Beta-blockers for heart failure: why, which, when, and where

Management of Heart Failure With Preserved Ejection Fraction in Elderly Patients: Effectiveness and Safety

The proportion of the elderly population continues to increase due to the global increase in longevity. Heart failure with preserved ejection fraction (HFpEF) is common in the elderly due to cellular aging, myocardial stiffness, and multiple comorbidities. This age group is often under-represented in clinical trials. In this narrative review, we looked into the latest evidence-based lines of management of HFpEF in this vulnerable cohort. In this narrative review, we brought the latest evidence on the treatment of HFpEf in the elderly. We searched the largest three scientific databases (Pubmed, Google Scholar, and EMBASE) using the search words (elderly, HFpEF, heart failure with preserved ejection fraction, guidelines, treatment, and management) in different combinations. To date, screening for and treatment of the causes of HFpEF (such as hypertension, coronary artery disease [CAD], valvular heart disease, and cardiac amyloidosis) and associated comorbidities (such as diabetes mellitus [DM], iron deficiency, obesity, and thyroid dysfunction) are the main line of management of HFpEF. A multidisciplinary team, including an HF specialist cardiologist, an HF nurse, a geriatrician, a dietician, a psychologist, a physiotherapist, and an occupational therapist, should manage HFpEF elderly patients. Other specialist input may be needed according to the patient's requirements. The evidence on the effective management of HFpEF in the elderly age group is scarce and controversial. Some studied non-pharmacological approaches include supervised exercise training, pulmonary artery pressure monitoring, and the interatrial shunt device (an emerging modality that includes a small percutaneously inserted interatrial left to right valve aiming to reduce the left atrial and pulmonary wedge pressures). These modalities can only improve the symptoms and HF hospitalizations without robustly impacting cardiovascular (CV) death. Among the pharmacological approaches to treat HFpEF, only the sodium-glucose cotransporter 2 (SGLT-2) inhibitors proved efficacy in reducing the hard outcomes of CV death, HF hospitalizations, and urgent visits for HF when used in elderly HFpEF patients, irrespective of the presence of diabetes mellitus. Diuretics are only beneficial to alleviate the symptoms of fluid overload, with a risk of renal impairment in volume-depleted patients. The evidence on the effectiveness of other HF-specific disease-modifying agents in elderly HFpEF patients is controversial. Elderly patients have a higher risk of having side effects from HF medications due to the higher prevalence of polypharmacy, cognitive decline, and impairment of kidney and liver functions. Therefore, cautious initiation of HF treatment with a close follow-up of the blood pressure, liver functions, kidney functions, and electrolytes are of utmost importance.

β-blocker dialyzability and the risk of mortality and cardiovascular events in patients undergoing hemodialysis

BACKGROUND

β-blocker (BB) dialyzability has been proposed to limit their efficacy among hemodialysis (HD) patients. We attempted to confirm this hypothesis by comparing health outcomes associated with the initiation of dialyzable or nondialyzable BBs in a nationwide cohort of HD patients.

METHODS

We created a prospective cohort study of 15 699 HD patients who initiated dialyzable BBs (atenolol, acebutolol, metoprolol and bisoprolol) and 20 904 hemodialysis patients who initiated nondialyzable BBs (betaxolol, carvedilol and propranolol) between 2004 and 2011 in Taiwan healthcare. We compared the risk of all-cause mortality and major adverse cardiovascular events (MACEs, a composite of the acute coronary syndrome, ischemic stroke and heart failure) between users of dialyzable versus nondialyzable BBs during a 2-year follow-up.

RESULTS

New users of dialyzable BBs were younger, more often men, with diabetes mellitus, hypertension and hyperlipidemia compared with users of nondialyzable BBs. Compared with nondialyzable BBs, initiation of dialyzable BBs was associated with lower all-cause mortality {hazard ratio [HR] 0.82 [95% confidence interval (CI) 0.75-0.88]} and lower risk of MACEs [HR 0.89 (95% CI 0.84-0.93)]. Results were confirmed in subgroup analyses, censoring at BB discontinuation or switch, after 1:1 propensity score matching, reclassifying bisoprolol or excluding bisoprolol/carvedilol users.

CONCLUSIONS

This study does not offer support for the hypothesis that the dialyzability of BBs reduces their efficacy in HD patients.

Duration of β-adrenoceptor blockade associated with once-daily oral administration of atenolol in healthy dogs

OBJECTIVE To test the hypothesis that once-daily oral administration of atenolol would attenuate the heart rate response to isoproterenol for 24 hours. ANIMALS 20 healthy dogs. PROCEDURES A double-blind randomized placebo-controlled crossover study was conducted. Dogs were assigned to receive atenolol (1 mg/kg, PO, q 24 h) or a placebo for 5 to 7 days. After a washout period of 7 days, dogs then received the other treatment. Heart rate at rest (HR_r) and heart rate induced by administration of isoproterenol (HR_i) as a constant rate infusion (0.2 μg/kg/min for 5 to 7 minutes) were obtained by use of ECG 0, 0.25, 3, 6, 12, 18, and 24 hours after administration of the final dose of atenolol or the placebo. A mixed-model ANOVA was used to evaluate effects of treatment, time after drug or placebo administration, treatment-by-time interaction, period, and sequence on HR_r and HR_i. RESULTS Effects of sequence or period were not detected. There was a significant effect of treatment and the treatment-by-time interaction on HR_i. Atenolol significantly attenuated HR_i for 24 hours but did so maximally at 3 hours (least squares mean ± SE, 146 ± 5 beats/min and 208 ± 5 beats/min for atenolol and placebo, respectively). The effect at 24 hours was small (193 ± 5 beats/min and 206 ± 5 beats/min for atenolol and placebo, respectively). Atenolol had a small but significant effect on HR_r. CONCLUSIONS AND CLINICAL RELEVANCE This study of healthy dogs receiving atenolol supported a recommendation for a dosing interval < 24 hours.

Pharmacodynamics ofβ-Blockers in Heart Failure: Lessons from the Carvedilol Or Metoprolol European Trial

Heart failure is a growing public health problem in the United States, and the approach to the treatment of heart failure has undergone a radical transformation in the past decade. The use of β-blocker therapy in heart failure patients is now widely recommended, based on evidence from large-scale clinical trials demonstrating that bisoprolol, carvedilol, and extended-release metoprolol succinate significantly reduce morbidity and mortality in patients with heart failure. Although these agents appear to provide similar benefits, the question remains whether pharmacologic differences among them could translate to differences in clinical outcomes. The Carvedilol Or Metoprolol European Trial (COMET) compared nonselective blockade of the β1-/β2-/α1-adrenergic receptors with carvedilol versus selective β1-blockade with immediate-release metoprolol tartrate in patients with chronic heart failure. The trial found that carvedilol significantly reduced all-cause mortality compared with immediate-release metoprolol tartrate, although there were no differences in hospitalizations. Herein we review the pharmacokinetics and pharmacodynamics of metoprolol and carvedilol. In doing so, several issues regarding the design of COMET are identified that could alter the interpretation of the results of this trial. These include the choice of dose and dosage regimen of immediate-release metoprolol tartrate, a dosage form that has never been shown to reduce mortality in patients with heart failure. Additional studies are needed to fully understand whether there are any advantages of selective versus nonselective adrenergic blockade and whether there are any clinically meaningful differences in effectiveness between β-blockers with proven benefit in the management of chronic heart failure. The results of COMET demonstrate that all β-blockers and dosage forms are not interchangeable when prescribed for heart failure. Clinicians should choose only those agents (and dosage forms) that have been proven to reduce mortality in this patient population.

Influence of crossover on mortality in a randomized study of revascularization in patients with systolic heart failure and coronary artery disease

BACKGROUND

To assess the influence of therapy crossovers on treatment comparisons and mortality at 5 years in patients with ischemic heart disease and heart failure randomly assigned to medical therapy alone (MED) or to MED and coronary artery bypass graft (CABG) surgery in the Surgical Treatment for Ischemic Heart Failure (STICH) trial.

METHODS AND RESULTS

The influence of early crossover (within the first year after randomization) on 5-year mortality was assessed using time-dependent multivariable Cox models. CABG was performed in 65/602 patients (10.8%) assigned to MED, and 55/610 patients (9.0%) assigned to CABG received MED only. Common reasons for crossover from MED to CABG were progressive symptoms or acute decompensation. MED-assigned patients who underwent CABG had lower 5-year mortality than those who received MED only (25% vs 42%; hazard ratio, 0.50; 95% confidence interval, 0.30-0.85; P=0.008).The main reason for crossover from CABG to MED was patient/family decision. Five patients did not undergo their assigned CABG within a year but died before receiving surgery without status change. They were deemed crossover to MED. The CABG-to-MED crossover population had higher 5-year mortality compared with those treated with CABG per-protocol (59% vs 33%; hazard ratio, 2.01; 95% confidence interval, 1.36-2.96; P<0.001). CABG was associated with lower mortality compared with MED in per-protocol and several time-dependent analyses (all P<0.05).

CONCLUSIONS

CABG reduced mortality in both the per-protocol and crossover STICH patient populations. Crossover from assigned therapy, therefore, diminished the impact of CABG on survival in STICH when analyzed by intention to treat.

CLINICAL TRIAL REGISTRATION

URL: http://www.clinicaltrials.gov. Unique identifier: NCT00023595.

Hypertension 2010: what was new for the cardiologist?

IMPORTANCE OF THE FIELD

Despite extensive clinical research, still there is some uncertainty regarding management of hypertension, in particular initial and goal blood pressure levels and selection of optimal pharmacotherapy, as well as concomitant medications, to reduce other risk factors.

AREAS COVERED IN THIS REVIEW

An overview of recent findings from major clinical trials in hypertension (until July 2010), along with a reappraisal of the European Society of Hypertension 2009 guidelines.

WHAT THE READER WILL GAIN

Practical overview of the management of hypertension, including threshold and goal blood pressure in specific situations, choice of antihypertensive medications and indications for treatment of concomitant risk factors.

TAKE HOME MESSAGE

Primary benefits of antihypertensive therapy are mediated by blood pressure reduction and the majority of patients will require at least two drugs, with the preference of fixed-dose combinations for effective blood pressure control.

Action of propranolol in the reaction of smooth musculature of tracheal rings induced with acetylcholine, histamine, serotonin (5-HT) and prostaglandin (PGF2-alfa) in vitro and in vivo

Actions of acetylcholine (ACh), histamines, serotonins (5-HT) and prostaglandins (PGF2-alfa) in concentrations of 10(-4), 10(-3), 10(-2) and 10(-1) mol/dm(3) were analyzed in vitro conditions in isolated specimens of tracheas of 24 pigs, 7 guinea pigs, and dead persons for different reasons (8), in the presence and without presence of propranolol. Whilst, research regarding actions of aerosolized histamines (10 mg, 1%, 2 min), in the presence and without the presence of aerosolized propranolol (20 mg, 2%, 2 min) was done in vivo in 6 healthy persons. Study results show that propranolol does not emphasize contraction of the airways smooth musculature as induced by ACh, histamine, 5-HT and PGF2-alfa in vitro conditions (p>0,1). Also, in vivo we found a non-significance of tracheal smooth musculature constriction (p>0,1).

Effects of serotonin in failing cardiac ventricle: signalling mechanisms and potential therapeutic implications

Previously, cardioexcitation by serotonin (5-hydroxytryptamine, 5-HT) was believed to be confined to atria in mammals including man, and mediated through 5-HT(4) receptors in pig and man, but 5-HT(2A) receptors in rat. Recent studies, reviewed here, demonstrate that functional 5-HT(4) receptors can be revealed in porcine and human ventricular myocardium during phosphodiesterase inhibition, and that 5-HT(4) receptor mRNA is increased in human heart failure. In rats, functional 5-HT(4) and 5-HT(2A) receptors appear in the cardiac ventricle during heart failure and mediate inotropic responses through different mechanisms. 5-HT(2A) receptor signalling resembles that from alpha(1)-adrenoceptors and causes inotropic effects through increased myosin light chain phosphorylation, resulting in Ca(2+) sensitisation. 5-HT(4) receptor signalling resembles that from beta-adrenoceptors and causes inotropic effects through a pathway involving cAMP and PKA-mediated phosphorylation of proteins involved in Ca(2+) handling, resulting in enhanced contractility through increased Ca(2+) availability. Cyclic AMP generated through 5-HT(4) receptor stimulation seems more efficiently coupled to increased contractility than cAMP generated through beta-adrenoceptor stimulation. Increasing contractility through cAMP is considered less energy efficient than Ca(2+) sensitisation and this may be one reason why beta-adrenoceptor antagonism is beneficial in heart failure patients. Treatment of heart failure rats with the 5-HT(4) antagonist SB207266 (piboserod) resulted in potentially beneficial effects, although small. Further studies are needed to clarify if such treatment will be useful for patients with heart failure.

Metabolic profile of nebivolol, a beta-adrenoceptor antagonist with unique characteristics

beta-Adrenoceptor antagonists (beta-blockers) have historically been considered an effective and safe option for first-line treatment of hypertension. However, very recently, it has been proposed that beta-blockers should no longer be considered suitable for first-line therapy in the patient with uncomplicated hypertension because of unfavourable morbidity and mortality data. New evidence from recent clinical studies of nebivolol, a third-generation highly selective beta(1)-blocker with additional endothelial nitric oxide (NO)-mediated vasodilating activity, confirms previous findings that this drug differs from other beta-blockers. The combined mechanisms of beta-adrenoceptor antagonism and NO-mediated vasodilation may potentiate the blood pressure-lowering effect of this agent, and confer a broader favourable metabolic profile, which may be clinically relevant for hypertensive patients. The antioxidant properties of nebivolol and its neutral or even favourable effects on both carbohydrate and lipid metabolism are well documented. These properties consistently differentiate nebivolol from nonvasodilating beta-blockers such as atenolol, metoprolol or bisoprolol. Therapeutic indications for beta-blockers include a wide range of co-morbidities found in hypertensive patients, including ischaemic heart disease, tachyarrhythmias and heart failure. Given that the majority of hypertensive patients require more than one drug to control blood pressure, the multiple mechanisms of action and favourable metabolic profile of nebivolol could make it an alternative therapeutic option for hypertensive patients requiring beta-adrenoceptor therapy.

Hemodynamic effects of orally administered carvedilol in healthy conscious dogs

OBJECTIVE

To evaluate the hemodynamic effects of orally administered carvedilol in healthy dogs with doses that might be used to initiate treatment in dogs with congestive heart failure.

ANIMALS

24 healthy dogs.

PROCEDURE

Dogs were randomly allocated to receive carvedilol PO at a dose of 1.56, 3.125, or 12.5 mg, twice daily for 7 to 10 days; 6 dogs served as controls. Investigators were blinded to group assignment. Hemodynamic variables were recorded prior to administration of the drug on day 1 and then 2, 4, and 6 hours after the morning dose on day 1 and days 7 to 10. Change in heart rate after IV administration of 1microg of isoproterenol/kg and change in systemic arterial blood pressure after IV administration of 8 microg of phenylephrine/kg were recorded 2 and 6 hours after administration of carvedilol.

RESULTS

Administration of carvedilol did not significantly affect resting hemodynamic variables or response to phenylephrine. The interaction of day and carvedilol dose had a significant effect on resting heart rate, but a significant main effect of carvedilol dose on resting heart rate was not detected. Increasing carvedilol dose resulted in a significant linear decrease in heart rate response to isoproterenol.

CONCLUSIONS AND CLINICAL RELEVANCE

In healthy conscious dogs, orally administered carvedilol at mean doses from 0.08 to 0.54 mg/kg given twice daily did not affect resting hemodynamics. Over the dose range evaluated, there was a dose-dependent attenuation of the response to isoproterenol, which provided evidence of beta-adrenergic receptor antagonism.

Beta-blockade in the management of systolic dysfunction

The concept that heart failure is simply the consequence of impaired pump function is now outmoded. Congestive heart failure is a neuroendocrine syndrome in with activation of the adrenergic nervous system and specific endocrine pathways is integral to its pathogenesis. It is now clear that chronic increases in adrenergic drive associated with heart failure have detrimental effects on myocardial function. The use of BAAs is now standard therapy for people who develop heart failure caused by systolic dysfunction. Beta-blockade may have a role in the management of dogs with heart failure.

New developments in the use of β-blockers for the management of heart failure

Chronic heart failure (HF) has become a significant healthcare problem in the US. The number of new cases per year continues to grow steadily due to an ageing population and improved survival from acute coronary syndromes. As a consequence, the management of HF patients is of great importance. Effective management of HF includes stabilising the patient and improving the clinical symptoms associated with HF. Patients with HF have increased sympathetic nervous system activity that contributes to impaired cardiovascular function over time and subsequently results in death. beta-blockers prevent such impairment through inhibition of the sympathetic nervous system neurohormonal pathway. Numerous clinical trials conducted over the past decade have demonstrated that beta-blockers, in conjunction with angiotensin-converting enzyme inhibitors, are not only effective but are superior to other medical interventions for the treatment of HF. The standard of care for patients with HF now includes beta-blockers as well as ACE inhibitors.