Effect of beta-blocker on left ventricular function and natriuretic peptides in patients with chronic heart failure treated with angiotensin-converting enzyme inhibitor

Beta-blockers and inhibitors of the renin-angiotensin aldosterone system for chronic heart failure with preserved ejection fraction

BACKGROUND

Beta-blockers and inhibitors of the renin-angiotensin aldosterone system improve survival and reduce morbidity in people with heart failure with reduced left ventricular ejection fraction. There is uncertainty whether these treatments are beneficial for people with heart failure with preserved ejection fraction and a comprehensive review of the evidence is required.

OBJECTIVES

To assess the effects of beta-blockers, angiotensin converting enzyme inhibitors, angiotensin receptor blockers, angiotensin receptor neprilysin inhibitors, and mineralocorticoid receptor antagonists in people with heart failure with preserved ejection fraction.

SEARCH METHODS

We searched CENTRAL, MEDLINE, Embase and two clinical trial registries on 25 July 2017 to identify eligible studies. Reference lists from primary studies and review articles were checked for additional studies. There were no language or date restrictions.

SELECTION CRITERIA

We included randomised controlled trials with a parallel group design enrolling adult participants with heart failure with preserved ejection fraction, defined by a left ventricular ejection fraction of greater than 40 percent.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected studies for inclusion and extracted data. The outcomes assessed included cardiovascular mortality, heart failure hospitalisation, hyperkalaemia, all-cause mortality and quality of life. Risk ratios (RR) and, where possible, hazard ratios (HR) were calculated for dichotomous outcomes. For continuous data, mean difference (MD) or standardised mean difference (SMD) were calculated. We contacted trialists where neccessary to obtain missing data.

MAIN RESULTS

37 randomised controlled trials (207 reports) were included across all comparisons with a total of 18,311 participants.Ten studies (3087 participants) investigating beta-blockers (BB) were included. A pooled analysis indicated a reduction in cardiovascular mortality (15% of participants in the intervention arm versus 19% in the control arm; RR 0.78; 95% confidence interval (CI) 0.62 to 0.99; number needed to treat to benefit (NNTB) 25; 1046 participants; 3 studies). However, the quality of evidence was low and no effect on cardiovascular mortality was observed when the analysis was limited to studies with a low risk of bias (RR 0.81; 95% CI 0.50 to 1.29; 643 participants; 1 study). There was no effect on all-cause mortality, heart failure hospitalisation or quality of life measures, however there is uncertainty about these effects given the limited evidence available.12 studies (4408 participants) investigating mineralocorticoid receptor antagonists (MRA) were included with the quality of evidence assessed as moderate. MRA treatment reduced heart failure hospitalisation (11% of participants in the intervention arm versus 14% in the control arm; RR 0.82; 95% CI 0.69 to 0.98; NNTB 41; 3714 participants; 3 studies; moderate-quality evidence) however, little or no effect on all-cause and cardiovascular mortality and quality of life measures was observed. MRA treatment was associated with a greater risk of hyperkalaemia (16% of participants in the intervention group versus 8% in the control group; RR 2.11; 95% CI 1.77 to 2.51; 4291 participants; 6 studies; high-quality evidence).Eight studies (2061 participants) investigating angiotensin converting enzyme inhibitors (ACEI) were included with the overall quality of evidence assessed as moderate. The evidence suggested that ACEI treatment likely has little or no effect on cardiovascular mortality, all-cause mortality, heart failure hospitalisation, or quality of life. Data for the effect of ACEI on hyperkalaemia were only available from one of the included studies.Eight studies (8755 participants) investigating angiotensin receptor blockers (ARB) were included with the overall quality of evidence assessed as high. The evidence suggested that treatment with ARB has little or no effect on cardiovascular mortality, all-cause mortality, heart failure hospitalisation, or quality of life. ARB was associated with an increased risk of hyperkalaemia (0.9% of participants in the intervention group versus 0.5% in the control group; RR 1.88; 95% CI 1.07 to 3.33; 7148 participants; 2 studies; high-quality evidence).We identified a single ongoing placebo-controlled study investigating the effect of angiotensin receptor neprilysin inhibitors (ARNI) in people with heart failure with preserved ejection fraction.

AUTHORS' CONCLUSIONS

There is evidence that MRA treatment reduces heart failure hospitalisation in heart failure with preserverd ejection fraction, however the effects on mortality related outcomes and quality of life remain unclear. The available evidence for beta-blockers, ACEI, ARB and ARNI is limited and it remains uncertain whether these treatments have a role in the treatment of HFpEF in the absence of an alternative indication for their use. This comprehensive review highlights a persistent gap in the evidence that is currently being addressed through several large ongoing clinical trials.

Biologic Variability of Soluble ST2 in Patients With Stable Chronic Heart Failure and Implications for Monitoring

Soluble ST2 (sST2) is a novel biomarker implicated in myocardial remodeling and fibrosis. Recent studies in normal subjects have suggested that the biologic variability (BV) of sST2 is significantly lower than that of the B-type natriuretic peptides and N-terminal pro B-type natriuretic peptide (NTproBNP). It may, consequently, be a better biomarker for monitoring patients with chronic heart failure (CHF). To date, no published studies have examined the BV of sST2 in a heart failure population. Blood samples from 50 outpatients with pharmacologically optimized stable CHF and persistent left ventricular dysfunction (ejection fraction <40%) were collected at baseline, 1 hour, 1 month, 3 months, and 6 months. Using log-transformed data, mean intra-individual coefficients of variation (CVI) and subsequent reference change values were calculated for both NTproBNP and sST2. Results demonstrate significantly lower CVI and reference change values for sST2 compared with NTproBNP at 1 month (12.02 [36%] vs 36.75 [103%]), p <0.001, 3 months (12.23 [36%] vs 40.98 [114%]), p <0.001, and 6 months (16.41 [47%] vs 46.02 [128%]), p <0.001. In conclusion, the BV of sST2 is significantly lower than that of NTproBNP in patients with CHF. These results support previous indications that sST2 may be a better biomarker for monitoring such patients.

Biological variation of galectin-3 and soluble ST2 for chronic heart failure: implication on interpretation of test results

BACKGROUND

Galectin-3 and soluble ST2 (sST2) are novel serum biomarkers of chronic heart failure.

METHODS AND RESULTS

The biological variability of galectin-3 and sST2 was measured from a cohort of 17 healthy subjects where blood was taken once every 2 weeks for 8 weeks (n = 4 samples) and from 12 subjects where blood was taken hourly (for galectin-3 only). The analytical, intraindividual, and interindividual variation were measured for galectin-3 (BG Medicine, Waltham, MA) and sST2 (Critical Diagnostics, San Diego, CA). From these measurements, the reference change (RCV) and index of individuality was 39% (hourly) and 61% (weekly) and 1.0 (hourly and weekly) for galectin-3. Corresponding RCV and index of individuality values for sST2 were 30% and 0.25.

CONCLUSION

The RCV result for sST2 was lower than the corresponding results for galectin-3, B-type natriuretic peptide, and N-terminal pro-B-type natriuretic peptide. These data suggest that sST2 may be more useful for monitoring long-term heart failure, and galectin-3 may be more useful for the diagnosis of heart failure remodeling.

Review on natriuretic peptides: where we are, where we are going

BACKGROUND

Tremendous advances have been made in our understanding of the pathophysiology and treatment of congestive heart failure. However, diagnosis of the disease still remains difficult, even with a comprehensive physical examination. Symptoms such as dyspnea are nonspecific and insensitive indicators for heart failure, which can go largely undetected. Several studies have suggested the need for new diagnostic capabilities, especially with the increasing prevalence of heart failure in the US. The discovery of natriuretic peptides as diagnostic biomarkers has been one of the most critical advances for the management of heart failure. Both B-type natriuretic peptide and N-terminal pro-B-type natriuretic peptide have the potential to diagnose heart failure, assess prognostic risk of rehospitalization and mortality, and even help guide treatment. Their relative cost-effectiveness and availability have also facilitated their acceptance into many emergency departments, clinics and in-patient units as standard care when evaluating patients with suspected heart failure. Our understanding of the natriuretic peptide system is still in its infancy, but natriuretic peptides have emerged as important diagnostic and prognostic tools that have generated interest in finding broader applications for their use.

OBJECTIVE

The purpose of this review is to discuss the clinical approaches and future applications of natriuretic peptides in diagnosing and managing treatment of congestive heart failure.

METHOD

A comprehensive review of studies to assess the utility of natriuretic peptides for diagnosis and prognosis of heart failure and other conditions.

CONCLUSION

Natriuretic peptides are powerful tools to aid the physician in the diagnosis, prognosis and management of heart failure in both in-patient and out-patient settings. However, natriuretic peptides should be used as an adjunct test as many circumstances can also influence changes in natriuretic peptide levels.

Therapeutic changes of plasma N-terminal pro-brain natriuretic peptide concentrations in 9 dogs with patent ductus arteriosus

The plasma N-terminal proBNP (NT-proBNP) concentration is measured for determining the diagnosis and severity of heart failure in dogs. However, it is still unclear whether measurements of circulating NT-proBNP levels provide clinical utility as an indicator of therapeutic efficacy. Thus, we investigated the surgical correction-related changes of plasma NT-proBNP concentrations in 9 dogs with patent ductus arteriosus (PDA). Physical examination, thoracic radiography and echocardiography were conducted both before and after surgery. Similarly, the plasma NT-proBNP concentrations were determined using an enzyme immunoassay for canine pro-BNP. The International Small Animal Cardiac Health Council (ISACHC) class and murmur grade were significantly improved after surgery compared with before surgery. Vertebral heart size (VHS) and cardiothoracic ratio (CTR) were significantly decreased after surgery. Fractional shortening was significantly decreased and relative wall thickness (RWT) was significantly increased after surgery. Furthermore, the plasma NT-proBNP concentrations were significantly decreased by surgical correction. The plasma NT-proBNP concentration showed significant positive correlation with the ISACHC class, murmur grade, VHS and CTR and significant negative correlation with the RWT. Therefore, measurement of plasma NT-proBNP levels can be used to monitor the effectiveness of therapies such as surgical correction of PDA.

Can we use B-type natriuretic peptides to monitor patients with heart failure?

The B-type natriuretic peptides (BNPs) now have a well-established role in the diagnosis of heart failure. There is also a wealth of evidence on their ability as prognostic markers in patients with heart failure. The other potential role of BNPs is in the arena of therapy monitoring, although much less is known regarding this putative application. This review summarizes what evidence there is both for and against using BNPs to monitor heart failure patients.

The effects of medications on circulating levels of cardiac natriuretic peptides

Circulating cardiac natriuretic peptide levels are being used increasingly in a range of clinical circumstances. Since it is evident that drugs used in the treatment of cardiovascular disorders can modulate natriuretic peptide levels, we here review the literature documenting these effects. Diuretics, blockers of the renin-angiotensin system, vasodilator agents, dopamine-like agonists, amiodarone, and perhaps allopurinol and statins suppress natriuretic peptide levels, most obviously in heart failure. Beta-blockers stimulate natriuretic peptide concentrations in hypertensive subjects, whereas in heart failure they have little effect or are stimulatory in the short term and inhibitory with sustained therapy. Digitalis compounds and aspirin tend to increase natriuretic peptide levels, and calcium channel blocking agents have varying effects depending on the individual drug and duration of administration. The effects of other drugs are less clear. Additional information is needed regarding the effects of medications along with dissection of the role of altered cardiac secretion versus changes in plasma clearance as explanation for drug-induced perturbations in natriuretic peptide concentrations. In the meantime, clinicians need to consider the known effects of medications when interpreting plasma levels of the cardiac natriuretic peptides.

Serial testing of B-type natriuretic peptide and NTpro-BNP for monitoring therapy of heart failure: the role of biologic variation in the interpretation of results

BACKGROUND

B-Type natriuretic peptide (BNP) and NTpro-BNP are widely used for diagnosis and risk stratification of patients with heart failure (HF). Although not currently cleared by the Food and Drug Administration as a test indication, there is interest in using these biomarkers for monitoring the success of HF medications. An assessment of the analytical and biologic variations is necessary to interpret the results of serial testing.

METHODS AND RESULTS

The intra-individual biologic variances and analytical assay variances of BNP and NT-proBNP from healthy subjects and those with stable HF were reviewed. The analytical variability of BNP and NT-proBNP assays was reported, as some have suggested that only the analytical variance is important in interpreting the results of tightly regulated hormones. The reference change values (RCV) for serial measurements were derived and used to interpret results of therapeutic studies whereby serial changes in BNP and NT-proBNP concentrations were obtained to evaluate the therapeutic success of short-term (inpatient) and long-term (outpatient) management. The use of RCV may also be important in studies comparing BNP-guided versus physician-guided HF drug therapy.

CONCLUSIONS

Relative to the RCV, short-term therapeutic studies of inpatients have largely resulted in a statistically significant decline in BNP and NT-proBNP with clinical evidence of patient improvements. In contrast, many therapeutic studies involving long-term outpatient monitoring have produced changes in BNP/NT-proBNP that do not exceed the biologic variances. The value of BNP for monitoring therapeutic success can be questioned for trials that demonstrate clinical benefit without statistically significant decreases in biomarker levels.

Beta-blocker therapy for cardiac dysfunction in patients with muscular dystrophy

BACKGROUND

In muscular dystrophy, cardiac function deteriorates with time and heart failure is one of the major causes of death. Although the combination of angiotensin-converting enzyme inhibitors (ACEI) and beta-blockers improves cardiac function in adults, little is known about the efficacy of those drugs in patients with muscular dystrophy.

METHODS AND RESULTS

The effect of the beta-blocker, carvedilol, and/or ACEI on ventricular function in patients with muscular dystrophy was studied. Carvedilol and an ACEI were given to 13 patients (ACEI group; mean age 18 years, range 7-27 years), and an ACEI only to 15 patients (carvedilol group; mean age 15 years, range 8-29 years). Diagnoses included Duchenne muscular dystrophy (n=25), Fukuyama muscular dystrophy (n=2), and Emery-Dreifuss muscular dystrophy (n=1). Echocardiographic parameters of the left ventricle were measured during the 2-3 years of follow-up. In the carvedilol group, combination therapy of carvedilol and an ACEI for 2 years resulted in a significant increase in left ventricular fractional shortening (LVFS). In the ACEI group, there was no significant change in LVFS. Left ventricular end-diastolic dimension increased in the ACEI group, but not in the carvedilol group.

CONCLUSION

Carvedilol plus an ACEI improves left ventricular systolic function in patients with muscular dystrophy.

Brain natriuretic peptide (BNP) testing in the emergency department

In the past decade a large amount of attention has been focused on brain natriuretic peptide (BNP) testing in the evaluation of patients with acute dyspnea as well as the screening of patients for congestive heart failure (CHF). Because BNP is secreted by myocytes in response to ventricular stretch, it has long been thought that BNP could become a biochemical marker for CHF. Rapid assays have been developed and BNP testing has been studied in detection of CHF and predictive outcomes in a large variety of settings. We review the clinical evidence associated with the use of BNP testing in the acute care setting. We conclude with a discussion of clinical utility in the emergency department for the evaluation of patients presenting with acute dyspnea.

Abnormal rhythmic oscillations of atrial natriuretic peptide and brain natriuretic peptide in chronic renal failure

Secretion of ANP (atrial natriuretic peptide) and BNP (brain natriuretic peptide) is pulsatile in healthy humans. However, the patterns of secretion of ANP and BNP have not been studied in chronic renal failure. The aim of the present study was to test the hypotheses that ANP and BNP are secreted in pulses in dialysis patients, and that pulsatile secretion is regulated by prostaglandins. Blood samples were drawn every 2 min through an intravenously inserted plastic needle over a period of 1-2 h in 13 dialysis patients and 13 healthy control subjects (Study 1), and in 15 healthy control subjects, who participated in a randomized placebo-controlled cross-over study after treatment with indomethacin and placebo (Study 2). Plasma concentrations of ANP and BNP were determined by RIAs, and the results were analysed for pulsatile behaviour by Fourier transformation. The results from Study 1 showed that the secretion of ANP and BNP was pulsatile in nine patients with chronic renal failure. The maximum amplitude was significantly higher in chronic renal failure compared with control subjects for both ANP and BNP (ANP, 4.3 compared with 0.7 pmol/l; BNP, 2.0 compared with 0.3 pmol/l; values are medians) and correlated positively with the mean plasma level of ANP (rho=0.900, P=0.001; n=9) and BNP (rho=0.983, P=0.000; n=9). The frequency was the same for patients and controls. The results from Study 2 demonstrated pulsatile secretion in all subjects, but both the amplitude and frequency were unaffected by indomethacin. The maximum amplitude correlated positively with the mean plasma level of ANP and BNP during both placebo and indomethacin treatment. It can be concluded that the secretion of ANP and BNP is pulsatile with abnormally high amplitude in chronic renal failure, that prostaglandins apparently are not involved in the secretion of these peptides in healthy subjects and that the high secretion rate in chronic renal failure results in higher ANP and BNP in plasma.

Introduction of metoprolol increases plasma B-type cardiac natriuretic peptides in mild, stable heart failure

BACKGROUND

The effect of beta-blockade on the cardiac natriuretic peptides is poorly understood but could contribute to their beneficial treatment effect and may be relevant to clinical use of plasma brain natriuretic peptide (BNP)/N-terminal pro brain natriuretic peptide (NTproBNP) measurements in risk stratification and in titration of anti-heart failure therapy.

METHODS AND RESULTS

Sixteen men with mild, stable heart failure (NYHA class II to III; left ventricular ejection fraction <40%) underwent serial blood sampling for plasma natriuretic peptide levels and received infusions of atrial natriuretic peptide (ANP) and BNP before and 6 weeks after the introduction and uptitration of metoprolol or 6 weeks unchanged therapy in a randomized, parallel-group design. Plasma natriuretic peptides (BNP, NTproBNP, ANP, and NTproANP) were increased by metoprolol (P<0.01 for all). The natriuretic responses to ANP and BNP infusions were sustained with the introduction of metoprolol despite reduced renal perfusion pressure. The levels of the noninfused natriuretic peptide were increased by both ANP and BNP infusions, and this effect was enhanced by metoprolol. The early plasma half-life (t(1/2)alpha) of BNP was prolonged by metoprolol (5.6+/-0.45 to 11+/-1.3 versus 5.7+/-0.8 to 6.6+/-1.3 minutes in control subjects; P=0.019).

CONCLUSIONS

Plasma cardiac natriuretic peptide levels increase significantly with the introduction of metoprolol in heart failure as a result of effects on secretion and clearance. Natriuretic responses to NP infusions are sustained with beta-blockade despite reduced renal perfusion pressure. Clinicians should be aware that the introduction of metoprolol causes a rise in plasma BNP/NTproBNP that is unrelated to deterioration in clinical status and must be considered when measurements are undertaken for risk stratification or titration of treatment.

Utility of brain natriuretic peptide (BNP) measurement in cardiovascular disease

Cardiac failure is a prevalent and costly condition in Western society. The ageing of the population, together with current medical options which improve, rather than eradicate heart failure, lead to the projection that this problem will increase substantially in the foreseeable future. The availability of a simple test to assist the diagnosis and effective management of heart failure would greatly assist the clinical approach to this problem. This review examines the physiological basis for the measurement of natriuretic peptides as markers of the presence or risk of heart failure. It considers its use in the hospital and non-hospital setting and examines the cost-effectiveness of current assays. It is possible that in future natriuretic peptides may offer a form of treatment for heart failure, but this is beyond the scope of this review. Nevertheless, the review highlights the potential benefits of this group of tests in the management of heart failure.

Carvedilol Exerts More Potent Antiadrenergic Effect than Metoprolol in Heart Failure

BACKGROUND

It is still uncertain whether or not there is a difference between metoprolol and carvedilol for the treatment of congestive heart failure. We attempted to determine the difference between the two beta-blockers in terms of their antiadrenergic effect during exercise in patients with heart failure and their efficacy based on the baseline plasma brain natriuretic peptide concentration.

METHODS

Fifty-three patients with mild to moderate heart failure with a radionuclide left ventricular ejection fraction <40% received open label metoprolol or carvedilol in a randomized fashion. The increase in the heart rate normalized to the increase in the plasma norepinephrine concentration during exercise, was calculated as an index of adrenergic responsiveness during exercise.

RESULTS

The increase in heart rate normalized by the increase in plasma norepinephrine concentration, decreased after the initiation of beta-blockers in the carvedilol group, but not in the metoprolol group. The change in cardiac function was more favorable for carvedilol than metoprolol in patients who exhibited a higher baseline brain natriuretic peptide concentration.

CONCLUSIONS

Carvedilol exerts a more potent antiadrenergic effect than metoprolol during stress in patients with mild to moderate heart failure. Carvedilol appears to be more efficacious than metoprolol in patients who exhibit higher baseline brain natriuretic peptide concentrations. These differences should be kept in mind when selecting appropriate pharmacologic agents in the treatment of heart failure.

Effect of Beta-Blocker Therapy on Myocardial Perfusion Defects in Thallium-201 Scintigraphy in Patients with Dilated Cardiomyopathy

BACKGROUND

The beneficial effects of beta-blocker therapy in patients with heart failure have been confirmed. However, the effects of beta-blockers on myocardial perfusion defects are unclear. The aim of this study was to evaluate the effect of beta-blockers on myocardial perfusion defects estimated by thallium-201 myocardial scintigraphy in patients with dilated cardiomyopathy (DCM) and to investigate the relationships between beta-blocker treatment and myocardial damage and cardiac function.

METHODS

201Tl and echocardiography were performed in 37 patients before and after 6 months of beta-blocker therapy. Extent score (ES) by 201Tl was used to quantitate myocardial perfusion defects before and after treatment.

RESULTS

ES was significantly decreased by beta-blocker therapy. According to the change in ES, DCM patients were classified into three groups, patients who improved, patients showing no change and patients who deteriorated. In the improvement and no-change groups, beta-blocker therapy induced a reduction in left ventricular dimensions and an associated increase in ejection fraction. However, in the deterioration group, left ventricular dimensions and ejection fraction were unchanged. There was a significant relationship between the change in left ventricular dimension at end-diastole and the change in ES.

CONCLUSIONS

beta-Blocker therapy could attenuate myocardial perfusion defects in some patients with DCM. The improvement in left ventricular function associated with beta-blocker therapy may be related to the attenuation in myocardial perfusion defects.

Clinical and Hemodynamic Effects of Nesiritide (B-Type Natriuretic Peptide) in Patients With Decompensated Heart Failure Receiving ? Blockers

The use of beta blockers in congestive heart failure presents a therapeutic challenge for patients with acute episodes of decompensation. Such patients may be less responsive to positive inotropic agents, whereas the beneficial effects of nesiritide, which are not dependent on the beta-adrenergic receptor signal-transduction pathway, may be preserved. This analysis of the Vasodilation in the Management of Acute CHF trial evaluated the safety and efficacy of nesiritide in decompensated congestive heart failure patients receiving beta blockers. The Vasodilation in the Management of Acute CHF trial was a multicenter, randomized, controlled evaluation of nesiritide in 489 hospitalized patients with decompensated congestive heart failure. One hundred twenty-three patients were on chronic beta-blocker therapy at enrollment (31 randomized to placebo, 50 to nesiritide, and 42 to nitroglycerin). Primary end points included pulmonary capillary wedge pressure and dyspnea evaluation at 3 hours. Patients receiving nesiritide, but not IV nitroglycerin, had significantly reduced pulmonary capillary wedge pressure vs. placebo at 3 hours regardless of beta-blocker use. The use of beta blockers did not alter the beneficial effects of nesiritide on systemic blood pressure, heart rate, or dyspnea evaluation. In nesiritide-treated subjects, safety profiles were similar regardless of beta-blocker use. Thus, the clinical and hemodynamic benefits and safety of nesiritide are preserved in decompensated congestive heart failure patients receiving chronic beta blockade.

Effects of carvedilol on plasma B-type natriuretic peptide concentration and symptoms in patients with heart failure and preserved ejection fraction

Although the benefits of carvedilol in patients with heart failure and depressed ejection fraction (EF) have been elucidated, those in patients with preserved EF are not understood. We enrolled 40 patients with mild or moderate heart failure and EF >/=45%. They were randomly assigned to carvedilol (n = 19) or conventional therapy (n = 21). After 12 months of treatment, carvedilol significantly improved all end points (plasma concentration of B-type natriuretic peptide [BNP] from 175 (35 to 209) to 106 (52 to 160) pg/ml, mean (95% confidence interval) p <0.01; New York Heart Association functional class from 2.37 (2.13 to 2.61) to 1.56 (1.21 to 1.91), p <0.01; exercise capacity estimated with the Specific Activity Scale from 4.75 (4.50 to 5.00) to 5.68 (5.22 to 6.14) METs, p <0.02), whereas conventional therapy did not (plasma BNP concentration from 150 (114 to 186) to 174 (100 to 248) pg/ml; New York Heart Association functional class from 2.29 (2.08 to 2.50) to 2.11 (1.73 to 2.49); exercise capacity from 4.57 (4.34 to 4.80) to 4.72 (4.41 to 5.03) METs). Univariate regression analyses showed that only the use of carvedilol was correlated with the decrease in plasma BNP concentration (p <0.03). Multivariate analyses demonstrated that an ischemic cause of heart failure (p <0.02), high plasma concentration of BNP (p <0.02), left ventricular dilation (p <0.03), and use of carvedilol (p <0.04) at baseline were predictive of a decrease in plasma concentration of BNP. In conclusion, carvedilol potentially decreased neurohumoral activation, decreased symptoms, and increased exercise capacity in patients with heart failure and preserved EF.

Brain natriuretic peptide response is heterogeneous during β-blocker therapy for congestive heart failure

BACKGROUND

Plasma brain natriuretic peptide (BNP) levels are useful marker to guide medical treatment in patients with congestive heart failure (CHF). We tested the hypothesis that the plasma BNP concentration would be a useful marker of beta-blocker therapy for CHF.

METHODS AND RESULTS

Eighty-four patients with New York Heart Association class II-IV CHF and a left ventricular ejection fraction (LVEF) <40% were treated with beta-blockers, including metoprolol and carvedilol, for at least 16 weeks. End-diastolic and end-systolic dimensions decreased, and radionuclide LVEF increased 4 weeks after introduction of beta-blockers (early phase). LV end-diastolic and end-systolic dimensions both decreased, and LVEF increased 16 to 48 weeks after the therapy (late phase). However, the BNP concentration did not change during the observation period. Overall LV function improved in all 4 subgroups divided according to the baseline BNP levels.

CONCLUSIONS

Plasma BNP concentration is not a sensitive marker of successful beta-blocker therapy for CHF.

Brain Natriuretic Peptide in the Management of Heart Failure

Brain natriuretic peptide (BNP), also called B-type natriuretic peptide, is a member of a family of structurally related hormones, the natriuretic peptides. Current data suggest that measurement of BNP plasma concentrations is a useful tool in the diagnosis of acute heart failure in patients presenting to an emergency department with acute dyspnea. Furthermore, BNP constitutes a promising new marker of prognosis after an acute coronary syndrome episode and in patients with chronic heart failure. Nesiritide, the human recombinant form of BNP, is a new vasodilator used in the treatment of acute heart failure that has several potential advantages over current drug therapy.

Cardiac natriuretic hormones, neuro-hormones, thyroid hormones and cytokines in normal subjects and patients with heart failure

The derangement of neuro-endocrine control of circulation influences both disease evolution and response to treatment in patients with heart failure, but little data are available about the complex relationships between the degree of neuro-hormonal activation and clinical severity. We studied the relationships between cardiac natriuretic hormones (CNHs) and several neuro-hormones and immunological markers in a prospective cohort of 105 consecutive patients with cardiomyopathy (77 men and 28 women, mean age 66.7±12.4 years, range 33–89 years). We assayed the circulating levels of CNHs (atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP)), plasma renin activity (PRA), aldosterone, cortisol, adrenaline, noradrenaline, thyroid hormones and thyroid stimulating hormone (TSH), tumour necrosis factor-α (TNF-α) and interleukin-6 (IL-6). The concentrations of all CNHs and neuro-hormones were higher in patients with heart failure compared to normal subjects, except for free triiodothyronine (FT3), which was below normal values. ANP was positively related to NYHA class, IL-6, adrenaline, noradrenaline and cortisol, while negatively with ejection fraction and FT3. BNP was positively related to age, NYHA class, IL-6, TNF-α, adrenaline, noradrenaline and cortisol, while negatively with ejection fraction and FT3. A stepwise multiple linear regression indicated that plasma ANP depended only on ejection fraction, adrenaline and noradrenaline values, while for plasma BNP variation NYHA class contributed too. Our data confirm a progressive activation of hormonal and immunological systems in patients with heart failure. Furthermore, CNH circulating levels in heart failure are affected not only by cardiac function and disease severity, but also by activation of neuro-hormonal and stress-related cytokine systems, as well as by the thyroid hormones, even on usual medical treatment.

Relation of Myocardial Blood Volume to Left Ventricular Function and Future Cardiac Events in Patients With Idiopathic Dilated Cardiomyopathy

BACKGROUND

The hypothesis that myocardial blood volume is associated with left ventricular (LV) dysfunction and future cardiovascular events in patients with idiopathic dilated cardiomyopathy (IDC) was tested using intravenous myocardial contrast echocardiography (MCE).

METHODS AND RESULTS

Thirty-five patients with IDC and 10 age-matched healthy control subjects were enrolled. Using MCE, background-subtracted and peak myocardial contrast intensity (calibrated PMCI) were calculated as measures of myocardial blood volume. LV ejection fraction (LVEF) was calculated using the modified Simpson method. Patients with IDC were stratified into 2 groups according to the median value of the calibrated PMCI [high value group (n=17): calibrated PMCI > or = -22.7 dB, low value group (n=18): calibrated PMCI < -22.7 dB]. The calibrated PMCI was markedly reduced in patients with IDC compared with the control subjects (p=0.0025) and closely related to LVEF (r=0.688, p<0.0001). In the multivariate model, calibrated PMCI was the independent variable that predicted cardiac events in patients with IDC. According to the Kaplan-Meier analysis, cardiac event-free rates were significantly lower in the low-value group than in the high-value group (p<0.01).

CONCLUSIONS

Myocardial blood volume is closely related to LV dysfunction and future cardiac events in patients with IDC.

Diagnostic accuracy and prognostic relevance of the measurement of cardiac natriuretic peptides: a review

BACKGROUND

The pathophysiologic and clinical relevance of cardiac natriuretic hormone (CNH) assays has been investigated in numerous experimental and clinical studies. Authors have sought to evaluate the diagnostic accuracy and prognostic relevance of the measurement of CNHs according to evidence-based laboratory medicine principles.

METHODS

In June 2003, we ran a computerized literature search on National Library of Medicine using keywords "ANP" and "BNP" and found more than 12 300 and 1200 articles, respectively. A more refined search with keywords "ANP or BNP assay" extracted approximately 7000 and 800 articles, respectively. Only studies specifically designed to evaluate the diagnostic accuracy and prognostic relevance of CNH measurements were selected from this huge mass of articles to be discussed in this review.

CONTENT

Several studies suggested that CNH assays may be clinically useful for the screening and classification of patients with heart failure, as a prognostic marker in cardiovascular disease, in the follow-up of patients with heart failure, and because they may reduce the need for further cardiac investigation. However, it is difficult to compare even the best-designed studies because not only did the authors evaluate different populations, they also used different gold standards.

CONCLUSIONS

CNH assays and conventional diagnostic work-ups provide complementary information for evaluation of the presence and severity of cardiac dysfunction and clinical disease. Several aspects of CNH assays are still to be elucidated, and further work is needed to carefully assess their diagnostic accuracy and prognostic value in cardiac disease.

Effect of beta-blockers on insulin resistance in patients with dilated cardiomyopathy

The aim of this study was to evaluate the effect of beta-blockers on insulin resistance in patients with dilated cardiomyopathy (DCM). A secondary aim was to determine the effect of this treatment on plasma concentrations of tumor necrosis factor-alpha (TNF-alpha) and to investigate the relationships between this adipocytokine and insulin resistance. Insulin resistance determined using the Homeostatic Model Assessment (HOMA), echocardiographic measurements and analysis of plasma TNF-alpha concentration were carried out in 47 patients with DCM without diabetes mellitus before and after 6 months of beta-blocker therapy. A reduction in left ventricular dimensions and an associated increase in ejection fraction occurred with beta-blocker. The treatment resulted in a significant decrease in insulin resistance (HOMA index: Baseline, 2.73+/-3.36 vs, Month 6, 1.58+/-1.33, p=0.0347). Beta-blockade was also associated with a decrease in plasma TNF-alpha concentration although no significant relationship between this change and the improvement in insulin resistance was observed. Beta-blocker therapy in patients with DCM improved not only cardiac function, but also insulin resistance. The mechanism of the change in insulin function remains unclear, but may be related to improvements in left ventricular function or an attenuation of the inhibitory effect of reduction in TNF-alpha on insulin signaling.

Plasma N-terminal pro-brain natriuretic peptide in Type 1 diabetic patients with and without diabetic nephropathy

AIMS

Plasma N-terminal pro-brain natriuretic peptide (NT proBNP) is produced and released from cardiac ventricles; it is elevated in patients with heart failure, hypertension and chronic renal failure. This study aimed to examine the plasma levels of NT proBNP and their relationship in Type 1 diabetic patients with and without diabetic nephropathy.

METHODS

We developed a non-competitive immunoluminometric assay with in-house antibodies to the N- and C-terminal domains of NT proBNP. We compared NT proBNP levels between 47 normoalbuminuric patients (group 1), 12 microalbuminuric patients (group 2) and 12 patients with macroalbuminuria (group 3).

RESULTS

There were significant differences in 24-h systolic and diastolic blood pressure, diabetes duration, serum creatinine, LDL-cholesterol and HbA1c between the three groups; other parameters did not differ significantly. NT proBNP (median and range) levels were 5 (0.75-68), 22 (0.75-82) and 23 (0.75-374) fmol/ml for groups 1-3, respectively. Log-transformed data of NT proBNP were used to compare all three groups (P=0.016). The Pearson correlation between NT proBNP and albuminuria (R=0.27; P=0.02) was positive; HbA1c (R=0.25; P=0.03) and age (R=0.33; P=0.005) correlated significantly as well. On the basis of multiple regression analysis, the adjusted difference remained significant between the three groups.

CONCLUSIONS

This is the first demonstration that NT proBNP levels are significantly higher in Type 1 diabetic patients with albuminuria. This may be caused by a down-regulation of A-type guanylate cyclase-coupled natriuretic peptide receptors in renal tubules or by elevated NT proBNP levels leading to higher glomerular hydraulic pressure or higher capillary permeability and possibly increased albumin excretion. Further studies are required to investigate the potential role of NT proBNP in patients with diabetic nephropathy and such other co-morbidities as cardiovascular disease.

Cardiac hormones as diagnostic tools in heart failure

In patients with heart failure, plasma levels of atrial natriuretic peptide (ANP), B-type natriuretic peptide (BNP), and the N-terminal fragments of their prohormones (N-ANP and N-BNP) are elevated, because the cardiac hormonal system is activated by increased wall stretch due to increased volume and pressure overload. Patients suspected of having heart failure can be selected for further investigations on the basis of having an elevated plasma concentration of N-ANP, BNP, and N-BNP. High levels of cardiac hormones identify those at greatest risk for future serious cardiovascular events. Moreover, adjusting heart failure treatment to reduce plasma levels of N-BNP may improve outcome. Cardiac hormones are most useful clinically as a rule-out test. In acutely symptomatic patients, a very high negative predictive value is coupled with a relatively high positive predictive value. Measurement of cardiac hormones in patients with heart failure may reduce the need for hospitalizations and for more expensive investigations such as echocardiography. However, there have also been conflicting reports on the diagnostic value of cardiac hormones, they are not specific for any disease, and the magnitude of the effects of age and gender on BNP in the normal subgroup suggests that these parameters need to be considered when interpreting cardiac hormone levels.

Health-related quality of life of Japanese patients with chronic heart failure: assessment using the Medical Outcome Study Short Form 36

Chronic heart failure is characterized by impaired cardiac function, but the relationship between clinical indices and subjective perception is not clear. This study was undertaken to investigate the relationship between cardiac function, exercise capacity and clinical classification, and the health-related quality of life (HRQOL) in 91 outpatients with an left ventricular ejection fraction (LVEF) less than 40%. Exercise capacity was evaluated by the Specific Activity Scale, and HRQOL by the Medical Outcome Study Short Form 36. Exercise capacity and the cardiothoracic ratio were correlated with the HRQOL related to physical functioning, although the correlation between exercise capacity and mental health was not significant. LVEF was not related to HRQOL. Factor analysis revealed (1) LVEF was independent of physical functioning; (2) physical function and exercise capacity comprise a factor reflecting physical HRQOL; and (3) socio-emotional functioning is the third factor independent of LVEF and physical function. Physical and socio-mental HRQOL measurement included information independent of the widely used clinical indices such as LVEF and New York Heart Association classification. The evaluation of HRQOL should be included in the assessment of patient status.

Use of thallium-201 myocardial scintigraphy for the prediction of the response to beta-blocker therapy in patients with dilated cardiomyopathy

This study was performed to evaluate whether thallium-201 myocardial scintigraphy (Tl-201) and iodine-123-metaiodobenzylguanidine (MIBG) myocardial scintigraphy could predict the usefulness of beta-blocker therapy in patients with dilated cardiomyopathy (DCM). Tl-201 and MIBG were performed in 47 patients before beta-blocker therapy. Patients were classified into group A, if their cardiac function improved, and group B, whose function remained unchanged. Two types of extent score (ES) by Tl-201 were proposed to quantitate myocardial damage, mean-2SD (ES-2) and mean-3SD (ES-3). The ES difference between ES-2 and ES-3 was calculated, and according to ES and ES difference, DCM cases were classified into 3 groups: mild-defect type (mild-type), moderate-defect type (moderate-type) and severe-defect type (severe-type). The heart-to-mediastinum (H/M) MIBG uptake ratio was evaluated, and the percent washout ratio of myocardial MIBG was obtained from these data. Group A comprised 18 mild-type, 14 moderate-type and 1 severe-type cases, and group B comprised 5 mild-type, 4 moderate-type and 5 severe-type cases. A significant relation was observed between the defect type on Tl-201 and the response to beta-blocker therapy (p=0.0090). Both H/M MIBG uptake ratios and washout ratio were not significantly different in the 2 groups. Tl-201 may be useful for predicting the response to beta-blocker therapy in patients with DCM.

Atenolol improves ventricular function without changing plasma noradrenaline but decreasing plasma atrial natriuretic factor in chronic heart failure

1 There is good evidence that beta-blockers improve ventricular function, disease progression and survival in patients with left ventricular systolic dysfunction. The aim of this study was to determine the effects of atenolol therapy on the sympathetic nervous system at rest and after ergometric exercise, on left ventricular function and on baseline plasma atrial natriuretic factor (ANF) in ambulatory patients with chronic heart failure (CHF). 2 Twenty-two patients [left ventricular ejection fraction (LVEF) <36%; New York Heart Association II-III] were studied before atenolol treatment. Because of cardiac events (new Hospital admission or death) only 13 patients completed 1 year of treatment. Baseline noradrenaline (NE) concentrations were similar in patients and controls while ANF was higher in patients than in controls (328 +/- 35 pg ml(-1) vs. 37 +/- 3 pg ml(-1); P<0.01). 3 Patients with events showed higher NE (540 +/- 87 pg ml(-1) vs. 303 +/- 44 pg ml(-1); P<0.01) and ANF (460 +/- 70 pg ml(-1) vs. 291 +/- 44 pg ml(-1); P<0.03) at rest; and greater NE response to exercise (2.003 +/- 525 pg ml(-1) vs. 694 +/- 121 pg ml(-1); P<0.005). Atenolol treatment improved LVEF (19.5 +/- 1.9% vs. 33 +/- 3.9%; P<0.001), increased exercise tolerance (9 +/- 3.2 min vs. 17 +/- 4.8 min; P<0.001) and decreased plasma ANF (292 +/- 42 pg ml(-1) vs. 133 +/- 35 pg ml(-1); P<0.01). 4 Reduced basal dihydroxyphenylglycol (DHPG)/NE ratio (3.4 +/- 0.46 vs. 4.3 +/- 0.35; P<0.01) was observed in patients compared with healthy volunteers. Atenolol increased DHPG plasma levels (1.398 +/- 129 pg ml(-1) vs. 913 +/- 86 pg ml(-1); P<0.005) but the DHPG/NE ratio during exercise was not modified after treatment, suggesting that re-uptake of released NE is not changed by beta-blocker treatment. 5 In conclusion, the fact that atenolol treatment improves ventricular dysfunction and clinical status without changing plasma NE levels in CHF patients, suggests that plasma NE is a poor surrogate measurement for cardiac sympathetic activity in this pathology. In addition, decrease in plasma ANF produced by atenolol treatment may reflect the improvement of ventricular function.

Long-term survival of non-elderly patients with severe heart failure treated with angiotensin-converting enzyme inhibitors assessment of treatment with captopril and enalapril survival study (ACESS)

The present study examined the effect of treatment with angiotensin-converting enzyme inhibitors (ACEIs) on the long-term prognosis in 119 patients with dilated cardiomyopathy (DCM). Conventional therapy was used in 29 patients and 90 patients were treated with ACEIs: 50 were taking captopril and 40 were taking enalapril; 24 were taking > or = 75 mg captopril or > or = 20 mg enalapril daily (high-dose group) and 66 patients received smaller doses (low-dose group). No significant differences between groups were detected with respect to demographics and clinical signs of congestive heart failure (CHF). During follow-up, 65 patients survived and 54 patients died: 34 patients were in group 1 and 20 patients were in the placebo group. Patients treated with ACEIs had a significantly better survival during the first to third year, but the difference was not significant between the high- and low-dose groups. Comparison of the cumulative probability of death in the enalapril and captopril groups showed a trend of significant reduction of mortality by 13% in the enalapril group (p<0.10). These data indicate that ACEIs have a beneficial effect on prolonging the short- and long-term survival in DCM patients, so it is strongly recommended that all patients with DCM should be treated with ACEIs unless contraindicated. In this study, lower doses of ACEI seemed prognostically equivalent to higher doses, and enalapril appeared to be preferable to captopril in the treatment of severe CHF. Additional prospective large studies are necessary to verify the relationship observed here between the optimal dosage as well as the duration of action of different ACEIs and their outcomes.

Beneficial effect of replacing of angiotensin-converting enzyme inhibitor with angiotensin II antagonist for heart failure patients

OBJECTIVE

Angiotensin-converting enzyme (ACE) inhibitors and beta-blockers improve prognosis inpatients with chronic heart failure. Some patients, however, show little response to combined treatment with an ACE inhibitor and a beta-blocker. In addition, the ACE inhibitor cannot completely suppress angiotensin II production. Our objective was to examine whether replacing the ACE inhibitor with an angiotensin II antagonist can improve the condition of patients with chronic heart failure.

METHODS

In 11 patients with chronic heart failure treated with an ACE inhibitor and a beta-blocker, who have had severe left ventricular dysfunction or high plasma level of natriuretic peptides, left ventricular dimension, and fractional shortening, plasma atrial and brain natriuretic peptide (ANP and BNP) levels were determined before and 3 months after the change of treatment.

RESULTS

After substituting the ACE inhibitor with an angiotensin II antagonist, patients showed New York Heart Association functional class improvement, and significant decrease in left ventricular dimension and BNP.

CONCLUSION

In patients with severe chronic heart failure treated with an ACE inhibitor and a beta-blocker, replacing the ACE inhibitor with an angiotensin II antagonist may be effective. However, this has to be confirmed by an adequately powered randomized controlled study.

BNP in hormone-guided treatment of heart failure

The pharmacotherapy of heart failure has become complex. Angiotensin-converting enzyme inhibitors (or angiotensin II receptor blockers), beta-blockers, spironolactone, diuretics and digoxin can be prescribed concurrently. Endothelin antagonists and combined inhibitors of converting enzyme and neutral endopeptidase are under investigation. Optimal dosing will become increasingly difficult to judge. Plasma brain natriuretic peptide (BNP) indicates the severity of left ventricular dysfunction. The C-terminal bioactive peptide and N-terminal BNP (N-BNP) circulate at concentrations related to cardiac status. We proposed that plasma levels of N-BNP would provide an index to guide drug treatment in established heart failure. Sixty-nine patients were randomized to treatment adjusted according to clinical criteria or plasma N-BNP. Hormone-guided therapy resulted in fewer clinical end points than did clinical management. This encourages further exploration of hormone guidance of anti-heart failure therapy, which could be extended to patients with preserved ejection fraction, in addition to those with established systolic dysfunction.

Surrogate end points in heart failure

OBJECTIVE

To describe the potential utility of a true surrogate marker of heart failure outcomes, historically investigate the validity of surrogates most commonly evaluated in heart failure, and identify specific end points offering the most potential for future use.

DATA SOURCES

A MEDLINE search (1966-June 2001) was completed to identify relevant literature. Additional references were also retrieved from selected articles. Search terms included b-type natriuretic peptide, cardiac remodeling, end-diastolic volume, heart failure, and surrogate end points.

DATA SYNTHESIS

By definition, true surrogate end points must predict outcomes associated with disease progression and response to therapy. A validated surrogate measure of mortality would render significant utility in both heart failure drug development and clinical practice. Improvements in traditional functional markers of heart failure, including ejection fraction and exercise capacity, have produced inconsistent results in regard to mortality in a number of clinical trials. Numerous measures of cardiac remodeling and neurohormonal activation, however, have proven to be reliable predictors of disease progression and therapeutic response. These findings have contributed significantly to the current understanding of heart failure pathophysiology and approach to treatment. Specifically, measures such as left-ventricular end-diastolic volume (LVEDV) and, potentially, b-type natriuretic peptide (BNP) concentrations may correlate with disease progression and parallel the mortality reductions observed with angiotensin-converting enzyme inhibitor and beta-blocker therapy.

CONCLUSIONS

Currently, LVEDV and plasma BNP offer the greatest potential as surrogate end points in heart failure. Further investigation of these measures is required before routine implementation in drug development and clinical practice can be justified.

Clinical significance of blood brain natriuretic peptide level measurement in the detection of heart disease in untreated outpatients: comparison of electrocardiography, chest radiography and echocardiography

The aim of present study was to compare the predictive characteristics and cost-benefit of measuring the concentration of blood brain natriuretic peptide (BNP), compared with electrocardiography (ECG), chest radiography and echocardiography, as a diagnostic test for heart disease. The study group comprised 130 untreated patients who had symptoms suggestive of heart disease. According to the results of additional examinations and follow-up checks, 86 patients were diagnosed as having heart disease and 44 patients were judged free of heart disease. Positive findings in each test suggestive of heart disease were checked in accordance with criteria, and the number of positive and negative cases for each test was calculated. The predictive characteristics, such as specificity, sensitivity, accuracy, positive and negative predictive values, of each test and the cost-benefit value were calculated and analyzed statistically. The sensitivity, specificity and accuracy of blood BNP and echocardiography were significantly greater than those of ECG and chest radiography. Echocardiography had a significantly lower cost-benefit value compared with measuring blood BNP concentration. Thus, the blood BNP concentration had significantly higher predictive characteristics than ECG and chest radiography, and a cost-benefit value significantly greater than that of echocardiography.

Relationship between cardiac 123I-metaiodobenzylguanidine imaging and the transcardiac gradient of neurohumoral factors in patients with dilated cardiomyopathy

Cardiac sympathetic nervous function is altered in congestive heart failure (CHF) and the uptake and washout rate of cardiac 123I-metaiodobenzylguanidine (MIBG) are useful markers for evaluating the severity of it. To assess what parameters predict decreased uptake or increased washout rate of MIBG, the concentrations of neurohumoral factor in both the aorta (Ao) and coronary sinus (CS) were measured, as well as hemodynamic parameters by catheterization, in patients with dilated cardiomyopathy (DCM). MIBG imaging was performed within 1 week of cardiac catheterization. Regarding MIBG parameters, the correlation with the transcardiac gradient of norepinephrine (NE), brain natriuretic peptide (BNP) and hemodynamics was investigated. Stepwise multivariate regression analysis was used to determine which variables closely correlated with cardiac MIBG parameters. There was a significant increase in the NE level between the Ao (446 pg/ml) and the CS (727 pg/ml). According to stepwise multivariate regression analysis, the heart/mediastinum (H/M) ratio independently correlated with the transcardiac gradient of BNP (r=-0.480, p<0.01), and the washout rate independently correlated with the transcardiac gradient of NE (r=0.481, p<0.01). These findings indicate that the H/M ratio may reflect the transcardiac gradient of BNP, which implies the degree of left ventricular dysfunction and/or damage and the washout rate may reflect altered cardiac sympathetic nerve terminal in DCM patients with CHF, suggesting that both the H/M ratio and washout rate provide important information about the failing ventricle.

Brain natriuretic peptide-guided therapy for heart failure

The drug treatment of heart failure, once simple, has become complex. Apart from a loop diuretic and digoxin, most patients should now be receiving an angiotensin-converting enzyme inhibitor (or angiotensin II receptor blocker), a beta-blocker and spironolactone. Newer drugs, such as endothelin-receptor antagonists and combined blockers of converting-enzyme and neutral endopeptidase, might soon become available. When to introduce these drugs and what dose is optimal for any individual, are questions that currently vex clinicians. We proposed that plasma levels of the cardiac hormone brain natriuretic peptide (BNP, or better, its 1-76 amino-acid N-terminal fragment, N-BNP), would provide an objective index for guiding drug treatment in patients with established, stable cardiac failure. In a pilot study, 69 patients were randomized to drug treatment based on clinical criteria, or based on plasma levels of N-BNP. After a median follow-up of 9.6 months, those in the N-BNP group had fewer clinical end-points than those in the group managed by clinical criteria alone (19 vs 54; P= 0.02). These preliminary data encourage the concept that the increasingly complex pharmacotherapy for heart failure, both chronic (as in this trial) and acute, might best be guided by an objective measure such as plasma levels of BNP or N-BNP.

Effect of beta-blockers on circulating levels of inflammatory and anti-inflammatory cytokines in patients with dilated cardiomyopathy

OBJECTIVES

This study was designed to evaluate the beneficial effect of beta-blockers on circulating cytokine levels in patients with dilated cardiomyopathy (DCM).

BACKGROUND

Elevated circulating levels of inflammatory cytokines have been reported in patients with DCM. However, alterations of the levels of inflammatory and anti-inflammatory cytokines in association with beta-blocker therapy are unknown.

METHODS

We studied 32 patients with idiopathic DCM who had been treated with digitalis, diuretics and angiotensin-converting enzyme inhibitors. In addition to this combination therapy, beta-blockers were started in all patients. Serum levels of interleukin (IL)-10, tumor necrosis factor-alpha (TNF-alpha) and soluble TNF receptors (sTNF-R1 and R2) were measured at baseline and 12 weeks after the initiation of beta-blocker therapy. We also measured plasma levels of neurohumoral factors, as well as left ventricular (LV) size and function. Ten age-matched subjects with no cardiac disease served as the control group.

RESULTS

Baseline levels of IL-10, TNF-alpha and sTNF-R2 were significantly higher in patients with DCM than in control subjects (p < 0.05). There was a significant positive correlation between IL-10 and TNF-alpha levels (r = 0.545, p = 0.029). The TNF-alpha/IL-10 ratio correlated well with plasma epinephrine levels (r = 0.677, p = 0.025), and the level of sTNF-R2 was closely related to LV size. Serum levels of IL-10, TNF-alpha and sTNF-R2 were significantly decreased during beta-blocker therapy (p < 0.005).

CONCLUSIONS

Our findings indicate that beta-blockers have an important immunoregulatory role in modifying the dysregulated cytokine network in DCM. This effect of beta-blockers may be partly responsible for the efficacy of therapeutic drugs for heart failure.