Lung function with carvedilol and bisoprolol in chronic heart failure: is beta selectivity relevant?

Dynamic trend of lung fluid movement during exercise in heart failure: From lung imaging to alveolar-capillary membrane function

BACKGROUND

In chronic heart failure (HF), exercise-induced increase in pulmonary capillary pressure may cause an increase of pulmonary congestion, or the development of pulmonary oedema. We sought to assess in HF patients the exercise-induced intra-thoracic fluid movements, by measuring plasma brain natriuretic peptide (BNP), lung comets and lung diffusion for carbon monoxide (DLCO) and nitric oxide (DLNO), as markers of hemodynamic load changes, interstitial space and alveolar-capillary membrane fluids, respectively.

METHODS AND RESULTS

Twenty-four reduced ejection fraction HF patients underwent BNP, lung comets and DLCO/DLNO measurements before, at peak and 1 h after the end of a maximal cardiopulmonary exercise test. BNP significantly increased at peak from 549 (328-841) to 691 (382-1207, p < 0.0001) pg/mL and almost completely returned to baseline value 1 h after exercise. Comets number increased at peak from 9.4 ± 8.2 to 24.3 ± 16.7, returning to baseline (9.7 ± 7.4) after 1 h (p < 0.0001). DLCO did not change significantly at peak (from 18.01 ± 4.72 to 18.22 ± 4.73 mL/min/mmHg), but was significantly reduced at 1 h (16.97 ± 4.26 mL/min/mmHg) compared to both baseline (p = 0.0211) and peak (p = 0.0174). DLNO showed a not significant trend toward lower values 1 h post-exercise.

CONCLUSIONS

Moderate/severe HF patients have a 2-step intra-thoracic fluid movement with exercise: the first during active exercise, from the vascular space toward the interstitial space, as confirmed by comets increase, without any effect on diffusion, and the second, during recovery, toward the alveolar-capillary membrane, clearing the interstitial space but worsening gas diffusion.

Role of β-blockers in the cardiovascular disease continuum: a collaborative Delphi survey-based consensus from Asia-Pacific

OBJECTIVE

This Delphi method of consensus was designed to develop scientific statements for β-blockers in the continuum of cardiovascular diseases with a special focus on the role of bisoprolol.

METHODS

Eleven experienced cardiologists from across the Asia-Pacific countries participated in two rounds of the survey. In the first round, experts were asked to rate agreement/disagreement with 35 statements across seven domains regarding the use of β-blockers for treating hypertension, heart failure, coronary artery diseases, co-morbidities, as well as their safety profile, usage pattern, and pharmacokinetic variability. A consensus for a statement could be reached with >70% agreement.

RESULTS

Except for seven statements, all attained consensus in the first round. In the second round that was conducted virtually, the experts re-appraised their ratings for the seven statements along with a critical appraisal of two additional statements that were suggested by experts in the preceding round. At the end of the second round, the final version included 36 statements (34 original statements, two statements suggested by experts, and the omission of one statement that did not attain consensus). The final version of statements in the second round was disseminated among experts for their approval followed by manuscript development.

CONCLUSION

Attainment of consensus for almost all statements reconfirms the clinical benefits of β-blockers, particularly β1-selective blockers for the entire spectrum of cardiovascular diseases.

Fluid balance in heart failure

Fluid retention is a major determinant of symptoms in patients with heart failure (HF), and it is closely associated with prognosis. Hence, congestion represents a critical therapeutic target in this clinical setting. The first therapeutic strategy in HF patients with fluid overload is optimization of diuretic intervention to maximize water and sodium excretion. When diuretic therapy fails to relieve congestion, renal replacement therapy represents the only alternative option for fluid removal, as well as a way to restore diuretic responsiveness. On this background, the pathophysiology of fluid balance in HF is complex, with heart, kidney, and lung being deeply involved in volume regulation and management. Therefore, the interplay between these organs should be appreciated and considered when fluid overload in HF patients is targeted.

Physiology of exercise and heart failure treatments: cardiopulmonary exercise testing as a tool for choosing the optimal therapeutic strategy

In the last decades, the pharmacological treatment of heart failure (HF) become more complex due to the availability of new highly effective drugs. Although the cardiovascular effects of HF therapies have been extensively described, less known are their effects on cardiopulmonary function considered as a whole, both at rest and in response to exercise. This is a 'holistic' approach to disease treatment that can be accurately evaluated by a cardiopulmonary exercise test. The aim of this paper is to assess the main differences in the effects of different drugs [angiotensin-converting enzyme (ACE)-inhibitors, Angiotensin II receptor blockers, β-blockers, Angiotensin receptor-neprilysin inhibitors, renal sodium-glucose co-transporter 2 inhibitors, iron supplementation] on cardiopulmonary function in patients with HF, both at rest and during exercise, and to understand how these differences can be taken into account when choosing the most appropriate treatment protocol for each individual patient leading to a precision medicine approach.

Impact of beta blockers on resting respiratory rate in older adults: A cross-sectional study

[Purpose] Beta blockers, commonly prescribed for older adults, affect heart rates and blood pressure and may reduce respiratory rates, which are used to evaluate patient status and predict outcomes. However, limited clinical evidence is available on the impact of beta blockers on respiratory rates. This study aimed to investigate the impact of beta blockers on respiratory rates in older adults. [Methods] This cross-sectional study included patients aged ≥60 years who underwent an annual checkup. Patients were excluded if they had a diagnosis of severe heart failure, chronic obstructive pulmonary disease, interstitial pneumonitis, severe anemia, or neurodegenerative disease. Doubly robust estimation with inverse probability weighting was applied to estimate the mean differences between beta blocker users and non-users. The dose-response relationship between the administered beta blockers and respiratory rates was examined using multivariable regression models. [Results] Of 637 participants, 108 had received beta blockers regularly. The adjusted mean differences (95% confidence interval, CI) in respiratory rates, pulse rates, systolic blood pressure, and diastolic blood pressure between beta blocker users and non-users were 0.35 (-0.68 to 1.37), -3.56 (-6.34 to -0.78), -5.53 (-8.53 to -2.52), and -4.70 (-8.27 to -1.14), respectively. The adjusted mean differences (95% CI) in respiratory rates per 1 mg of a carvedilol equivalent dose in all beta blocker users, liposoluble beta blocker users, and carvedilol users were -0.10 (-0.18 to -0.02), -0.35 (-0.59 to -0.11), and -0.29 (-0.54 to -0.06), respectively. [Conclusions] Beta blockers may dose-dependently reduce the respiratory rates of older adults. However, in clinical settings, the impact of beta-blocker use or non-use on the respiratory rate may not occur at a clinically important level. Clinicians should note the potentially suppressive impact of beta blockers on respiratory rates according to the situation.

Excess ventilation and exertional dyspnoea in heart failure and pulmonary hypertension

Increased ventilation relative to metabolic demands, indicating alveolar hyperventilation and/or increased physiological dead space (excess ventilation), is a key cause of exertional dyspnoea. Excess ventilation has assumed a prominent role in the functional assessment of patients with heart failure (HF) with reduced (HFrEF) or preserved (HFpEF) ejection fraction, pulmonary arterial hypertension (PAH) and chronic thromboembolic pulmonary hypertension (CTEPH). We herein provide the key pieces of information to the caring physician to 1) gain unique insights into the seeds of patients' shortness of breath and 2) develop a rationale for therapeutically lessening excess ventilation to mitigate this distressing symptom. Reduced bulk oxygen transfer induced by cardiac output limitation and/or right ventricle-pulmonary arterial uncoupling increase neurochemical afferent stimulation and (largely chemo-) receptor sensitivity, leading to alveolar hyperventilation in HFrEF, PAH and small-vessel, distal CTEPH. As such, interventions geared to improve central haemodynamics and/or reduce chemosensitivity have been particularly effective in lessening their excess ventilation. In contrast, 1) high filling pressures in HFpEF and 2) impaired lung perfusion leading to ventilation/perfusion mismatch in proximal CTEPH conspire to increase physiological dead space. Accordingly, 1) decreasing pulmonary capillary pressures and 2) mechanically unclogging larger pulmonary vessels (pulmonary endarterectomy and balloon pulmonary angioplasty) have been associated with larger decrements in excess ventilation. Exercise training has a strong beneficial effect across diseases. Addressing some major unanswered questions on the link of excess ventilation with exertional dyspnoea under the modulating influence of pharmacological and nonpharmacological interventions might prove instrumental to alleviate the devastating consequences of these prevalent diseases.

Effects of β2-receptor stimulation by indacaterol in chronic heart failure treated with selective or non-selective β-blockers: a randomized trial

Alveolar β₂-receptor blockade worsens lung diffusion in heart failure (HF). This effect could be mitigated by stimulating alveolar β₂-receptors. We investigated the safety and the effects of indacaterol on lung diffusion, lung mechanics, sleep respiratory behavior, cardiac rhythm, welfare, and exercise performance in HF patients treated with a selective (bisoprolol) or a non-selective (carvedilol) β-blocker. Study procedures were performed before and after indacaterol and placebo treatments according to a cross-over, randomized, double-blind protocol in forty-four patients (27 on bisoprolol and 17 on carvedilol). No differences between indacaterol and placebo were observed in the whole population except for a significantly higher VE/VCO₂ slope and lower maximal P_ETCO₂ during exercise with indacaterol, entirely due to the difference in the bisoprolol group (VE/VCO₂ 31.8 ± 5.9 vs. 28.5 ± 5.6, p < 0.0001 and maximal P_ETCO₂ 36.7 ± 5.5 vs. 37.7 ± 5.8 mmHg, p < 0.02 with indacaterol and placebo, respectively). In carvedilol, indacaterol was associated with a higher peak heart rate (119 ± 34 vs. 113 ± 30 bpm, with indacaterol and placebo) and a lower prevalence of hypopnea during sleep (3.8 [0.0;6.3] vs. 5.8 [2.9;10.5] events/hour, with indacaterol and placebo). Inhaled indacaterol is well tolerated in HF patients, it does not influence lung diffusion, and, in bisoprolol, it increases ventilation response to exercise.

Choosing among β-blockers in heart failure patients according to β-receptors' location and functions in the cardiopulmonary system

Several large clinical trials showed a favorable effect of β-blocker treatment in patients with chronic heart failure (HF) as regards overall mortality, cardiovascular mortality, and hospitalizations. Indeed, the use of β-blockers is strongly recommended by current international guidelines, and it remains a cornerstone in the pharmacological treatment of HF. Although different types of β-blockers are currently approved for HF therapy, possible criteria to choose the best β-blocking agent according to HF patients' characteristics and to β-receptors' location and functions in the cardiopulmonary system are still lacking. In such a context, a growing body of literature shows remarkable differences between β-blocker types (β1-selective blockers versus β1-β2 blockers) with respect to alveolar-capillary gas diffusion and chemoreceptor response in HF patients, both factors able to impact on quality of life and, most likely, on prognosis. This review suggests an original algorithm for choosing among the currently available β-blocking agents based on the knowledge of cardiopulmonary pathophysiology. Particularly, starting from lung physiology and from some experimental models, it focuses on the mechanisms underlying lung mechanics, chemoreceptors, and alveolar-capillary unit impairment in HF. This paper also remarks the significant benefit deriving from the correct use of the different β-blockers in HF patients through a brief overview of the most important clinical trials.

Optimizing Drug Therapies in Patients with COPD in the US Nursing Home Setting

Chronic obstructive pulmonary disease (COPD) can be a disabling disease, and the impact on older adults is particularly evident in the nursing home setting. Chronic obstructive pulmonary disease is present in about 20% of nursing home residents, most often in women, and accounts for significant healthcare utilization including acute care visits for exacerbations and pneumonia, as well as worsening heart disease and diabetes mellitus. The emphasis on hospital readmissions is particularly important in nursing homes where institutions have quality measures that have financial implications. Optimizing drug therapies in individuals with COPD involves choosing medications that not only improve symptoms, but also decrease the risk of exacerbations. Optimizing the treatment of comorbidities such as heart disease, infections, and diabetes that may affect COPD outcomes is also an important consideration. Depending on the nursing home setting and the patient, the options for optimizing COPD drug therapies may be limited owing to patient-related factors such as cognition and physical impairment or available resources, primarily reimbursement-related issues. Choosing the best drug therapy for COPD in older adults is limited by the difficulty in assessing respiratory symptoms using standardized assessment tools and potentially decreased inspiratory ability of frail individuals. Because of cognitive and physical impediments, ensuring optimal delivery of inhaled medications into the lungs has significant challenges. Long-acting bronchodilators, inhaled corticosteroids, and roflumilast decrease the risk of exacerbations, although inhaled corticosteroids should be used judiciously in this population because of the risk of pneumonia and oropharyngeal side effects. Treatment of COPD exacerbations should occur early and consideration should be made to the benefits and risks of systemic corticosteroids and antibiotics. Clinical research in the COPD population in nursing homes is clearly lacking, and ripe for discovery of effective management strategies.

COPD and heart failure: differential diagnosis and comorbidity

Heart failure (HF) and chronic obstructive pulmonary disease (COPD) represent the most important differential diagnoses of dyspnea in elderly people. Heart failure is the inability of the heart to pump sufficient amounts of blood through the cardiovascular system. Pump failure is caused by compromised contractility and/or filling of the ventricles leading to forward and backward failure and subsequently to dyspnea. In COPD, the destruction and remodeling processes of the bronchiolar architecture inhibit proper exhalation of air, thereby leading to exhaustion of the thoracic muscles, insufficient oxygen diffusion, and dyspnea. Despite these fundamental differences in the pathophysiology of both disorders, their clinical presentation may be very similar. This renders accurate and timely diagnosis and therapy, especially in patients with coexisting disease, difficult. This clinical review summarizes typical problems in the diagnosis of COPD, HF, and coincident disease, and describes strategies that help avoid misdiagnosis and ineffective treatment.

Current challenges in managing comorbid heart failure and COPD

INTRODUCTION

Heart failure (HF) with reduced ejection fraction and chronic obstructive pulmonary disease (COPD) frequently coexist, particularly in the elderly. Given their rising prevalence and the contemporary trend to longer life expectancy, overlapping HF-COPD will become a major cause of morbidity and mortality in the next decade. Areas covered: Drawing on current clinical and physiological constructs, the consequences of negative cardiopulmonary interactions on the interpretation of pulmonary function and cardiopulmonary exercise tests in HF-COPD are discussed. Although those interactions may create challenges for the diagnosis and assessment of disease stability, they provide a valuable conceptual framework to rationalize HF-COPD treatment. The impact of COPD or HF on the pharmacological treatment of HF or COPD, respectively, is then comprehensively discussed. Authors finalize by outlining how the non-pharmacological treatment (i.e. rehabilitation and exercise reconditioning) can be tailored to the specific needs of patients with HF-COPD. Expert commentary: Randomized clinical trials testing the efficacy and safety of new medications for HF or COPD should include a sizeable fraction of patients with these coexistent pathologies. Multidisciplinary clinics involving cardiologists and respirologists trained in both diseases (with access to unified cardiorespiratory rehabilitation programs) are paramount to decrease the humanitarian and social burden of HF-COPD.

The Association Between β-Blocker Use and Cardiorespiratory Fitness: The Maastricht Study

Purpose:

β-Blockers (BBs) have been associated with a reduced cardiorespiratory fitness (CRF). This is possibly caused by inhibition of β2-receptors in the airways. However, there are limited data available on β-receptor selectivity and CRF. We therefore aimed to assess the association between BB use and CRF and to assess the association between β-receptor selectivity and CRF.

Methods:

Participants in the Maastricht Study were aged between 40 and 75 years. Exposure to BB use was determined by use of pharmacy records. General linear models were used to obtain adjusted means of 2 proxies for CRF: covered distance during the 6-minute walk test (6MWT) and estimated maximum power output adjusted for body mass (W_max kg⁻¹) during the submaximal cycle ergometer test. Adjusted means were compared between current, past, and never BB users. Current users were subsequently stratified by β-receptor selectivity and dose.

Results:

Compared to never use, current use was associated with a lower CRF, based on the 6MWT (current use: 569.7 m; never use: 580.4 m [P = .010]), but not based on the cycling test (current use: 2.14 W kg⁻¹; never use: 2.13 W kg⁻¹ [P = .690]). There was no difference between current selective and current nonselective BB use.

Conclusion:

β-Blockers use was associated with CRF based on the 6MWT but not the cycling test. There was no difference between current selective and nonselective BB users, possibly due to the small number of nonselective BB users, differential underlying diseases, other pharmacological properties, and limitations related to the proxies of the outcome.

Cardiopulmonary Exercise Test as a Tool to Choose Therapy in Heart Failure

Heart failure treatment depends on several drugs, all providing improvement in outcome, but that cannot be realistically used all together in the same patient. It would be useful to have a tool that allows the arrangement of the most appropriate therapy cocktail for each patient. The aim of this article is to show the main differences in the effects of several drugs on cardiopulmonary function in patients with heart failure, both while resting and during exercise, and to discuss how these differences can be taken into account when choosing the most appropriate therapeutic protocol. In summary, angiotensin-converting enzyme inhibitors and angiotensin II receptor blockers act synergistically to increase exercise capacity and peak oxygen uptake, but through different mechanisms: the former improving lung diffusion and exercise ventilatory efficiency, an action that is counteracted by concomitant aspirin therapy, and the latter probably by improving muscle perfusion. As for β-blockers, nonselective compounds, such as carvedilol, improve ventilation efficiency on the one hand, but interfere with lung diffusion on the other, and they are probably less tolerated under hypoxic conditions. On the contrary, β₁-selective compounds, such as bisoprolol or nebivolol, have a neutral effect on both lung diffusion and ventilation efficiency. These observations could be the basis for the choice of pharmacological therapy in patients with heart failure.

Prognostic role of β-blocker selectivity and dosage regimens in heart failure patients. Insights from the MECKI score database

AIMS

The use of β-blockers represents a milestone in the treatment of heart failure with reduced ejection fraction (HFrEF). Few studies have compared β-blockers in HFrEF, and there is little data on the effects of different doses. The present study aimed to investigate in a large database of HFrEF patients (MECKI score database) the association of β-blocker treatment with a composite outcome of cardiovascular death, urgent heart transplantation or left ventricular assist device implantation, addressing the role of β-selectivity and dosage regimens.

METHODS AND RESULTS

In 5242 HFrEF patients, we investigated the role of: (i) β-blocker treatment vs. non-β-blocker treatment, (ii) β1-/β2-receptor-blockers vs. β1-selective blockers, and (iii) daily β-blocker dose. Patients were followed for 3.58 years, and 1101 events (18.3%) were observed; 4435 patients (86.8%) were on β-blockers, while 807 (13.2%) were not. At 5 years, β-blocker-patients showed a better outcome than non-β-blocker-subjects [hazard ratio (HR) 0.48, P < 0.0001], while also considering potential confounders. A comparable prognosis was observed at 5 years in the β1-/β2-receptor-blocker (n = 2219) vs. β1-selective group (n = 2216) (HR 0.95, P = ns). A better prognosis was observed in high-dose (>2 5 mg carvedilol equivalent daily dose, n = 1005) patients than in both medium dose (12.5-25 mg, n = 1431) and low dose (<12.5 mg, n = 1960) (HR 1.97, P < 0.001; HR 1.95, P = 0.001, respectively), with no differences between the last two groups (HR 0.84, P = ns).

CONCLUSION

In a large population of chronic HFrEF patients, β-blockers were associated with a more favourable prognosis without any difference between β1- and β2-receptor-blockers vs. β1-selective blockers. A better outcome was observed in subjects receiving a high daily dose.

Obstructive Ventilatory Disorder in Heart Failure-Caused by the Heart or the Lung?

Heart failure (HF) is a clinical syndrome frequently associated with airway obstruction, either as a respiratory comorbidity or as a direct consequence of HF pathophysiology. Recognizing the relative contribution of an underlying airway disease as opposed to airway obstruction due to volume overload and left atrial pressure elevation is of importance for the appropriate management of patients affected by HF. This review focuses on "les liaisons dangereuses" between the heart and the lungs, outlying recent advances linking in a vicious circle of chronic obstructive lung disease (COPD) and obstructive sleep apnea (OSA) on one side and HF on the other side. It also discusses the role of pivotal diagnostic tools such as pulmonary function tests and cardiopulmonary exercise test to determine the contribution of HF and COPD to symptoms and clinical status. Treatment implications are discussed as well.

Expression of β1- and β2-adrenergic receptors in the lungs and changes in the levels of corresponding autoantibodies in an aged rat model of heart failure

β-adrenergic receptors (β-ARs) and anti-β1-AR autoantibodies play important roles in heart failure. This study was designed to investigate the expression of β1- and β2-ARs in the lungs, and their relevance to the corresponding autoantibodies in an aged rat model of heart failure. In addition, we investigated the association between anti-β-AR autoantibody and soluble Fas (sFas) and soluble Fas ligand (sFasL). Aged male Wistar rats were divided into the sham-operated control group and the heart failure group. At 0 and 9 weeks post-surgery, the protein levels of β1- and β2-ARs in the heart and lungs were measured by western blot analysis. The plasma concentrations of autoantibodies, sFas and sFasL were determined by enzyme-linked immunosorbent assay (ELISA). The protein levels of pulmonary β1- and β2-ARs were decreased in the heart failure group when compared with the control group (P<0.01). Both the frequencies of the occurrence and the titers of autoantibodies against β2-AR increased at 9 weeks post-surgery (P<0.01). The levels of sFas and sFasL were also elevated, although there was no difference in the levels of sFas and sFasL between the groups, with positive and negative anti-β-AR autoantibody. These findings suggested that during the development of heart failure, the densities of pulmonary β1- and β2-ARs decreased. The levels of anti-β2-AR autoantibody exhibited similar changes as those of anti-β1-AR autoantibody, and there was no definite association between anti-β-AR autoantibody and the levels of sFas/sFasL.

β-Blockers for the prevention of acute exacerbations of chronic obstructive pulmonary disease (βLOCK COPD): a randomised controlled study protocol

INTRODUCTION

A substantial majority of chronic obstructive pulmonary disease (COPD)-related morbidity, mortality and healthcare costs are due to acute exacerbations, but existing medications have only a modest effect on reducing their frequency, even when used in combination. Observational studies suggest β-blockers may reduce the risk of COPD exacerbations; thus, we will conduct a randomised, placebo-controlled trial to definitively assess the impact of metoprolol succinate on the rate of COPD exacerbations.

METHODS AND ANALYSES

This is a multicentre, placebo-controlled, double-blind, prospective randomised trial that will enrol 1028 patients with at least moderately severe COPD over a 3-year period. Participants with at least moderate COPD will be randomised in a 1:1 fashion to receive metoprolol or placebo; the cohort will be enriched for patients at high risk for exacerbations. Patients will be screened and then randomised over a 2-week period and will then undergo a dose titration period for the following 6 weeks. Thereafter, patients will be followed for 42 additional weeks on their target dose of metoprolol or placebo followed by a 4-week washout period. The primary end point is time to first occurrence of an acute exacerbation during the treatment period. Secondary end points include rates and severity of COPD exacerbations; rate of major cardiovascular events; all-cause mortality; lung function (forced expiratory volume in 1 s (FEV1)); dyspnoea; quality of life; exercise capacity; markers of cardiac stretch (pro-NT brain natriuretic peptide) and systemic inflammation (high-sensitivity C reactive protein and fibrinogen). Analyses will be performed on an intent-to-treat basis.

ETHICS AND DISSEMINATION

The study protocol has been approved by the Department of Defense Human Protection Research Office and will be approved by the institutional review board of all participating centres. Study findings will be disseminated through presentations at national and international conferences and publications in peer-reviewed journals.

TRIAL REGISTRATION NUMBER

NCT02587351; Pre-results.

The Effect of beta-blockade on objectively measured physical fitness in patients with abdominal aortic aneurysms--A blinded interventional study

BACKGROUND

Perioperative beta-blockade is widely used, especially before vascular surgery; however, its impact on exercise performance assessed using cardiopulmonary exercise testing (CPET) in this group is unknown. We hypothesized that beta-blocker therapy would significantly improve CPET-derived physical fitness in this group.

METHODS

We recruited patients with abdominal aortic aneurysms (AAA) of <5.5 cm under surveillance. All patients underwent CPET on and off beta-blockers. Patients routinely prescribed beta-blockers underwent a first CPET on medication. Beta-blockers were stopped for one week before a second CPET. Patients not routinely taking beta-blockers underwent the first CPET off treatment, then performed a second CPET after commencement of bisoprolol for at least 48 h. Oxygen uptake (.VO2) at estimated lactate threshold and .VO2 at peak were primary outcome variables. A linear mixed-effects model was fitted to investigate any difference in adjusted CPET variables on and off beta-blockers.

RESULTS

Forty-eight patients completed the study. No difference was observed in .VO2 at estimated lactate threshold and .VO2 at peak; however, a significant decrease in .VE/.VCO2 at estimated lactate threshold and peak, an increase in workload at estimated lactate threshold., O2 pulse and heart rate both at estimated lactate threshold and peak was found with beta-blockers. Patients taking beta-blockers routinely (chronic group) had worse exercise performance (lower .VO2 ).

CONCLUSIONS

Beta blockade has a significant impact on CPET-derived exercise performance, albeit without changing .VO2 at estimated lactate threshold and.VO2 at peak. This supports performance of preoperative CPET on or off beta-blockers depending on local perioperative practice.

CLINICAL TRIAL REGISTRATION

NCT 02106286.

Surfactant-derived proteins as markers of alveolar membrane damage in heart failure

Background

In heart failure (HF) alveolar-capillary membrane is abnormal. Surfactant-derived proteins (SPs) and plasma receptor for advanced-glycation-end-products (RAGE) have been proposed as lung damage markers.

Methods

Eighty-nine chronic HF and 17 healthy subjects were evaluated by echocardiography, blood parameters, carbon monoxide lung diffusion (DLCO) and cardiopulmonary exercise test. We measured immature SP-B, mature SP-B, SP-A, SP-D and RAGE plasma levels.

Results

Immature SP-B (arbitrary units), mature SP-A (ng/ml) and SP-D (ng/ml), but not mature SP-B (ng/ml) and RAGE (pg/ml) levels, were higher in HF than in controls [immature SP-B: 15.6 (13.1, 75^th–25^th interquartile range) Vs. 11.1 (6.4), p<0.01; SP-A, 29.6 (20.1) Vs. 18.3 (13.5), p = 0.01; SP-D: 125 (90) Vs. 78 (58), p<0.01]. Immature SP-B, SP-A, SP-D and RAGE values were related to DLCO, peak oxygen consumption, ventilatory efficiency, and brain natriuretic peptide (BNP), whereas plasma mature SP-B was not. The DLCO Vs. immature SP-B correlation was the strongest one. At multivariate analysis, RAGE was associated to age and creatinine, SP-A to DLCO and BNP, SP-D to BNP, mature SP-B to DLCO and creatinine, and immature SP-B only but strongly to DLCO.

Conclusions

Immature SP-B is the most reliable biological marker of alveolar-capillary membrane function in HF.

Gas exchange consequences of left heart failure

This review explores the pathophysiology of gas exchange abnormalities arising consequent to either acute or chronic elevation of pulmonary venous pressures. The initial experimental studies of acute pulmonary edema outlined the sequence of events from lymphatic congestion with edema fluid to frank alveolar flooding and its resultant hypoxemia. Clinical studies of acute heart failure (HF) suggested that hypoxemia was associated only with the final stage of alveolar flooding. However, in patients with chronic heart failure and normal oxygenation, hypoxemia could be produced by the administration of potent pulmonary vasodilators, suggesting that hypoxic pulmonary vasoconstriction is an important reflex for these patients. Patients with chronic left HF commonly manifest a reduced diffusing capacity, an abnormality that appears to be a consequence of chronic elevation of left atrial pressure. That reduction in diffusing capacity does not appear to be primarily attributable to increases in lung water but is improved by any sustained treatment that improves overall cardiac function. Patients with heart failure may also manifest an abnormally elevated VE/VCO2 during exercise, and that exercise ventilation abnormality arises as a consequence of both alveolar hyperventilation and elevated physiologic dead space. That elevated exercise VE/VCO2 in an HF patient has proven to be a powerful predictor of an adverse outcome and hence it has received sustained attention in the HF literature. At least three of the classes of drugs used to treat HF will normalize the exercise VE/VCO2, suggesting that the excessive ventilation response may be linked to elevated sympathetic activity.

Heart failure and chronic obstructive pulmonary disease: the challenges facing physicians and health services

Pulmonary disease is common in patients with heart failure, through shared risk factors and pathophysiological mechanisms. Adverse pulmonary vascular remodelling and chronic systemic inflammation characterize both diseases. Concurrent chronic obstructive pulmonary disease presents diagnostic and therapeutic challenges, and is associated with increased morbidity and mortality. The cornerstones of therapy are beta-blockers and beta-agonists, whose pharmacological properties are diametrically opposed. Each disease is implicated in exacerbations of the other condition, greatly increasing hospitalizations and associated health care costs. Such multimorbidity is a key challenge for health-care systems oriented towards the treatment of individual diseases. Early identification and treatment of cardiopulmonary disease may alleviate this burden. However, diagnostic and therapeutic strategies require further validation in patients with both conditions.

Role of alveolar β2-adrenergic receptors on lung fluid clearance and exercise ventilation in healthy humans

Background

In experimental conditions alveolar fluid clearance is controlled by alveolar β₂-adrenergic receptors. We hypothesized that if this occurs in humans, then non-selective β-blockers should reduce the membrane diffusing capacity (D_M), an index of lung interstitial fluid homeostasis. Moreover, we wondered whether this effect is potentiated by saline solution infusion, an intervention expected to cause interstitial lung edema. Since fluid retention within the lungs might trigger excessive ventilation during exercise, we also hypothesized that after the β₂-blockade ventilation increased in excess to CO₂ output and this was further enhanced by interstitial edema.

Methods and Results

22 healthy males took part in the study. On day 1, spirometry, lung diffusion for carbon monoxide (DLCO) including its subcomponents D_M and capillary volume (V_Cap), and cardiopulmonary exercise test were performed. On day 2, these tests were repeated after rapid 25 ml/kg saline infusion. Then, in random order 11 subjects were assigned to oral treatment with Carvedilol (CARV) and 11 to Bisoprolol (BISOPR). When heart rate fell at least by 10 beats·min⁻¹, the tests were repeated before (day 3) and after saline infusion (day 4). CARV but not BISOPR, decreased D_M (−13±7%, p = 0.001) and increased V_Cap (+20±22%, p = 0.016) and VE/VCO₂ slope (+12±8%, p<0.01). These changes further increased after saline: −18±13% for D_M (p<0.01), +44±28% for V_Cap (p<0.001), and +20±10% for VE/VCO₂ slope (p<0.001).

Conclusions

These findings support the hypothesis that in humans in vivo the β₂-alveolar receptors contribute to control alveolar fluid clearance and that interstitial lung fluid may trigger exercise hyperventilation.

Multiparametric comparison of CARvedilol, vs. NEbivolol, vs. BIsoprolol in moderate heart failure: the CARNEBI trial

BACKGROUND

Several β-blockers, with different pharmacological characteristics, are available for heart failure (HF) treatment. We compared Carvedilol (β1-β2-α-blocker), Bisoprolol (β1-blocker), and Nebivolol (β1-blocker, NO-releasing activity).

METHODS

Sixty-one moderate HF patients completed a cross-over randomized trial, receiving, for 2 months each, Carvedilol, Nebivolol, Bisoprolol (25.6 ± 12.6, 5.0 ± 2.4 and 5.0 ± 2.4 mg daily, respectively). At the end of each period, patients underwent: clinical evaluation, laboratory testing, echocardiography, spirometry (including total DLCO and membrane diffusion), O2/CO2 chemoreceptor sensitivity, constant workload, in normoxia and hypoxia (FiO2=16%), and maximal cardiopulmonary exercise test.

RESULTS

No significant differences were observed for clinical evaluation (NYHA classification, Minnesota questionnaire), laboratory findings (including kidney function and BNP), echocardiography, and lung mechanics. DLCO was lower on Carvedilol (18.3 ± 4.8*mL/min/mmHg) compared to Nebivolol (19.9 ± 5.1) and Bisoprolol (20.0 ± 5.0) due to membrane diffusion 20% reduction (*=p<0.0001). Constant workload exercise showed in hypoxia a faster VO2 kinetic and a lower ventilation with Carvedilol. Peripheral and central sensitivity to CO2 was lower in Carvedilol while response to hypoxia was higher in Bisoprolol. Ventilation efficiency (VE/VCO2 slope) was 26.9 ± 4.1* (Carvedilol), 28.8 ± 4.0 (Nebivolol), and 29.0 ± 4.4 (Bisoprolol). Peak VO2 was 15.8 ± 3.6*mL/kg/min (Carvedilol), 16.9 ± 4.1 (Nebivolol), and 16.9 ± 3.6 (Bisoprolol).

CONCLUSIONS

β-Blockers differently affect several cardiopulmonary functions. Lung diffusion and exercise performance, the former likely due to lower interference with β2-mediated alveolar fluid clearance, were higher in Nebivolol and Bisoprolol. On the other hand, Carvedilol allowed a better ventilation efficiency during exercise, likely via a different chemoreceptor modulation. Results from this study represent the basis for identifying the best match between a specific β-blocker and a specific HF patient.

Lungs in heart failure

Lung function abnormalities both at rest and during exercise are frequently observed in patients with chronic heart failure, also in the absence of respiratory disease. Alterations of respiratory mechanics and of gas exchange capacity are strictly related to heart failure. Severe heart failure patients often show a restrictive respiratory pattern, secondary to heart enlargement and increased lung fluids, and impairment of alveolar-capillary gas diffusion, mainly due to an increased resistance to molecular diffusion across the alveolar capillary membrane. Reduced gas diffusion contributes to exercise intolerance and to a worse prognosis. Cardiopulmonary exercise test is considered the “gold standard” when studying the cardiovascular, pulmonary, and metabolic adaptations to exercise in cardiac patients. During exercise, hyperventilation and consequent reduction of ventilation efficiency are often observed in heart failure patients, resulting in an increased slope of ventilation/carbon dioxide (VE/VCO₂) relationship. Ventilatory efficiency is as strong prognostic and an important stratification marker. This paper describes the pulmonary abnormalities at rest and during exercise in the patients with heart failure, highlighting the principal diagnostic tools for evaluation of lungs function, the possible pharmacological interventions, and the parameters that could be useful in prognostic assessment of heart failure patients.

Differences between bisoprolol and carvedilol in patients with chronic heart failure and chronic obstructive pulmonary disease: a randomized trial

BACKGROUND

Chronic obstructive pulmonary disease (COPD) frequently coexists in patients with chronic heart failure (CHF) and is a key factor for beta blocker underprescription and underdosing. This study compared effects of bisoprolol and carvedilol in patients with both conditions.

METHODS

This was a randomized open-label study, of bisoprolol and carvedilol during initiation and uptitration to target or maximal tolerated dose. Pulmonary function testing, 12-lead electrocardiogram, and N-terminal pro brain natriuretic peptide were measured at baseline and follow-up.

RESULTS

We randomized 63 elderly patients (73 ± 9 years, 81% men, left ventricular ejection fraction 33 ± 7%) with mild to moderate CHF (54% New York Heart Assocation class II) and moderate to severe COPD (76% Global initiative for chronic Obstructive Lung Disease stage 2). Target dose was tolerated by 31 (49%) patients and 19 (30%) patients experienced adverse events during follow-up (19% bisoprolol, 42% carvedilol, p = 0.045). Study medication had to be withdrawn in 8 (13%) patients (bisoprolol: 2 due to hypotension, 1 due to bradycardia; carvedilol: 2 due to hypotension and 1 due to wheezing, dyspnoea, and oedema, respectively). Forced expiratory volume in 1(st) second significantly increased in bisoprolol (1561 ± 414 ml to 1698 ± 519 ml, p = 0.046) but not carvedilol (1704 ± 484 to 1734 ± 548, p = 0.44) group. Both agents reduced heart rate (bisoprolol: 75 ± 14 to 68 ± 10, p = 0.007; carvedilol 78 ± 14 to 72 ± 12, p = 0.016) and had no effect on N-terminal pro brain natriuretic peptide.

CONCLUSIONS

Beta blockers frequently caused adverse events, and thus 49% of patients could tolerate the target dose. Bisoprolol induced demonstrable improvement in pulmonary function and caused less adverse events.

High-altitude exposure of three weeks duration increases lung diffusing capacity in humans

Background: high-altitude adaptation leads to progressive increase in arterial PaO2. In addition to increased ventilation, better arterial oxygenation may reflect improvements in lung gas exchange. Previous investigations reveal alterations at the alveolar-capillary barrier indicative of decreased resistance to gas exchange with prolonged hypoxia adaptation, but how quickly this occurs is unknown. Carbon monoxide lung diffusing capacity and its major determinants, hemoglobin, alveolar volume, pulmonary capillary blood volume, and alveolar-capillary membrane diffusion, have never been examined with early high-altitude adaptation. Methods and Results: lung diffusion was measured in 33 healthy lowlanders at sea level (Milan, Italy) and at Mount Everest South Base Camp (5,400 m) after a 9-day trek and 2-wk residence at 5,400 m. Measurements were adjusted for hemoglobin and inspired oxygen. Subjects with mountain sickness were excluded. After 2 wk at 5,400 m, hemoglobin oxygen saturation increased from 77.2 ± 6.0 to 85.3 ± 3.6%. Compared with sea level, there were increases in hemoglobin, lung diffusing capacity, membrane diffusion, and alveolar volume from 14.2 ± 1.2 to 17.2 ± 1.8 g/dl ( P < 0.01), from 23.6 ± 4.4 to 25.1 ± 5.3 ml·min−1·mmHg−1 ( P < 0.0303), 63 ± 34 to 102 ± 65 ml·min−1·mmHg−1 ( P < 0.01), and 5.6 ± 1.0 to 6.3 ± 1.1 liters ( P < 0.01), respectively. Pulmonary capillary blood volume was unchanged. Membrane diffusion normalized for alveolar volume was 10.9 ± 5.2 at sea level rising to 16.0 ± 9.2 ml·min−1·mmHg−1·l−1 ( P < 0.01) at 5,400 m. Conclusions: at high altitude, lung diffusing capacity improves with acclimatization due to increases of hemoglobin, alveolar volume, and membrane diffusion. Reduction in alveolar-capillary barrier resistance is possibly mediated by an increase of sympathetic tone and can develop in 3 wk.

Exercise intolerance in chronic heart failure: mechanisms and therapies. Part II

Muscular fatigue and dyspnoea on exertion are among the most common symptoms in chronic heart failure; however their origin is still poorly understood. Several studies have shown that cardiac dysfunction alone cannot fully explain their origin, but the contribution of the multiorgan failure present in this syndrome must be highlighted. We aimed to summarize the existing evidence and the most controversial aspects of the complex interplay of different factors involved in the symptom generation. In the first part of the review, six key factors were revised (the heart, the lung, the skeletal muscle, the hormonal changes, the O2 delivery to the periphery, the endothelium). In this second part, the role of the excitatory reflexes and the cardiac cachexia are presented. Finally, potential therapeutic implications are discussed here. We believe that a better knowledge of the pathophysiology of this syndrome may contribute to the management of the patients and to the improvement in their stress tolerance and quality of life.

Nebivolol in chronic heart failure: current evidence and future perspectives

IMPORTANCE OF THE FIELD

Chronic activation of the sympathetic nervous system leads to deterioration of cardiovascular function in heart failure patients. In systolic heart failure, beta-blockers were proven to be effective in decreasing the number of deaths and improving morbidity. However, beta-blockers are a heterogeneous drug group, consisting of agents with different selectivity for adrenergic receptors and/or additional effects in heart or peripheral circulation.

AREAS COVERED IN THE REVIEW

We describe the role of the sympathetic nervous system, beta-blockers and specifically nebivolol in chronic heart failure.

WHAT THE READER WILL GAIN

Nebivolol is a third-generation beta-blocker, with high beta(1)/beta(2) selectivity. Moreover, it has important vasodilating properties, by stimulating the production of nitric oxide. Smaller studies have already shown beneficial effects of nebivolol treatment on surrogate end points in heart failure patients. The recently published SENIORS (Phase III) study in an elderly heart failure population demonstrated a decreased number of clinical events in patients treated with nebivolol. Importantly, this effect was observed in patients with both impaired and preserved left ventricular systolic function.

TAKE HOME MESSAGE

Specific beta-blockers may have distinct effects in various subgroups of heart failure patients. So far, nebivolol is the only beta-blocker to have been shown effective in elderly heart failure patients, regardless of their left ventricular ejection fraction.

Effects of beta-blockers on ventilation efficiency in heart failure

BACKGROUND

Hyperventilation and consequent reduction of ventilation (VE) efficiency are frequently observed during exercise in heart failure (HF) patients, resulting in an increased slope of VE/carbon dioxide (VE/Vco(2)) relationship. The latter is an independent predictor of HF prognosis. beta-Blockers improve the prognosis of HF patients. We evaluated the effect on the efficiency of VE of a beta(1)-beta(2) unselective (carvedilol) versus a beta(1) selective (bisoprolol) beta-blocker.

METHODS

We analyzed consecutive maximal cardiopulmonary exercise tests performed on 572 clinically stable HF patients (New York Heart Association class I-III, left ventricle ejection fraction < or =50%) categorized in 3 groups: 81 were not treated with beta-blocker, 304 were treated with carvedilol, and 187 were treated with bisoprolol. Clinical conditions were similar.

RESULTS

The VE/Vco(2) slope was lower in carvedilol- compared with bisoprolol-treated patients (29.7 +/- 0.4 vs 31.6 +/- 0.5, P = .023, peak oxygen consumption adjusted) and with patients not receiving beta-blockers (31.6 +/- 0.7, P = .036). Maximum end-tidal CO(2) pressure during the isocapnic buffering period was higher in patients treated with carvedilol (39.0 +/- 0.3 mm Hg) than with bisoprolol (37.2 +/- 0.4 mm Hg, P < .001) and in patients not receiving beta-blockers (37.2 +/- 0.5 mm Hg, P = .001).

CONCLUSIONS

Reduction of hyperventilation, with improvement of VE efficiency during exercise (reduction of VE/Vco(2) slope and increase of maximum end-tidal CO(2) pressure), is specific to carvedilol (beta(1)-beta(2) unselective blocker) and not to bisoprolol (beta(1)-selective blocker).

Clinical updates on carvedilol: a first choice beta-blocker in the treatment of cardiovascular diseases

IMPORTANCE OF THE FIELD

Carvedilol, a non-selective beta-blocker, has recently drawn attention because of its therapeutic benefits over other prescribed analogues for the treatment of cardiovascular diseases (CVDs).

AREAS COVERED IN THIS REVIEW

The present review attempts to present the clinical efficacy of carvedilol in comparison to other available beta-blockers. The literature search was carried out in three electronic databases (Unbound Medline, Pubmed and Sciencedirect) and internet search engines (Scirus and Google Scholar) without time constraints to ensure maximum literature coverage.

WHAT THE READER WILL GAIN

A relatively large number of comparative studies have revealed that carvedilol has advantage over traditional beta-blockers with respect to hemodynamic and metabolic effects, due to its unique non-selective alpha-/beta-adrenoceptor affinity. Such results indicate its safe and effective therapeutic application particularly in patients with complicated CVDs, even in pediatric and geriatric patients.

TAKE HOME MESSAGE

The therapeutic profile of carvedilol indicates its suitability for treatment of complicated CVDs than other non-selective beta-blockers. However, there is a limitation in terms of its dose due to its low bioavailability (approximately 25%). Therefore, there is still need for bioavailability enhancement and dose reduction to further improve the therapeutic efficacy of the drug.

Alveolar gas diffusion abnormalities in heart failure

In heart failure (HF), development of pressure or volume overload of the lung microcirculation elicits a series of structural adaptations, whose functional correlate is an increased resistance to gas transfer across the alveolar-capillary membrane. Acutely, hydrostatic mechanical injury causes endothelial and alveolar cell breaks, impairment of the cellular pathways involved in fluid filtration and reabsorption, and resistance to gas transfer. This process, which is reminiscent of the so-called alveolar-capillary stress failure, is generally reversible. When the alveolar membrane is chronically challenged, tissue alterations are sustained and a typical remodeling process may take place that is characterized by fixed extracellular matrix collagen proliferation and reexpression of fetal genes. Remodeling leads to a persistent reduction in alveolar-capillary membrane conductance and lung diffusion capacity. Changes in gas transfer not only reflect the underlying lung tissue damage but also bring independent prognostic information and may play a role in the pathogenesis of exercise limitation and ventilatory abnormalities. They are not responsive to fluid withdrawal by ultrafiltration and tend to be refractory even to heart transplantation. Some drugs can be effective that modulate lung remodeling (eg, angiotensin-converting enzyme inhibitors, whose impact on the natural course of cardiac remodeling is well known) or that increase nitric oxide availability and nitric oxide-mediated pulmonary vasodilation (eg, type 5 phosphodiesterase inhibitors). This review focuses on the current knowledge of these topics.