest that only robust decreases in natriuretic peptide concentrations should be targeted to reduce mortality and heart failure-related hospitalizations.

Introduction of an NT-proBNP assay to an acute admission unit--a 2-year audit

BACKGROUND

The differential diagnosis of dyspnoea is difficult due to the low predictive value of clinical and laboratory parameters. The elevated levels of NT-proBNP in congestive heart failure may improve diagnostic accuracy. We have evaluated the effect of the introduction of an NT-proBNP assay on hospital length of stay (LOS) and mortality.

METHODS

There were 11,853 AMAU patient episodes in the 22 months study period (March 2005-Dec 2006). An NT-proBNP assay was requested in 657 (5.5%) of these. Comparison between categorical variables such as diagnosis, NT-proBNP testing, LOS, and in-hospital mortality was made using Chi-square tests. Literature review suggested that an NT-proBNP cut-off >or=5000 ng/L should predict acute in-patient mortality. Logistic regression analysis was used to examine the association between such an elevated NT-proBNP level and outcomes.

RESULTS

Of the 396 patients with NT-proBNP <5000 ng/L, 8.1% died compared with 22.5% of the 178 patients dying with values >or=5000 ng/L (p<0.0001). An NT-proBNP >or=5000 ng/L was predictive of both LOS >or=9 days (odds ratios (OR) 1.54 (95% CI 1.06, 2.24: p=0.02) and LOS >or=14 days (OR=1.87 (95% CI 1.29, 2.71: p=0.0009). NT-proBNP requests increased over time, from 2.6% to 8.2% of all patients; the result fell in the diagnostic range for CHF in 60% of requests.

CONCLUSION

The introduction of an NT-proBNP was reflected in an appropriate but rapidly increasing pattern of requests from clinicians. High NT-proBNP levels predicted in-hospital mortality and longer LOS in an acute medical population.

B-type natriuretic peptides in heart failure: update on clinical applications and limitations

Heart failure remains an important clinical and public health problem with significant mortality, morbidity and economic consequences. The identification of natriuretic peptides and the large number of investigations that followed have led to a better understanding of the neurohormonal pathophysiology of heart failure. The clinical usefulness of natriuretic peptides in heart failure diagnosis, prognosis and treatment guidance remains to be fully clarified but B-type natriuretic peptides and N-terminal pro-BNP appear to have an emerging role. Like any clinical test, the usefulness of natriuretic peptides measurements depends upon appropriate use and recognition of limitations. This review focuses on these issues.

Low plasma levels of brain natriuretic peptide in severe acute heart failure: Merely a case?

Brain natriuretic peptide (BNP) is commonly used for diagnosis and prognosis of patients with congestive heart failure (HF). High levels of BNP are associated with high probability of cardiogenic dyspnea and higher risk of subsequent cardiovascular events. We describe a case of acute HF (worsening chronic HF) in a 74-year-old male with low plasma BNP levels on admission, in whom a rapid and consistent increase in the marker's concentration occurred after administration of diuretics and vasodilators, despite a prompt clinical and hemodynamic improvement. Reports of cardiogenic dyspnea with moderate increase or normal plasma levels of BNP have been recently published: does this signify a pitfall for BNP as a useful diagnostic and prognostic tool? Clinical implications of our observation are discussed, and we conclude that neurohumoral biomarkers do not obviate the need for a careful physical and instrumental examination of patient.

Concentrations of brain natriuretic peptide in the plasma predicts outcomes of treatment of children with decompensated heart failure admitted to the Intensive Care unit

OBJECTIVES

It is known that levels of brain natriuretic peptide predict outcomes of treatment for adults with decompensated heart failure. We hypothesized that it could predict outcomes in children with this condition.

METHODS

We divided retrospectively 82 patients with serial measurements of brain natriuretic peptide into 3 groups: those who survived and did not need readmission within less than 60 days; those who survived but needed readmission within less than 60 days; and those who died in hospital or within less than 60 days. Initial and final levels of the peptide correlated with adverse outcomes.

RESULTS

The percent change in level of the peptide was minus 78 percent, minus 38 percent, and 138 percent in the readmission-free group, the readmitted, and nonsurviving groups, respectively. Final levels were significantly lower in the readmission-free group than in the readmitted and nonsurviving groups (p equals 0.013 and p is less than 0.00001, respectively) and in the readmitted group than in the nonsurvivors (p equals 0.013). On univariate analysis, the final level, the change in level, and the percentage change in level significantly predicted outcomes (p equals 0.0002, 0.0072 and 0.0005, respectively). On multivariate analysis, only the final level of the peptide significantly predicted outcomes (p equals 0.01).

CONCLUSIONS

A final level of brain natriuretic peptide of greater than or equal to 760 picograms per millilitre strongly predicted an adverse outcome. Patients with higher final levels may be at higher risk of death and readmission, suggesting that this variable effectively predicts the response to treatment and prognosis in children with heart failure.

A single health status question had important prognostic value among outpatients with chronic heart failure

OBJECTIVE

Health status is an important marker of the impact of disease on function among patients with chronic heart failure (CHF). However, the prognostic value of CHF-specific health status on long-term mortality has not been adequately evaluated. Our objective was to assess CHF-specific health status and 5-year mortality among outpatients with CHF.

STUDY DESIGN AND SETTING

We analyzed data from 494 Veterans Affairs outpatients with diagnoses of CHF and objective evidence of left ventricular dysfunction who enrolled in a quality improvement intervention. We extracted information about comorbid diagnoses, severity of illness (Charlson index), health care utilization, drug therapy, laboratory, and vital sign data along with generic and CHF-specific health status. We then identified multivariate correlates of subsequent mortality at 5 years.

RESULTS

Five-year mortality was 44%. Age (chi2=26.1, hazard ratio [HR]=1.63, confidence interval [CI]: 1.35, 1.97; P<0.0001) and Charlson index (chi2=12.9, HR=1.39, CI: 1.16, 1.67; P=0.0003) were significantly associated with 5-year mortality. Controlling for clinical, lab, medication, and administrative data, a single-item assessing change in CHF-specific health status was independently associated with 5-year mortality (chi2=11.4, HR=0.87, CI: 0.80, 0.94, P=0.0007).

CONCLUSIONS

Given the strength of the association with mortality, health care providers should routinely assess this single-item change in health status among outpatients with CHF to identify higher risk patients and guide therapy.

Serial biomarker measurements in ambulatory patients with chronic heart failure: the importance of change over time

BACKGROUND

Cardiac troponin T (cTnT) and B-type natriuretic peptide (BNP) have been used to estimate prognosis in heart failure; however, most studies have evaluated decompensated patients with single measurements. To determine if there are advantages to serial measurements, we evaluated stable chronic heart failure patients every 3 months for 2 years.

METHODS AND RESULTS

A cohort of 190 New York Heart Association class III-IV heart failure patients was prospectively enrolled from June 2001 to January 2004. Primary end points were death, cardiac transplantation, or hospitalization. At study enrollment cTnT was < 0.01 ng/mL in 87 (45.8%) patients, 0.01 to 0.03 ng/mL in 50 (26.3%) patients, and > 0.03 ng/mL in 53 (27.9%) patients. An increase in cTnT above normal (< 0.01 ng/mL) carried a 3.4-fold increased risk (P=0.019). Further increases (> or = 20%) from an elevated level worsened the overall risk (hazard ratio, 5.09; P<0.001). BNP was elevated (> 95th percentile for age and gender normal population) in 122 (64.2%) patients. An elevation of BNP from normal at any time during the study was associated with a poor outcome, but, once elevated, further changes in BNP (increases or decreases) remained associated with the same risk (hazard ratio, 5.09; P<0.001). Combined elevations of cTnT (> 0.03 ng/mL) and BNP defined the highest risk group (hazard ratio, 8.58; P<0.001).

CONCLUSIONS

Elevations of cTnT or BNP from normal detected at any time during clinical follow-up in ambulatory patients with chronic heart failure are highly associated with an increased risk of events. Further increases in cTnT contribute to additional risk. Combined elevations of cTnT and BNP contribute the highest risk. The ability to monitor changes by serial measurements adds substantially to the assessment of risk in this patient population.

Troponin, B-type natriuretic peptides and outcomes in severe heart failure: differences between ischemic and dilated cardiomyopathies

BACKGROUND

Ischemic (ISCM) and idiopathic dilated (IDCM) cardiomyopathies have different responses to therapy and outcomes. Both may demonstrate elevations in troponin and B-type natriuretic peptides, but biomarker levels have not been reported to differ as a function of the etiology of heart failure (HF). Accordingly, we compared these biomarkers in patients with chronic HF.

HYPOTHESIS

Biomarker levels of troponin T, troponin I, B-type natriuretic peptide (BNP), and N-terminal prohormone brain natriuretic peptide (NT-proBNP) are quantitatively different between ischemic and idiopathic dilated etiologies of chronic HF.

METHODS

Forty patients (27 male, 68 +/- 2 years; LVEF 25 +/- 1%; NYHA Class III-IV) admitted to hospital for acute HF were studied. Biomarkers were drawn at admission prior to treatment intervention.

RESULTS

Of the 40 patients, 27 had ISCM and 13 IDCM. Baseline clinical characteristics were similar with the exception of GFR. cTnT, cTnI, and BNP levels were higher in ISCM patients (cTnT: 0.373 +/- 0.145 vs. 0.064 +/- 0.016 ng/mL, p < 0.05; cTnI: 2.02 +/- 0.76 vs. 0.21 +/- 0.11 ng/mL, p < 0.05; BNP: 776 +/- 91 vs. 532 +/- 85 pg/mL, p < 0.05). Cardiovascular mortality during follow up (10 +/- 1 months) was 48% in patients with ISCM and 23% with IDCM (p < 0.05).

CONCLUSIONS

Patients with acutely decompensated chronic HF have elevations in troponin and BNP. These elevations, as well as mortality are significantly higher in patients with ISCM compared to IDCM. The differential levels in biomarkers may be due to differences in disease pathogenesis, and fit with the adverse prognosis in these patients.

Lack of association between worsening renal function and mortality in heart failure patients treated with nesiritide

BACKGROUND

Nesiritide is approved for the treatment of decompensated heart failure. Because nesiritide may exacerbate renal dysfunction, it has been claimed that there may be a link between worsening renal function caused by nesiritide and increased mortality.

AIMS

We analyzed our inpatient experience with nesiritide to determine if changes in renal function were associated with worsened mortality.

METHODS AND RESULTS

A retrospective study of 167 patients [65% male, median age 70 years, left ventricular ejection fraction (LVEF) 30%, glomerular filtration rate (GFR) 36 mL/min/1.73 m(2), serum creatinine (sCr)1.8 mg/dL] treated with standard dose nesiritide was undertaken for the period September 2001-March 2005. Mortality was 12.5% at 1 month and 51% at 24 months (median follow-up was 5.4 months [interquartile ranges (IQR) 1.3, 18.6]. Higher mortality was associated with lower pre-infusion GFR (hazard ratio for a 10 mL/min/1.72 m(2) decrease=1.22, p=0.004). Pre-to-post nesiritide changes in GFR (median 0.0, IQR-5.8, 8.4; p=0.51) and creatinine (median 0.0, IQR -0.3, 0.3; p=0.91), however, were not significant and not detected to be associated with worsened mortality by Cox proportional hazards (p=0.46 and p=0.40, respectively).

CONCLUSIONS

While we found that nesiritide infusion in decompensated heart failure patients worsened renal function (decrease in GFR) in 29% of patients, changes in renal function could not be related to an incremental worsening of mortality. Our findings do not support an association of worsening renal function and worsening mortality after nesiritide.

Alternate Circulating Pro-B-Type Natriuretic Peptide and B-Type Natriuretic Peptide Forms in the General Population

OBJECTIVES

This study was designed to determine whether alternate pro-B-type natriuretic peptide (proBNP) and BNP forms circulate in the general population.

BACKGROUND

Bioactive BNP(1-32) and NT-proBNP(1-76) are derived from a precursor molecule, proBNP(1-108). Recent data suggest that aminodipeptidase-processed forms of BNP(1-32) (BNP(3-32)) and of proBNP(1-108) itself (proBNP(3-108)) may circulate and have additional diagnostic potential.

METHODS

Residents (age > or =45 years) of Olmsted County, Minnesota, underwent medical review, echocardiography, and phlebotomy for 2 novel assays specific for proBNP(3-108) and BNP(3-32) and 2 commercial assays (Triage BNP and Roche NT-proBNP). Groups included normal subjects (n = 613), cardiovascular disease with normal ventricular function (n = 1,043), preclinical ventricular dysfunction (ALVD, n = 130), and chronic heart failure (HF, n = 52).

RESULTS

ProBNP(3-108) levels were above assay detection limits in 68% of normal subjects (50th; 25th to 75th percentiles: 7.85; 3.00 to 22.45 pmol/l) and correlated with age, gender, body size, and renal function and with results of commercial assays. ProBNP(3-108) levels were higher in ALVD (17.88; 6.07 to 42.76 pmol/l) or HF (42.75; 20.51 to 65.73 pmol/l), where they correlated more strongly with commercial assays. BNP(3-32) was above assay detection limits in 22% of normal subjects; levels were not correlated with age, body size, or renal function but were higher in HF. Neither novel assay was superior to commercial assays for the detection of ALVD or HF.

CONCLUSIONS

The presence of alternate circulating proBNP and BNP forms provides evidence for diverse proBNP and BNP processing in the general population. The physiologic consequences of these observations, both in terms of assay performance and endogenous BNP bioactivity, deserve further study.

Prognostic value of B-type natriuretic peptide in patients with chronic and advanced heart failure

BACKGROUND

An increase in circulating B-type natriuretic peptide (BNP) is associated with a poor outcome in patients with acute heart failure. The primary aim of this study was to investigate the prognostic value of BNP levels in patients with chronic and advanced heart failure.

METHODS

Fifty patients with New York Heart Association functional classes III and IV were enrolled in the study. Their blood BNP levels at admission were measured and patients were on follow up for 12 +/- 2 months.

RESULTS

There was no significant correlation between BNP levels on admission and left ventricular ejection fraction (r = 0.12, P > 0.05). Twelve patients (24%) died during the follow up. BNP levels were lower in patients who died (501 +/- 72 vs 877 +/- 89 ng/L, P < 0.01). The logistic stepwise regression analysis showed that lower BNP level (<520 ng/L) on admission was an independent predictor of cardiovascular mortality in these patients (odds ratio 1.21, 95% confidence interval 1.06-2.32, P < 0.01).

CONCLUSION

We conclude that patients with chronic and advanced heart failure have a lower circulating BNP level than those who survive. The paradoxically low BNP level is an adverse prognostic marker in advanced heart failure.

Low levels of B-type natriuretic peptide predict poor clinical outcomes in patients with chronic and advanced heart failure

B-type natriuretic peptide (BNP) is a neurohormone produced mainly by ventricular myocytes in response to increased left ventricular end-diastolic pressure. Patients with acute decompensated heart failure often have elevated plasma BNP. However, recent clinical observations have demonstrated that in patients with advanced heart failure, the plasma level of BNP is lower than those with acute heart failure. We hypothesized that a lower circulating BNP level in patients with chronic and advanced heart failure is due to the exhaustion of the biosynthesis mechanisms and is associated with a poor outcome in these patients.

Comparison of Abbott AxSYM and Roche Elecsys 2010 for measurement of BNP and NT-proBNP

BACKGROUND

B-type natriuretic peptide (BNP) and N-terminal pro-brain natriuretic peptide (NT-proBNP) are small cardiac hormones released from the heart. They can be used as an important aid to diagnose congestive heart failure (CHF).

METHODS

We compared the performances of the Abbott AxSYM and Roche Elecsys 2010 for the measurement of BNP and NT-proBNP. The first method uses a microparticle enzyme-linked immunoassay, whereas the other uses chemiluminescent immunometric assay.

RESULTS

The CVs using pooled sera ranged from 3.7% to 12.7% for the AxSYM and 0.9% to 2.2% for the Elecsys 2010. The Passing and Bablok regression was Elecsys 2010 NT-proBNP=7.23xAxSYM BNP+2.53. The BNP in EDTA plasma was more stable than in serum. The immunoreactivity difference of NT-proBNP in serum or EDTA plasma was within 10% when stored at 4 degrees Celsius or 25 degrees Celsius for 72 h. Receiver operating characteristic (ROC) curves were different for both assays, and the areas under the curves were 0.704 and 0.841 for the AxSYM and Elecsys 2010 method, respectively.

CONCLUSIONS

Both assays were not entirely specific for heart failure. The precision and stability for NT-proBNP was better than for BNP in serum. It is important to use method-appropriate reference ranges (or cutoff) for the BNP and NT-proBNP, respectively, in the assessment of CHF.

Biomarkers in acute cardiac disease: the present and the future

The use of biomarkers to aid diagnosis and treatment is increasing rapidly as genomics and proteomics help us expand the number of markers we can use and as an improved understanding of the pathophysiology of cardiac disease guides their use. However, as with all rapidly expanding fields, there is the risk of excessive enthusiasm unless we are circumspect about the data that guide the clinical use of these new tools. This review focuses first on how to use troponin, which at present is the best validated of the new markers, and will hopefully provide insight into how to use this biomarker more productively by distinguishing subsets of patients and by providing an understanding of the meaning of elevations in various clinical situations. The review then discusses the use as well as the knowledge gaps associated with emerging biomarkers such as B-type natriuretic peptide and C-reactive protein, which are increasingly moving toward more productive clinical use. Finally, it reflects on some of the large number of markers that are still in development.

Clinical relevance of biological variation: the lesson of brain natriuretic peptide (BNP) and NT-proBNP assay

The clinical relevance of brain natriuretic peptide (BNP) and N-terminal (NT)-proBNP assays as a diagnostic tool and prognostic marker in patients with cardiovascular diseases has recently been confirmed. However, several studies demonstrated variation of intra-individual BNP concentrations of >30% (ranging from 30% to 50%) with reference change values at the 95% confidence interval (i.e., the estimated critical difference) ranging from 99% to 130% in healthy subjects and heart failure patients. According to this estimated confidence interval, only a great variation in plasma BNP levels should be considered significant in an individual patient (for example, a decrease of >50% or an increase of more than two-fold). Many recent clinical studies have demonstrated that BNP variations below this estimated critical difference could also have clinical relevance. Like the concentration of other neuro-hormones, levels of plasma BNP fluctuate widely and rapidly along with heart rhythm and blood pressure variations in response to physiological stimuli. However, biological variation of BNP should not be interpreted strictly as random fluctuation around a homeostatic set point, as assumed by the common model used in all studies on biological variation of BNP reported in the literature. These results cannot be directly transferred to clinical practice. While awaiting more accurate studies, we suggest that variations of plasma BNP three-fold greater than the analytical imprecision should be considered as potentially relevant from a physiological and clinical point of view.