Brain Natriuretic Peptide in the Management of Heart Failure

Clinical value of combined plasma brain natriuretic peptide and serum cystatin C measurement on the prediction of heart failure in patients after acute myocardial infarction

This research investigated the predictive value of combined detection of brain natriuretic peptide (BNP) and cystatin C (Cys C) in heart failure after percutaneous coronary intervention (PCI) in patients with acute myocardial infarction (AMI). Sixty-five AMI patients complicated by heart failure (HF) after PCI and 79 non-heart failure (non-HF) patients were involved in this research. The levels of Cys C and BNP were measured. Risk factors for heart failure in AMI patients after PCI were analyzed by multivariate logistic regression analysis. Efficacy of BNP and Cys C on predicting heart failure were analyzed by receiver operating characteristic (ROC) curve. Cys C and BNP levels were significantly higher in the HF group than in the non-HF group. BNP and Cys C levels were the independent influencing factors causing heart failure within one year after PCI. The area under the predicted curve (AUC) of Cys C, BNP, and combined Cys C and BNP were 0.763, 0.829, and 0.893, respectively. The combined detection of Cys C and BNP was highly valuable in predicting heart failure in AMI patients after PCI, which can be regarded as the serum markers for diagnosis and treatment of heart failure.

Relationship between free fatty acids, body mass index and depressive symptoms in patients with chronic heart failure

AIM

To explore the prevalence of depressive symptoms among patients with chronic heart failure (CHF) and analyse the relationship between free fatty acids (FFAs), body mass index (BMI) and depressive symptoms among patients with CHF.

DESIGN

A cross-sectional study.

METHODS

Questionnaires were distributed to 200 patients with CHF in the department of Cardiology at a tertiary first-class hospital in Shandong province. A total of 195 hospitalized patients completed the survey. Data collected from February 2017-November 2017 were analysed by using Pearson's correlation and multiple linear regression. The depressive status of the patients was assessed by the Zung Self-rating Depression Scale (SDS), and the relationships between FFA, BMI and depressive symptoms were analysed using SPSS 20.0.

RESULTS

The results showed that 71.28% CHF patients have depressive symptoms. The serum FFA level was significantly higher in CHF patients with depressive symptoms than those without depressive symptoms (p = .003), and FFA level was significantly positively correlated with the SDS score (r = .242, p = .001). The differences in SDS scores were statistically significant between two different BMI groups (p < .01), and BMI was negatively correlated with the SDS score (r = -.139, p = .040). Regression analysis showed that high FFAs (β = 0.184, p = .009) and low BMI (β = -0.116, p = .049) were risk factors for depressive symptoms in CHF patients. Gender, age, FFA and BMI were associated with depressive symptoms, accounting for 7.1% of the variance in depressive symptoms.

CONCLUSIONS

The prevalence of depressive symptoms in CHF patients is very high, and high FFAs and low BMI are risk factors for depressive symptoms. Targeted interventions to strengthen nutritional support in CHF patients may be benefit to improve depression-related outcomes.

A prospective study of the impact of AGTR1 A1166C on the effects of candesartan in patients with heart failure

AIM

To evaluate the impact of AGTR1 A1166C (rs5186) on the response to candesartan in patients with heart failure.

MATERIALS & METHODS

Prospective, multicentre, open-label study. We studied 299 symptomatic patients with heart failure presenting a left ventricular ejection fraction ≤40%.

RESULTS

Reductions in the primary end points of natriuretic peptides were not significantly associated with AGTR1 A1166C. Nevertheless, carrying the 1166C allele was associated with a greater compensatory increase in renin activity (p = 0.037) after 16 weeks of treatment with candesartan and a more modest effect on aldosterone concentrations (p = 0.022).

CONCLUSION

AGTR1 1166C carriers may experience a greater long-term compensatory renin-angiotensin-aldosterone system activation following treatment with candesartan. Whether these associations ultimately influence clinical outcomes requires investigation. Clinicaltrials.gov : NCT00400582.

NT-proBNP and Echocardiographic Parameters in Patients with Acute Heart Failure

Aim. The aim of this study was to analyse the relation between clinical, haemodynamic and X-ray parameters and plasma NT-proBNP level in pts with symptoms of left ventricular dysfunction. Methods. The plasma NT-proBNP levels, chest x-ray, transthoracic 2-d and Doppler echocardiography were performed at the time of admission in a group of 96 consecutive patients (mean age 68 ± 11 years) with symptoms of acute heart failure. NT-proBNP levels were assessed with the use of commercial tests (Roche Diagnostics). Results. All patients have significant increase in NT-proBNP (8 000 ± 9 000 pg/mL vs. controls 90 ± 80 pg/mL, p < 0.001). The group of all patients has shown a significant increase in cardiothoracic ratio (CTR, 0.6 ± 0.1, vs. 0.4 ± 0.1, p <0.001), left atrium diameter (LAD, 4.4 ± 0.8 cm, vs.3.5 ± 0.4 cm, p <0.01). Left ventricular ejection fraction (LVEF) was decreased (37 ± 15%, vs. 64 ± 5%, p <0.001). In patients with acute heart failure, NT-proBNP significantly correlated with end-systolic and end-diastolic left ventricle diameters, ejection fraction, vena cava inferior diameter and plasma creatinine levels. Conclusion. Increased plasma NT-proBNP level is influenced by the clinical severity of acute heart failure and correlates with LVEF and IVCD. NT-proBNP can serve as a marker for the clinical severity of the disease.

Concurrence of Inappropriate Antidiuretic Hormone Secretion and Cerebral Salt Wasting Syndromes after Traumatic Brain Injury

Syndrome of inappropriate antidiuretic hormone (SIADH) and cerebral salt wasting syndrome (CSWS) as the two most common neuroendocrine diseases, have been recognized and understood by many neurologists. Although SIADH and CSWS are the common causes of central hyponatremia after traumatic brain injury (TBI), a few cases are mixed, with the coexistence of the two pathological pathomechanism. However, the mixed type of both SIADH and CSWS has not been clearly reported in any literature. Here, we present the first description of the concurrent syndrome of SIADH and CSWS after TBI in four patients who underwent standard diagnostic procedures, treatment and follow up. Our findings further support that this rare neuroendocrine disease may exist in clinical practice, in which the traditional-conventional treatment shows poor efficacy.

The multifaceted role of natriuretic peptides in metabolic syndrome

Due to globalization and sophisticated western and sedentary lifestyle, metabolic syndrome has emerged as a serious public health challenge. Obesity is significantly increasing worldwide because of increased high calorie food intake and decreased physical activity leading to hypertension, dyslipidemia, atherosclerosis, and insulin resistance. Thus, metabolic syndrome constitutes cardiovascular disease, type 2 diabetes, obesity, and nonalcoholic fatty liver disease (NAFLD) and recently some cancers are also considered to be associated with this syndrome. There is increasing evidence of the involvement of natriuretic peptides (NP) in the pathophysiology of metabolic diseases. The natriuretic peptides are cardiac hormones, which are produced in the cardiac atrium, ventricles of the heart and the endothelium. These peptides are involved in the homeostatic control of body water, sodium intake, potassium transport, lipolysis in adipocytes and regulates blood pressure. The three known natriuretic peptide hormones present in the natriuretic system are atrial natriuretic peptide (ANP), brain natriuretic peptide (BNP) and c-type natriuretic peptide (CNP). These three peptides primarily function as endogenous ligands and mainly act via their membrane receptors such as natriuretic peptide receptor A (NPR-A), natriuretic peptide receptor B (NPR-B) and natriuretic peptide receptor C (NPR-C) and regulate various physiological and metabolic functions. This review will shed light on the structure and function of natriuretic peptides and their receptors and their role in the metabolic syndrome.

Clinical Utility of B-Type Natriuretic Peptide in Early Severe Sepsis and Septic Shock

B-type natriuretic peptide (BNP) has diagnostic, therapeutic, and prognostic utility in critically ill patients. For severe sepsis and septic shock patients in particular, similar clinical utility from the most proximal aspects of hospital presentation to the intensive care unit has not been examined. BNP levels were measured at 0, 3, 6, 12, 24, 36, 48, 60, and 72 hours in 252 patients presenting to the emergency department with severe sepsis and septic shock. The clinicians were blinded to the BNP levels. Elevated BNP levels (>100 pg/mL) were seen in 42% and 69% of patients on presentation and at 24 hours, respectively. Elevated BNP ranges (>230 pg/mL) were significantly associated with myocardial dysfunction and severity of global tissue hypoxia. When adjusted for age, gender, history of heart failure, renal function, organ dysfunction, and mean arterial pressure, a BNP greater than 210 pg/mL at 24 hours was the most significant independent indicator of increased mortality: odds ratio 1.061 (1.026-1.097), P < .001, 95% confidence interval. Patients with severe sepsis and septic shock often have elevated BNP levels, which are significantly associated with organ and myocardial dysfunction, global tissue hypoxia, and mortality. Serial BNP levels may be a useful adjunct in the early detection, stratification, treatment, and prognostication of high-risk patients.

The Significance of Elevated Brain Natriuretic Peptide Levels in Chronic Obstructive Pulmonary Disease

We investigated the clinical significance of brain natriuretic peptide (BNP), a cardiac hormone, in chronic obstructive pulmonary disease (COPD). Subjects were 38 patients with stable COPD, of whom 20 had cor pulmonale (CP), and 22 were healthy individuals. Plasma BNP levels were measured and pulmonary arterial pressure (PAP) was estimated by echocardiography. Arterial blood gas analysis, forced vital capacity (FVC) and forced expiratory volume in 1 s (FEV1) were also recorded. BNP levels of patients with COPD were higher than those of controls (48.2 ± 37.5 and 9.3 ± 3.0 pg/ml). Patients with CP had a higher mean BNP level with respect to those without CP (73.9 ± 35.8 and 21.0 ± 10.2 pg/ml, respectively). BNP levels correlated with PAP ( r = 0.68), partial arterial oxygen pressure ( r = −0.70), FEV1 ( r = −0.65) and FVC ( r = −0.52). We have concluded that BNP determination has a role in the diagnosis of CP in patients with COPD.

The effects of wenxin keli on left ventricular ejection fraction and brain natriuretic Peptide in patients with heart failure: a meta-analysis of randomized controlled trials

Objective. To evaluate the beneficial and adverse effects of Wenxin Keli (WXKL), either alone or in combination with Western medicine, on the left ventricular ejection fraction (LVEF) and plasma brain natriuretic peptide (BNP) in the treatment of heart failure (HF). Methods. Seven major electronic databases were searched to retrieve potential randomized controlled trials (RCTs) designed to evaluate the clinical effectiveness of WXKL, either alone or in combination with Western medicine, for HF, with the LVEF or BNP after eight weeks of treatment as main outcome measures. The methodological quality of the included studies was assessed using criteria from the Cochrane Handbook for Systematic Review of Interventions, Version 5.1.0, and analyzed using RevMan 5.1.0 software. Results. Eleven RCTs of WXKL were included. The methodological quality of the trials was generally evaluated as low. The risk of bias was high. The results of the meta-analysis showed that WXKL, either alone or in combination with Western medicine, was more effective in LVEF and BNP, compared with no medicine or Western medicine alone, in patients with HF or HF complicated by other diseases. Five of the trials reported adverse events, while the others did not mention them, indicating that the safety of WXKL remains uncertain. Conclusions. WXKL, either alone or in combination with Western medicine, appears to be more effective in improving the LVEF and BNP in patients with HF and HF complications.

Role of B-type natriuretic peptide as a marker of mortality in acute kidney injury patients treated with continuous renal replacement therapy

OBJECTIVES

Acute kidney injury (AKI) treated with continuous renal replacement therapy (CRRT) is associated with poor outcome. Plasma B-type natriuretic peptide (BNP) is a biomarker related to fluid volume overload, and is elevated in AKI patients. The purpose of the study was to assess whether BNP levels at the time of starting CRRT could be used as a predictor of mortality in patients with AKI receiving CRRT.

METHODS

We conducted a prospective observational cohort study enrolling 149 patients with AKI receiving CRRT. The primary outcome was mortality during CRRT.

RESULTS

The median BNP level of 84 (56.3%) patients who expired was significantly higher than that of those who survived (1812.5 vs. 475.0 pg/mL; p = 0.01). Receiver operating characteristic curves demonstrated BNP levels as a predictor of mortality during CRRT with an area under the curve of 0.77 (p = 0.000), and the optimal threshold for BNP was 1054 pg/mL. Patients with BNP levels above 1054 pg/mL had a significantly higher mortality (76.6 vs. 34.7%; p = 0.01).

CONCLUSION

Elevated BNP level is associated with mortality in patients with AKI receiving CRRT.

Relationship between CT findings and the plasma levels of brain natriuretic peptide in 29 patients with acute cardiogenic pulmonary edema

RATIONALE AND OBJECTIVES

Brain natriuretic peptide (BNP) is a useful biomarker for the assessment of cardiogenic pulmonary edema. This study evaluated the relationship between computed tomography (CT) findings and plasma BNP levels in patients with cardiogenic pulmonary edema.

MATERIALS AND METHODS

Twenty-nine consecutive outpatients with severe respiratory failure from cardiogenic edema presenting to emergency departments were enrolled. They underwent chest CT and plasma BNP levels were measured in the emergency room. CT findings were independently evaluated by two radiologists who were unaware of the patients' clinical information.

RESULTS

The plasma BNP levels only correlated with the volume of pleural effusion in each side (right: r(s) = 0.519, P = .004; left: r(s) = 0.460, P = .012). No significant correlation was observed between the BNP levels and the findings of lung parenchyma or cardiovascular enlargement.

CONCLUSION

Estimating the pleural effusion volume with CT may be a feasible method as well as measuring the plasma BNP level in the assessment of acute cardiogenic pulmonary edema.

Diastolic function in pregnant patients with cardiac symptoms

OBJECTIVE

Dyspnea on exertion and peripheral edema occur routinely during normal gestational stage, making early diagnosis of congestive heart failure (CHF) during pregnancy difficult. Abnormal left ventricular (LV) diastolic function may be associated with dyspnea on exertion and peripheral edema, and brain natriuretic peptide (BNP) correlates with volume overload in nonpregnant populations. We tested the hypothesis that abnormal echocardiographic diastolic parameters and elevated BNP correlate in symptomatic pregnant patients.

METHODS

Sixty-six gravidas presented to an Obstetric Cardiology Clinic were analyzed. Data including symptoms of CHF, BNP, and maternal and gestational ages were recorded. Echocardiograms were reviewed to measure the diastolic parameters E, A, e', and a' wave velocities and left atrial volume index (LAVI). Logistic regression was performed to characterize the relationship between diastolic parameters and BNP.

RESULTS

Among the 66 pregnant patients included in the analysis, only 6 were found to have significant LV systolic dysfunction. LAVI, E, and E/e' ratio correlated positively with BNP in this symptomatic population (p = 0.008, 0.007, and 0.002, respectively).

CONCLUSIONS

Abnormal diastolic parameters that represent increased LV filling pressures correlated with higher BNP levels in pregnant patients with symptoms of CHF. This suggests that symptoms may be due to diastolic dysfunction, and BNP levels may identify elevated LV filling pressures in symptomatic pregnant patients.

[Evaluation of contractility and postloading in the intensive care unit]

Cardiovascular failure is a common disorder in critical care medicine. When admitted to the ICU, patients with hemodynamic deterioration should be examined rapidly to correctly assess the main determinants of cardiovascular function (preload, afterload and contractility). This review examines the assessment of contractility and afterload involving the combined use of several hemodynamic monitors, which allows different approaches to the same problem, with a view to improving the efficiency of management and treatment in critically ill patients.

Catestatin is useful in detecting patients with stage B heart failure

Screening patients with stage B heart failure(HF) may be one strategy for reducing human morbidity. To describe catestatin levels in different stages of HF and evaluate the diagnostic utility of catestatin for detecting stage B HF, we included 300 patients. Catestatin, BNP testing and echocardiogram were performed. Our studies showed catestatin decreased gradually from stage A to C. There was significant difference between stage A and B. Cutoff value for detecting stage B HF was 19.73 ng/ml for catestatin with 90% sensitivity and 50.9% specificity. These results may have implications in the new method to detect patients with stage B HF.

Evaluation of intraoperative brain natriuretic peptide as a predictor of 1-year mortality after liver transplantation

BACKGROUND

Although brain natriuretic peptide (BNP), a marker of cardiac dysfunction, has been known to predict postoperative mortality, little is known about the postoperative prognostic ability of BNP in liver transplantation (OLT) recipients. We aimed to determine whether intraoperative BNP level can predict 1-year all-cause mortality after OLT.

METHODS

We retrospectively investigated 525 OLT recipients. BNP and hemodynamic parameters were simultaneously measured 1 hour after induction of anesthesia. Cox regression analysis and receiver operating characteristic curve analysis were performed to determine clinical predictors and optimal cutoff values of post-OLT mortality.

RESULTS

The 1-year all-cause mortality rate was 9.7% (51/525). Median BNP concentration was significantly higher in nonsurvivors than in survivors (114 vs 56 pg/mL, P < .001). Significant factors in univariate Cox regression analysis were Child-Pugh score, model for end-stage liver disease (MELD) score, logBNP, hemoglobin, creatinine, heart rate, systolic pulmonary arterial pressure, and central venous pressure. In multivariate Cox regression analysis, independent predictors of posttransplant mortality were MELD score and logBNP. However, simultaneously measured hemodynamic parameters did not remain predictors. BNP levels greater than a cutoff of 136 pg/mL (specificity = 83.5%, negative predictive value = 93.6%) were associated with increased post-OLT mortality (log-rank test P < .001).

CONCLUSIONS

Intraoperative BNP level is an independent predictor of 1-year all-cause mortality after OLT with a high negative predictive value, suggesting that its measurement appears useful in identifying patients at low risk of post-OLT mortality.

Dietary salt exacerbates isoproterenol-induced cardiomyopathy in rats

Spontaneously hypertensive heart failure rats (SHHFs) take longer to develop compensated heart failure (HF) and congestive decompensation than common surgical models of HF. Isoproterenol (ISO) infusion can accelerate cardiomyopathy in young SHHFs, while dietary salt loading in hypertensive rats induces cardiac fibrosis, hypertrophy, and--in a minority-congestive HF. By combining ISO with dietary salt loading in young SHHFs, the authors sought a nonsurgical model that is more time--and resource-efficient than any of these factors alone. The authors hypothesized that salt loading would enhance ISO-accelerated cardiomyopathy, promoting fibrosis, hypertrophy, and biochemical characteristics of HF. SHHFs (lean male, 90d) were infused for 4 wk with ISO (2.5 mg/kg/day) or saline. After 2 wk of infusion, a 6-wk high-salt diet (4%, 6%, or 8% NaCl) was initiated. Eight percent salt increased heart weight, HF markers (plasma B-type natriuretic peptide, IL-6), lung lymphocytes, and indicators of lung injury and edema (albumin and protein) relative to control diet, while increasing urine pro-atrial natriuretic peptide relative to ISO-only. High salt also exacerbated ISO-cardiomyopathy and fibrosis. Thus, combining ISO infusion with dietary salt loading in SHHFs holds promise for a new rat HF model that may help researchers to elucidate HF mechanisms and unearth effective treatments.

Prognostic utility of NT-proBNP in acute exacerbations of chronic pulmonary diseases

BACKGROUND

The prognostic value of NT-proBNP levels in patients admitted to hospital due to acute exacerbations of chronic pulmonary diseases (CPDs) is unknown.

SETTING

Internal Medicine units at two general hospitals.

METHODS

NT-proBNP levels were obtained within 72 h after admission in 192 consecutive patients with acute exacerbations of CPDs and no history of heart failure or diuretic treatment. Clinical characteristics and main outcomes were assessed over a 12-month follow-up. NT-proBNP cut-points for outcomes were obtained by ROC (receiver operating characteristics) curve analysis.

RESULTS

Chronic obstructive lung disease (69.3%) and chronic asthma (22.4%) were the most prevalent CPDs, and non-pneumonic acute respiratory infection (72.4%) and pneumonia (22.9%) were the most frequent causes of exacerbation. Atrial flutter or fibrillation rate was 11%. During the one-year follow-up period, 22 patients died, 42 were re-admitted, 46 received new long-term oxygen therapy, and 39 received new diuretic treatment. NT-proBNP values correlated with hospitalisation days. NT-proBNP values over 587.9 pg/ml were associated with significantly raised one-year mortality (OR=3.90; 95% IC 1.46-10.47; p=0.006) and over 782.2 pg/ml with cardio-pulmonary deaths (OR=6.38; 95% IC 1.91-21.3; p=0.002). That association persisted after adjustment for age, gender, creatinine levels and cardiac rhythm. NT-proBNP values over 628.7 pg/ml were associated with significantly higher probability of new diuretic treatment (OR=4.38; IC 95% 2.07-9.25; p<0.001). The negative predictive values for these cut-points ranged from 89% to 97%.

CONCLUSION

NT-proBNP levels below 587.9 pg/ml in patients with acute exacerbations of CPD were associated with favourable one-year outcomes.

Hyponatremia and brain injury: absence of alterations of serum brain natriuretic peptide and vasopressin

OBJECTIVE

To study any possible relation between hyponatremia following brain injury and the presence of cerebral salt-wasting syndrome (CSWS) or the syndrome of inappropriate secretion of antidiuretic hormone (SIADH), and if vasopressin, brain natriuretic peptide (BNP) and aldosterone have a role in its mechanism.

METHOD

Patients with brain injury admitted to the intensive care unit were included and had their BNP, aldosterone and vasopressin levels dosed on day 7.

RESULTS

Twenty six adult patients were included in the study. Nine (34.6%) had hyponatremia and presented with a negative water balance and higher values of urinary sodium, serum potassium and diuresis than patients with normonatremia. The serum levels of BNP, aldosterone, and vasopressin were normal and no relation was observed between plasma sodium and BNP, aldosterone or vasopressin.

CONCLUSION

The most likely cause of hyponatremia was CSWS and there was no correlation between BNP, aldosterone and vasopressin with serum sodium level.

Nesiritide following maze and mitral valve surgery

BACKGROUND

Fluid retention following "maze" and mitral valve surgery has been associated with diminished levels of atrial natriuretic peptide (ANP). We hypothesized prophylactic administration of nesiritide (human recombinant brain natriuretic peptide, NES, Natrecor, Scios, Fremont, CA, USA), which has similar physiologic properties to ANP and would promote diuresis in maze and mitral patients postoperatively.

METHODS

Randomized, blinded, prospective pilot study comparing patients undergoing maze and mitral surgery including excision of the left atrial appendage. Three hours after cardiopulmonary bypass, patients received either a 72-hour infusion of NES at 0.01 mcg/kg/min (n = 9) or placebo (n = 10). Diuresis, diuretics, time to extubation, oxygenation, ANP, and serum Endothelin-1 levels were measured. Nonparametric analysis with Mann-Whitney test was performed with SPSS (SPSS Inc., Chicago, IL, USA).

RESULTS

In both groups, postoperative ANP levels fell from baseline (NES 330 to 280 ng/mL and control 220 to 150 ng/mL). There were no significant differences in patients receiving NES compared to controls in diuresis (1.33 mL/kg/hour urine output NES vs. 1.68 mL/kg/hour controls, p = 0.14); furosemide dosage (0.04 mg/kg/hour NES vs. 0.04 mg/kg/hour controls, p = 0.08); time to extubation (17.5 hours NES vs. 19.5 control, p = 0.42) or PaO2/FiO2 ratio at 48 hours (NES 200 vs. 273 control, p > 0.05). Endothelin-1 levels were higher at baseline with NES but not at 1 and 72 hours after cardiopulmonary bypass (NES 3.1, 3.8, 2.9 pg/mL vs. control 1.85, 4.05, 2.75 pg/mL; p = 0.01, 0.77, 0.47).

CONCLUSIONS

This pilot study did not demonstrate additional diuresis with nesiritide in postoperative mitral/maze patients already following a loop diuretic protocol.

B type natriuretic peptide--a diagnostic breakthrough in peri-operative cardiac risk assessment?

The B-type natriuretic peptides; B-type natriuretic peptide and N-terminal pro-B-type natriuretic peptide, are increasing being used as biomarkers for the diagnosis, management and prognostication of cardiac failure, but their application in the peri-operative period is unclear. This review examines the current understanding of the role of B-type natriuretic peptides in both the operative and non-operative settings. Normal values, diagnostic thresholds, monitoring targets and significant prognostic levels are identified. Using this as a background, the role of B-type natriuretic peptides in the prediction of peri-operative mortality and morbidity is examined and potential confounders, such as renal failure and body mass index, which may impact significantly on the utility of the biomarkers, are discussed. Clinical recommendations with regard to its use are made and a research agenda is proposed for future peri-operative studies.

Effects of AGTR1 A1166C gene polymorphism in patients with heart failure treated with candesartan

BACKGROUND

The benefits of angiotensin II receptor blockers (ARBs) in patients with heart failure who are treated with standard pharmacotherapy, including an angiotensin-converting enzyme (ACE) inhibitor, were demonstrated in 2 large randomized trials. It is currently impossible to determine which patient will benefit from the addition of an ARB.

OBJECTIVE

To explore the impact of selected candidate genes on the hemodynamic, neurohormonal, and antiinflammatory effects of candesartan in patients with heart failure who are already being treated with an ACE inhibitor.

METHODS

We investigated the impact of 10 candidate genetic polymorphisms on the effects of candesartan in patients with heart failure who are treated with an ACE inhibitor. We evaluated their impact on acute (2 wk) and long-term (24 wk) changes in blood pressure and N-terminal proB-type natriuretic peptide (NT-proBNP) and high sensitivity C-reactive protein (hsCRP) during treatment with candesartan.

RESULTS

Thirty-one patients were included. Homozygotes of the AGTR1 A1166 allele (n = 13) had a greater decrease in systolic (-9.1 +/- 4.7 vs 1.1 +/- 3.3 mm Hg; p = 0.04 by analysis of variance [ANOVA], adjusting for dose) and diastolic blood pressure (-5.1 +/- 1.5 vs 1.9 +/- 1.9 mm Hg; p = 0.005 by ANOVA, adjusting for dose) compared with C1166 allele carriers (n = 18) following 2 weeks of treatment. After 6 months of treatment, C1166 carriers experienced a greater decrease in NT-proBNP (-151.4 [-207; -19.8] ng/L vs 147.3 [-61.3; 882.9] ng/L; p = 0.03) and hsCRP (-0.8 [-2.2; -0.03] mg/L) vs 0.2 [-1.8; 5.3] mg/L; p = 0.09) compared with patients carrying the AA1166 genotype. No other significant association was found.

CONCLUSIONS

The results of this proof-of concept study provide the first evidence that the AGTR1 A1166C polymorphism could influence the response to candesartan in patients with heart failure who are receiving ACE inhibitors. Validation of these exploratory findings in larger populations is required before use of the AGTR1 A1166C genotype can be incorporated into clinical practice.

Molecular regulation of cardiac hypertrophy

Heart failure is one of the leading causes of mortality in the western world and encompasses a wide spectrum of cardiac pathologies. When the heart experiences extended periods of elevated workload, it undergoes hypertrophic enlargement in response to the increased demand. Cardiovascular disease, such as that caused by myocardial infarction, obesity or drug abuse promotes cardiac myocyte hypertrophy and subsequent heart failure. A number of signalling modulators in the vasculature milieu are known to regulate heart mass including those that influence gene expression, apoptosis, cytokine release and growth factor signalling. Recent evidence using genetic and cellular models of cardiac hypertrophy suggests that pathological hypertrophy can be prevented or reversed and has promoted an enormous drive in drug discovery research aiming to identify novel and specific regulators of hypertrophy. In this review we describe the molecular characteristics of cardiac hypertrophy such as the aberrant re-expression of the fetal gene program. We discuss the various molecular pathways responsible for the co-ordinated control of the hypertrophic program including: natriuretic peptides, the adrenergic system, adhesion and cytoskeletal proteins, IL-6 cytokine family, MEK-ERK1/2 signalling, histone acetylation, calcium-mediated modulation and the exciting recent discovery of the role of microRNAs in controlling cardiac hypertrophy. Characterisation of the signalling pathways leading to cardiac hypertrophy has led to a wealth of knowledge about this condition both physiological and pathological. The challenge will be translating this knowledge into potential pharmacological therapies for the treatment of cardiac pathologies.

Acute heart failure syndromes: clinical scenarios and pathophysiologic targets for therapy

Acute heart failure syndromes (AHFS) represent the most common discharge diagnosis in patients over age 65 years, with an exceptionally high mortality and readmission rates at 60-90 days. Recent surveys and registries have generated important information concerning the clinical characteristics of patients with AHFS and their prognosis. Most patients with AHFS present either with normal systolic blood pressure or elevated blood pressure. Patients who present with elevated systolic blood pressure usually have pulmonary congestion, a relatively preserved left ventricular ejection fraction (LVEF), are often elderly women, and their symptoms develop typically and abruptly. Patients with normal systolic blood pressure present with systemic congestion, reduced LVEF, are usually younger with a history of chronic HF, and have symptoms that develop gradually over days or weeks. In addition to the abnormal hemodynamics (increase in pulmonary capillary wedge pressure and/or decrease in cardiac output) that characterize patients with AHFS, myocardial injury, which may be related to a decrease in coronary perfusion and/or further activation of neurohormones and renal dysfunction, probably contributes to short-term and post-discharge cardiac events. Patients with AHFS also have significant cardiac and noncardiac underlying conditions that contribute to the pathogenesis of AHFS, including coronary artery disease (ischemia, hibernating myocardium, and endothelial dysfunction), hypertension, atrial fibrillation, and type 2 diabetes mellitus. Therefore, the targets of therapy for AHFS should be not only to improve symptoms and hemodynamics but also to preserve or improve renal function, prevent myocardial damage, modulate neurohumoral and inflammatory activation, and to manage other comorbidities that may cause and/or contribute to the progression of this syndrome.

Effects of combined candesartan and ACE inhibitors on BNP, markers of inflammation and oxidative stress, and glucose regulation in patients with symptomatic heart failure

BACKGROUND

We assessed the effects of candesartan in addition to angiotensin-converting enzyme (ACE) inhibitors on N-terminal pro-type natriuretic peptide (Nt-proBNP), systemic markers of inflammation and oxidative stress as well as on glucose regulation in patients with heart failure (HF).

METHODS AND RESULTS

Eighty patients with HF ages 62.5 +/- 8.4 years presenting mostly with New York Heart Association class II symptoms (class II = 57.5%, III = 41.3%), and mean left ventricular ejection fraction 27.1 +/- 7.3% were recruited. The patients were randomized to receive candesartan titrated to 32 mg 1 per day versus placebo in double-blind fashion for 6 months. Nt-proBNP, markers of inflammation and oxidative stress, glucose, insulin, and fasting insulin resistance index were analyzed. Candesartan decreased Nt-proBNP (median value = 12.4% versus -20.4%; [candesartan] P = .05), and high-sensitivity C-reactive protein (hsCRP) (+5.32% versus -20.3% [candesartan]; P = 0.046), without significantly influencing serum interleukin-6, interleukin-18, adhesion molecules, or markers of oxidative stress. Blood glucose decreased in patients treated with candesartan with a significantly greater effect in patients with higher blood glucose levels (P < .01 for interaction).

CONCLUSIONS

The addition of candesartan to ACE inhibitor and beta-blocker decreases Nt-proBNP and hsCRP, but does not change the other markers of inflammation or oxidative stress in patients with heart failure. Dual angiotensin-II suppression also decreased blood glucose with a greater impact in patients with higher blood glucose level.

Administration of brain natriuretic peptide improves cardiac function following operations using extracorporeal circulation in an animal model

The critical phase during cardiosurgical procedures is weaning the diseased heart from the ECC (extracorporeal circulation). Post-ischaemic heart failure sometimes requires the administration of inotropic and/or vasconstrictive agents. The natriuretic peptides influence pre- and after-load through their natriuretic, diuretic and vasodilating actions. To date, there are only a few reports describing the therapeutic effect of BNP (brain natriuretic peptide) administration during cardiosurgical procedures. The aim of the present study was to evaluate the effect of BNP administration following ECC in an animal model. Surgery was performed on 20 pigs using ECC. A 30-min ischaemic episode was simulated. Following de-clamping, BNP was administered to the BNP group (n=10) by an i.v. (intravenous) bolus at 0.3 microg x kg(-1) of body weight x min(-1), followed by an infusion at a rate of 0.015 microg x kg(-1) of body weight x min(-1) for 60 min. The animals in the control group (n=10) received a saline solution instead of BNP. Haemodynamic and clinical chemistry parameters as well as the amount of catecholamines that were required were measured. All of the animals in the BNP group had a significantly better cardiac output and cardiac index at the end of the experiment. Seven out of 10 animals from the control group required catecholamines, whereas only one animal from the BNP group did. Creatine kinase levels were significantly lower in the BNP group. Systemic vascular resistance was markedly lower in the BNP group. In conclusion, administration of BNP is highly effective in treating post-ischaemic heart failure following ECC. Haemodynamics are greatly improved, and there is almost no need for pharmacological support.

Brain natriuretic peptide levels and cardiac functional capacity in patients with dyspnea and isolated diastolic dysfunction

Diastolic heart failure affects approximately 40%-50% of patients presenting with signs and symptoms of heart failure. The aim of this study was to investigate the relationship between brain natriuretic peptide (BNP) levels and functional capacity in patients admitted with dyspnea and diagnosed with isolated diastolic dysfunction. Fifty-four patients (mean age, 57.4 +/- 8.5 years) with class-2 dyspnea with isolated diastolic dysfunction were enrolled. Serum levels of BNP were measured, and peak oxygen consumption (peak VO(2)), anaerobic threshold (AT), and metabolic equivalent (MET) values were determined with a cardiopulmonary exercise test (CPET). There was a negative correlation between BNP levels and exercise duration (P < 0.05, r = -0.304), AT (P < 0.05, r = -0.380), and number of MET (P < 0.05, r = -0.322) determined by CPET. When patients were divided into 2 groups according to BNP levels; BNP < or = 50 pg/mL (n = 40) versus BNP > 50 pg/mL (n = 14) and analyzed, those with BNP levels > 50 pg/mL had lower peak VO(2) (P = 0.05) and anaerobic threshold (P = 0.01) compared with patients with BNP < or = 50 pg/mL. The results suggest that BNP levels provide an indication about the functional capacity determined by CPET in patients admitted with dyspnea and isolated diastolic dysfunction.

Interpretation of B-type natriuretic peptide in cardiac disease and other comorbid conditions

B-Type natriuretic peptide (BNP) is elevated in states of increased ventricular wall stress. BNP is most commonly used to rule out congestive heart failure (CHF) in dyspneic patients. BNP levels are influenced by age, gender and, to a surprisingly large extent, by body mass index (BMI). In addition, it can be elevated in a wide variety of clinical settings with or without CHF. BNP is elevated in other cardiac disease states such as the acute coronary syndromes, diastolic dysfunction, atrial fibrillation (AF), amyloidosis, restrictive cardiomyopathy (RCM), and valvular heart disease. BNP is elevated in non-cardiac diseases such as pulmonary hypertension, chronic obstructive pulmonary disease, pulmonary embolism, and renal failure. BNP is also elevated in the setting of critical illness such as in acute decompensated CHF (ADHF) and sepsis. This variation across clinical settings has significant implications given the increasing frequency with which BNP testing is being performed. It is important for clinicians to understand how to appropriately interpret BNP in light of the comorbidities of individual patients to maximize its clinical utility. We will review the molecular biology and physiology of natriuretic peptides as well as the relevant literature on the utilization of BNP in CHF as well as in other important clinical situations, conditions that are commonly associated with CHF and or dyspnea.

B-type natriuretic peptide concentrations and myocardial dysfunction in critical illness

B-type natriuretic peptide (BNP) is the first biomarker of proven value in screening for left ventricular dysfunction. The availability of point-of-care testing has escalated clinical interest and the resultant research is defining a role for BNP in the investigation and treatment of critically ill patients. This review was undertaken with the aim of collecting and assimilating current evidence regarding the use of BNP assay in the evaluation of myocardial dysfunction in critically ill humans. The information is presented in a format based upon organ system and disease category. BNP assay has been studied in a spectrum of clinical conditions ranging from acute dyspnoea to subarachnoid haemorrhage. Its role in diagnosis, assessment of disease severity, risk stratification and prognostic evaluation of cardiac dysfunction appears promising, but requires further elaboration. The heterogeneity of the critically ill population appears to warrant a range of cut-off values. Research addressing progressive changes in BNP concentration is hindered by infrequent assay and appears unlikely to reflect the critically ill patient's rapidly changing haemodynamics. Multi-marker strategies may prove valuable in prognostication and evaluation of therapy in a greater variety of illnesses. Scant data exist regarding the use of BNP assay to alter therapy or outcome. It appears that BNP assay offers complementary information to conventional approaches for the evaluation of cardiac dysfunction. Continued research should augment the validity of BNP assay in the evaluation of myocardial function in patients with life-threatening illness.

Plasma level of N terminal pro-brain natriuretic peptide as a prognostic marker in critically ill patients

We studied whether N-terminal pro brain natriuretic peptide (NT-pro BNP) measured at intensive care unit admission is an independent predictor of mortality in critically ill patients. We conducted a prospective observational cohort study enrolling 78 patients with APACHE II scores more than 12. Serum NT-pro BNP and cardiac troponin T were measured at admission, and echocardiography was performed within 24 h. The primary end-point was 30-day mortality. The median NT-pro BNP levels of the 22 (28.2%) patients who died were significantly more frequent than that of those who survived (8328 versus 1016 pg/mL; P = 0.001). Patients with NT-pro BNP levels more than 1900 pg/mL had significantly more frequent mortality (47.2% versus 11.9%; P = 0.03). This group also had more frequent moderate to severe left ventricular dysfunction (30.6% versus 9.5%; P = 0.02) and abnormal cardiac troponin T levels (33.3% versus 14.3%; P = 0.05). Multivariate analyses adjusted for APACHE-II revealed that a NT-pro BNP level more than 1900 pg/mL is an independent predictor of mortality.

Relevance of brain natriuretic peptide in preload-dependent regulation of cardiac sarcoplasmic reticulum Ca2+ ATPase expression

BACKGROUND

In heart failure (HF), ventricular myocardium expresses brain natriuretic peptide (BNP). Despite the association of elevated serum levels with poor prognosis, BNP release is considered beneficial because of its antihypertrophic, vasodilating, and diuretic properties. However, there is evidence that BNP-mediated signaling may adversely influence cardiac remodeling, with further impairment of calcium homeostasis.

METHODS AND RESULTS

We studied the effects of BNP on preload-dependent myocardial sarcoplasmic reticulum Ca2+ ATPase (SERCA2a) expression. In rabbit isolated muscle strips stretched to high preload and shortening isotonically over 6 hours, the SERCA/glyceraldehyde phosphate dehydrogenase mRNA ratio was enhanced by 168% (n=8) compared with unloaded preparations (n=8; P<0.001). Recombinant human BNP at a concentration typically found in end-stage HF patients (350 pg/mL) abolished SERCA upregulation by stretch (n=9; P<0.0001 versus BNP free). Inhibition of cyclic guanosine 3',5' monophosphate (cGMP)-phosphodiesterase-5 mimicked this effect, whereas inhibition of cGMP-dependent protein kinase restored preload-dependent SERCA upregulation in the presence of recombinant human BNP. Furthermore, in myocardium from human end-stage HF patients undergoing cardiac transplantation (n=15), BNP expression was inversely correlated with SERCA levels. Moreover, among 23 patients treated with left ventricular assist devices, significant SERCA2a recovery occurred in those downregulating BNP.

CONCLUSIONS

Our data indicate that preload stimulates SERCA expression. BNP antagonizes this mechanism via guanylyl cyclase-A, cGMP, and cGMP-dependent protein kinase. This novel action of BNP to uncouple preload-dependent SERCA expression may adversely affect contractility in patients with HF.

Nesiritide in cardiovascular anesthesia

PURPOSE OF REVIEW

Acute heart failure has become a major medical issue in the western population. Because mortality is still as high as 50%, the treatment of these patients has been the focus of many studies. A new approach has recently been proposed, including B-type natriuretic peptide as a medication. The purpose of this review is to discuss these new developments.

RECENT FINDINGS

Recent studies have shown that plasma levels of B-type natriuretic peptide may serve as a marker for the severity of acute decompensated heart failure. Nesiritide, which is the recombinant equivalent of B-type natriuretic peptide, is a vasodilator, acting by increasing cyclic guanosine 3', 5'-monophosphate in the vascular smooth muscle cells. It is mainly considered to be an alternative for nitroglycerin, because it has fewer side-effects, and its activity is more prolonged. Treatment with nesiritide has shown fewer arrhythmias and a lower mortality rate compared with dobutamine and milrinone. In cardiac surgery, nesiritide is mainly administered to patients awaiting heart transplantation, but intraoperatively the doses of nesiritide and anesthetics must be adjusted because of a potential interaction. A few anecdotal reports have shown the advantageous effects of nesiritide in the early post-bypass period.

SUMMARY

Anesthesiologists will be confronted with increasing numbers of patients with heart failure, who require new forms of medication. Nesiritide is a promising new tool, and its application, which is still mainly restricted to the preoperative period, will probably soon be extended to the early post-bypass period.

Natriuretic peptides, their receptors, and cyclic guanosine monophosphate-dependent signaling functions

Natriuretic peptides are a family of structurally related but genetically distinct hormones/paracrine factors that regulate blood volume, blood pressure, ventricular hypertrophy, pulmonary hypertension, fat metabolism, and long bone growth. The mammalian members are atrial natriuretic peptide, B-type natriuretic peptide, C-type natriuretic peptide, and possibly osteocrin/musclin. Three single membrane-spanning natriuretic peptide receptors (NPRs) have been identified. Two, NPR-A/GC-A/NPR1 and NPR-B/GC-B/NPR2, are transmembrane guanylyl cyclases, enzymes that catalyze the synthesis of cGMP. One, NPR-C/NPR3, lacks intrinsic enzymatic activity and controls the local concentrations of natriuretic peptides through constitutive receptor-mediated internalization and degradation. Single allele-inactivating mutations in the promoter of human NPR-A are associated with hypertension and heart failure, whereas homozygous inactivating mutations in human NPR-B cause a form of short-limbed dwarfism known as acromesomelic dysplasia type Maroteaux. The physiological effects of natriuretic peptides are elicited through three classes of cGMP binding proteins: cGMP-dependent protein kinases, cGMP-regulated phosphodiesterases, and cyclic nucleotide-gated ion channels. In this comprehensive review, the structure, function, regulation, and biological consequences of natriuretic peptides and their associated signaling proteins are described.

Newer approaches to the pharmacological management of heart failure

PURPOSE OF REVIEW

The treatment of acute heart failure is gaining importance, specifically in the perioperative setting. Increasing evidence shows that established forms of therapy using beta-adrenergic inotropic drugs have no effect on long-term survival; thus, anesthetists and intensive care specialists are focusing on new strategies. This review examines, with respect to the literature of the past year, whether these strategies will gain significance in the perioperative setting.

RECENT FINDINGS

Owing to its unique efficacy profile, levosimendan, a calcium sensitizer, improves long-term survival in patients with acute heart failure and has been incorporated into the European Society of Cardiology guidelines. Improved heart function without increased oxygen consumption, anti-ischemic effects, no arrhythmogenic effect and positive effects on intestinal perfusion have been described. Despite the positive effects on hemodynamics and symptoms, tezosentan, an endothelin antagonist, did not improve outcome, perhaps due to too high dosages of the drug. Nesiritide, a recombinant brain natriuretic peptide, may represent an alternative to nitroglycerin and dobutamine and possibly have a benefit for survival. No final conclusions can yet be drawn, however. L-NAME, a nitric oxide synthase antagonist, represents a promising new approach for the treatment of cardiogenic shock. The results must be confirmed in large, randomized studies.

SUMMARY

For perioperative treatment of acute heart failure, levosimendan, nesiritide and L-NAME constitute promising alternatives to conventional inotropic and vasodilatory drugs. The strongest evidence for improving outcome is given for levosimendan. According to the present literature, tezosentan does not currently have any significance for treatment of perioperative heart failure.

[Are neurohumoral parameters predictive for the efficacy of cardiac resynchronization therapy? The role of natriuretic peptides]

During recent years, heart failure has been recognized as a complex disease involving both hemodynamic abnormalities caused by reduced contractile forces and neurohormonal changes characterized by an increase in sympathetic tone and an activation of the renin-angiotensin-aldosterone system as well as the endothelial pathways. Neurohumoral factors represent the natural response of the individual to heart failure. Among them natriuretic peptides, i. e., brain natriuretic peptide (BNP) and amino-terminal pro BNP (Nt-proBNP) release have recently been shown to be a reliable and rapid marker for diagnosis, optimization of pharmacological treatment and risk stratification in heart failure patients. This article summarizes important aspects of the release of natriuretic peptides as a guide for diagnosis, therapy and prognosis of patients with heart failure and cardiac resynchronization therapy.

B-type natriuretic peptide level in a patient with constrictive pericarditis

We report the case of a 35-year-old man with constrictive pericarditis who had a B-type natriuretic peptide (BNP) level of 129 pg/dl despite a left ventricular end diastolic pressure of 35 mmHg. We discuss a possible explanation for the relatively low BNP level given this patient's markedly elevated intracavitary pressures in the setting of constrictive pericarditis.

Risk Factors for Myocardial Injury during Off-Pump Coronary Artery Bypass Grafting

BACKGROUND

Although off-pump coronary artery bypass grafting (CABG) is now used worldwide for coronary revascularization, the pre- and intraoperative risk factors for myocardial injury associated with the surgical procedure remain to be elucidated. We performed a multivariate analysis to investigate factors that contribute to myocardial injury during off-pump CABG.

METHODS

The study population consisted of 22 patients who underwent off-pump CABG without apparent intraoperative complications. Blood samples were obtained before surgery and at 3 and 12 hours after the last anastomosis and serum Troponin T (cTnT) levels were measured to assess myocardial injury. Patient characteristics and factors related to preoperative cardiac function and the intraoperative process were analyzed to determine their correlation with serum cTnT levels, and the Spearman's correlation coefficient (r(s)) was computed.

RESULTS

Neither age, preoperative cardiac function, time required for anastomosis, the number of grafts, nor the total amount of bleeding were associated with serum cTnT levels. Serum cTnT at 3 and 12 hours after completed anastomosis correlated with the product of mean systolic blood pressure and mean heart rate (double product) during anastomosis. The r(s) values at 3 and 12 hours were 0.62 (P = .002) and 0.58 (P = .004), respectively. With respect to the serum cTnT level at 12 hours, creatinine clearance (Ccr) had a slight effect on the serum cTnT values.

CONCLUSIONS

High blood pressure and an increased heart rate during anastomosis are unfavorable factors for off-pump CABG. However, strict control of the blood pressure and heart rate makes it possible to subject even patients at high-risk to off-pump CABG from the viewpoints of myocardial injury.

Influence of renal function on N-terminal pro-brain natriuretic peptide (NT-proBNP) in patients admitted for dyspnoea in the Emergency Department: Comparison with brain natriuretic peptide (BNP)

BACKGROUND

Renal dysfunction influences the optimum brain natriuretic peptide (BNP) threshold for a diagnosis of cardiac-related dyspnoea, but this has not been demonstrated for N-terminal pro-brain natriuretic peptide (NT-proBNP). We studied the influence of renal function on NT proBNP and BNP concentrations in dyspnoeic patients admitted by night to the Emergency Department (ED).

METHODS

NT-proBNP, BNP, and creatinine levels were measured in blood samples collected routinely from 381 patients; estimated glomerular filtration rate (eGFR) was calculated.

RESULTS

Cardiac-related dyspnoea was found in 115 patients (30.2%). NT-proBNP and BNP values were elevated in patients with cardiac-related dyspnoea (6823+/-6569 vs. 2716+/-4838 pg/ml, and 642+/-329 vs. 243+/-267 pg/ml, p<0.0001, respectively). Log-transformed NT-proBNP and BNP values were correlated to eGFR values. Mean NT-proBNP and BNP values stratified by ED diagnosis increased in line with eGFR categories, but in each category both peptide concentrations remained elevated in cardiac-related dyspnoea when compared with non-cardiac-related dyspnoea (p<0.05). NT-proBNP (and BNP) cut-off points rose as a function of eGFR categories: from 1360 (and 290) pg/ml in patients with eGFR 60-89 ml/min/1.73 m2, to 6550 (and 515) pg/ml in patients with eGFR 15-29 ml/min/1.73 m2.

CONCLUSION

Renal function influences the optimal cut-off points of NT-proBNP and BNP for the diagnosis of cardiac-related dyspnoea.

Dipeptidyl-peptidase IV converts intact B-type natriuretic peptide into its des-SerPro form

BACKGROUND

Analysis of plasma B-type natriuretic peptide (BNP) has suggested the in vivo formation of a truncated form, BNP (3-32), also called des-SerPro-BNP. The objectives of this study were to investigate (a) whether BNP and other natriuretic peptides are truncated by dipeptidyl-peptidase IV (DPP IV/CD26; EC 3.4.14.5) and (b) whether this truncation affects the susceptibility to cleavage by neutral endopeptidase (NEP; EC 3.4.24.11).

METHODS

Human BNP (1-32), A-type natriuretic peptide 1-28 (ANP 1-28), and related peptides were incubated with purified DPP IV and with human plasma. In addition, BNP (1-32), BNP (3-32), and ANP (1-28) were subjected to hydrolysis by NEP. Cleavage products were analyzed by mass spectrometry.

RESULTS

BNP (1-32) was cleaved by purified DPP IV with a specificity constant of 0.37 x 10(6) L.mol(-1).s(-1). The DPP IV activity in EDTA-plasma was able to truncate BNP (1-32) ex vivo. Addition of Vildagliptin, a specific DPP IV inhibitor, prevented this truncation in a concentration-dependent manner. Under in vitro circumstances in which ANP was hydrolyzed extensively, BNP (1-32) and BNP (3-32) were very resistant to NEP-mediated cleavage.

CONCLUSIONS

DPP IV cleaves BNP (1-32) with an efficiency higher than or comparable to several known in vivo substrates of the enzyme. Even after loss of the amino-terminal dipeptide, BNP remains highly resistant to cleavage by NEP.

Pathophysiologic targets in the early phase of acute heart failure syndromes

An episode of acute heart failure syndromes (AHFS) can be defined as a rapid or gradual onset of signs and symptoms of heart failure (HF) in hospital admission and can arise from a variety of pathophysiologic mechanisms. This article reviews our current understanding of the pathophysiology of AHFS in order to identify potential therapeutic targets. Most patients with AHFS present with either normal systolic blood pressure or elevated blood pressure. Patients who present with elevated systolic blood pressure usually have pulmonary congestion and a relatively preserved left ventricular ejection fraction (LVEF), and have symptoms that typically develop abruptly, these patients often are elderly women. Patients with normal systolic blood pressure presenting with systemic congestion and reduced LVEF are usually younger, with a history of chronic HF, and have symptoms that develop gradually over days or weeks. Accordingly, most episodes of AHFS can be classified as either "vascular" failure or "cardiac" failure. In addition to the abnormal hemodynamics (increase in pulmonary capillary wedge pressure and/or decrease in cardiac output) that characterize patients with AHFS, myocardial injury--which may be related to a decrease in coronary perfusion and/or further activation of neurohormones and renal dysfunction (ie, the cardiorenal syndrome)--probably contributes to short-term and post-discharge cardiac events. Patients with AHFS also have significant cardiac and non-cardiac underlying conditions that contribute to the pathogenesis of AHFS, including coronary artery disease (ischemia, hibernating myocardium, and endothelial dysfunction), hypertension, atrial fibrillation, and type 2 diabetes mellitus. The goals of therapy for AHFS should be not only to improve symptoms and hemodynamics, but also to preserve or improve renal function and prevent myocardial damage.

The use of probrain natriuretic peptide in pleural fluid for the diagnosis of pleural effusions resulting from heart failure

PURPOSE OF REVIEW

Natriuretic peptides are secreted by the myocardium in response to mechanical stretch and have been proposed as a possible test for assisting the diagnosis of heart failure. This article reviews the rationale for measuring N terminal probrain natriuretic peptide in pleural fluid to identify heart failure as the cause of a pleural effusion.

RECENT FINDINGS

Rapid and accurate testing of natriuretic peptides as biomarkers for heart failure is now a clinical reality. In patients presenting with dyspnea, heart failure is usually absent at blood brain natriuretic peptide levels less than 100 pg/mL, possible from 100 to 500 pg/mL, and probable at levels greater than 500 pg/mL. In evaluating natriuretic peptide assays, one needs to consider carefully laboratory and biologic variation, including gender, sex, obesity, renal function, and the assay used. Potential future applications of natriuretic peptide testing include the differential diagnosis of pleural effusion. A recent study has shown good diagnostic characteristics in cardiac pleural effusions, with likelihood ratios of 13 and a diagnostic accuracy of more than 90% for pleural fluid N terminal probrain natriuretic peptide levels > or =1500 pg/mL. Specifically, N terminal probrain natriuretic peptide pleural levels correctly categorized most cardiac effusions misclassified as exudates by standard criteria, and discriminated between cardiac and hepatic transudates.

SUMMARY

Pleural fluid N terminal probrain natriuretic peptide may help accurately differentiate cardiac from noncardiac conditions in patients presenting with pleural effusion.