Long-term treatment with metoprolol after myocardial infarction: effect on 3 year mortality and morbidity

Anti-hypertensive medications and erectile dysfunction: focus on β-blockers

PURPOSE

Although anti-hypertensive medications, including thiazides and β-blockers (BBs) in particular, have been suggested to cause erectile dysfunction (ED) their real contribution is still conflicting. The aim of this paper is to summarize available evidence providing an evidence-based critical analysis of the topic.

METHODS

An overall comprehensive narrative review was performed using Medline, Embase and Cochrane search. In addition, to better understand the impact of BBs on ED a specific systematic review was also performed.

RESULTS

The negative role of centrally acting drugs, such as clonidine and α-methyldopa, is well documented althuogh limited controlled trials are available. Angiotensin-converting enzyme inhibitors (ACEis), angiotensin receptor blockers (ARBs), and calcium-channel-blockers (CCBs) have neutral (CCBs) or even positive (ACEis and ARBs) effects on erectile function. Despite some preliminary negative reports, more recent evidence does not confirm the negative impact of thiazides. BBs should be still considered the class of medications more often associated with ED, although better outcomes can be drawn with nebivolol.

CONCLUSION

Sexual function should be assessed in all patients with arterial hypertension, either at diagnosis or after the prescription of specific medications. A close related patient-physician interaction and discussion can overcome possible negative outcomes allowing a successful management of possible side effects.

Effects of Metoprolol on Periprocedural Myocardial Infarction After Percutaneous Coronary Intervention (Type 4a MI): An Inverse Probability of Treatment Weighting Analysis

Background: Metoprolol is the most used cardiac selective β-blocker and has been recommended as a mainstay drug in the management of acute myocardial infarction (AMI). However, the evidence supporting this regimen in periprocedural myocardial infarction (PMI) is limited.

Methods: This study identified 860 individuals who suffered PMI following percutaneous coronary intervention (PCI) procedure and median followed up for 3.2 years. Subjects were dichotomized according to whether they received chronic oral sustained-release metoprolol succinate following PMI. After inverse probability of treatment weighting (IPTW) adjustment, logistic regression analysis, Kaplan-Meier curve, and Cox regression analysis were performed to estimate the effects of metoprolol on major adverse cardiovascular events (MACEs) which composed of cardiac death, myocardial infarction (MI), stroke, and revascularization. Moreover, an exploratory analysis was performed according to hypertension, cardiac troponin I (cTnI) elevation, and cardiac function. A double robust adjustment was used for sensitivity analysis.

Results: Among enrolled PMI subjects, 456 (53%) patients received metoprolol treatment and 404 (47%) patients received observation. After IPTW adjustment, receiving metoprolol was found to reduce the subsequent 3-year risk of MACEs by nearly 7.1% [15 vs. 22.1%, absolute risk difference (ARD) = 0.07, number needed to treat (NNT) = 14, relative risk (RR) = 0.682]. In IPTW-adjusted Cox regression analyses, receiving metoprolol was related to a reduced risk of MACEs (hazard ratio [HR] = 0.588, 95%CI [0.385–0.898], P = 0.014) and revascularization (HR = 0.538, 95%CI [0.326–0.89], P = 0.016). Additionally, IPTW-adjusted logistic regression analysis showed that receiving metoprolol reduced the risk of MI at the third year (odds ratio [OR] = 0.972, 95% CI [0.948–997], P = 0.029). Exploratory analysis showed that the protective effect of metoprolol was more pronounced in subgroups of hypertension and cTnI elevation ≥1,000%, and was remained in patients without cardiac dysfunction. The benefits above were consistent when double robust adjustments were performed.

Conclusion: In the real-world setting, receiving metoprolol treatment following PCI-related PMI has decreased the subsequent risk of MACEs, particularly the risk of recurrent MI and revascularization.

Beta-blockers in patients without heart failure after myocardial infarction

BACKGROUND

Cardiovascular disease is the number one cause of death globally. According to the World Health Organization (WHO), 7.4 million people died from ischaemic heart disease in 2012, constituting 15% of all deaths. Beta-blockers are recommended and are often used in patients with heart failure after acute myocardial infarction. However, it is currently unclear whether beta-blockers should be used in patients without heart failure after acute myocardial infarction. Previous meta-analyses on the topic have shown conflicting results. No previous systematic review using Cochrane methods has assessed the effects of beta-blockers in patients without heart failure after acute myocardial infarction.

OBJECTIVES

To assess the benefits and harms of beta-blockers compared with placebo or no treatment in patients without heart failure and with left ventricular ejection fraction (LVEF) greater than 40% in the non-acute phase after myocardial infarction.

SEARCH METHODS

We searched CENTRAL, MEDLINE, Embase, LILACS, Science Citation Index - Expanded, BIOSIS Citation Index, the WHO International Clinical Trials Registry Platform, ClinicalTrials.gov, European Medicines Agency, Food and Drug Administration, Turning Research Into Practice, Google Scholar, and SciSearch from their inception to February 2021.

SELECTION CRITERIA

We included all randomised clinical trials assessing effects of beta-blockers versus control (placebo or no treatment) in patients without heart failure after myocardial infarction, irrespective of publication type and status, date, and language. We excluded trials randomising participants with diagnosed heart failure at the time of randomisation.

DATA COLLECTION AND ANALYSIS

We followed our published protocol, with a few changes made, and methodological recommendations provided by Cochrane and Jakobsen and colleagues. Two review authors independently extracted data. Our primary outcomes were all-cause mortality, serious adverse events, and major cardiovascular events (composite of cardiovascular mortality and non-fatal myocardial reinfarction). Our secondary outcomes were quality of life, angina, cardiovascular mortality, and myocardial infarction during follow-up. We assessed all outcomes at maximum follow-up. We systematically assessed risks of bias using seven bias domains and we assessed the certainty of evidence using the GRADE approach.

MAIN RESULTS

We included 25 trials randomising a total of 22,423 participants (mean age 56.9 years). All trials and outcomes were at high risk of bias. In all, 24 of 25 trials included a mixed group of participants with ST-elevation myocardial infarction and non-ST myocardial infarction, and no trials provided separate results for each type of infarction. One trial included participants with only ST-elevation myocardial infarction. All trials except one included participants younger than 75 years of age. Methods used to exclude heart failure were various and were likely insufficient. A total of 21 trials used placebo, and four trials used no intervention, as the comparator. All patients received usual care; 24 of 25 trials were from the pre-reperfusion era (published from 1974 to 1999), and only one trial was from the reperfusion era (published in 2018). The certainty of evidence was moderate to low for all outcomes. Our meta-analyses show that beta-blockers compared with placebo or no intervention probably reduce the risks of all-cause mortality (risk ratio (RR) 0.81, 97.5% confidence interval (CI) 0.73 to 0.90; I² = 15%; 22,085 participants, 21 trials; moderate-certainty evidence) and myocardial reinfarction (RR 0.76, 98% CI 0.69 to 0.88; I² = 0%; 19,606 participants, 19 trials; moderate-certainty evidence). Our meta-analyses show that beta-blockers compared with placebo or no intervention may reduce the risks of major cardiovascular events (RR 0.72, 97.5% CI 0.69 to 0.84; 14,994 participants, 15 trials; low-certainty evidence) and cardiovascular mortality (RR 0.73, 98% CI 0.68 to 0.85; I² = 47%; 21,763 participants, 19 trials; low-certainty evidence). Hence, evidence seems to suggest that beta-blockers versus placebo or no treatment may result in a minimum reduction of 10% in RR for risks of all-cause mortality, major cardiovascular events, cardiovascular mortality, and myocardial infarction. However, beta-blockers compared with placebo or no intervention may not affect the risk of angina (RR 1.04, 98% CI 0.93 to 1.13; I² = 0%; 7115 participants, 5 trials; low-certainty evidence). No trials provided data on serious adverse events according to good clinical practice from the International Committee for Harmonization of Technical Requirements for Pharmaceuticals for Human Use (ICH-GCP), nor on quality of life.

AUTHORS' CONCLUSIONS

Beta-blockers probably reduce the risks of all-cause mortality and myocardial reinfarction in patients younger than 75 years of age without heart failure following acute myocardial infarction. Beta-blockers may further reduce the risks of major cardiovascular events and cardiovascular mortality compared with placebo or no intervention in patients younger than 75 years of age without heart failure following acute myocardial infarction. These effects could, however, be driven by patients with unrecognised heart failure. The effects of beta-blockers on serious adverse events, angina, and quality of life are unclear due to sparse data or no data at all. All trials and outcomes were at high risk of bias, and incomplete outcome data bias alone could account for the effect seen when major cardiovascular events, angina, and myocardial infarction are assessed. The evidence in this review is of moderate to low certainty, and the true result may depart substantially from the results presented here. Future trials should particularly focus on patients 75 years of age and older, and on assessment of serious adverse events according to ICH-GCP and quality of life. Newer randomised clinical trials at low risk of bias and at low risk of random errors are needed if the benefits and harms of beta-blockers in contemporary patients without heart failure following acute myocardial infarction are to be assessed properly. Such trials ought to be designed according to the SPIRIT statement and reported according to the CONSORT statement.

One-Year Landmark Analysis of the Effect of Beta-Blocker Dose on Survival After Acute Myocardial Infarction

Background Although beta-blockers are recommended following myocardial infarction (MI), the benefits of long-term treatment have not been established. The study's aim was to evaluate beta-blocker efficacy by dose in 1-year post-MI survivors. Methods and Results The OBTAIN (Outcomes of Beta-Blocker Therapy After Myocardial Infarction) registry included 7057 patients with acute MI, with 6077 one-year survivors. For this landmark analysis, beta-blocker dose status was available in 3004 patients and analyzed by use (binary) and dose at 1 year after MI. Doses were classified as no beta-blocker and >0% to 12.5%, >12.5% to 25%, >25% to 50%, and >50% of target doses used in randomized clinical trials. Age was 63 to 64 years, and approximately two thirds were men. Median follow-up duration was 1.05 years (interquartile range, 0.98-1.22). When analyzed dichotomously, beta-blocker therapy was not associated with improved survival. When analyzed by dose, propensity score analysis showed significantly increased mortality in the no-beta-blocker group (hazard ratio,1.997; 95% CI, 1.118-3.568; P<0.02), the >0% to 12.5% group (hazard ratio, 1.817; 95% CI, 1.094-3.016; P<0.02), and the >25% to 50% group (hazard ratio, 1.764; 95% CI, 1.105-2.815; P<0.02), compared with the >12.5% to 25% dose group. The mortality in the full-dose group was not significantly higher (hazard ratio, 1.196; 95% CI, 0.687-2.083). In subgroup analyses, only history of congestive heart failure demonstrated significant interaction with beta-blocker effects on survival. Conclusions This analysis suggests that patients treated with >12.5% to 25% of the target dose used in prior randomized clinical trials beyond 1 year after MI may have enhanced survival compared with no beta-blocker and other beta-blocker doses. A new paradigm for post-MI beta-blocker therapy is needed that addresses which patients should be treated, for how long, and at what dose.

Beta-blockers in hypertension: overview and meta-analysis of randomized outcome trials

BACKGROUND

Meta-analyses from randomized outcome-based trials have challenged the role of beta-blockers for the treatment of hypertension. However, because they often include trials on diseases other than hypertension, the role of these drugs in the choice of the blood pressure (BP)-lowering treatment strategies remains unclear.

METHODS

Electronic databases were searched for randomized trials that compared beta-blockers vs. placebo/no-treatment/less-intense treatment (BP-lowering trials) or beta-blockers vs. other antihypertensive agents in patients with or without hypertension (comparison trials). Among BP-lowering trials and according to baseline comorbidity, we separately considered trials in hypertension, trials without chronic heart failure or acute myocardial infarction, and trials with either chronic heart failure or acute myocardial infarction. Seven fatal and nonfatal outcomes were calculated (random-effects model) for BP-lowering or comparison trials.

RESULTS

A total of 84 BP-lowering or comparison trials (165 850 patients) were eligible. In 67 BP-lowering trials (68 478 patients; mean follow-up 2.5 years; baseline SBP/DBP, 136/82 mmHg), beta blockers were associated with a lower incidence of major cardiovascular events [risk ratio 0.85 and 95% confidence interval (95% CI) 0.78-0.92] and all-cause death (risk ratio 0.81 and 95% CI 0.75-0.86). Restriction of the analysis to five trials recruiting exclusively hypertensive patients (18 724 patients; mean follow-up 5.1 years; baseline SBP/DBP 163/94 mmHg), a -10.5/-7.0 mmHg BP decrease was accompanied by reduction of major cardiovascular events by 22% (95% CI, 6-34). In 24 comparison trials (103 764 patients, 3.92 years of mean follow-up), beta-blockers compared with other agents were less protective for stroke and all-cause death in all trials and in trials conducted exclusively in hypertensive patients (averaged risk ratio increase 20 and 6%, respectively, for both cases).

CONCLUSION

Compared with other antihypertensive agents, beta-blockers appear to be substantially less protective against stroke and overall mortality. However, they exhibit a substantial risk-reducing ability for all events when prescribed to lower BP in patients with modest or more clear BP elevations, and therefore can be used as additional agents in hypertensive patients.

Comparison of Metoprolol Versus Carvedilol After Acute Myocardial Infarction

Beta-blockers are typically prescribed following myocardial infarction (MI), but no specific beta-blocker is recommended. Of 7,057 patients enrolled in the OBTAIN multi-center registry of patients with acute MI, 4142 were discharged on metoprolol and 1487 on carvedilol. Beta-blocker dose was indexed to the target daily dose used in randomized clinical trials (metoprolol-200 mg; carvedilol-50 mg), reported as %. Beta-blocker dosage groups were >0% to12.5% (n = 1,428), >12.5% to 25% (n = 2113), >25% to 50% (n = 1,392), and >50% (n = 696). The Kaplan-Meier method was used to calculate 3-year survival. Correction for baseline differences was achieved by multivariable adjustment. Patients treated with carvedilol were older (64.4 vs 63.3 years) and had more comorbidities: hypertension, diabetes, prior MI, congestive heart failure, reduced left ventricular ejection fraction, and a longer length of stay. Mean doses for metoprolol and carvedilol did not significantly differ (37.2 ± 27.8% and 35.8 ± 31.0%, respectively). The 3-year survival estimates were 88.2% and 83.5% for metoprolol and carvedilol, respectively, with an unadjusted HR = 0.72 (p <0.0001), but after multivariable adjustment HR = 1.073 (p = 0.43). Patients in the >12.5% to 25% dose category had improved survival compared with other dose categories. Subgroup analysis of patients with left ventricular ejection fraction ≤40%, showed worse survival with metoprolol versus carvedilol (adjusted HR = 1.281; 95% CI: 1.024 to 1.602, p = 0.03). In patients with left ventricular ejection fraction >40%, there were no differences in survival with carvedilol versus metoprolol. In conclusion, overall survival after acute MI was similar for patients treated with metoprolol or carvedilol, but may be superior for carvedilol in patients with left ventricular ejection fraction ≤40%.

Neutrophil-Mediated Cardiac Damage After Acute Myocardial Infarction: Significance of Defining a New Target Cell Type for Developing Cardioprotective Drugs

Significance: Acute myocardial infarction (AMI) is a leading cause of death worldwide. Post-AMI survival rates have increased with the introduction of angioplasty as a primary coronary intervention. However, reperfusion after angioplasty represents a clinical paradox, restoring blood flow to the ischemic myocardium while simultaneously inducing ion and metabolic imbalances that stimulate immune cell recruitment and activation, mitochondrial dysfunction and damaging oxidant production. Recent Advances: Preclinical data indicate that these metabolic imbalances contribute to subsequent heart failure through sustaining local recruitment of inflammatory leukocytes and oxidative stress, cardiomyocyte death, and coronary microvascular disturbances, which enhance adverse cardiac remodeling. Both left ventricular dysfunction and heart failure are strongly linked to inflammation and immune cell recruitment to the damaged myocardium. Critical Issues: Overall, therapeutic anti-inflammatory and antioxidant agents identified in preclinical trials have failed in clinical trials. Future Directions: The versatile neutrophil-derived heme enzyme, myeloperoxidase (MPO), is gaining attention as an important oxidative mediator of reperfusion injury, vascular dysfunction, adverse ventricular remodeling, and atrial fibrillation. Accordingly, there is interest in therapeutically targeting neutrophils and MPO activity in the setting of heart failure. Herein, we discuss the role of post-AMI inflammation linked to myocardial damage and heart failure, describe previous trials targeting inflammation and oxidative stress post-AMI, highlight the potential adverse impact of neutrophil and MPO, and detail therapeutic options available to target MPO clinically in AMI patients.

Periodontal therapy and cardiovascular risk

Cardiovascular diseases are the worldwide leading cause of mortality. Cardiovascular diseases are noncommunicable conditions with a complex pathogenesis, and their clinical manifestations include major cardiovascular events such as myocardial infarction and stroke. Epidemiologic evidence suggests a consistent association between periodontitis and increased risk of cardiovascular diseases. Some evidence supports a beneficial effect of the treatment of periodontitis on both surrogate and hard cardiovascular outcomes. This narrative review has been conducted as an update of the most recent evidence on the effects of periodontitis treatment on cardiovascular outcomes since the last commissioned review of the European Federation of Periodontology-American Academy of Periodontology World Workshop in 2012. Newer evidence originating from published randomized controlled trials confirms a positive effect of periodontal treatment on surrogate measures of cardiovascular diseases, whereas there have been no randomized controlled trials investigating the effect of periodontal treatment on the incidence of cardiovascular disease events such as myocardial infarction and stroke. In conclusion, there is sufficient evidence from observational and experimental studies on surrogate cardiovascular measures to justify the design and conduct of appropriately powered randomized controlled trials investigating the effect of effective periodontal interventions on cardiovascular disease outcomes (ie, myocardial infarction and stroke) with adequate control of traditional cardiovascular risk factors.

From Clinical Trial Efficacy to Real-Life Effectiveness: Why Conventional Metrics do not Work

Background

Randomised, double-blind, clinical trial methodology minimises bias in the measurement of treatment efficacy. However, most phase III trials in non-orphan diseases do not include individuals from the population to whom efficacy findings will be applied in the real world. Thus, a translation process must be used to infer effectiveness for these populations. Current conventional translation processes are not formalised and do not have a clear theoretical or practical base. There is a growing need for accurate translation, both for public health considerations and for supporting the shift towards personalised medicine.

Objective

Our objective was to assess the results of translation of efficacy data to population efficacy from two simulated clinical trials for two drugs in three populations, using conventional methods.

Methods

We simulated three populations, two drugs with different efficacies and two trials with different sampling protocols.

Results

With few exceptions, current translation methods do not result in accurate population effectiveness predictions. The reason for this failure is the non-linearity of the translation method. One of the consequences of this inaccuracy is that pharmacoeconomic and postmarketing surveillance studies based on direct use of clinical trial efficacy metrics are flawed.

Conclusion

There is a clear need to develop and validate functional and relevant translation approaches for the translation of clinical trial efficacy to the real-world setting.

Electronic supplementary material

The online version of this article (10.1007/s40801-019-0159-z) contains supplementary material, which is available to authorized users.

ST-segment elevation myocardial infarction

ST-segment elevation myocardial infarction (STEMI) is the most acute manifestation of coronary artery disease and is associated with great morbidity and mortality. A complete thrombotic occlusion developing from an atherosclerotic plaque in an epicardial coronary vessel is the cause of STEMI in the majority of cases. Early diagnosis and immediate reperfusion are the most effective ways to limit myocardial ischaemia and infarct size and thereby reduce the risk of post-STEMI complications and heart failure. Primary percutaneous coronary intervention (PCI) has become the preferred reperfusion strategy in patients with STEMI; if PCI cannot be performed within 120 minutes of STEMI diagnosis, fibrinolysis therapy should be administered to dissolve the occluding thrombus. The initiation of networks to provide around-the-clock cardiac catheterization availability and the generation of standard operating procedures within hospital systems have helped to reduce the time to reperfusion therapy. Together with new advances in antithrombotic therapy and preventive measures, these developments have resulted in a decrease in mortality from STEMI. However, a substantial amount of patients still experience recurrent cardiovascular events after STEMI. New insights have been gained regarding the pathophysiology of STEMI and feed into the development of new treatment strategies.

Through the Decades: β-Blocker Use and Outcomes in Acute Coronary Syndromes

Beta-adrenergic receptor antagonists, or β-blockers, have been a cornerstone of treatment in patients with acute coronary syndromes (ACS) for more than 4 decades. First studied in the 1960s, β-blockers in ACS have been shown to decrease the risk of death, recurrent ischemic events, and arrhythmias by reducing catecholamine-mediated effects and reducing myocardial oxygen demand. Through the decades, the β-blocker of choice, timing of initiation, duration of therapy, and dosing have evolved considerably. Despite having clear benefits in certain patient populations (eg, patients with systolic dysfunction who are hemodynamically stable), the benefit of β-blockers in other populations (ie, in patients at low risk for complications receiving modern revascularization therapies and optimal medical management) remains unclear. This article provides a review of the landmark clinical trials of β-blockers in ACS and highlights the chronology and evolution of guideline recommendations through the decades.

Effects of Bisoprolol Are Comparable with Carvedilol in Secondary Prevention of Acute Myocardial Infarction in Patients Undergoing Percutaneous Coronary Intervention

Although the benefits of carvedilol have been demonstrated in the era of percutaneous coronary intervention (PCI), very few studies have evaluated the efficacy of bisoprolol in the secondary prevention of acute myocardial infarction (MI) in patients treated with PCI. We hypothesized that the effect of bisoprolol would not be different from carvedilol in post-MI patients. A total of 13,813 patients who underwent PCI were treated either with carvedilol or bisoprolol at the time of discharge. They were enrolled from the Korean Acute MI Registry (KAMIR). After 1:2 propensity score matching, 1,806 patients were enrolled in the bisoprolol group and 3,612 patients in the carvedilol group. The primary end point was the composite of major adverse cardiac events (MACEs), which was defined as cardiac death, nonfatal MI, target vessel revascularization, and coronary artery bypass surgery. The secondary end point was defined as all-cause mortality, cardiac death, nonfatal MI, any revascularization, or target vessel revascularization. After adjustment for differences in baseline characteristics by propensity score matching, the MACE-free survival rate was not different between the groups (HR=0.815, 95% CI:0.614-1.081, p=0.156). In the subgroup analysis, the cumulative incidence of MACEs was lower in the bisoprolol group in patients having a Killip class of III or IV than in the carvedilol group (HR=0.512, 95% CI: 0.263-0.998, p=0.049). The incidence of secondary end points was similar between the two beta-blocker groups. In conclusion, the benefits of bisoprolol were comparable with those of carvedilol in the secondary prevention of acute MI.

Current use of beta-blockers in patients with coronary artery disease

Beta-blockers have long comprised a cornerstone in the symptomatic treatment of ischemic heart disease and in the secondary prevention of myocardial infarction and heart failure. The majority of studies underlying the evidence of a beneficial effect of beta-blockers on outcomes were conducted more than 25 years ago. In a contemporary era where treatment strategies and secondary prophylactic therapy have undergone several changes, the continued role of beta-blockers in ischemic heart disease has been questioned, especially in the absence of heart failure or a recent myocardial infarction. In summary, few randomized clinical trials are available on the effect of beta-blockers in the reperfusion era, especially on hard endpoints. Likewise, the results of numerous observational studies and meta-analysis are conflicting, emphasizing the need for additional large-scale randomized clinical trials to evaluate the role of beta-blocker therapy in current clinical practice.

Stabilisation of atherosclerotic plaques

Plaque rupture and subsequent thrombotic occlusion of the coronary artery account for as many as three quarters of myocardial infarctions. The concept of plaque stabilisation emerged about 20 years ago to explain the discrepancy between the reduction of cardiovascular events in patients receiving lipid lowering therapy and the small decrease seen in angiographic evaluation of atherosclerosis. Since then, the concept of a vulnerable plaque has received a lot of attention in basic and clinical research leading to a better understanding of the pathophysiology of the vulnerable plaque and acute coronary syndromes. From pathological and clinical observations, plaques that have recently ruptured have thin fibrous caps, large lipid cores, exhibit outward remodelling and invasion by vasa vasorum. Ruptured plaques are also focally inflamed and this may be a common denominator of the other pathological features. Plaques with similar characteristics, but which have not yet ruptured, are believed to be vulnerable to rupture. Experimental studies strongly support the validity of anti-inflammatory approaches to promote plaque stability. Unfortunately, reliable non-invasive methods for imaging and detection of such plaques are not yet readily available. There is a strong biological basis and supportive clinical evidence that low-density lipoprotein lowering with statins is useful for the stabilisation of vulnerable plaques. There is also some clinical evidence for the usefulness of antiplatelet agents, beta blockers and renin-angiotensin-aldosterone system inhibitors for plaque stabilisation. Determining the causes of plaque rupture and designing diagnostics and interventions to prevent them are urgent priorities for current basic and clinical research in cardiovascular area.

Meta-Analysis Comparing Metoprolol and Carvedilol on Mortality Benefits in Patients With Acute Myocardial Infarction

Although carvedilol, a nonselective beta-blocker with alpha-adrenergic blocking and multiple ancillary activities, has been demonstrated to be superior to metoprolol in chronic heart failure, it remains unclear whether the superiority of carvedilol still exists in myocardial infarction (MI). Therefore, we performed a network meta-analysis of randomized controlled trials (RCTs) to compare the 2 drugs in patients with MI. All RCTs that compared either 2 of the following interventions, carvedilol, metoprolol, and placebo, for the treatment of MI were included. The Cochrane Collaboration Central Register of Controlled Trials, Embase, and PubMed were searched thoroughly for potential eligible studies. Finally, 12 RCTs involving 61,081 patients were included. Pooled results showed that compared with placebo, carvedilol and metoprolol significantly reduced composite cardiovascular events (risk ratio [RR] 0.63; 95% credible interval [CrI] 0.41, 0.85 for carvedilol; RR 0.78; 95% CrI 0.65, 0.93 for metoprolol) and re-infarction (RR 0.57; 95% CrI 0.37, 0.84 for carvedilol; RR 0.77; 95% CrI 0.62, 0.91 for metoprolol) in patients with MI. However, neither carvedilol nor metoprolol showed significant benefits on all-cause death, cardiovascular death, revascularization, and rehospitalization. Also, no obvious difference was found when comparing carvedilol and metoprolol on primary or secondary outcomes. In conclusion, there is insufficient evidence supporting the superiority of carvedilol over metoprolol for the treatment of MI. Further studies are needed to confirm our findings.

Effects of local cardiac denervation on cardiac innervation and ventricular arrhythmia after chronic myocardial infarction

Background

Modulation of the autonomic nervous system (ANS) has already been demonstrated to display antiarrhythmic effects in patients and animals with MI. In this study, we investigated whether local cardiac denervation has any beneficial effects on ventricular electrical stability and cardiac function in the chronic phase of MI.

Methods

Twenty-one anesthetized dogs were randomly assigned into the sham-operated, MI and MI-ablation groups, respectively. Four weeks after local cardiac denervation, LSG stimulation was used to induce VPCs and VAs. The ventricular fibrillation threshold (VFT) and the incidence of inducible VPCs were measured with electrophysiological protocol. Cardiac innervation was determined with immunohistochemical staining of growth associated protein-43 (GAP43) and tyrosine hydroxylase (TH). The global cardiac and regional ventricular function was evaluated with doppler echocardiography in this study.

Results

Four weeks after operation, the incidence of inducible VPC and VF in MI-ablation group were significantly reduced compared to the MI dogs (p<0.05). Moreover, local cardiac denervation significantly improved VFT in the infarcted border zone (p<0.05). The densities of GAP43 and TH-positive nerve fibers in the infarcted border zone in the MI-ablation group were lower than those in the MI group (p<0.05). However, the local cardiac denervation did not significantly improve cardiac function in the chronic phase of MI, determined by the left ventricle diameter (LV), left atrial diameter (LA), ejection fraction (EF).

Conclusions

Summarily, in the chronic phase of MI, local cardiac denervation reduces the ventricular electrical instability, and attenuates spatial heterogeneity of sympathetic nerve reconstruction. Our study suggests that this methodology might decrease malignant ventricular arrhythmia in chronic MI, and has a great potential for clinical application.

Prevention of ventricular arrhythmia complicating acute myocardial infarction by local cardiac denervation

BACKGROUND

Augmentation of sympathetic nerve activity after acute myocardial infarction (AMI) contributes to fatal arrhythmia. In this study, we investigated whether local ablation of the coronary sinus (CS) and great cardiac vein (GCV) peripheral nerves could reduce ventricular arrhythmias (VA) in a canine AMI model.

METHODS

Twenty-one anesthetized dogs were randomly assigned into the sham-operated, MI and MI-ablation groups, respectively. The incidence and duration of VA were monitored among different groups. The ventricular effective refractory period (ERP), the ERP dispersion and the ventricular fibrillation threshold (VFT) were measured during the experiments. Norepinephrine (NE) levels in CS blood and cardiac tissue were also detected in this study.

RESULTS

The incidence and duration of VA in MI-ablation group were significantly reduced as compared to the MI dogs (p<0.05). Furthermore, local cardiac denervation drastically prolonged the ventricular ERP in the ischemia area, decreased the ERP dispersion, and reduced NE levels in CS blood (P<0.05). VFT also showed an increased trend in the AMI-ablation group.

CONCLUSIONS

The results of this study indicate that, in the canine AMI model, local ablation of CS and GCV peripheral nerves reduces VA occurrence and improves ventricular electrical stability with no obvious effects on heart rate, mean arterial pressure and infarct size. This study suggests that local cardiac denervation may prevent ventricular arrhythmias complicating AMI.

Development of a LC-MS/MS method for simultaneous determination of metoprolol and its metabolites, α-hydroxymetoprolol and O-desmethylmetoprolol, in rat plasma: application to the herb-drug interaction study of metoprolol and breviscapine

A simple, specific and sensitive LC-MS/MS method was developed and validated for the simultaneous determination of metoprolol (MET), α-hydroxymetoprolol (HMT) and O-desmethylmetoprolol (DMT) in rat plasma. The plasma samples were prepared by protein precipitation, then the separation of the analytes was performed on an Agilent HC-C18 column (4.6 × 250 mm, 5 µm) at a flow rate of 1.0 mL/min, and post-column splitting (1:4) was used to give optimal interface flow rates (0.2 mL/min) for MS detection; the total run time was 8.5 min. Mass spectrometric detection was achieved using a triple-quadrupole mass spectrometer equipped with an electrospray source interface in positive ionization mode. The method was fully validated in terms of selectivity, linearity, accuracy, precision, stability, matrix effect and recovery over a concentration range of 3.42-7000 ng/mL for MET, 2.05-4200 ng/mL for HMT and 1.95-4000 ng/mL for DMT. The analytical method was successfully applied to herb-drug interaction study of MET and breviscapine after administration of breviscapine (12.5 mg/kg) and MET (40 mg/kg). The results suggested that breviscapine have negligible effect on pharmacokinetics of MET in rats; the information may be beneficial for the application of breviscapine in combination with MET in clinical therapy.

Prognostic Benefit of Beta-blockers After Acute Coronary Syndrome With Preserved Systolic Function. Still Relevant Today?

INTRODUCTION AND OBJECTIVES

The scientific evidence for using beta-blockers after acute coronary syndrome stems from studies conducted in the days before coronary revascularization and in patients with ventricular dysfunction. The aim of this study was to analyze the current long-term prognostic benefit of beta-blockers in patients with acute coronary syndrome and preserved left ventricular ejection fraction.

METHODS

We conducted a retrospective cohort study of 3236 patients with acute coronary syndrome and left ventricular ejection fraction ≥ 50%. We performed a propensity-matched analysis to draw up two groups of 555 patients paired according to whether or not they had been treated with beta-blockers. The prognostic value of beta-blockers to predict mortality during follow-up was analyzed using Cox regression.

RESULTS

During the follow-up (median, 5.2 years), 506 patients (15.6%) died. Patients treated with beta-blockers (n=2277 [70.4%]) had a lower mortality rate (11.6% vs 25.2%; P<.001). After propensity score matching, we found that mortality during follow-up was still lower in the beta-blocker group (14.4% vs 18.9%; P=.020). Therefore, this treatment was an independent protective factor after adjusting for confounding variables in the multivariate Cox regression analysis (hazard ratio=0.64; 95% confidence interval, 0.48-0.87; P=.004).

CONCLUSIONS

Beta-blocker treatment in patients with acute coronary syndrome and preserved left ventricular ejection fraction is associated with lower long-term mortality.

Effect of the potent CYP2D6 inhibitor sarpogrelate on the pharmacokinetics and pharmacodynamics of metoprolol in healthy male Korean volunteers

1. Recently, we demonstrated that sarpogrelate is a potent and selective CYP2D6 inhibitor in vitro. Here, we evaluated the effect of sarpogrelate on the pharmacokinetics and pharmacodynamics of metoprolol in healthy subjects. 2. Nine healthy male subjects genotyped for CYP2D6*1/*1 or *1/*2 were included in an open-label, randomized, three treatment-period and crossover study. A single oral dose of metoprolol (100 mg) was administered with water (treatment A) and sarpogrelate (100 mg bid.; a total dose of 200 mg and treatment B), or after pretreatment of sarpogrelate for three days (100 mg tid.; treatment C). Plasma levels of metoprolol and α-hydroxymetoprolol were determined using a validated LC-MS/MS method. Changes in heart rate and blood pressure were monitored as pharmacodynamic responses to metoprolol. 3. Metoprolol was well tolerated in the three treatment groups. In treatment B and C groups, the AUCt of metoprolol increased by 53% (GMR, 1.53; 90% CI, 1.17-2.31) and by 51% (1.51; 1.17-2.31), respectively. Similar patterns were observed for the increase in Cmax of metoprolol by sarpogrelate. However, the pharmacodynamics of metoprolol did not differ significantly among the three treatment groups. 4. Greater systemic exposure to metoprolol after co-administration or pretreatment with sarpogrelate did not result in clinically relevant effects. Co-administration of both agents is well tolerated and can be employed without the need for dose adjustments.

Simultaneous determination of metoprolol and its metabolites, α-hydroxymetoprolol and O-desmethylmetoprolol, in human plasma by liquid chromatography with tandem mass spectrometry: Application to the pharmacokinetics of metoprolol associated with CYP2D6 genotypes

A rapid and simple LC with MS/MS method for the simultaneous determination of metoprolol and its two CYP2D6-derived metabolites, α-hydroxy- and O-desmethylmetoprolol, in human plasma was established. Metoprolol (MET), its two metabolites, and the internal standard chlorpropamide were extracted from plasma (50 μL) using ethyl acetate. Chromatographic separation was performed on a Luna CN column with an isocratic mobile phase consisting of distilled water and methanol containing 0.1% formic acid (60:40, v/v) at a flow rate of 0.3 mL/min. The total run time was 3.0 min per sample. Mass spectrometric detection was conducted by ESI in positive ion selected-reaction monitoring mode. The linear ranges of concentration for MET, α-hydroxymetoprolol, and O-desmethylmetoprolol were 2-1000, 2-500, and 2-500 ng/mL, respectively, with a lower limit of quantification of 2 ng/mL for all analytes. The coefficient of variation for the assay's precision was ≤ 13.2%, and the accuracy was 89.1-110%. All analytes were stable under various storage and handling conditions and no relevant cross-talk and matrix effect were observed. Finally, this method was successfully applied to assess the influence of CYP2D6 genotypes on the pharmacokinetics of MET after oral administration of 100 mg to healthy Korean volunteers.

Benefit of β-blocker treatment for patients with acute myocardial infarction and preserved systolic function after percutaneous coronary intervention

OBJECTIVE

β-blockers are the standard treatment for myocardial infarction (MI) based on evidence from the pre-thrombolytic era. The aim of this study was to examine the effect of β-blocker treatment in patients with acute MI and preserved systolic function in the era of percutaneous coronary intervention (PCI).

METHODS

We analysed a multicentre registry and identified 3019 patients who presented with acute MI between 2004 and 2009. Patients were treated with PCI, had left ventricular EFs ≥50% according to echocardiograms that were performed during the index PCI, and were alive at the time of discharge. The association between β-blocker use after discharge and mortality (all-cause death and cardiac death) within 3 years was examined.

RESULTS

Patients who were not treated with β-blockers (n=595) showed higher rates of all-cause death and cardiac death compared to patients treated with β-blockers (10.8% vs 5.7%, p<0.001, 7.6% vs 2.6%, p<0001). The multivariate Cox proportional hazards model showed that β-blocker treatment was associated with a significant reduction in all-cause death (adjusted HR 0.633, 95% CI 0.464 to 0.863; p=0.004) and cardiac death (adjusted HR 0.47, 95% CI 0.32 to 0.70; p<0.001). Comparable results were obtained after propensity score matching.

CONCLUSIONS

β-blocker treatment was associated with reduced long term mortality in patients with acute MI and preserved systolic function who received PCI.

Beta blocker use after acute myocardial infarction in the patient with normal systolic function: when is it "ok" to discontinue?

Beta-Blockers [BB] have been used extensively in the last 40 years after acute myocardial infarction [AMI] as part of therapy and in secondary prevention. The evidence for “routine” therapy with beta-blocker use post AMI rests largely on results of trials conducted over 25 years ago. However, there remains no clear recommendation regarding the appropriate duration of treatment with BBs in post AMI patients with normal left ventricular ejection fraction [LVEF] who are not experiencing angina, or who require BB for hypertension or dysrhythmia. Based on the latest ACC/AHA guidelines, BBs are recommended for early use in the setting of AMI, except in patients who are at low risk and then indefinitely as secondary prevention after AMI. This recommendation was downgraded to class IIa in low risk patients and the updated 2007 ACC/AHA guidelines suggest that the rationale for BB for secondary prevention is from limited data derived from extrapolations of chronic angina and heart failure trials. In this review, we examine the key trials that have shaped the current guidelines and recommendations. In addition, we attempt to answer the question of the duration of BB use in patients with preserved LVEF after acute MI, as well as which subgroups of patients benefits most from post AMI use of beta blockers.

Atherosclerosis: from biology to pharmacological treatment

A recent explosion in the amount of cardiovascular risk has swept across the globe. Primary prevention is the preferred method to lower cardiovascular risk. Lowering the prevalence of obesity is the most urgent matter, and is pleiotropic since it affects blood pressure, lipid profiles, glucose metabolism, inflammation, and atherothrombotic disease progression. Given the current obstacles, success of primary prevention remains uncertain. At the same time, the consequences of delay and inaction will inevitably be disastrous, and the sense of urgency mounts. Pathological and epidemiological data confirm that atherosclerosis begins in early childhood, and advances seamlessly and inexorably throughout life. Risk factors in childhood are similar to those in adults, and track between stages of life. When indicated, aggressive treatment should begin at the earliest indication, and be continued for many years. For those patients at intermediate risk according to global risk scores, C-reactive protein, coronary artery calcium, and carotid intima-media thickness are available for further stratification. Using statins for primary prevention is recommended by guidelines, is prevalent, but remains under prescribed. Statin drugs are unrivaled, evidence-based, major weapons to lower cardiovascular risk. Even when low density lipoprotein cholesterol targets are attained, over half of patients continue to have disease progression and clinical events. Though clinical evidence is incomplete, altering or raising the blood high density lipoprotein cholesterol level continues to be pursued. The aim of this review is to point out the attention of key aspects of vulnerable plaques regarding their pathogenesis and treatment.

MicroRNA expression analysis: clinical advantage of propranolol reveals key microRNAs in myocardial infarction

Background

As playing important roles in gene regulation, microRNAs (miRNAs) are believed as indispensable involvers in the pathogenesis of myocardial infarction (MI) that causes significant morbidity and mortality. Working on a hypothesis that modulation of only some key members in the miRNA superfamily could benefit ischemic heart, we proposed a microarray based network biology approach to identify them with the recognized clinical effect of propranolol as a prompt.

Methods

A long-term MI model of rat was established in this study. The microarray technology was applied to determine the global miRNA expression change intervened by propranolol. Multiple network analyses were sequentially applied to evaluate the regulatory capacity, efficiency and emphasis of the miRNAs which dysexpression in MI were significantly reversed by propranolol.

Results

Microarray data analysis indicated that long-term propranolol administration caused 18 of the 31 dysregulated miRNAs in MI undergoing reversed expression, implying that intentional modulation of miRNA expression might show favorable effects for ischemic heart. Our network analysis identified that, among these miRNAs, the prime players in MI were miR-1, miR-29b and miR-98. Further finding revealed that miR-1 focused on regulation of myocyte growth, yet miR-29b and miR-98 stressed on fibrosis and inflammation, respectively.

Conclusion

Our study illustrates how a combination of microarray technology and functional protein network analysis can be used to identify disease-related key miRNAs.

Impact of medical therapy on atheroma volume measured by different cardiovascular imaging modalities

Atherosclerosis is a systemic disease that affects most vascular beds. The gold standard of atherosclerosis imaging has been invasive intravascular ultrasound (IVUS). Newer noninvasive imaging modalities like B-mode ultrasound, cardiac computed tomography (CT), positron emission tomography (PET), and magnetic resonance imaging (MRI) have been used to assess these vascular territories with high accuracy and reproducibility. These imaging modalities have lately been used for the assessment of the atherosclerotic plaque and the response of its volume to several medical therapies used in the treatment of patients with cardiovascular disease. To study the impact of these medications on atheroma volume progression or regression, imaging modalities have been used on a serial basis providing a unique opportunity to monitor the effect these antiatherosclerotic strategies exert on plaque burden. As a result, studies incorporating serial IVUS imaging, quantitative coronary angiography (QCA), B-mode ultrasound, electron beam computed tomography (EBCT), and dynamic contrast-enhanced magnetic resonance imaging have all been used to evaluate the impact of therapeutic strategies that modify cholesterol and blood pressure on the progression/regression of atherosclerotic plaque. In this review, we intend to summarize the impact of different therapies aimed at halting the progression or even result in regression of atherosclerotic cardiovascular disease evaluated by different imaging modalities.

MicroRNA-1 downregulation by propranolol in a rat model of myocardial infarction: a new mechanism for ischaemic cardioprotection

AIMS

The present study was designed to investigate whether the beneficial effects of beta-blocker propranolol are related to regulation of microRNA miR-1.

METHODS AND RESULTS

We demonstrated that propranolol reduced the incidence of arrhythmias in a rat model of myocardial infarction by coronary artery occlusion. Overexpression of miR-1 was observed in ischaemic myocardium and strikingly, administration of propranolol reversed the up-regulation of miR-1 nearly back to the control level. In agreement with its miR-1-reducing effect, propranolol relieved myocardial injuries during ischaemia, restored the membrane depolarization and cardiac conduction slowing, by rescuing the expression of inward rectifying K(+) channel subunit Kir2.1 and gap junction channel connexin 43. Our results further revealed that the beta-adrenoceptor-cAMP-Protein Kinase A (PKA) signalling pathway contributed to the expression of miR-1, and serum response factor (SRF), which is known as one of the transcriptional enhancers of miR-1, was up-regulated in ischaemic myocardium. Moreover, propranolol inhibited the beta-adrenoceptor-cAMP-PKA signalling pathway and suppressed SRF expression.

CONCLUSION

We conclude that the beta-adrenergic pathway can stimulate expression of arrhythmogenic miR-1, contributing to ischaemic arrhythmogenesis, and beta-blockers produce their beneficial effects partially by down-regulating miR-1, which might be a novel strategy for ischaemic cardioprotection.

Effects on mortality during five years after early intervention with metoprolol in suspected acute myocardial infarction

This study reports the mortality over a 5-year-period determined a double-blind trial, which evaluated the effect of early intervention with metoprolol in suspected acute myocardial infarction. In all, there were 1,395 randomized patients, 698 and 697 of whom were allocated to metoprolol 200 mg daily and placebo treatments, respectively, for the first 3 months. Thereafter, the two groups were treated in a similar fashion implying beta-blockade to a majority. Within the first 3 months, mortality in the metoprolol group was 5.7% versus 8.9% of the placebo group (p = 0.02). This difference persisted after 2 years (metoprolol 13.2%; placebo 17.2%; p = 0.04). Over a 5-year-period, 24.2% of the patients who originally were allocated to metoprolol had died as compared to 25.7% of those originally allocated to placebo (p greater than 0.2). Among patients in whom treatment started early (less than or equal to 8 hours after onset of pain = the median delay time), enzyme activities in the metoprolol group was lower (p = 0.03) than in the placebo group. Mortality during the first 2 years among these patients treated early was lower in the metoprolol (11.8%) than in the placebo group (17.3%; p = 0.04). Corresponding figures after 5 years were 22.0% and 25.3%, respectively (p greater than 0.2). Among patients in whom treatment started later than 8 hours onset of pain, there was neither any difference in enzyme activity nor in mortality after 2 and 5 years. It can be concluded that early treatment with metoprolol in suspected acute myocardial infarction reduced mortality during the first 3 months compared with placebo. The difference persisted after 2 years. However, 5 years after randomization, no significant difference in mortality was observed between the two treatment groups.

Prognosis and clinical follow-up of patients resuscitated from out-of hospital cardiac arrest

A new organization has been formed in which ambulance personnel have been trained to recognize ventricular tachycardia and ventricular fibrillation (VF) and to defibrillate. Cardiac arrest (CA) occurred in 307 patients and 140 were defibrillated. Twenty-eight patients were resuscitated and admitted for further hospital care. A previous history of ischaemic heart disease was found in 24 patients. Twenty-two of the patients admitted were found to have VF, two asystole and four other rhythms. All 11 survivors regained circulation at the site of the CA. At the time of admission all but one of the patients were unconscious and one long-time survivor remained unconscious until the 5th day following admission. Seventeen patients died while still in hospital. In 16 cases a diagnosis of acute myocardial infarction was established, a further six had VF without evidence of acute myocardial infarction and six had other diagnoses. Ten out of the 11 survivors were still alive six months after discharge. Only one case of recurrent VF was seen during a median follow-up period of 16 months. Prolonged coma, especially in combination with convulsions, was associated with a poor prognosis, while early return of circulation was significantly more common among survivors. Ongoing medication with beta-blockers, a high QRS rate on admission and VF without proof of any acute myocardial infarction were also found to be more common in survivors.

High-dose prenalterol in beta-blockade intoxication

This study presents a case of beta-blocker intoxication due to massive overdose of metoprolol (7.5 g). Prenalterol in a dose of 420 mg was given as antidote, in combination with epinephrine in intermittent doses. Resuscitation was performed during 4 hours because of mechanical asystole. The patient regained health in 24 hours after further repeated doses of 30 mg prenalterol. Prenalterol is valuable in the management of toxic doses of beta-blocking drugs, and a titration to extremely high doses of prenalterol might be necessary.

Reduction of nonfatal reinfarctions in patients with a history of hypertension by chronic postinfarction treatment with metoprolol

The Stockholm Metoprolol Trial is a prospective double-blind placebo-controlled postmyocardial infarction study of 301 patients treated with metoprolol, 100 mg b.i.d., or matching placebo for three years. From this study we have retrospectively evaluated the outcome in patients with a history of treatment for hypertension prior to the index infarction. There were 41 such patients in the placebo group and 35 in the metoprolol group. Blood pressures during follow-up were nearly identical in the two groups. During the three years 11 patients died in the placebo group and 7 in the metoprolol group. Corresponding figures for nonfatal events such as reinfarction, coronary artery bypass surgery, cerebrovascular events and lower limb amputation were 12 vs. 1 (p less than 0.005), 3 vs. 0, 4 vs. 0 and 1 vs. 0, respectively. The numbers of patients with fatal and nonfatal events were 24 vs. 8 (p less than 0.01). In a retrospective subgroup analysis the results must always be interpreted with caution. The present results may, however, imply that postinfarction treatment with metoprolol reduces nonfatal atherosclerotic complications, especially nonfatal reinfarctions, in patients with a history of hypertension.

Complete atrioventricular block associated with concomitant use of metoprolol and paroxetine

A 63-year-old woman, who had been treated with 20 mg of paroxetine and 0.5 mg of alprazolam daily for 1 year and with 50 mg of metoprolol daily for 15 days, presented to a facility elsewhere with presyncope and complete atrioventricular block. Three days after her initial presentation and cessation of metoprolol treatment, she was transferred to our clinic to be considered for permanent pacemaker implantation. Paroxetine treatment was discontinued on day 1 and atrioventricular block resolved on day 5, which was confirmed with a 24-hour Holter recording. No bradyarrhythmia was induced with similar doses of either metoprolol or paroxetine alone. At 2- and 3-year follow-up, the patient was still free of bradyarrhythmia documented with electrocardiography and 24-hour Holter recordings. To our knowledge, we report the first case of complete atrioventricular block associated with coadministration of paroxetine and metoprolol. Increasing physicians' awareness of drug-induced severe bradyarrhythmia might prevent unnecessary implantation of permanent pacemakers.

Inhibition of metoprolol metabolism and potentiation of its effects by paroxetine in routinely treated patients with acute myocardial infarction (AMI)

OBJECTIVE

To investigate the influence of paroxetine on metoprolol concentrations and its effect in patients treated for acute myocardial infarction (AMI) who are routinely given paroxetine as a co-treatment of depression.

METHODS

We recruited 17 depressed AMI patients who received metoprolol as a routine part of their therapy (mean dose 75 +/- 39 mg/day). Patients were genotyped for CYP2D6 3, 4 and gene duplication. Metoprolol and alpha-hydroxy-metoprolol were analyzed in plasma 0, 2, 6 and 12 h post-dose. Heart rates (HR) at rest were registered after each sampling. Paroxetine 20 mg daily was then administered, and all measurements were repeated on day 8.

RESULTS

All patients were genotypically extensive metabolizers (EMs) (nine with 1/1 and eight with 1/3 or 4). Following the administration of paroxetine, mean metoprolol areas under the concentration-time curve (AUC) increased (1064 +/- 1213 to 4476 +/- 2821 nM x h/mg per kg, P = 0.0001), while metabolite AUCs decreased (1492 +/- 872 to 348 +/- 279 n M x h/mg per kg, P < 0.0001), with an increase of metabolic ratios (MR) (0.9 +/- 1.3 to 26 +/- 29; P < 0.0001). Mean HRs were significantly lower after the study week at each time point. Mean area under the HR versus time curve (AUEC) decreased (835 +/- 88 to 728 +/- 84 beats x h/min; P = 0.0007). Metoprolol AUCs correlated with patients' AUECs at the baseline (Spearman r = -0.64, P < 0.01), but not on the eighth day of the study. A reduction of metoprolol dose was required in two patients due to excessive bradycardia and severe orthostatic hypotension. No other adverse effects of the drugs were identified.

CONCLUSION

A pronounced inhibition of metoprolol metabolism by paroxetine was observed in AMI patients, but without serious adverse effects. We suggest, however, that the metoprolol dose is controlled upon initiation and withdrawal of paroxetine.

Prognostic implications of renal dysfunction in patients with stable angina pectoris

OBJECTIVE

Impaired renal function is emerging as an independent risk factor for cardiovascular (CV) disease. We analysed the prognostic implications of estimated renal function in patients with angina pectoris.

DESIGN

Post hoc analysis of the Angina Prognosis Study In Stockholm (APSIS). The estimated creatinine clearance (eCrCl) was calculated according to the Cockcroft-Gault formula in 808 patients. Outcomes were compared for subgroups with CrCl > or =90, 60-89 and<60 mL min(-1). Setting. Hospital-based study with patients referred from primary care and hospital.

SUBJECTS

A total of 809 patients (248 women) with clinically diagnosed stable angina pectoris. Intervention. Double-blind treatment with metoprolol or verapamil.

RESULTS

One hundred and sixty-four patients (91 women) had an eCrCl below 60 mL min(-1). During a median follow-up of 40 months, 38 patients suffered CV death and 31 patients had a nonfatal myocardial infarction (MI). In a univariate analysis a lower eCrCl was related to a higher risk for CV death or MI amongst men (log rank P = 0.036). A multivariate Cox analysis showed an independent prognostic importance of eCrCl for CV death (P = 0.046) and for CV death or MI (P = 0.042) amongst all patients. When analysed as a continuous variable, a 1 mL min(-1) decrease in eCrCl was associated with a 1.6% (0.1-3.1) increase in the risk for CV death or MI, and a 2.1% (0-4.1) increase in the risk for CV death alone.

CONCLUSION

Renal dysfunction was found to be common in patients with stable angina pectoris and estimated creatinine clearances carried significant independent prognostic information regarding CV death and nonfatal MI.

Favourable long term prognosis in stable angina pectoris: an extended follow up of the angina prognosis study in Stockholm (APSIS)

OBJECTIVE

To evaluate the long term prognosis of patients with stable angina pectoris.

DESIGN

Registry based follow up (median 9.1 years) of patients participating in the APSIS (angina prognosis study in Stockholm), which was a double blind, single centre trial of antianginal drug treatment.

PATIENTS

809 patients (31% women) with stable angina pectoris < 70 (mean (SD) 59 (7) years at inclusion) and an age and sex matched reference population from the same catchment area.

INTERVENTIONS

Double blind treatment with metoprolol or verapamil during 3.4 years (median), followed by referral for usual care with open treatment.

MAIN OUTCOME MEASURES

Cardiovascular (CV) death and non-fatal myocardial infarction (MI) in the APSIS cohort and total mortality in comparison with reference subjects.

RESULTS

123 patients died (41 MI, 36 other CV causes) and 72 had non-fatal MI. Mortality (19% v 6%, p < 0.001) and fatal MI (6.6% v 1.6%, p < 0.001) were increased among male compared with female patients. Diabetes, previous MI, hypertension, and male sex independently predicted CV mortality (p < 0.001). Diabetes greatly increased the risk in a small subgroup of female patients. Male patients had higher mortality than men in the reference population during the first three years (cumulative absolute difference 3.8%) but apparently not thereafter. Female patients had similar mortality to women in the reference population throughout the 9.1 years of observation.

CONCLUSIONS

Female patients with stable angina had similar mortality to matched female reference subjects but male patients had an increased risk. Diabetes, previous MI, hypertension, and male sex were strong risk factors for CV death or MI.

Comparison of Hypertension Management After Stroke and Myocardial Infarction

BACKGROUND AND PURPOSE

Hypertension control is a cornerstone of preventive treatment in patients at risk for cerebral attack. The aim of this study was to analyze hypertension management in secondary prevention of stroke as compared with patients in secondary prevention of myocardial infarction (MI).

METHODS

The ECLAT1 study was a cross-sectional study conducted in all French regions in a random sample of 3009 practitioners. Patients with a documented history of atherothrombotic disease were included. Risk factors and the last measurement of blood pressure (BP) available in the medical record were noted. In the current study, patients with treated hypertension and a unique manifestation of atherothrombotic disease, ischemic stroke or MI, were analyzed.

RESULTS

Among the 4346 patients included in the ECLAT1 study, 1416 patients with treated hypertension and stroke or MI were analyzed. Hypertension control was poorer in patients with stroke as compared with patients with MI (24.56% versus 34.16% P<0.01). Compared with patients with MI, systolic BP (140.61+/-14.14 versus 144.21+/-14.99; P<0.0001), pulse pressure (59.91+/-11.94 versus 62.48+/-12.49; P<0.001), and, to a lesser extent, diastolic BP (80.69+/-8.39 versus 81.72+/-8.85; P<0.05) were higher in stroke patients. Moreover, antihypertensive monotherapy was more frequently used in stroke than in MI patients (43.16% versus 31.44% P<0.0001).

CONCLUSIONS

With respect to the beneficial influence of tight BP control in secondary prevention of stroke, our results highlight the need for information provided to practitioners to recall the importance of hypertension control in this situation and to increase the use of combination therapy.

Combined endpoints: can we use them?

Analysing specific non-fatal events in isolation may lead to spurious conclusions about efficacy unless the events considered are combined with all-cause mortality. The use of combined endpoints has therefore become widespread, at least in cardiovascular disease trials. Combining all-cause mortality with selected non-fatal events is useful because event-free survival, an important criterion in therapy evaluation, is addressed in this manner. In many clinical trials, symptoms, signs or paraclinical measures (for example, blood pressure, exercise duration, quality of life scores) are used as endpoints. If the patient died before the endpoint was measured, or it was otherwise not possible to perform follow-up assessments as planned, the effect of treatment on these endpoints may be distorted if the patients concerned are ignored in the analysis. Examples are given of how distortion can be avoided by including all patients randomized in an analysis that uses a ranked combined endpoint based both on clinical events and on paraclinical measures. A distinction is made between a pseudo intention-to-treat analysis that disregards study medication status at the time of endpoint assessment but is confined to patients with data, and a true intention-to-treat analysis that takes into account all patients randomized based on a ranked combined endpoint.

Effect of the CYP2D6 genotype on metoprolol metabolism persists during long-term treatment

The beta1 selective beta-blocker metoprolol is metabolized predominantly but not exclusively by CYP2D6. Due to the polymorphism of the CYP2D6 gene, CYP2D6 activity varies markedly between individuals. Consequently, after short-term administration metoprolol plasma concentrations were found to be several fold higher in poor metabolizers than in extensive metabolizers. However, it is currently not known, whether the impact of the CYP2D6 polymorphism persists during long-term therapy, since alternate mechanisms of elimination or metabolism could be effective in this setting. The study comprised 91 Caucasian patients on long-term treatment with metoprolol (median duration of treatment 12.6 months; median daily drug dose: 47.5 mg/day). Metoprolol and alpha-OH-metoprolol plasma concentrations were assessed by HPLC. Genotyping detected the null alleles (*0): *3, *4, *5, *6, *7, *8, *12, *14, *15, the alleles *9, *10 and *41 associated with reduced enzymatic activity as well as the fully functional alleles *1 and *2. Genotype and allele frequencies were in accordance with published frequencies for the German population. The plasma metabolic ratio of metoprolol/alpha-OH-metoprolol was markedly affected by the genotype (P < 0.0001). In accordance, median adjusted metoprolol plasma concentrations were 6.2- and 3.9-fold higher in patients with *0/*0 genotypes (n = 8) and intermediate genotypes (n = 10), respectively, as compared to those with two fully functional alleles (n = 31; P < 0.01). In summary, the pronounced effect of the CYP2D6 genotype persists during long-term therapy, affecting both metabolic ratio and metoprolol plasma concentration.

Are beta-blockers effective in patients who develop heart failure soon after myocardial infarction? A meta-regression analysis of randomised trials

BACKGROUND

The great majority of post-infarction studies of beta-blockers were conducted in an era when these agents were widely held to be contra-indicated for the management of heart failure. We now know that beta-blockers are highly effective for the management of patients with chronic stable heart failure. However, there remains uncertainty about their role in the setting of post-infarction heart failure and ventricular dysfunction.

AIM

the primary objective in this paper, was to investigate the extent to which heart failure or evidence of major cardiac dysfunction influenced outcome in previous trials of beta-blockers in heart failure after myocardial infarction.

METHODS

We assessed the extent to which the inclusion of patients with heart failure or major cardiac dysfunction influenced outcome in randomised trials of long-term use of beta-blockade after myocardial infarction. The primary analysis was to assess the extent to which the proportion of patients included in each trial with heart failure influenced the relative odds of all-cause mortality in the trials. All randomised trials without crossover with treatment lasting more than one month and with 50 or more patients were considered. All those that provided information on the proportion of patients with heart failure or major cardiac dysfunction in the original or subsequent articles were included in the analysis.

RESULTS

Overall treatment with a beta-blocker was associated with a 22.6% reduction in the odds of death (95% C1 11-32.3%). There were very few data on the effects of beta-blockers after myocardial infarction in patients with documented left ventricular systolic dysfunction. In the analysis that included heart failure as a factor, treatment with a beta-blocker was associated with a non-significant interaction with the presence of heart failure. However, because the group including heart failure patients were at higher risk, the absolute benefit of treatment with beta-blockers appeared greater in this group.

CONCLUSIONS

This analysis suggests that the relative benefit of beta-blockers on mortality after a myocardial infarction is similar in the presence or absence of heart failure but that the absolute benefit may be greater in the former. However, as current clinical practice has changed radically from the time when the majority of these trials were conducted, further trial evidence would be desirable.

Modulation of antiarrhythmic drug effects by beta-adrenergic sympathetic stimulation

Appreciation has grown for the impact of the autonomic nervous system on the development of clinical cardiac arrhythmias. Antiarrhythmic medications work to significantly prolong cardiac repolarization and slow conduction. The question has arisen whether these pharmacologic actions of antiarrhythmic drugs can be modulated by alterations in the sympathetic nervous system. This article examines the data pertaining to modulation of the class I and class III effects of antiarrhythmic drugs during beta-adrenergic stimulation, the body's natural response to stress. The actions of several antiarrhythmic drugs can be fully reversed during beta-adrenergic sympathetic stimulation. Overall, the data suggest that pure class III drugs are the most susceptible to reversal of their effects on refractoriness, followed by class IA agents, amiodarone (which has partial resistance), and d,l-sotalol (which is highly resistant to reversal). Whereas retrospective analyses of a number of trials suggest that sympathetic-stimulation-induced reversal of the electrophysiologic effects of certain antiarrhythmic drugs can decrease their clinical efficacy, prospective trials examining this issue are needed. At the current time it appears reasonable to administer beta blockers to patients receiving antiarrhythmic agents that do not have intrinsic antiadrenergic effects.