Effects of beta-blockers on neurohormonal activation in patients with congestive heart failure

Discontinuation of angiotensin-converting enzyme inhibitors or beta-blockers and the impact on heart failure hospitalization rates

BACKGROUND

Adherence to evidence-based therapy is essential for optimal management of heart failure. Yet, medication adherence is poor in heart failure patients. The Ascertaining Barriers to Compliance Project decomposed the medication adherence process into initiation, implementation, and discontinuation stages, but electronic monitoring-based adherence analyses usually do not consider this process.

AIMS

The aim of this study was to describe individual-patient patterns of medication adherence from electronic monitoring data among adults with chronic heart failure, adherence types, and risk factors for increased all-cause hospitalization including measures of poor adherence such as discontinuation.

METHODS

Data from two prospective studies of adherence measured with electronic monitoring for heart failure patients were combined and restricted to monitoring of angiotensin-converting enzyme inhibitors and beta-blockers over an initial three-month period. Hospitalizations were recorded for this period as well as for a three-month follow-up period. Analyses were conducted using adaptive modeling methods to identify individual-patient adherence patterns, adherence types, and risk factors for an increased hospitalization rate.

RESULTS

Using electronic monitoring data for 254 heart failure patients, four adherence types were identified: highly consistent, consistent but variable, moderately consistent, and poorly consistent. Sixteen individually significant risk factors for increased hospitalization rates were identified and used to generate a multiple risk factors model. Medication discontinuation was the most important individual risk factor and most important in the multiple risk factors model.

CONCLUSION

Discontinuation of angiotensin-converting enzyme inhibitors or beta-blockers increases hospitalization rates for heart failure patients. Interventions that effectively address this problem are urgently needed.

The nitric oxide/soluble cyclic guanylase/cyclic guanosine monophosphate pathway is involved in the cardiovascular effects of a novel α1- and β-adrenoceptor antagonist

The compound MH-78 ((+/-)-1-(2,6-dimethylphenoxy)-3-{4-[2-(2-methoxyphenoxy)ethyl]-piperazin-1-yl}propan-2-ol dihydrochloride) contains structural elements that are typical for α1- and β-blockers. This study aimed to investigate the hypotensive activity as well as the in vitro and in vivo cardiovascular effects of a novel α1- and β-adrenoceptor antagonist (MH-78) and compare it with carvedilol and urapidil. The procedures were performed on aortic rings of normotensive anesthetized rats. MH-78 decreased the blood pressure and heart rate after intravenous and oral administration. MH-78 possesses both α1- and β-adrenoceptor blocking activity, which was confirmed in the in vivo study. In biofunctional assays, MH-78 displayed vasorelaxant activity due to α1-adrenoceptor antagonism and calcium channel blocking properties. Moreover, in endothelium-intact aortic rings, pretreatment with Nω-nitro-L-arginine methyl ester (L-NAME) and 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one (ODQ) reduced the MH-78-induced vasorelaxation to a level that is characteristic for MH-78 affinity to α1-adrenoceptors. Our results demonstrated that MH-78 possesses α1- and β-adrenoceptor blocking properties and induces potent hypotensive and vasorelaxant effects. Moreover, it relaxes vascular smooth muscle not only due to α1-adrenoceptor blocking activity, but also via the endothelium-dependent nitric oxide/soluble guanylyl cyclase/cyclic guanosine monophosphate signalling pathway.

Meditation Reduces Sympathetic Activation and Improves the Quality of Life in Elderly Patients with Optimally Treated Heart Failure: A Prospective Randomized Study

OBJECTIVE

We tested whether meditation can reduce sympathetic activation, evaluated by norepinephrine blood levels (NE), and improve quality of life in elderly persons with congestive heart failure (CHF).

DESIGN AND SETTING

This was a prospective, randomized study conducted from April 2000 to October 2001 in an ambulatory care teaching hospital in São Paulo, Brazil.

SUBJECTS

We studied 19 patients with CHF, 74.8 +/- 6.7 years old, receiving diuretics, optimal doses of an angiotensin-converting enzyme inhibitor or angiotensin II inhibitor, maximum tolerated carvedilol dose (23.1 +/- 13.6 mg) and spironolactone 25 mg (10 patients).

INTERVENTIONS

After 2 months of optimal treatment with carvedilol, patients were randomized into two groups. The meditation group (M) was provided an audiotape, 30 minutes long, to listen to at home, twice a day, for 12 weeks, plus a weekly meeting. The control group (C) just had weekly meetings.

MAIN OUTCOME MEASURES

We determined before and after 14 +/- k1 weeks, NE (in pg/mL); quality of life with the Minnesota Living with Heart Failure Questionnaire (MLWHFQ); VO2 and VE/VCO2 slope by cardiopulmonary exercise testing; left ventricular ejection fraction (LVEF), and left ventricular end-diastolic volume index (LVDDi) measured by echocardiography.

RESULTS

Meditation reduced NE (mean +/- SEM) from 677.7 +/- 96.6 to 387.1 +/- 39.1 pg/mL (p = 0.008) in M versus 491.4 +/- 35.9 to 470.6 +/- 31.2 (p = 0.34) in C; improved MLWHFQ total score (mean +/- SEM) from 33.2 +/- 6.6 to 21.6 +/- 6.8 points (p = 0.02) in M versus 18.4 +/- 8.0 to 25.1 +/- 8.9 (p = 0.41) in C; and reduced the VE/VCO2 slope (mean +/- SEM) from 31.2 +/- 3.0 to 28.2 +/- 2.6 (p = 0.04) in M versus 28.4 +/- 2.7 to 28.8 +/- 2.6 (p = 0.24) in C. No changes occurred in LVEF, LVDDi, and VO(2).

CONCLUSIONS

In elderly patients with optimally treated CHF, meditation reduced NE, improved quality of life, and reduced the VE/VCO(2) slope. Our results support the possible role of meditation as a new hope in the treatment of CHF.

Beneficial effect of candesartan treatment on cardiac autonomic nervous activity in patients with chronic heart failure: simultaneous recording of ambulatory electrocardiogram and posture

BACKGROUND

Reclining in the right lateral decubitus position in chronic heart failure (CHF) is a self-protective mechanism for normalizing impaired cardiac autonomic nervous activity (CANA).

HYPOTHESIS

Candesartan, an angiotensin II receptor blocker, exerts beneficial effects on CANA and postural preferences in patients with CHF.

METHODS

We studied 15 patients with CHF due to coronary artery disease. Cardiac autonomic nervous activity was assessed using spectral heart rate variability (HRV) analysis based on 24-h ambulatory electrocardiogram monitoring before and after an 8-week treatment with candesartan. The patients' posture was simultaneously recorded using a specially devised detector, as the right (R) or left (L) lateral decubitus or supine (S) positions, to evaluate postural modulations of CANA. Normalized high-frequency (0.15 to 0.40 Hz) power (nHF) and the low-frequency (0.04 to 0.15 Hz)/high-frequency power ratio (LF/HF) were used as indices of vagal activity and sympathovagal balance, respectively.

RESULTS

When HRV was analyzed in each position, CANA was changed in L and S, but not in R, from sympathetic to parasympathetic prevalence by the treatment (R, nHF, 50 +/- 20 vs. 52 +/- 19 nu, p = 0.87; LF/HF, 1.39 +/- 1.11 vs. 1.32 +/- 1.32, p =0.93; L, nHF, 28 +/- 13 vs. 47 +/- 19 nu, p = 0.019; LF/HF, 3.34 +/- 2.48 vs. 1.56 +/- 1.39, p = 0.029; S, nHF, 38 +/- 17 vs. 53 +/- 16 nu, p = 0.0023; LF/HF, 2.43 +/- 2.21 vs. 1.03 +/- 0.59, p = 0.025). The fractions of the time in R and L were decreased and increased, respectively, by the treatment (R, 40 +/- 30 vs. 18 +/- 24%, p = 0.0018; L, 11 +/- 20 vs. 27 +/- 26%, p = 0.025).

CONCLUSIONS

In patients with CHF, candesartan treatment improves cardiac autonomic balance, and the preference for the right lateral decubitus position disappears after the treatment.

Comparative effects of carvedilol and metoprolol on regional vascular responses to adrenergic stimuli in normal subjects and patients with chronic heart failure

BACKGROUND

Adrenergic receptor blockers used in the treatment of heart failure have distinct receptor affinity profiles. We hypothesized that alpha-adrenergic-blocking effects of carvedilol would limit vasoconstriction in response to adrenergic stimuli when compared with metoprolol.

METHODS AND RESULTS

Forearm vascular resistance responses to isometric handgrip and cold pressor test were determined by plethysmography before and during adrenergic receptor blockade in prospective randomized trials. Acute effects were assessed in a crossover trial in normal subjects (single dose of 25 mg carvedilol, 100 mg metoprolol tartrate, and placebo). Chronic effects (25 mg carvedilol BID versus 200 mg extended-release metoprolol succinate daily for 6 months) were assessed in a parallel group trial of chronic heart failure subjects. In normal subjects, carvedilol decreased forearm vascular resistance responses to adrenergic stimuli when compared with metoprolol and placebo (isometric handgrip -3.5 U for carvedilol versus -1.2 U for metoprolol and -2.2 U for placebo, P=0.15; cold pressor test 3.1+/-8.9 U for carvedilol versus 9.0+/-2.7 U for metoprolol and 8.2+/-5.8 U for placebo, P<0.05). In heart failure subjects, vasomotor responses to isometric handgrip and cold pressor test did not differ between treatment groups.

CONCLUSIONS

Acute administration of carvedilol attenuates the vasoconstriction response to adrenergic stimuli when compared with placebo and metoprolol in normal subjects, whereas chronic administration of carvedilol does not attenuate the vasoconstrictor response to adrenergic stimuli when compared with metoprolol in heart failure subjects. These data suggest that long-term benefits of carvedilol in heart failure are not mediated by alpha-adrenergic blockade.

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

BACKGROUND

Brain natriuretic peptide (BNP) and norepinephrine (NE) are strongly related to severity of and are independent predictors of outcome in heart failure. The long-term effects of angiotensin receptor blockers on BNP and NE in heart failure patients are not known.

METHODS AND RESULTS

Both BNP and NE were measured in 4284 patients randomized to valsartan or placebo in the Valsartan Heart Failure Trial (Val-HeFT) at baseline and 4, 12, and 24 months after randomization. The effects of valsartan were tested by ANCOVA, controlling for baseline values and concomitant ACE inhibitors and/or beta-blockers. BNP and NE concentrations were similar at baseline in the 2 groups and were decreased by valsartan starting at 4 months and up to 24 months. BNP increased over time in the placebo group. At the end point, least-squares mean (+/-SEM) BNP increased from baseline by 23+/-5 pg/mL in the placebo group (n=1979) but decreased by 21+/-5 pg/mL (n=1940) in the valsartan group (P<0.0001). NE increased by 41+/-6 pg/mL (n=1979) and 12+/-6 pg/mL (n=1941) for placebo and valsartan, respectively (P=0.0003). Concomitant therapy with both ACE inhibitors and beta-blockers significantly reduced the effect of valsartan on BNP but not on NE (P for interaction=0.0223 and 0.2289, respectively).

CONCLUSIONS

In Val-HeFT, the largest neurohormone study in patients with symptomatic chronic heart failure, BNP and NE rose over time in the placebo group. Valsartan caused sustained reduction in BNP and attenuated the increase in NE over the course of the study. These neurohormone effects of valsartan are consistent with the clinical benefits reported in Val-HeFT.

Role of brain natriuretic peptide in the diagnosis and management of heart failure: current concepts

BACKGROUND

Progression of heart failure is related to ventricular remodeling, a process associated to neurohormonal activation. Brain natriuretic peptide (BNP), a member of the natriuretic peptide family, has recently emerged as an important neurohormone in the pathophysiology of heart failure.

METHODS

In this update, some of the recent advances on the role of BNP in heart failure are summarized. In particular, the role of BNP in diagnosis of heart disease, as a prognostic marker of cardiovascular events and as a possible guide to optimize heart failure therapy is discussed.

RESULTS

Recent results from 4,300 patients enrolled in the Valsartan Heart Failure Trial (Val-HeFT) confirmed that BNP is the strongest predictor of outcome in heart failure, when compared to other neurohormones and clinical markers. The current use of BNP in the screening and diagnosis of heart failure and its possible future roles are presented.

CONCLUSION

In recent years, there has been an impressive accumulation of data supporting an important role of BNP as a diagnostic and prognostic marker of heart failure. Development of rapid, accurate and affordable diagnostic methods will allow the routine monitoring of BNP in a wide spectrum of settings, from general practice to controlled clinical trials.

Mediators of chronic heart failure: how drugs work

OBJECTIVE

To critically review the pathophysiology of chronic heart failure at the neurohormonal level, and discuss the effect of present and future therapeutic options on these neurohormones.

DATA SOURCES

A MEDLINE search (1986-November 2000) was used to identify important primary literature and reviews. Additional references were obtained from these articles.

DATA SYNTHESIS

Chronic heart failure is a common, progressive disorder with high morbidity and mortality. Progression is due in large part to several redundant neurohormonal responses. The neurohormones include angiotensin II, norepinephrine, aldosterone, endothelin-1, arginine vasopressin, and tumor necrosis factor. These responses are initially adaptive, but become maladaptive in the long term, impairing the function of the heart, vasculature, and kidneys. Counter-regulatory hormones, such as bradykinin and natriuretic peptides, are insufficient to offset the adverse effects of the other neurohormones. Most drugs used to treat chronic heart failure, such as angiotensin-converting enzyme inhibitors, beta-adrenergic antagonists, and spironolactone, achieve their benefits through altering the neurohormonal pathways. New agents that affect more or different neurohormones may soon be available.

CONCLUSIONS

Multiple agents are required for treatment of chronic heart failure, as no single agent can counteract all of the various adverse pathways. The appropriate prescription and use of such inherently complex regimens require significant physician and patient education.