Carvedilol improves endothelium-dependent dilatation in patients with coronary artery disease

Ischemia With Nonobstructive Coronary Artery Disease: Concept, Assessment, and Management

In daily clinical practice, physicians often encounter patients with angina or those with evidence of myocardial ischemia from noninvasive tests but not having obstructive coronary artery disease. This type of ischemic heart disease is referred to as ischemia with nonobstructive coronary arteries (INOCA). INOCA patients often suffer from recurrent chest pain without adequate management and are associated with poor clinical outcomes. There are several endotypes of INOCA, and each endotype should be treated based on its specific underlying mechanism. Therefore, identifying INOCA and discriminating its underlying mechanisms are important issues and of clinical interest. Invasive physiologic assessment is the first step in the diagnosis of INOCA and discriminating the underlying mechanism; additional provocation tests help physicians identify the vasospastic component in INOCA patients. Comprehensive information acquired from these invasive tests can provide a template for mechanism-specific management for patients with INOCA.

The critical issue linking lipids and inflammation: Clinical utility of stopping oxidative stress

The formation of an atheroma begins when lipoproteins become trapped in the intima. Entrapped lipoproteins become oxidized and activate the innate immune system. This immunity represents the primary association between lipids and inflammation. When the trapping continues, the link between lipids and inflammation becomes chronic and detrimental, resulting in atherosclerosis. When entrapment ceases, the association between lipids and inflammation is temporary and healthy, and the atherogenic process halts. Therefore, the link between lipids and inflammation depends upon lipoprotein retention in the intima. The entrapment is due to electrostatic forces uniting apolipoprotein B to polysaccharide chains on intimal proteoglycans. The genetic transformation of contractile smooth muscle cells in the media into migratory secretory smooth muscle cells produces the intimal proteoglycans. The protein, platelet-derived growth factor produced by activated platelets, is the primary stimulus for this genetic change. Oxidative stress is the main stimulus to activate platelets. Therefore, minimizing oxidative stress would significantly reduce the retention of lipoproteins. Less entrapment decreases the association between lipids and inflammation. More importantly, it would halt atherogenesis. This review will analyze oxidative stress as the critical link between lipids, inflammation, and the pathogenesis of atherosclerosis. Through this perspective, we will discuss stopping oxidative stress to disrupt a harmful association between lipids and inflammation. Numerous therapeutic options will be discussed to mitigate oxidative stress. This paper will add a new meaning to the Morse code distress signal SOS-stopping oxidative stress.

Sustained Activation of CLR/RAMP Receptors by Gel-Forming Agonists

Background: Adrenomedullin (ADM), adrenomedullin 2 (ADM2), and CGRP family peptides are important regulators of vascular vasotone and integrity, neurotransmission, and fetoplacental development. These peptides signal through CLR/RAMP1, 2, and 3 receptors, and protect against endothelial dysfunction in disease models. As such, CLR/RAMP receptor agonists are considered important therapeutic candidates for various diseases. Methods and Results: Based on the screening of a series of palmitoylated chimeric ADM/ADM2 analogs, we demonstrated a combination of lipidation and accommodating motifs at the hinge region of select peptides is important for gaining an enhanced receptor-activation activity and improved stimulatory effects on the proliferation and survival of human lymphatic endothelial cells when compared to wild-type peptides. In addition, by serendipity, we found that select palmitoylated analogs self-assemble to form liquid gels, and subcutaneous administration of an analog gel led to the sustained presence of the peptide in the circulation for >2 days. Consistently, subcutaneous injection of the analog gel significantly reduced the blood pressure in SHR rats and increased vasodilation in the hindlimbs of adult rats for days. Conclusions: Together, these data suggest gel-forming adrenomedullin analogs may represent promising candidates for the treatment of various life-threatening endothelial dysfunction-associated diseases such as treatment-resistant hypertension and preeclampsia, which are in urgent need of an effective drug.

Myocardial Ischemia Related to Common Cancer Therapy-Prevention Insights

Modern antineoplastic therapy improves survival and quality of life in cancer patients, but its indisputable benefits are accompanied by multiple and major side effects, such as cardiovascular ones. Endothelial dysfunction, arterial spasm, intravascular thrombosis, and accelerated atherosclerosis affect the coronary arteries, leading to acute and chronic coronary syndromes that negatively interfere with the oncologic treatment. The cardiac toxicity of antineoplastic agents may be mitigated by using adequate prophylactic measures. In the absence of dedicated guidelines, our work provides the most comprehensive, systematized, structured, and up-to-date analyses of the available literature focusing on measures aiming to protect the coronary arteries from the toxicity of cancer therapy. Our work facilitates the implementation of these measures in daily practice. The ultimate goal is to offer clinicians the necessary data for a personalized therapeutic approach for cancer patients receiving evidence-based oncology treatments with potential cardiovascular toxicity.

Coronary Microvascular Angina: A State-of-the-Art Review

Up to 60–70% of patients, undergoing invasive coronary angiography due to angina and demonstrable myocardial ischemia with provocative tests, do not have any obstructive coronary disease. Coronary microvascular angina due to a dysfunction of the coronary microcirculation is the underlying cause in almost 50% of these patients, associated with a bad prognosis and poor quality of life. In recent years, progress has been made in the diagnosis and management of this condition. The aim of this review is to provide an insight into current knowledge of this condition, from current diagnostic methods to the latest treatments.

Microvascular Angina: Diagnosis and Management

Recognition of suspected ischaemia with no obstructive coronary artery disease – termed INOCA – has increased over the past decades, with a key contributor being microvascular angina. Patients with microvascular angina are at higher risk for major adverse cardiac events including MI, stroke, heart failure with preserved ejection fraction and death but to date there are no clear evidence-based guidelines for diagnosis and treatment. Recently, the Coronary Vasomotion Disorders International Study Group proposed standardised criteria for diagnosis of microvascular angina using invasive and non-invasive approaches. The management strategy for remains empirical, largely due to the lack of high-levelevidence- based guidelines and clinical trials. In this review, the authors will illustrate the updated approach to diagnosis of microvascular angina and address evidence-based pharmacological and non-pharmacological treatments for patients with the condition.

Pre-Clinical Investigation of Cardioprotective Beta-Blockers as a Therapeutic Strategy for Preeclampsia

Despite significant maternal and fetal morbidity, a treatment for preeclampsia currently remains an unmet need in clinical care. As too does the lifelong cardiovascular risks imparted on preeclampsia sufferers. Endothelial dysfunction and end-organ injury are synonymous with both preeclampsia and cardiovascular disease, including heart failure. We propose that beta-blockers, known to improve endothelial dysfunction in the treatment of cardiovascular disease, and specifically known to reduce mortality in the treatment of heart failure, may be beneficial in the treatment of preeclampsia. Here, we assessed whether the beta-blockers carvedilol, bisoprolol, and metoprolol could quench the release of anti-angiogenic factors, promote production of pro-angiogenic factors, reduce markers of inflammation, and reduce endothelial dysfunction using our in vitro pre-clinical preeclampsia models encompassing primary placental tissue and endothelial cells. Here, we show beta-blockers effected a modest reduction in secretion of anti-angiogenic soluble fms-like tyrosine kinase-1 and soluble endoglin and increased expression of pro-angiogenic placental growth factor, vascular endothelial growth factor and adrenomedullin in endothelial cells. Beta-blocker treatment mitigated inflammatory changes occurring after endothelial dysfunction and promoted cytoprotective antioxidant heme oxygenase-1. The positive effects of the beta-blockers were predominantly seen in endothelial cells, with a less consistent response seen in placental cells/tissue. In conclusion, beta-blockers show potential as a novel therapeutic approach in the treatment of preeclampsia and warrant further investigation.

A preliminary metabolites identification of a novel compound with β-adrenolytic activity

BACKGROUND

The identification of main metabolites and assessment of renal excretion of a novel compound with β-adrenolytic activity (2RS)-1-(1H-indol-4-yloxy)-3-((2-(2-methoxyphenoxy)ethyl)amino)propan-2-ol, briefly called (RS)-9 or 2F109, were studied in vivo in rat serum, urine, faeces, liver, intestine, lungs and kidneys, and in vitro in rat liver microsomes.

METHODS

Structures of the metabolites have been developed by comparing the high-resolution product ion mass spectra of metabolites and the parent compound based on the differences in mass values of main fragments. Quantitative analysis of (RS)-9 was done using a system of liquid chromatography coupled with a triple quadrupole mass spectrometer API 2000. Identification studies of predicted metabolites were made by a high-resolution mass spectrometer LTQ XL Orbitrap Discovery and using a Roxy^™ system, for online electrochemical mimicry of oxidative metabolism by cytochrome P450s connected to QTRAP 5500.

RESULTS

For (RS)-9 (m/z 357.2084) phase I metabolites derived from oxidation process: hydroxyl derivatives (m/z 373.2470) and dihydroxyl derivatives (m/z 389.4318), and phase II metabolites: N-methylated compound (m/z 371.1612), O-glucuronide (m/z 533.5118), and sulfate (m/z 437.2350) were identified.

CONCLUSION

(RS)-9 was extensively metabolised to several phase I and II metabolites, and renal excretion was a minor route in its elimination.

Coronary microvascular disease: current concepts of pathophysiology, diagnosis and management

Coronary microvascular disease (CMD) is present in 30% of patients with angina and is associated with increased morbidity and mortality. We now have an improved understanding of the pathophysiology of CMD and the invasive and noninvasive tests that can be used to make the diagnosis. Recent studies have shown that management of CMD guided by physiological testing yields better results than empirical treatment. Despite major advances in diagnosing and stratifying this condition, therapeutic strategies remain limited and poorly defined. This review article discusses recent advances in understanding the pathophysiology of CMD, the modalities that are available to diagnose it clinically, current management options and a look at what is in store for the future.

Role of endothelial dysfunction in determining angina after percutaneous coronary intervention: Learning from pathophysiology to optimize treatment

Endothelial dysfunction (EnD) is a hallmark feature of coronary artery disease (CAD), representing the key early step of atherosclerotic plaque development and progression. Percutaneous coronary intervention (PCI) is performed daily worldwide to treat symptomatic CAD, however a consistent proportion of patients remain symptomatic for angina despite otherwise successful revascularization. EnD plays a central role in the mechanisms of post-PCI angina, as it is strictly associated with both structural and functional abnormalities in the coronary arteries that may persist, or even accentuate, following PCI. The assessment of endothelial function in patients undergoing PCI might help to identify those patients at higher risk of future cardiovascular events and recurrent/persistent angina who might therefore benefit more from an intensive treatment. In this review, we address the role of EnD in determining angina after PCI, discussing its pathophysiological mechanisms, diagnostic approaches and therapeutic perspectives.

Coronary Artery Disease and Endothelial Dysfunction: Novel Diagnostic and Therapeutic Approaches

Coronary artery disease is the leading cause of morbidity and mortality worldwide. The most common pathophysiologic substrate is atherosclerosis which is an inflammatory procedure that starts at childhood and develops throughout life. Endothelial dysfunction is associated with the initiation and progression of atherosclerosis and is characterized by the impaired production of nitric oxide. In general, endothelial dysfunction is linked to poor cardiovascular prognosis and different methods, both invasive and non-invasive, have been developed for its evaluation. Ultrasound evaluation of flow mediated dilatation of the branchial artery is the most commonly used method to assessed endothelial function while intracoronary administration of vasoactive agents may be also be used to test directly endothelial properties of the coronary vasculature. Endothelial dysfunction has also been the subject of therapeutic interventions. This review article summarizes the knowledge about evaluation of endothelial function in acute coronary syndromes and stable coronary artery disease and demonstrates the current therapeutic approaches against endothelial dysfunction.

Effect of Different Classes of Antihypertensive Drugs on Endothelial Function and Inflammation

Hypertension is characterized by structural and functional changes in blood vessels that travel with increased arterial stiffness, vascular inflammation, and endothelial dysfunction. Some antihypertensive drugs have been shown to improve endothelial function and reduce levels of inflammatory markers regardless of the effect of blood pressure lowering. Third-generation β-blockers, such as nebivolol and carvedilol, because they have additional properties, have been shown to improve endothelial function in patients with hypertension. Calcium channel antagonists, because they have antioxidant effects, may improve endothelial function and vascular inflammation.The Angiotensin Receptor Blocker (ARBs) are able to improve endothelial dysfunction and vascular inflammation in patients with hypertension and other cardiovascular diseases. Angiotensin converting enzyme (ACE) inhibitors have shown beneficial effects on endothelial function in patients with hypertension and other cardiovascular diseases, however there are few studies evaluating the effect of treatment with this class on the reduction of C-reactive protein (CRP) levels. Further studies are needed to assess whether treatment of endothelial dysfunction and vascular inflammation may improve the prognosis of patients with essential hypertension.

Recognition and treatment of ischemic heart diseases in women

Heart disease is the leading cause of death among women in the industrialized world. However, women after myocardial infarctions (MIs) are less likely to receive preventive medications or revascularization and as many as 47% experience heart failure, stroke or die within 5 years. Premenopausal women with MIs frequently have coronary plaque erosions or dissections. Women under 50 years with angina and nonobstructive epicardial coronary artery disease often have coronary microvascular dysfunction (CMD) with reductions in coronary flow reserve that may require nontraditional therapies. In women with coronary artery disease treated with stents, the 3-year incidence of recurrent MI or death is 9.2%. Coronary bypass surgery operative mortality averages 4.6% for women compared with 2.4% in men. Addition of internal mammary artery and radial artery coronary grafts in women does not increase operative survival but improves 5-year outcome to greater than 80%.

Women's health: making cardiovascular disease real

PURPOSE OF REVIEW

When patients are seen for persistent chest pain in the absence of obstructive coronary artery disease, the physician must decide if the symptoms are due to myocardial ischemia in order to guide treatment.

RECENT FINDINGS

Recent findings indicate that ischemia due to coronary microvascular dysfunction (CMD) is associated with subclinical coronary atherosclerosis and an adverse prognosis. Therapeutic probe trials suggest that antiatherosclerotic and anti-ischemic therapeutic strategies may be useful. A large randomized clinical trial of high-intensity statin, maximally tolerated angiotensin-converting-enzyme inhibitor or angiotensin receptor blocker and low-dose aspirin (WARRIOR NCT#03417388) is in progress.

SUMMARY

The diagnosis of CMD should be considered in patients with persistent angina, evidence of myocardial ischemia and normal coronary angiogram. Because of the associated adverse prognosis of CMD , conservative empiric treatment or further diagnostic evaluation of the coronary microvasculature can be performed. Diagnosis involves the measurement of coronary blood blow in response to a vasodilator agent invasively or noninvasively. Treatment of CMD can include the use of traditional antianginal and antiatherosclerotic medications. Clinical trials are needed to assess therapeutic strategies on the outcomes of cardiovascular disease and quality of life, in order to develop evidence-based guidelines.

Sympathoexcitation constrains vasodilation in the human skeletal muscle microvasculature during postocclusive reactive hyperemia

We used diffuse correlation spectroscopy to investigate sympathetic vasoconstriction, local vasodilation, and integration of these two responses in the skeletal muscle microvasculature of 20 healthy volunteers. Diffuse correlation spectroscopy probes were placed on the flexor carpi radialis muscle or vastus lateralis muscle, and a blood flow index was derived continuously. We measured hemodynamic responses during sympathoexcitation induced by forehead cooling, after which the effects of the increased sympathetic tone on vasodilatory responses during postocclusive reactive hyperemia (PORH) were examined. PORH was induced by releasing arterial occlusion (3 min) in an arm or leg. To increase sympathetic tone during PORH, forehead cooling was begun 60 s before the occlusion release and ended 60 s after the release. During forehead cooling, mean arterial pressure rose significantly and was sustained at an elevated level. Significant vasoconstriction and decreases in blood flow index followed by gradual blunting of the vasoconstriction also occurred. The time course of these responses is in good agreement with previous observations in animals. The acute sympathoexcitation diminished the peak vasodilation during PORH only in the vastus lateralis muscle, but it hastened the decline in vasodilation after the peak in both the flexor carpi radialis muscle and vastus lateralis muscle. Consequently, the total vasodilatory response assessed as the area of the vascular conductance during the first minute of PORH was significantly diminished in both regions. We conclude that, in humans, the integrated effects of sympathetic vasoconstriction and local vasodilation have an important role in vascular regulation and control of perfusion in the skeletal muscle microcirculation.

NEW & NOTEWORTHY We used diffuse correlation spectroscopy to demonstrate that acute sympathoexcitation constrains local vasodilation in the human skeletal muscle microvasculature during postocclusive reactive hyperemia. This finding indicates that integration of sympathetic vasoconstriction and local vasodilation is importantly involved in vascular regulation and the control of perfusion of the skeletal muscle microcirculation in humans.

Vascular toxicities with VEGF inhibitor therapies-focus on hypertension and arterial thrombotic events

The vascular endothelial growth factor (VEGF) signaling pathway (VSP) fulfills a cardinal role in endothelial cells and its inhibition has profound cardiovascular impact. This is true not only for the normal vasculature but also for the tumor vasculature when VSP inhibitors are used as anti-angiogenic therapies. Generalized endothelial dysfunction predisposes to vasoconstriction, atherosclerosis, platelet activation, and thrombosis (arterial more than venous). All of these have been reported with VSP inhibitors and collectively give rise to vascular toxicities, the most concerning of which are arterial thromboembolic events (ATE). VSP inhibitors include antibodies, acting extracelluarly on VEGF, such as bevacizumab and tyrosine kinases inhibitors, acting intracellularly on the kinase domain of VEGF receptors, such as sunintib and sorafenib. The addition of bevacizumab and VSP tyrosine kinase inhibitor therapy to the cancer treatment regimen is associated with a 1.5-2.5-fold and 2.3-4.6-fold increase risk of ATEs, respectively. Risk factors for ATEs while on VSP inhibitor therapy include age older than 65 years, previous thromboembolic events, history of atherosclerotic disease, and duration of VSP inhibitor therapy. In clinical practice, hypertension remains the most commonly noted vascular manifestation of VSP inhibition. Optimal blood pressure goals and preferred therapeutic strategies toward reaching these goals are not defined at present. This review summarizes current data on this topic and proposes a more intensive management approach to patients undergoing VSP inhibitor therapy including Systolic Blood PRessure Intervention Trial (SPRINT) blood pressure goals, pleiotropic vasoprotective agents such as angiotensin converting enzyme inhibitors, amlodipine, and carvedilol, high-dose statin therapy, and aspirin.

Ischemia and No Obstructive Coronary Artery Disease (INOCA): Developing Evidence-Based Therapies and Research Agenda for the Next Decade

The Cardiovascular Disease in Women Committee of the American College of Cardiology, in conjunction with interested parties (from the National Heart, Lung, and Blood Institute, American Heart Association, and European Society of Cardiology), convened a working group to develop a consensus on the syndrome of myocardial ischemia with no obstructive coronary arteries. In general, these patients have elevated risk for a cardiovascular event (including acute coronary syndrome, heart failure hospitalization, stroke, and repeat cardiovascular procedures) compared with reference subjects and appear to be at higher risk for development of heart failure with preserved ejection fraction. A subgroup of these patients also has coronary microvascular dysfunction and evidence of inflammation. This document provides a summary of findings and recommendations for the development of an integrated approach for identifying and managing patients with ischemia with no obstructive coronary arteries and outlines knowledge gaps in the area. Working group members critically reviewed available literature and current practices for risk assessment and state-of-the-science techniques in multiple areas, with a focus on next steps needed to develop evidence-based therapies. This report presents highlights of this working group review and a summary of suggested research directions to advance this field in the next decade.

Coronary Microvascular Dysfunction - Epidemiology, Pathogenesis, Prognosis, Diagnosis, Risk Factors and Therapy

Angina has traditionally been thought to be caused by obstructive coronary artery disease (CAD). However, a substantial number of patients with angina are found to not have obstructive CAD when undergoing coronary angiography. A significant proportion of these patients have coronary microvascular dysfunction (CMD), characterized by heightened sensitivity to vasoconstrictor stimuli and limited microvascular vasodilator capacity. With the advent of non-invasive and invasive techniques, the coronary microvasculature has been more extensively studied in the past 2 decades. CMD has been identified as a cause of cardiac ischemia, in addition to traditional atherosclerotic disease and vasospastic disease. CMD can occur alone or in the presence obstructive CAD. CMD shares many similar risk factors with macrovascular CAD. Diagnosis is achieved through detection of an attenuated response of coronary blood flow in response to vasodilatory agents. Imaging modalities such as cardiovascular magnetic resonance, positron emission tomography, and transthoracic Doppler echocardiography have become more widely used, but have not yet completely replaced the traditional intracoronary vasoreactivity testing. Treatment of CMD starts with lifestyle modification and risk factor control. The use of traditional antianginal, antiatherosclerotic medications and some novel agents may be beneficial; however, clinical trials are needed to assess the efficacy of the pharmacologic and non-pharmacologic therapeutic modalities. In addition, studies with longer-term follow-up are needed to determine the prognostic benefits of these agents. We review the epidemiology, prognosis, pathogenesis, diagnosis, risk factors and current therapies for CMD.

Acute ingestion of citrulline stimulates nitric oxide synthesis but does not increase blood flow in healthy young and older adults with heart failure

To determine if age-associated vascular dysfunction in older adults with heart failure (HF) is due to insufficient synthesis of nitric oxide (NO), we performed two separate studies: 1) a kinetic study with a stable isotope tracer method to determine in vivo kinetics of NO metabolism, and 2) a vascular function study using a plethysmography method to determine reactive hyperemic forearm blood flow (RH-FBF) in older and young adults in the fasted state and in response to citrulline ingestion. In the fasted state, NO synthesis (per kg body wt) was ∼ 50% lower in older vs. young adults and was related to a decreased rate of appearance of the NO precursor arginine. Citrulline ingestion (3 g) stimulated de novo arginine synthesis in both older [6.88 ± 0.83 to 35.40 ± 4.90 μmol · kg body wt(-1) · h(-1)] and to a greater extent in young adults (12.02 ± 1.01 to 66.26 ± 4.79 μmol · kg body wt(-1) · h(-1)). NO synthesis rate increased correspondingly in older (0.17 ± 0.01 to 2.12 ± 0.36 μmol · kg body wt(-1) · h(-1)) and to a greater extent in young adults (0.36 ± 0.04 to 3.57 ± 0.47 μmol · kg body wt(-1) · h(-1)). Consistent with the kinetic data, RH-FBF in the fasted state was ∼ 40% reduced in older vs. young adults. However, citrulline ingestion (10 g) failed to increase RH-FBF in either older or young adults. In conclusion, citrulline ingestion improved impaired NO synthesis in older HF adults but not RH-FBF, suggesting that factors other than NO synthesis play a role in the impaired RH-FBF in older HF adults, and/or it may require a longer duration of supplementation to be effective in improving RH-FBF.

Is reversal of endothelial dysfunction still an attractive target in modern cardiology?

Although the endothelium has a number of important functions, the term endothelial dysfunction is commonly used to describe impairment in its vasodilatory capacity. There have been numerous studies evaluating the relationship between endothelial dysfunction and cardiovascular disease, however assessment of endothelial function is perhaps still primarily thought of as a research tool and has not reached widespread clinical acceptance. In this review we explore the relationship between endothelial dysfunction and cardiovascular disease, its prognostic significance, methods of pharmacological reversal of endothelial dysfunction, and ask the question, is reversal of endothelial dysfunction still an attractive target in modern cardiology?

Vascular endothelial function and self-reported sleep

BACKGROUND

The authors investigated the relationship between self-reported sleep characteristics and brachial artery flow-mediated dilation (FMD) in a community-based population. Previous studies document that sleep apnea may be related to endothelial dysfunction but disagree whether subjective reports of sleep may also reflect such associations.

METHODS

In 684 subjects (32% male) aged between 37 and 60 years enrolled in the Emory-Georgia Tech Predictive Health Institute study, the authors measured reported sleep characteristics using the Epworth Sleepiness Scale and the Pittsburgh Sleep Quality Index (PSQI) along with cardiovascular risk factors. Endothelial function was assessed using brachial artery FMD. Multivariate analysis of covariance was used to adjust for various cardiovascular risk factors including age, race, gender, smoking, hypertension, diabetes and body mass index.

RESULTS

Lower brachial artery FMD values were correlated with higher Epworth Sleepiness Scale scores (P = 0.0275), even after adjustment for risk factors (P = 0.03). Total PSQI score was unrelated to brachial artery FMD. However, lower sleep quality (PSQI component 1) was associated with lower brachial artery FMD (multivariate P = 0.038), and participants who coughed or snored during sleep also had lower brachial artery FMD (6.24% ± 3.42%) compared with those who did not (6.92% ± 4.30%) (P = 0.056). This difference remained significant after adjustment for risk factors (P = 0.03).

CONCLUSIONS

In a community-based population, our analysis indicates a significant association between sleepiness and snoring assessed by questionnaires and endothelial function. Simple subjective reports about individuals' sleep may be highly revealing indicators of endothelial function impairment and thus important indicators of cardiovascular disease risk.

The Relationship between Vascular Function and the Autonomic Nervous System

Endothelial dysfunction and autonomic nervous system dysfunction are both risk factors for atherosclerosis. There is evidence demonstrating that there is a close interrelationship between these two systems. In hypertension, endothelial dysfunction affects the pathologic process through autonomic nervous pathways, and the pathophysiological process of autonomic neuropathy in diabetes mellitus is closely related with vascular function. However, detailed mechanisms of this interrelationship have not been clearly explained. In this review, we summarize findings concerning the interrelationship between vascular function and the autonomic nervous system from both experimental and clinical studies. The clarification of this interrelationship may provide more comprehensive risk stratification and a new effective therapeutic strategy against atherosclerosis.

The influence of new beta-adrenolytics nebivolol and carvedilol on intraocular pressure and iris blood flow in rabbits

BACKGROUND

The aim of this study was to assess the influence of propranolol, nebivolol, and carvedilol on intraocular pressure and blood flow in vessels of rabbit's (New Zealand White) eyeball.

METHODS

The study was carried out on New Zealand white rabbits. Intraocular pressure was measured with the applanation tonometer Möller-Wedel and Icare; blood flow was measured with Doppler Laser Blood Flow Monitor MBD3.

RESULTS

Following a single administration into a conjunctival sac, all drugs decreased intraocular pressure. Iris blood flow was decreased following administration of propranol, but increased by nebivolol and carvedilol. After single and repeated oral administration of nebivolol and carvedilol an IOP decrease was demonstrated, but with no effect of all applied doses on iris or retina/choroid blood flow.

CONCLUSION

Studies performed on an animal model indicate that it is possible to reduce the intraocular pressure and increase ocular blood flow in humans, following topical administration of carvedilol and nebivolol. Confirmation of those results in clinical trials may lead to development of a new anti-glaucoma treatment. Further clinical studies of long-term nebivolol and carvedilol are recommended. They are necessary for evaluation of usefulness of those drugs for selected groups of patients, for example those with glaucoma and arterial hypertension.

The impact of acute mental stress on vascular endothelial function: evidence, mechanisms and importance

Cardiovascular disease is a principle cause of morbidity and mortality worldwide, and it has a complex etiology that involves lifestyle factors such as psychosocial stress. Recent evidence suggests that temporary impairments in vascular endothelial cell function may contribute to the relationship between stress and cardiovascular disease. Indeed, impaired endothelial function has been observed to occur transiently (lasting up to 1.5h) following mental stress, and such periods of impairment could accumulate to become clinically relevant over the long term. The finding of acute stress induced endothelial dysfunction is not universal however, and both physiological (e.g. sympathetic nervous system and hypothalamic-pituitary-adrenal axis reactivity), and methodological factors contribute to the conflicting results. A clear understanding of the interaction between stress response activation and endothelial function is critical to elucidating the complexities of the relationship between psychosocial stress and cardiovascular disease. Therefore, the purpose of this review is: 1) to briefly describe the importance of vascular endothelial function and how it is assessed, 2) to review the literature investigating the impact of acute mental stress on endothelial function in humans, identifying factors that may explain contradictory results, and 3) to summarize our current understanding of the mechanisms that may mediate an acute mental stress-endothelial function interaction.

Anti-oxidized low-density lipoprotein antibodies in chronic heart failure

Oxidative stress may play a significant role in the pathogenesis of heart failure (HF). Antibodies to oxidized low-density lipoprotein (oxLDL Abs) reflect an immune response to LDL over a prolonged period and may represent long-term oxidative stress in HF. The oxLDL plasma level is a useful predictor of mortality in HF patients, and measurement of the oxLDL Abs level may allow better management of those patients. Antibodies to oxLDL also significantly correlate with the New York Heart Association score. Hypercholesterolemia, smoking, hypertension, and obesity are risk factors for atherosclerotic coronary heart disease (CHD) leading to HF, but these factors account for only one-half of all cases, and understanding of the pathologic process underlying HF remains incomplete. Nutrients with antioxidant properties can reduce the susceptibility of LDL to oxidation. Antioxidant therapy may be an adjunct to lipid-lowering, angiotensin converting enzyme inhibition and metformin (in diabetes) therapy for the greatest impact on CHD and HF. Observational data suggest a protective effect of antioxidant supplementation on the incidence of HD. This review summarizes the data on oxLDL Abs as a predictor of morbidity and mortality in HF patients.

Effect of carvedilol and nebivolol on oxidative stress-related parameters and endothelial function in patients with essential hypertension

Oxidative stress and endothelial dysfunction have been associated with essential hypertension (EH) mechanisms. The purpose of this study was to evaluate the effect of carvedilol and nebivolol on the oxidative stress-related parameters and endothelial function in patients with EH. The studied population included 57 patients, either sex, between 30 and 75 years of age, with mild-to-moderate EH complications. Participants were randomized to receive either carvedilol (12.5 mg) (n = 23) or nebivolol (5 mg) (n = 21) for 12 weeks. Measurements included; 24-hr ambulatory blood pressure (BP), flow-mediated dilatation, levels of nitric oxide estimated as nitrite - a nitric oxide metabolite ( NO₂) - in plasma, and oxidative stress-related parameters in plasma and erythrocyte. EH patients who were treated with nebivolol or carvedilol showed systolic BP reductions of 17.4 and 19.9 mmHg, respectively, compared with baseline values (p < 0.01). Diastolic BP was reduced by 13.7 and 12.8 mmHg after the treatment with ebivolol and carvedilol, respectively (p < 0.01) (fig. 2B). Nebivolol and carvedilol showed 7.3% and 8.1% higher endothelium-dependent dilatation in relation to baseline values (p < 0.05). Ferric-reducing ability of plasma (FRAP) and reduced glutathione/oxidized glutathione (GSSH) ratio showed 31.5% and 29.6% higher levels in the carvedilol group compared with basal values; however, nebivolol-treated patients did not show significant differences after treatment. On the other hand, the NO₂ plasma concentration was not modified by the administration of carvedilol. However, nebivolol enhanced these levels in 62.1% after the treatment. In conclusion, this study demonstrated the antihypertensive effect of both beta-blockers. However, carvedilol could mediate these effects by an increase in antioxidant capacity and nebivolol through the raise in NO₂ concentration. Further studies are needed to determine the molecular mechanism of these effects.

Artist® tablets (carvedilol) for hypertensive patients in Japan: results of a drug use survey

Background: In Japan, when pharmaceutical companies launch a new drug, they are obligated to conduct a post-marketing survey to evaluate the safety and efficacy of the drug in accordance with Good Post-Marketing Surveillance Practice under Article 14.4 (re-examination) of the Pharmaceutical Affairs Law at contracted medical institutions. We report the results of a drug use survey, which we conducted as a post-marketing survey.

Objective: This prospective post-marketing drug use survey was conducted to assess the safety and efficacy of the β-adrenergic receptor antagonist (β-blocker) Artist® Tablets (carvedilol) in patients with hypertension in Japan.

Patients: Patients were carvedilol-naive and had essential hypertension or renal parenchymal hypertension.

Methods: This was a prospective survey conducted over 3 years from October 1993 to September 1996. The standard observation period for the patients was defined as 12 weeks of treatment with carvedilol.

Results: We collected data on 4961 patients at 561 medical institutions who had not been previously treated with carvedilol; 4574 patients were included in the safety analysis and 4422 in the efficacy analysis. The incidence of adverse drug reactions (the proportion of patients with adverse drug reactions) was 4.31% (197 of 4574 patients), which is less than that shown in the pre-approval clinical trial of carvedilol (6.85%[68 of 993]). The most common adverse drug reactions were bradycardia, dizziness, hypotension, headache, and feeling light-headed.

After 12 weeks’ treatment with carvedilol, systolic/diastolic blood pressure (SBP/DBP) was reduced from 168.2 ± 18.6/95.7 ± 11.3mmHg at baseline to 144.3 ± 17.3/83.4 ± 10.8mmHg. Patients were classified according to which antihypertensive drug they had been using when carvedilol treatment was initiated. Coadministered agents were calcium channel blockers (CCBs), angiotensinconverting enzyme inhibitors (ACEIs), diuretics, and a-adrenergic receptor antagonists (α-blockers). At 12 weeks, the change in SBP/DBP in the monotherapy group was −22.7/−12.2mmHg and that of each combination therapy subgroup, CCB, ACEI, diuretic, and b-blocker, was −26.1/−12.7mmHg, −25.4/−11.9mmHg, −26.3/−13.0mmHg, and −24.4/−11.5mmHg, respectively. The achievement rates for target BP (<140/90mmHg) were 29.5% in the monotherapy group, 34.8% in the CCB group, 31.3% in the ACEI group, 31.8% in the diuretic group, and 32.4% in the β-blocker group. There was no significant difference in the achievement of target BP among the four combination therapy subgroups (p = 0.475). These results indicate that carvedilol exerts reasonable BP reduction regardless of whether it is used as monotherapy or in combination therapy, and that the effect is not influenced by the coadministered drug. Moreover, carvedilol was also effective in reducing BP levels in elderly patients (≥65 years) and in patients with diabetes mellitus or renal diseases.

Conclusions: The results of this study reflect the results of clinical trials up to the time of approval and it was confirmed that carvedilol is a highly useful drug in the treatment of hypertension.

Carvedilol-lisinopril combination therapy and endothelial function in obese individuals with hypertension

The authors hypothesized that carvedilol controlled-release plus lisinopril combination therapy (C+L) would increase endothelial function and decrease oxidative stress to a greater extent than hydrochlorothiazide plus lisinopril combination therapy (H+L) in obese patients with hypertension. Twenty-five abdominally obese patients (aged 54.4±7.3 years; 14 women) with hypertension/prehypertension were enrolled in a 7-month (two 3-month treatment periods separated by a 1-month washout), randomized, double-blind, controlled, crossover clinical trial comparing C+L vs H+L. Endothelial function, measured by digital reactive hyperemic index (RHI), circulating oxidized low-density lipoprotein (oxLDL), 8-isoprostane, and asymmetric dimethylarginine (ADMA) were obtained at baseline, post-period 1, post-washout, and post-period 2. Analyses were adjusted for baseline measurements by analysis of covariance, with robust variance estimation for confidence intervals and P values. C+L treatment compared to H+L treatment significantly improved RHI (0.74, 95% confidence interval, 0.31-1.19, P =.001). This difference persisted after adjustment for the change in systolic blood pressure. No significant treatment differences were observed for oxLDL, 8-isoprostane, or ADMA. These data provide evidence that independent of blood pressure-lowering, C+L therapy improves endothelial function to a greater extent than H+L therapy. Levels of oxidative stress were not significantly different between treatments, suggesting that other mechanisms may be responsible for the improvement in endothelial function.

Endothelial function is unaffected by changing between carvedilol and metoprolol in patients with heart failure--a randomized study

Background

Carvedilol has been shown to be superior to metoprolol tartrate to improve clinical outcomes in patients with heart failure (HF), yet the mechanisms responsible for these differences remain unclear. We examined if there were differences in endothelial function, insulin stimulated endothelial function, 24 hour ambulatory blood pressure and heart rate during treatment with carvedilol, metoprolol tartrate and metoprolol succinate in patients with HF.

Methods

Twenty-seven patients with mild HF, all initially treated with carvedilol, were randomized to a two-month treatment with carvedilol, metoprolol tartrate or metoprolol succinate. Venous occlusion plethysmography, 24-hour blood pressure and heart rate measurements were done before and after a two-month treatment period.

Results

Endothelium-dependent vasodilatation was not affected by changing from carvedilol to either metoprolol tartrate or metoprolol succinate. The relative forearm blood flow at the highest dose of serotonin was 2.42 ± 0.33 in the carvedilol group at baseline and 2.14 ± 0.24 after two months continuation of carvedilol (P = 0.34); 2.57 ± 0.33 before metoprolol tartrate treatment and 2.42 ± 0.55 after treatment (p = 0.74) and in the metoprolol succinate group 1.82 ± 0.29 and 2.10 ± 0.37 before and after treatment, respectively (p = 0.27). Diurnal blood pressures as well as heart rate were also unchanged by changing from carvedilol to metoprolol tartrate or metoprolol succinate.

Conclusion

Endothelial function remained unchanged when switching the beta blocker treatment from carvedilol to either metoprolol tartrate or metoprolol succinate in this study, where blood pressure and heart rate also remained unchanged in patients with mild HF.

Trial registration

Current Controlled Trials NCT00497003

Treatment of angina and microvascular coronary dysfunction

OPINION STATEMENT

Microvascular coronary dysfunction (MCD) is an increasingly recognized cause of cardiac ischemia and angina that is diagnosed more commonly in women. Patients with MCD present with the triad of persistent chest pain, ischemic changes on stress testing, and no obstructive coronary artery disease on cardiac catheterization. Data from the National Heart, Lung, and Blood Institute-sponsored Women's Ischemia Syndrome Evaluation (WISE) study show that the diagnosis of MCD is not benign, with a 2.5% annual risk of adverse cardiac events including myocardial infarction, stroke, congestive heart failure, and death. The gold standard diagnostic test for MCD is the invasive coronary reactivity test (CRT), which uses acetylcholine, adenosine, and nitroglycerin to test endothelial-dependent and -independent microvascular and macrovascular coronary function. The CRT allows for diagnostic and treatment options as well as further risk stratification of patients for future cardiovascular events. Treatment of angina and MCD should be aimed at ischemia disease management to reduce the risk of adverse cardiac events, ameliorate symptoms to improve quality of life, and decrease morbidity from unnecessary and repeated cardiac catheterization in patients with open coronary arteries. A comprehensive treatment approach aimed at risk factor management, including lifestyle counseling regarding smoking cessation, nutrition, and physical activity, should be initiated. Current pharmacotherapy for MCD may include treatment of microvascular endothelial dysfunction (with statins, angiotensin-converting enzyme inhibitors, or low-dose aspirin), as well as treatment for angina and myocardial ischemia (with β-blockers, calcium channel blockers, nitrates, or ranolazine). Additional symptom management techniques may include tricyclic medication, enhanced external counterpulsation, hypnosis, and spinal cord stimulation. Although our current therapies are effective in treating angina and MCD, large randomized outcome trials are needed to optimize strategies to improve morbidity and mortality.

Metoprolol compared to carvedilol deteriorates insulin-stimulated endothelial function in patients with type 2 diabetes - a randomized study

AIM

Studies of beta blockade in patients with type 2 diabetes have shown inferiority of metoprolol treatment compared to carvedilol on indices of insulin resistance. The aim of this study was to examine the effect of metoprolol versus carvedilol on endothelial function and insulin-stimulated endothelial function in patients with type 2 diabetes.

METHOD

24 patients with type 2 diabetes were randomized to receive either 200 mg metoprolol succinate or 50 mg carvedilol daily. Endothelium-dependent vasodilation was assessed by using venous occlusion plethysmography with increasing doses of intra-arterial infusions of the agonist serotonin. Insulin-stimulated endothelial function was assessed after co-infusion of insulin for sixty minutes. Vaso-reactivity studies were done before and after the two-month treatment period.

RESULTS

Insulin-stimulated endothelial function was deteriorated after treatment with metoprolol, the percentage change in forearm blood-flow was 60.19% +/- 17.89 (at the highest serotonin dosages) before treatment and -33.80% +/- 23.38 after treatment (p = 0.007). Treatment with carvedilol did not change insulin-stimulated endothelial function. Endothelium-dependent vasodilation without insulin was not changed in either of the two treatment groups.

CONCLUSION

This study shows that vascular insulin sensitivity was preserved during treatment with carvedilol while blunted during treatment with metoprolol in patients with type 2 diabetes.

TRIAL REGISTRATION

Current Controlled Trials NCT00497003.

Association between endothelial function and chronotropic incompetence in subjects with chronic heart failure receiving optimal medical therapy

OBJECTIVE

Impairment of flow-mediated, endothelium-dependent vasodilatation (FMD) of the brachial artery identifies peripheral endothelial dysfunction in subjects with chronic congestive heart failure (CHF) and is associated with increased morbidity and mortality. To further elucidate the interaction of peripheral and central mechanisms in the syndrome of CHF, we examined the association between endothelial function and chronotropic incompetence, an emerging prognostic marker in CHF.

METHODS

Thirty subjects with stable New York Heart Association (NYHA) functional class II-III CHF were studied. A vascular ultrasound study was performed to measure brachial artery FMD. The percentage of age-adjusted maximal predicted heart rate (MPHR) reached during cardiopulmonary exercise tolerance testing (CPETT) was used to assess the degree of chronotropic competence. All patients received ACE inhibitors and beta-adrenoceptor blockers.

RESULTS

Brachial artery FMD averaged 1.3 +/- 2.4% and age-adjusted % MPHR 74.1 +/- 11.7%. FMD correlated with % MPHR among all patients (r = 0.60, P = 0.01). FMD and resting heart rate (RHR) did not significantly correlate (r = 0.13, P = 0.55).

CONCLUSIONS

FMD, a measure of peripheral endothelial dysfunction, and % MPHR, a central determinant of cardiac output, are moderately correlated in heart failure patients receiving optimal medical therapy. Whether a cause-effect relationship underlies this association remains to be investigated.

Radical scavenging and NO-releasing properties of selected β-adrenoreceptor antagonists

It is claimed that novel beta-adrenolytic drugs possess superior antioxidant properties as compared to classical selective or non-selective beta-adrenoceptor antagonists. Here we tested this notion by analyzing radical scavenging properties of selected beta-adrenolytic drugs and their ability to release nitric oxide in biological preparations. Selective beta1-adrenolytics such as nebivolol, atenolol, metoprolol and non-selective beta-adrenolytics with alpha1-receptor blocking properties such as carvedilol and labetalol were chosen for analysis. NO-releasing properties of nebivolol and carvedilol distinguished third generation beta-adrenolytics from their older counterparts while the reactivity towards hydroxyl and peroxyl radicals discerns only carvedilol but not nebivolol. Thus, superior clinical efficacy of third generation beta-adrenolytics may be related to their ability to release NO rather then to their direct antioxidant properties.

Pharmacological approaches to improve endothelial repair mechanisms

Endothelial injury is thought to play a pivotal role in the development and progression of vascular diseases, such as atherosclerosis, hypertension or restenosis, as well as their complications, including myocardial infarction or stroke. Accumulating evidence suggests that bone marrow-derived endothelial progenitor cells (EPCs) promote endothelial repair and contribute to ischemia-induced neovascularization. Coronary artery disease and its risk factors, such as diabetes, hypercholesterolemia, hypertension and smoking, are associated with a reduced number and impaired functional activity of circulating EPCs. Moreover, initial data suggest that reduced EPC levels are associated with endothelial dysfunction and an increased risk of cardiovascular events, compatible with the concept that impaired EPC-mediated vascular repair promotes progression of vascular disease. In this review we summarize recent data on the effects of pharmacological agents on mobilization and functional activity of EPCs. In particular, several experimental and clinical studies have suggested that statins, angiotensin-converting enzyme inhibitors, angiotensin II type 1 receptor blockers, PPAR-gamma agonists and erythropoietin increase the number and functional activity of EPCs. The underlying mechanisms remain largely to be defined; however, they likely include activation of the PI3-kinase/Akt pathway and endothelial nitric oxide synthase, as well as inhibition of NAD(P)H oxidase activity of progenitor cells.

Gender differences in short-term effects of atorvastatin on lipid profile, fibrinolytic parameters, and endothelial function

BACKGROUND AND AIM

Little is known about the impact of gender on short-term effects of atorvastatin. We investigated the gender differences in the short-term lipid-lowering and pleiotropic effects of atorvastatin therapy.

METHODS AND RESULTS

Seventy-two consecutive patients including 48 women with primary hypercholesterolemia, were assigned prospectively to treatment with atorvastatin (10mg/day) for 3 months. We measured fasting lipid concentrations, thiobarbituric acid reactive substances (TBARS) as marker of lipid peroxide, fibrinolytic parameters, and endothelial function by flow-mediated vasodilation of the brachial artery (FMD), at baseline and after 3 months of therapy. We assessed the impact of gender on temporal differences in these parameters. In men, atorvastatin decreased total, low-density lipoprotein (LDL), and small, dense LDL-cholesterol concentrations, and increased FMD after 3 months. In women, atorvastatin decreased TBARS, triglyceride, and total, LDL, small, dense LDL, and remnant-like lipoprotein particle-cholesterol concentrations, and increased FMD after 3 months. Fibrinolytic parameters did not change significantly in either men or women. With respect to the percent change in those parameters after 3 months, TBARS (-17.6+/-12.4 vs. -0.4+/-18.8%, p<0.01) and small, dense LDL-cholesterol (-96.7+/-8.3 vs. -68.6+/-29.7%, p<0.01) decreased to a greater degree in women, although the relative changes in other parameters were similar between men and women.

CONCLUSIONS

We found gender differences in some of the lipid altering changes, including TBARS and small, dense LDL-cholesterol concentrations, after short-term atorvastatin therapy, which were greater in women. However, short-term atorvastatin therapy may be beneficial in improving endothelial function equally in both men and women.

Application of liquid chromatography-tandem mass spectrometry method for the analysis of new nonselective beta-adrenergic blocker 1-(1-H-indol-4-yloxy)-3-{[2-(2-methoxy phenoxy)ethylo]amino}propan-2-ol (2F109) in rat plasma

A sensitive and specific liquid chromatography electrospray ionization-tandem mass spectrometry method for the enantioselective determination of the novel beta-adrenolytic compound, 1-(1-H-indol-4-yloxy)-3-{[2-(2-methoxyphenoxy)ethylo]amino} propan-2-ol, in rat plasma has been developed and validated. Chromatography was performed on a reversed-phase Chiralcel OD-RH analytical column (150x4.6 mm, 5 microm, Daicel Chemical Industries, Tokyo, Japan) with isocratic elution using a mobile phase containing acetonitrile and water with 0.01% formic acid. Detection was achieved by an Applied Biosystems MDS Sciex (Concord, Ontario, Canada) API 2000 triple quadrupole mass spectrometer. Electrospray ionization (ESI) was used for ion production. The limit of detection in the MRM mode was found to be 1.25 ng/ml. The limit of quantification of both enantiomers was 2.5 ng/ml. The precision and accuracy for both intra- and inter-day determination of 2F109 enantiomers ranged from 2.6 to 12% and from 89.1 to 107.1%. This analytical method allowed us to carry out pharmacokinetic studies in rats. Our findings demonstrate that 2F109 shows stereoselective disposition in rat plasma after i.v. administration. The terminal half-lives of (+)-(R)-2F109 and (-)-(S)-2F109 were 33.5 and 42.6 min, respectively. The AUC0-inf of (+)-(R)-2F109 exceeded that of (-)-(S)-2F109.

Aspects of nitric oxide in health and disease: a focus on hypertension and cardiovascular disease

Nitric oxide (nitrogen monoxide) (NO) plays an important role in a wide range of physiologic processes. A major mediator of endothelial function, NO regulates vasodilatory and antithrombotic actions in the vasculature and plays a role in reproductive functions, bronchodilation, bone formation, memory, insulin sensitivity, and gastrointestinal relaxation. NO is formed from NO synthase. Impaired NO bioactivity is strongly associated with endothelial dysfunction and cardiovascular disease, but is also implicated in a broad range of other disorders, including pulmonary hypertension, insulin resistance, erectile dysfunction, and preeclampsia. Numerous therapies designed to target NO are being investigated and developed, including NO donors and stimulants. The recent African-American Heart Failure Trial (A-HeFT) showed that the NO donor isosorbide dinitrate, combined with the vasodilator hydralazine, significantly reduced morbidity and mortality in black patients with moderate-to-severe heart failure. Antihypertensive drugs, including angiotensin-converting enzyme inhibitors, calcium channel blockers, and third-generation beta-blockers, are NO stimulants that have demonstrated significant improvement of endothelial function and NO bioactivity. Other cardiovascular therapies that may improve NO bioactivity include statins, l-arginine, and nonpharmacologic approaches such as exercise and dietary changes.

Carvedilol Protects Better Against Vascular Events Than Metoprolol in Heart Failure

OBJECTIVES

We explored whether vascular protection by carvedilol could contribute to its superior effects in the treatment of heart failure (HF) compared with metoprolol tartrate in the COMET (Carvedilol Or Metoprolol European Trial) study.

BACKGROUND

Full adrenergic blockade by carvedilol and additional (e.g., antioxidative) properties may lead to vascular protection relative to beta-1 blockade alone, and contribute to its efficacy in HF treatment.

METHODS

Three thousand twenty-nine patients with HF due to ischemic (51%) or idiopathic cardiomyopathy (44%) were randomized double-blind to carvedilol (n = 1,511) or metoprolol (n = 1,518) and followed for 58 months. Vascular end points were cardiovascular death, stroke, stroke death, myocardial infarction (MI), and unstable angina.

RESULTS

The effect of carvedilol on cardiovascular death improved consistently in subgroups with prespecified baseline variables. Myocardial infarctions were reported in 69 carvedilol and 94 metoprolol patients (hazard ratio [HR] 0.71, 95% confidence interval [CI] 0.52 to 0.97, p = 0.03). Cardiovascular death or nonfatal MI combined were reduced by 19% in carvedilol (HR 0.81, 95% CI 0.72 to 0.92, p = 0.0009 vs. metoprolol). Unstable angina was reported as an adverse event in 56 carvedilol and in 77 metoprolol patients (HR 0.71, 95% CI 0.501 to 0.998, p = 0.049). A stroke occurred in 65 carvedilol and 80 metoprolol patients (HR 0.79, 95% CI 0.57 to 1.10). Stroke or MI combined occurred in 130 carvedilol and 168 metoprolol patients (HR 0.75, 95% CI 0.60 to 0.95, p = 0.015), and fatal MI or fatal stroke occurred in 34 carvedilol and in 72 metoprolol patients (HR 0.46, 95% CI 0.31 to 0.69, p = 0.0002). Death after a nonfatal MI or stroke occurred in 61 of 124 carvedilol and in 106 of 160 metoprolol patients (HR 0.66, 95% CI 0.48 to 0.90, p = 0.0086).

CONCLUSIONS

Carvedilol improves vascular outcomes better than metoprolol. These results suggest a ubiquitous protective effect of carvedilol against major vascular events.

Beneficial effects of carvedilol as a concomitant therapy to angiotensin-converting enzyme inhibitor in patients with ischemic left ventricular systolic dysfunction

Studies are scant on the effects of short-term carvedilol treatment as an adjuvant to angiotensin-converting enzyme (ACE) inhibitor in patients with left ventricular (LV) systolic dysfunction. The objective of this study was to find the effects of short-term treatment of carvedilol on patients with ischemic LV systolic dysfunction (defined as LV ejection fraction (LVEF) ≤30% on 2D echocardiography) undergoing coronary artery bypass surgery (CABG). There were 74 patients that received ACE inhibitor without any β-blocker (control) and 67 patients that received carvedilol in addition to ACE inhibitor following CABG (carvedilol group). After 1 month of drug administration following CABG, the control group was found to have significantly greater percent improvement in LVEF (29.1% ± 5.39%) as compared with the carvedilol group (15.3% ± 4.89%). However, after 3 and 6 months, LVEF levels were found to be significantly greater in the carvedilol group as compared with the control group. Further, at 6 months of drug administration, LV end systolic diameter was significantly less in the carvedilol group (39.11 ± 1.10 mm) as compared with the control group (43.49 ± 1.39 mm). Thus, carvedilol produces beneficial effect on short-term administration in terms of LV contractility when given along with ACE inhibtior as compared with ACE inhibitor therapy alone.

Impaired endothelium-dependent and -independent vasodilation in elderly patients with chronic heart failure

BACKGROUND

Impaired endothelium-dependent and independent vasodilator responses in chronic heart failure (CHF) have been well described. Previous studies involved younger patients and omitted medications prior to study.

AIMS

We explored if new therapeutic interventions would restore vasodilator responses in typical patients with chronic heart failure.

METHODS AND RESULTS

24 patients and 15 controls were recruited, patients were maintained on their usual medications. Forearm blood flow responses were measured by venous occlusion plethysmography in response to incremental doses of sodium nitroprusside (SNP) (6, 9 and 12 nmol/min), acetylcholine (ACH) (120, 180 and 240 nmol/min), angiotensin II (AII) (1, 10 and 100 nmol/min) and N(g)-Nitro-L-arginine methyl ester (L-NAME) (1, 2 and 4 nmol/min) infused into the non-dominant brachial artery. FBF responses to SNP were impaired in patients compared with controls (13.7(9.9,17.4) vs. 24.8(18.6,30.9)) arbitrary units, P<0.001). Similarly FBF responses to ACH were reduced in patients compared with controls (7.5(4.2,10.9) vs. 24.8(16.4,33.2)) arbitrary units, P<0.001. Decreased FBF was noted in response to AII and L-NAME but was significant only for AII and did not differ between groups.

CONCLUSIONS

In elderly patients with CHF, endothelium-dependent and independent vasodilator responses were blunted compared with controls. Defects in nitric oxide bioavailability and smooth muscle responsiveness are not reversed by modern medical management of the heart failure syndrome.

Short-term improvement in submaximal exercise capacity by optimized therapy with ACE inhibitors and beta blockers in heart failure patients is associated with restoration of peripheral endothelial function

BACKGROUND

Improved exercise capacity in chronic heart failure (CHF) has been attributed to restoration of endothelial function. ACE inhibitors as well as beta blockers have previously been shown to enhance endothelial function and exercise capacity. The aim of this study was to determine whether short-term improvement in submaximal exercise capacity induced by optimized therapy with ACE inhibitors in combination with beta blockers is associated with restoration of endothelial function in CHF patients.

METHODS

Thirty-three patients with CHF were evaluated: six-minute walk test, NYHA class, brain natriuretic peptide (BNP), big Endothelin-1 (bigET-1) and flow-mediated vasodilation (FMD) of the brachial artery were assessed at baseline and after a 3-month period of optimized neurohormonal therapy. Two groups were formed retrospectively based on the changes in submaximal exercise capacity (responders and non-responders).

RESULTS

Optimization of neurohormonal therapy was comparable between groups. Responders (n=17) revealed a significant increase in walking distance (304+/-109 to 441+/-75 m; p<0.01), which was paralleled by a decrease in NYHA class (2.7+/-0.6 to 2.0+/-0.4; p<0.01), BNP (484+/-454 to 243+/-197 pg/ml; p<0.01), and bigET-1 (2.0+/-0.9 vs. 1.5+/-0.6 fmol/ml; p=0.04). By contrast, the latter variables did not change in non-responders. Improvement in functional capacity in responders was associated with an increase in FMD (8.2+/-3.9% to 11.0+/-5.6%; p<0.05). Increments in FMD were directly correlated with increases in walking distance (r=0.34; p<0.05).

CONCLUSION

Short-term improvement of submaximal exercise capacity in CHF patients following optimized therapy with ACE inhibitors and beta blockers is associated with restoration of endothelial function in conduit arteries.

Vascular adrenergic tone and structural narrowing constrain reactive hyperemia in skeletal muscle of obese Zucker rats

Previous studies have demonstrated that skeletal muscle perfusion is impaired in obese Zucker rats (OZR) under control conditions and with elevated metabolic demand versus responses in lean Zucker rats (LZR). To further our understanding of processes contributing to impaired perfusion, we determined whether hyperemic responses following periods of occlusion were altered in skeletal muscle of OZR versus LZR. In isolated hindlimbs, basal blood flow in OZR was less than in LZR, and total perfusion responses after 30, 90, and 180 s of occlusion were reduced. Treatment of animals with an antioxidant (polythethylene glycol-superoxide dismutase) had no effect on reactive hyperemia, although blockade of alpha-adrenoreceptors (alpha1 > alpha2) improved responses to 30 and 90 s of occlusion; responses to 180 s of occlusion were unaltered. Pump perfusion of a dilated distal hindlimb demonstrated that increased volume flow elicited a greater increase in perfusion pressure in OZR versus LZR, suggesting structural contributions to an increased vascular resistance. Responses were comparable for in situ cremaster muscle because reactive hyperemia following serial arteriolar occlusion was attenuated in OZR versus LZR, treatment with polythethylene glycol-superoxide dismutase was ineffective, and hyperemic responses were improved following inhibition of alpha-adrenoreceptors (alpha1 > alpha2). Treatment of cremaster muscle with adenosine (10(-3) M) caused flow to increase to a level comparable to that following 180 s of occlusion in both strains, although this level was reduced in OZR versus LZR. These results suggest that increased adrenergic tone may constrain reactive hyperemia in OZR with brief occlusion, although structural increases in vascular resistance can contribute to constrained perfusion after longer periods of occlusion.

Effects of metoprolol and carvedilol on cause-specific mortality and morbidity in patients with chronic heart failure--COMET

BACKGROUND

Beta-blockers with different receptor bindings reduce mortality in patients with chronic heart failure. We compared the effects of the beta1-blocker metoprolol tartrate and the beta1-, beta2-, and alpha1-blocker carvedilol.

METHODS

In a randomized double-blind design, 3029 patients with chronic congestive heart failure requiring diuretic therapy and with left ventricular dysfunction were randomized to treatment with carvedilol (n = 1511) or metoprolol tartrate (n = 1518) and titrated to target doses of 25 mg of carvedilol twice daily or 50 mg of metoprolol tartrate twice daily. The main outcome measures were total mortality and the combination of mortality or hospitalization for any cause. Secondary end points were cardiovascular death, combinations of morbidity and mortality, New York Heart Association class, worsening of heart failure, hospitalizations, and discontinuation of study therapy.

RESULTS

A total of 512 and 600 patients in the carvedilol group and metoprolol group, respectively, died (hazard ratio [HR] 0.83, 95% CI 0.74-0.93, P = .0017). Cardiovascular death was reduced by carvedilol (HR 0.80, 95% CI 0.70-0.90, P = .0004). There were fewer sudden deaths and deaths caused by circulatory failure or by stroke in the carvedilol group. There was no difference in all-cause hospitalizations or in worsening heart failure between treatment groups. The incidence of fatal or nonfatal acute myocardial infarction was significantly lower in the carvedilol group (HR 0.71, 95% CI 0.52-0.97, P = .03). Discontinuations of study therapy were similar in the 2 groups.

CONCLUSION

Compared with metoprolol tartrate, carvedilol reduced cardiovascular mortality, sudden death, death caused by circulatory failure, death caused by stroke, as well as fatal and nonfatal myocardial infarctions.

Assessment of flow-mediated vasodilatation (FMD) of the brachial artery: effects of technical aspects of the FMD measurement on the FMD response

AIMS

The ability to assess endothelial function non-invasively with B-mode ultrasound has lead to its widespread application in a variety of studies. However, the absolute values obtained using this approach vary considerably across studies. We studied whether technical aspects of the methodology can explain the wide variety in absolute values across studies.

METHODS AND RESULTS

A literature search was performed to identify published reports on flow-mediated vasodilatation (FMD) of the brachial artery published between 1992 and 2001. Information on type of equipment (wall track/B-mode), location of the measurement (antecubital fossa/upper arm), occlusion site (lower/upper arm), occlusion duration (min), and occlusion pressure was extracted. Patient characteristics were also extracted. For the healthy populations, mean FMD varied from 0.20 to 19.2%; for the coronary heart disease (CHD) patients FMD varied from -1.3 to 14%; for subjects with diabetes mellitus FMD varied from 0.75 to 12%. Compared with occlusion at the upper arm, lower arm occlusion was related to decreased FMD (mean difference in FMD -2.47%; 95% CI 0.55-4.39). An occlusion duration of > or =4.5 min was related to an increased FMD compared with an occlusion time of < or =4 min (mean difference 1.30%; 95% CI 0.35-2.46). These findings were adjusted for other technical aspects of the methodology and for differences in risk factors between populations.

CONCLUSION

Mean FMD differs widely between studies. There is a great overlap between populations (healthy, CHD, diabetics). Our findings suggest that the technical aspects of the measurements, the location, and the duration of the occlusion may explain some of these differences, whereas type of equipment, location of the measurement, and occlusion pressure do not.