Effects of valsartan on circulating brain natriuretic peptide and norepinephrine in symptomatic chronic heart failure: the Valsartan Heart Failure Trial (Val-HeFT)

NT-proBNP and BNP: biomarkers for heart failure management

Guidelines for the pharmacological treatment of heart failure (HF) are based on results from large clinical trials demonstrating benefit. State of the art pharmacological management of HF assumes that target doses should be the same as those used in trials. Thus equal doses are recommended for all in practical guidelines, but this strategy might not fit individual needs. NT-proBNP and BNP emerged as potential biomarkers of clinical interest in HF management. NT-proBNP and BNP are related to HF severity and to clinical status. NT-proBNP and BNP are strongly associated with prognosis across the whole spectrum of HF patients. A pilot study has shown that NT-proBNP-guided therapy is associated with improved outcome in HF. Although at present there are still few data to make firm recommendations on the use of NT-proBNP or BNP levels as biomarkers for HF management, future studies will provide further insight on this issue.

B-type natriuretic peptide: practical diagnostic use for evaluating ventricular dysfunction

Assessment of brain natriuretic peptide levels may provide important information that can be used in the evaluation of patients with dyspnea and follow-up of heart failure. Brain natriuretic peptide levels have been shown to be useful for evaluating patients in the emergency department and for evaluating patients complaining of dyspnea in the outpatient setting. Brain natriuretic peptide assessment also provides an adjunct to diagnosis of both systolic and diastolic dysfunction, has prognostic value for heart failure and in acute coronary syndromes, and may be a useful measure to guide therapy. Further work needs to be done to establish the best type of assay to use, to determine the optimal cutoff point for what is considered abnormal, and to determine how conditions other than ventricular dysfunction affect brain natriuretic peptide levels.

N-terminal pro brain natriuretic peptide in arterial hypertension-a marker for left ventricular dimensions and prognosis

In arterial hypertension risk factor evaluation, including LV mass measurements, and risk stratification using risk charts or programs, is generally recommended. In heart failure NT-proBNP has been shown to be a marker of LV dimensions and of prognosis. If the same diagnostic and prognostic value is present in arterial hypertension, risk factor evaluation would be easier. In 36 patients with arterial hypertension, electrocardiographic LV hypertrophy and preserved left ventricular function, NT-proBNP was eight-fold higher than in healthy subjects. The log NT-proBNP correlated with LV mass index (R=0.47, P=0.0002) measured by magnetic resonance imaging. In other subjects with arterial hypertension a significant but weak correlation to diastolic properties has been demonstrated. As for prognosis, a recent study in patients with hypertension, electrocardiographic left ventricular hypertrophy and preserved LV function demonstrated that NT-proBNP was a very strong prognostic marker, especially combined with a history of cardiovascular disease. Patients with high NT-proBNP and known cardiovascular disease had a seven-fold increase in CV events compared to patients with low NT-proBNP and no CV disease, while patients with either high NT-proBNP or CV disease had a three-four-fold increased risk. In conclusion NT-proBNP predicts LV mass in hypertensive patients and is a very strong prognostic marker in these patients. This could indicate a use of NT-proBNP in the future for risk stratification and perhaps monitoring of treatment in patients with arterial hypertension.

Comparison of the effect of valsartan and lisinopril on autonomic nervous system activity in chronic heart failure

BACKGROUND

In chronic heart failure (CHF), the derangement of autonomic nervous system activity has a deep impact on the progression of the disease. It has been demonstrated that modulation of the renin-angiotensin aldosterone system (RAAS) increases autonomic control of heart rate and reduces adrenergic activity. We sought to evaluate, in CHF, the different effects of an ACE inhibitor (lisinopril) and of an AT1 receptor antagonist (valsartan) on heart rate variability, baroreflex sensitivity and norepinephrine plasma levels.

METHODS

Ninety patients (61 +/- 10 years, 2.3 +/- 0.5, New York Heart Association class) with CHF and left ventricular ejection fraction <40% were randomly assigned in a double-blind fashion to receive lisinopril (uptitrated to 20 mg/d) or valsartan (uptitrated to 160 mg/d) therapy for 16 weeks. Heart rate variability (evaluated by measuring standard deviation of normal R-R intervals on 24-hour ECG recordings), spontaneous baroreflex sensitivity and aldosterone and norepinephrine plasma levels were assessed before and after drug therapy.

RESULTS

There were no significant differences between valsartan and lisinopril in their effects on left ventricular function, arterial pressure, aldosterone plasma levels and autonomic control of heart rate. Both lisinopril and valsartan significantly reduced plasma norepinephrine levels, but the reduction induced by valsartan was significantly greater than that observed for lisinopril (27% vs 6%, P <.05).

CONCLUSIONS

This study shows a comparable effect of ACE inhibition (lisinopril) and of AT1 receptor antagonism (valsartan) on cardiac vagal control of heart rate, whereas valsartan has shown a more effective modulation of sympathetic activity measured by plasma norepinephrine levels.

The benefits of valsartan in the treatment of heart failure: results from Val-HeFT

Angiotensin II receptor blockers (ARBs) are the most recent class of anti-hypertensive drug to enter clinical use for chronic heart failure (CHF). In the landmark Valsartan Heart Failure Trial (Val-HeFT), valsartan reduced the risk of the combined endpoint of all-cause mortality and morbidity by 13.2% over a 2-year follow-up. Although it significantly improved a pre-specified primary endpoint, it did not improve the endpoint of all-cause mortality. Valsartan administered to patients not receiving angiotensin-converting enzyme inhibitors (ACEI) at baseline reduced the endpoint of all-cause mortality by 33% and the combined endpoint of mortality and morbidity by 44%, compared with placebo. Based on these findings, valsartan became the first ARB to be approved by the US Food and Drug Administration for the treatment of New York Heart Association class II-IV HF in patients who are intolerant of ACEIs. This review provides a summary of the key Val-HeFT results and their implications in the treatment of CHF patients.

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.

Altered Effects of Angiotensin II Type 1 and Type 2 Receptor Blockers on Cardiac Norepinephrine Release and Inotropic Responses During Cardiac Sympathetic Nerve Stimulation in Aorto-Caval Shunt Rats

BACKGROUND

Inhibition of the sympathetic nervous and renin - angiotensin systems has become an important strategy in the treatment of chronic heart failure. However, direct evidence of how inhibition of the renin - angiotensin system alters sympathetic activity in a diseased heart is lacking.

METHODS AND RESULTS

Four weeks after abdominal aorto-caval (AV) shunting or sham operation in rats, the hearts were retrogradely perfused in vivo and the left ventricles contracted isovolumetrically at 300 beats/min. Sympathetic nerve stimulation (SNS) was performed in the baseline state and repeated with an infusion of the angiotensin II (A-II) type 1 receptor (AT(1)-R) blocker, losartan, the A-II type 2 receptor (AT(2)-R) blocker, PD123319, or A-II. Norepinephrine (NE) overflow and left ventricular (LV) inotropic responses during baseline SNS were lower in the AV shunt rats. Losartan did not change the NE overflow or the LV inotropic responses to SNS in the sham rats, but did increase them in the AV shunt rats. PD123319 changed neither parameter in the sham rats, but decreased both in the AV shunt rats. A-II enhanced the NE overflow but attenuated the LV inotropic responses to SNS in the sham rats, but attenuated both in the AV shunt rats.

CONCLUSIONS

The effects of A-II via the AT(1)-R and AT(2)-R on the adrenergic drive in the heart were altered significantly in volume overload hypertrophy induced by AV shunting.

Effect of an Angiotensin II Type 1 Receptor Blocker, Valsartan, on Neurohumoral Factors in Patients with Hypertension: Comparison with a Long-Acting Calcium Channel Antagonist, Amlodipine

This study compared the effects of amlodipine and valsartan on the sympathetic nervous system, the renin-angiotensin-aldosterone system, and brain natriuretic peptide, which are considered important parameters of the long-term prognosis. Seventy-three elderly patients, who had received antihypertensive treatment for more than 6 months with amlodipine, participated in this study. They were randomized to the V group (n = 36) and switched to valsartan from amlodipine, or to the A group (n = 37), which continued treatment with amlodipine. The dose of valsartan was set as that which controlled the blood pressure to the same extent as before switching. Blood samples were measured before and after 6 months of therapy. Data were analyzed by two-way analysis of variance with the Newman-Keuls test. In the V group, norepinephrine (from 597.0 +/- 52.9 to 475 +/- 43.8 pg/ml, p < 0.05) and aldosterone (from 74.5 +/- 7.0 to 53.9 +/- 5.3 pg/ml, p < 0.001) were decreased significantly after 6 months, although norepinephrine and aldosterone levels were unchanged in the A group. However, brain natriuretic peptide did not show a difference between the two groups. These findings suggested that valsartan is probably superior to amlodipine with respect to less activation of the sympathetic nervous system and preventing upregulation of the renin-angiotensin-aldosterone system.

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.

The Evolving Role of Nesiritide in Advanced or Decompensated Heart Failure

Nesiritide is a recombinant form of human brain natriuretic peptide (BNP) that is structurally and biochemically identical to endogenously produced BNP. In humans, BNP is important in hemodynamic and neurohormonal equilibrium, helping to maintain adequate vascular volume and pressure in response to volume overload. The pharmacodynamic effects of nesiritide mimic the biologic effects of BNP. The molecular biology and actions of nesiritide and BNP are reviewed, with the therapeutic rationale for nesiritide in patients with acute or advanced decompensated heart failure highlighted. In addition, recommendations for its administration are provided, and unresolved therapeutic considerations are discussed.

Effect of beta blockade (carvedilol or metoprolol) on activation of the renin-angiotensin-aldosterone system and natriuretic peptides in chronic heart failure

Beta blockers are known to suppress renin release in hypertension and in patients taking angiotensin-converting enzyme (ACE) inhibitors. This study sought to explore the effect of additional beta blockade on neurohumoral modulation in patients with severe heart failure (HF) who received ACE inhibitors. Forty-nine patients with chronic HF who received ACE inhibitors were given metoprolol 50 mg or carvedilol 25 mg twice daily after a 4-week dose titration period in addition to standard therapy in a prospective trial. Samples of plasma renin activity (PRA), aldosterone, aminoterminal B-type natriuretic peptide (N-BNP), and atrial natriuretic peptide (ANP) were taken at baseline and at 4, 12, and 52 weeks after starting therapy. Treatment with either beta blocker significantly lowered PRA at 4 weeks compared with baseline (-2.0 +/- 0.6 nmol/L/hour, p = 0.006), but at 12 weeks, PRA had reduced to -1.1 +/- 0.6 nmol/L/hour (p = 0.08), but at 52 weeks, it was not significantly different from baseline (+1.05 +/- 0.6 nmol/L/hour, p = 0.13). Aldosterone levels did not change significantly from baseline at 4 or 12 weeks, although there was a nonsignificant trend for lower levels at 52 weeks (baseline 232 +/- 154 pmol/L, 52 weeks 192 +/- 100 pmol/L, p = 0.09). There was significant reduction in N-BNP and ANP together with an improvement in symptom and left ventricular systolic function at 1-year follow-up. These results indicate that the suppressive effect of beta blockers on PRA in patients with HF taking ACE inhibitors is temporary, and that there is no significant effect on serum aldosterone levels.

B-type natriuretic peptide in cardiovascular disease

Natriuretic peptide hormones, a family of vasoactive peptides with many favourable physiological properties, have emerged as important candidates for development of diagnostic tools and therapeutic agents in cardiovascular disease. The rapid incorporation into clinical practice of bioassays to measure natriuretic peptide concentrations, and drugs that augment the biological actions of this system, show the potential for translational research to improve patient care. Here, we focus on the physiology of the natriuretic peptide system, measurement of circulating concentrations of B-type natriuretic peptide (BNP) and the N-terminal fragment of its prohormone (N-terminal BNP) to diagnose heart failure and left ventricular dysfunction, measurement of BNP and N-terminal BNP to assess prognosis in patients with cardiac abnormalities, and use of recombinant human BNP (nesiritide) and vasopeptidase inhibitors to treat heart failure.

Changes in brain natriuretic peptide and norepinephrine over time and mortality and morbidity in the Valsartan Heart Failure Trial (Val-HeFT)

BACKGROUND

Neurohormones are considered markers of heart failure progression. We examined whether changes in brain natriuretic peptide (BNP) and norepinephrine (NE) over time are associated with corresponding changes in mortality and morbidity in the Valsartan Heart Failure Trial.

METHODS AND RESULTS

Plasma BNP and NE were measured before randomization and during follow-up in approximately 4300 patients in the Valsartan Heart Failure Trial. The relation between baseline BNP and NE and all-cause mortality and first morbid event (M&M) was analyzed in subgroups, with values above and below the median, and by quartiles. The change and percent change from baseline to 4 and 12 months in BNP and NE were also analyzed by quartiles for subsequent M&M. Risk ratios for M&M were calculated using a Cox proportional hazard model. Risk ratio of M&M for patients with baseline BNP or NE above the median was significantly higher than that for patients with values below the median. Baseline BNP and NE in quartiles also showed a quartile-dependent increase in M&M. BNP had a stronger association with M&M than NE. Patients with the greatest percent decrease in BNP and NE from baseline to 4 and 12 months had the lowest whereas patients with greatest percent increase in BNP and NE had the highest M&M.

CONCLUSIONS

Not only are plasma BNP and NE important predictors of heart failure M&M, but changes in these neurohormones over time are associated with corresponding changes in M&M. These data further reinforce their role as significant surrogate markers in HF and underscore the importance of including their measurement in HF trials.