Diltiazem in acute myocardial infarction treated with thrombolytic agents: a randomised placebo-controlled trial. Incomplete Infarction Trial of European Research Collaborators Evaluating Prognosis post-Thrombolysis (INTERCEPT)

Trends in use of composite endpoints in clinical trials: A comparison between acute heart failure trials and COVID-19 trials

Composite endpoints can encode multiple pieces of information and are increasingly adopted in clinical trials. Advocacy for using composite endpoints began decades ago in cardiovascular trials, leading to incorporation of patient-oriented outcomes and consideration of a hierarchical ranking system. The use of composite endpoints in coronavirus disease (COVID-19) trials has evolved similarly. We conducted a literature review to investigate the use of composite endpoints in acute heart failure and COVID-19 clinical trials. The results showed more frequent use of patient-oriented outcomes and ordinal composite endpoints in COVID-19 trials, which might be driven by global consensus on a set of common outcome measures.

The protective effect of vagus nerve stimulation against myocardial ischemia/reperfusion injury: pooled review from preclinical studies

Aims: Myocardial ischemia-reperfusion (I/R) injury markedly undermines the protective benefits of revascularization, contributing to ventricular dysfunction and mortality. Due to complex mechanisms, no efficient ways exist to prevent cardiomyocyte reperfusion damage. Vagus nerve stimulation (VNS) appears as a potential therapeutic intervention to alleviate myocardial I/R injury. Hence, this meta-analysis intends to elucidate the potential cellular and molecular mechanisms underpinning the beneficial impact of VNS, along with its prospective clinical implications. Methods and Results: A literature search of MEDLINE, PubMed, Embase, and Cochrane Database yielded 10 articles that satisfied the inclusion criteria. VNS was significantly correlated with a reduced infarct size following myocardial I/R injury [Weighed mean difference (WMD): 25.24, 95% confidence interval (CI): 32.24 to 18.23, p < 0.001] when compared to the control group. Despite high heterogeneity (I2 = 95.3%, p < 0.001), sensitivity and subgroup analyses corroborated the robust efficacy of VNS in limiting infarct expansion. Moreover, meta-regression failed to identify significant influences of pre-specified covariates (i.e., stimulation type or site, VNS duration, condition, and species) on the primary estimates. Notably, VNS considerably impeded ventricular remodeling and cardiac dysfunction, as evidenced by improved left ventricular ejection fraction (LVEF) (WMD: 10.12, 95% CI: 4.28; 15.97, p = 0.001) and end-diastolic pressure (EDP) (WMD: 5.79, 95% CI: 9.84; -1.74, p = 0.005) during the reperfusion phase. Conclusion: VNS offers a protective role against myocardial I/R injury and emerges as a promising therapeutic strategy for future clinical application.

Clinical Outcomes of Calcium-Channel Blocker vs Beta-Blocker: From the Korean Acute Myocardial Infarction Registry

Background

Although current guidelines recommend beta-blockers (BBs) after acute myocardial infarction (AMI), the role of calcium-channel blockers (CCBs) has not been well investigated, especially nondihydropyridine.

Objectives

This study aimed to compare the effects of CCBs on cardiovascular outcomes compared with BBs in AMI because patients from East Asia have a higher incidence of a vasospastic angina component compared with Western countries.

Methods

Among 15,628 patients enrolled in the KAMIR-V (Korean Acute Myocardial Infarction Registry-V), we evaluated 10,650 in-hospital survivors who were treated with either CCBs or BBs. We applied a propensity score for 1:4 pair matching of baseline covariates and Cox regression to compare CCBs and BBs. The primary endpoint was all-cause death at 1 year. The secondary endpoints were 1-year major adverse cardiac and cerebrovascular events, which was the composite of cardiac death, myocardial infarction, revascularization, and readmission due to heart failure and stroke.

Results

There was a significant interaction with the treatment arm with left ventricular ejection fraction (LVEF) (P for interaction = 0.011). CCB groups at discharge had higher 1-year cardiac death and major adverse cardiac and cerebrovascular events for patients with LVEF <50% (HR: 4.950; 95% CI: 1.329-18.435; P = 0.017; and HR: 1.810; 95% CI: 1.038-3.158; P = 0.037, respectively) but not for patients with LVEF ≥50% (HR: 0.699; 95% CI: 0.435-1.124; P = 0.140).

Conclusions

CCB therapy did not increase adverse cardiovascular events for patients after AMI with preserved LVEF. CCBs can be considered as an alternative for BBs in East Asian patients after AMI with preserved LVEF.

Reperfusion injury in acute ischemic stroke: Tackling the irony of revascularization

Reperfusion injury is an unfortunate consequence of restoring blood flow to tissue after a period of ischemia. This phenomenon can occur in any organ, although it has been best studied in cardiac cells. Based on cardiovascular studies, neuroprotective strategies have been developed. The molecular biology of reperfusion injury remains to be fully elucidated involving several mechanisms, however these mechanisms all converge on a similar final common pathway: blood brain barrier disruption. This results in an inflammatory cascade that ultimately leads to a loss of cerebral autoregulation and clinical worsening. In this article, the authors present an overview of these mechanisms and the current strategies being employed to minimize injury after restoration of blood flow to compromised cerebral territories.

Adding flexibility to clinical trial designs: an example-based guide to the practical use of adaptive designs

Adaptive designs for clinical trials permit alterations to a study in response to accumulating data in order to make trials more flexible, ethical, and efficient. These benefits are achieved while preserving the integrity and validity of the trial, through the pre-specification and proper adjustment for the possible alterations during the course of the trial. Despite much research in the statistical literature highlighting the potential advantages of adaptive designs over traditional fixed designs, the uptake of such methods in clinical research has been slow. One major reason for this is that different adaptations to trial designs, as well as their advantages and limitations, remain unfamiliar to large parts of the clinical community. The aim of this paper is to clarify where adaptive designs can be used to address specific questions of scientific interest; we introduce the main features of adaptive designs and commonly used terminology, highlighting their utility and pitfalls, and illustrate their use through case studies of adaptive trials ranging from early-phase dose escalation to confirmatory phase III studies.

STIM2 knockdown protects against ischemia/reperfusion injury through reducing mitochondrial calcium overload and preserving mitochondrial function

Mitochondrial dysfunction caused by calcium overload is a vital factor for mediating cardiomyocyte death following ischemia/reperfusion (I/R) injury. The stromal interactive molecule 2 (STIM2) is a calcium sensor protein that regulates the store-operated calcium entry (SOCE). Whereas, whether STIM2 is associated with I/R injury remains largely unclear. We report here that STIM2, but not its homologue STIM1, is upregulated in cultured H9c2 cells, a cell model for cardiomyocytes, following I/R injury. In addition, the knockdown of STIM2, but not STIM1, reduces H9c2 cell apoptosis following I/R injury, and similar results were obtained in primary neonatal cardiomyocytes. This anti-apoptotic effect could be attributed to the inhibited activation of mitochondrial apoptosis pathway. Moreover, STIM2 knockdown reduces ER calcium release and simultaneously alleviates mitochondrial calcium overload in H9c2 cells following I/R injury. Furthermore, STIM2 knockdown decreases mitochondrial injury and preserves mitochondrial function following I/R injury. Collectively, these results suggest that the protective role of STIM2 knockdown against I/R injury in cardiomyocytes is associated with the reduced mitochondrial calcium overload and preserved mitochondrial function. Hence, our study may provide a novel insight into the regulation of mitochondrial-mediated cardiomyocyte apoptosis following I/R injury.

Mitochondrial transplantation: applications for pediatric patients with congenital heart disease

Mitochondrial transplantation refers to transplantation of respiratory competent mitochondria from healthy tissue into tissues injured by ischemia and reperfusion. This technique has been utilized for recovery of myocardial dysfunction in pediatric patients. The preclinical experience and initial patient experience with this technique are reviewed in this article. Initial experience is with pediatric patients undergoing extracorporeal membrane oxygenation support following myocardial ischemia and reperfusion. The initial pediatric experience suggests low side effect profile with favorable efficacy in a small group of patients.

TDCPP protects cardiomyocytes from hypoxia-reoxygenation injury induced apoptosis through mitigating calcium overload and promotion GSK-3β phosphorylation

TDCPP, Tris (1, 3-dichloro-2-propyl) phosphate belongs to a group of chemicals known as triester organophosphate flame retardants, It can alter calcium homeostasis at much lower concentrations in normal conditions, but the mechanism is unclear till now. Calcium overload is a leading cause of apoptosis in myocardial ischemia/reperfusion (I/R) injury, thus how to mitigate Ca²⁺-overload is deserved to be investigated. We therefore hypothesized that TDCPP could attenuate cardiomyocytes apoptosis in I/R injury. H/R (hypoxia/reoxygenation) experiments in vitro were used to simulate in vivo I/R injury. The present study aimed to explore the potential effect of TDCPP in cardiomyocytes after H/R injury, Ca²⁺ imaging technique was used to explore SOCE(store-operated calcium entry) and Ca²⁺-overload levels, western blot technique was used to explore the potential target, the cell morphology, cell viability and mitochondrial membrane potential were also detected. The results have shown that: TDCPP could decrease SOCE, restore H9c2 cell viability, mitigate Ca²⁺-overload in H/R injury and reduce the mitochondrial membrane potential. Furthermore, TDCPP decreased STIM1 expression and promoted GSK3β phosphorylation. Collectively, for the first time, this study suggest the antiapoptosis roles of TDCPP in H/R injury are via mitigation Ca²⁺-overload and promoting GSK-3β phosphorylation.

Mitochondrial Transplantation in Myocardial Ischemia and Reperfusion Injury

Ischemic heart disease remains the leading cause of death worldwide. Mitochondria are the power plant of the cardiomyocyte, generating more than 95% of the cardiac ATP. Complex cellular responses to myocardial ischemia converge on mitochondrial malfunction which persists and increases after reperfusion, determining the extent of cellular viability and post-ischemic functional recovery. In a quest to ameliorate various points in pathways from mitochondrial damage to myocardial necrosis, exhaustive pharmacologic and genetic tools have targeted various mediators of ischemia and reperfusion injury and procedural techniques without applicable success. The new concept of replacing damaged mitochondria with healthy mitochondria at the onset of reperfusion by auto-transplantation is emerging not only as potential therapy of myocardial rescue, but as gateway to a deeper understanding of mitochondrial metabolism and function. In this chapter, we explore the mechanisms of mitochondrial dysfunction during ischemia and reperfusion, current developments in the methodology of mitochondrial transplantation, mechanisms of cardioprotection and their clinical implications.

Major contribution of the 3/6/7 class of TRPC channels to myocardial ischemia/reperfusion and cellular hypoxia/reoxygenation injuries

The injury phase after myocardial infarcts occurs during reperfusion and is a consequence of calcium release from internal stores combined with calcium entry, leading to cell death by apoptopic and necrotic processes. The mechanism(s) by which calcium enters cells has(ve) not been identified. Here, we identify canonical transient receptor potential channels (TRPC) 3 and 6 as the cation channels through which most of the damaging calcium enters cells to trigger their death, and we describe mechanisms activated during the injury phase. Working in vitro with H9c2 cardiomyoblasts subjected to 9-h hypoxia followed by 6-h reoxygenation (H/R), and analyzing changes occurring in areas-at-risk (AARs) of murine hearts subjected to a 30-min ischemia followed by 24-h reperfusion (I/R) protocol, we found: (i) that blocking TRPC with SKF96365 significantly ameliorated damage induced by H/R, including development of the mitochondrial permeability transition and proapoptotic changes in Bcl2/BAX ratios; and (ii) that AAR tissues had increased TUNEL⁺ cells, augmented Bcl2/BAX ratios, and increased p(S240)NFATc3, p(S473)AKT, p(S9)GSK3β, and TRPC3 and -6 proteins, consistent with activation of a positive-feedback loop in which calcium entering through TRPCs activates calcineurin-mediated NFATc3-directed transcription of TRPC genes, leading to more Ca²⁺ entry. All these changes were markedly reduced in mice lacking TRPC3, -6, and -7. The changes caused by I/R in AAR tissues were matched by those seen after H/R in cardiomyoblasts in all aspects except for p-AKT and p-GSK3β, which were decreased after H/R in cardiomyoblasts instead of increased. TRPC should be promising targets for pharmacologic intervention after cardiac infarcts.

Stromal derived factor 1α: a chemokine that delivers a two-pronged defence of the myocardium

Alleviating myocardial injury associated with ST elevation myocardial infarction is central to improving the global burden of coronary heart disease. The chemokine stromal cell-derived factor 1α (SDF-1α) has dual potential benefit in this regard. Firstly, SDF-1α is up-regulated in experimental and clinical studies of acute myocardial infarction (AMI) and regulates stem cell migration to sites of injury. SDF-1α delivery to the myocardium after AMI is associated with improved stem cell homing, angiogenesis, and left ventricular function in animal models, and improvements in heart failure and quality of life in humans. Secondly, SDF-1α may have a role in remote ischaemic conditioning (RIC), the phenomenon whereby non-lethal ischaemia–reperfusion applied to an organ or tissue remote from the heart protects the myocardium from lethal ischaemia–reperfusion injury (IRI). SDF-1α is increased in the serum of rats subjected to RIC and protects against myocardial IRI in ex vivo studies. Despite these potential pleiotropic effects, a limitation of SDF-1α is its short plasma half-life due to cleavage by dipeptidyl peptidase-4 (DPP-4). However, DPP-4 inhibitors increase the half-life of SDF-1α by preventing its degradation and are also protective against lethal IRI. In summary, SDF-1 potentially delivers a ‘two-pronged’ defence of the myocardium: acutely protecting it from IRI while simultaneously stimulating repair by recruiting stem cells to the site of injury. In this article we examine the evidence for acute and chronic cardioprotective roles of SDF-1α and discuss potential therapeutic manipulations of this mechanism with DPP-4 inhibitors to protect against lethal tissue injury in the clinical setting.

Effect of plant polyphenols on ischemia-reperfusion injury of the isolated rat heart and vessels

In the present study, we investigated the potential protective effect of selected natural substances in a rat model of heart and mesenteric ischemia-reperfusion (I/R). Experiments were performed on isolated Langendorff-perfused rat hearts, subjected to 30-min global ischemia, followed by 30-min reperfusion. Arbutin, curcumin, rosmarinic acid and extract of Mentha x villosa were applied in the concentration of 1 × 10⁻⁵ mol/l 10 min before the onset of ischemia and during reperfusion, through the perfusion medium. Mesenteric ischemia was induced by clamping the superior mesenteric artery (SMA) for 60 min, subsequent reperfusion lasted 30 min. Production of reactive oxygen species (ROS) by SMA ex vivo was determined by luminol-enhanced chemiluminiscence (CL). The effect of the substances was tested after their incubation with tissue. Curcumin and extract of Mentha x villosa were found to be the most effective in reducing reperfusion-induced dysrhythmias--ventricular tachycardia and fibrillation. This effect was accompanied by bradycardic effect. The mesenteric I/R induced an increase in CL in vascular tissue which was dampened by substances tested. All substances tested were found to have antioxidant properties, as demonstrated by a reduction in ROS production in mesenteric vessels. This effect was confirmed in curcumin and extract of Mentha x villosa which reduced reperfusion dyshythmias.

Myocardial reperfusion injury: looking beyond primary PCI

Coronary heart disease (CHD) is the leading cause of death and disability in Europe. For patients presenting with an acute ST-segment elevation myocardial infarction (STEMI), timely myocardial reperfusion using either thrombolytic therapy or primary percutaneous coronary intervention (PPCI) is the most effective therapy for limiting myocardial infarct (MI) size, preserving left-ventricular systolic function and reducing the onset of heart failure. Despite this, the morbidity and mortality of STEMI patients remain significant, and novel therapeutic interventions are required to improve clinical outcomes in this patient group. Paradoxically, the process of myocardial reperfusion can itself induce cardiomyocyte death-a phenomenon which has been termed 'myocardial reperfusion injury' (RI), the irreversible consequences of which include microvascular obstruction and myocardial infarction. Unfortunately, there is currently no effective therapy for preventing myocardial RI in STEMI patients making it an important residual target for cardioprotection. Previous attempts to translate cardioprotective therapies (antioxidants, calcium-channel blockers, and anti-inflammatory agents) for reducing RI into the clinic, have been unsuccessful. An improved understanding of the pathophysiological mechanisms underlying RI has resulted in the identification of several promising mechanical (ischaemic post-conditioning, remote ischaemic pre-conditioning, therapeutic hypothermia, and hyperoxaemia), and pharmacological (atrial natriuretic peptide, cyclosporin-A, and exenatide) therapeutic strategies, for preventing myocardial RI, many of which have shown promise in initial proof-of-principle clinical studies. In this article, we review the pathophysiology underlying myocardial RI, and highlight the potential therapeutic interventions which may be used in the future to prevent RI and improve clinical outcomes in patients with CHD.

Prevention of airway hyperresponsiveness induced by left ventricular dysfunction in rats

Background

The effectiveness of strategies for treatment of the altered static lung volume and against the development of bronchial hyperreactivity (BHR) following a left ventricular dysfunction (LVD) induced by myocardial ischaemia was investigated in a rat model of sustained postcapillary pulmonary hypertension.

Methods

Airway resistance (Raw) was identified from the respiratory system input impedance (Zrs) in four groups of rats. End-expiratory lung volume (EELV) was determined plethysmographically, and Zrs was measured under baseline conditions and following iv infusions of 2, 6 or 18 μg/kg/min methacholine. Sham surgery was performed in the rats in Group C, while the left interventricular coronary artery was ligated and Zrs and its changes following identical methacholine challenges were reassessed in the same rats 8 weeks later, during which no treatment was applied (Group I), or the animals were treated daily with a combination of an angiotensin enzyme converter inhibitor and a diuretic (enalapril and furosemide, Group IE), or a calcium channel blocker (diltiazem, Group ID). The equivalent dose of methacholine causing a 100% increase in Raw (ED₅₀) was determined in each group. Diastolic pulmonary arterial pressure (Pap_D) was assessed by introducing a catheter into the pulmonary artery.

Results

The sustained presence of a LVD increased Pap_D in all groups of rats, with variable but significant elevations in Groups I (p = 0.004), ID (p = 0.013) and IE (p = 0.006). A LVD for 8 weeks induced no changes in baseline Raw but elevated the EELV independently of the treatments. In Group I, BHR consistently developed following the LVD, with a significant decrease in ED₅₀ from 10.0 ± 2.5 to 6.9 ± 2.5 μg/kg/min (p = 0.006). The BHR was completely abolished in both Groups ID and IE, with no changes in ED₅₀ (9.5 ± 3.6 vs. 10.7 ± 4.7, p = 0.33 and 10.6 ± 2.1 vs. 9.8 ± 3.5 μg/kg/min p = 0.56, respectively).

Conclusions

These findings suggest that a LVD following coronary ischaemia consistently induces BHR. The more consistent efficacy of both treatment strategies in preventing BHR than in treating the adverse pulmonary vascular consequences suggests the benefit of both calcium channel blockade and ACE inhibition to counteract the airway susceptibility following a LVD.

Pathogenesis of myocardial ischemia-reperfusion injury and rationale for therapy

Since the initial description of the phenomenon by Jennings et al 50 years ago, our understanding of the underlying mechanisms of reperfusion injury has grown significantly. Its pathogenesis reflects the confluence of multiple pathways, including ion channels, reactive oxygen species, inflammation, and endothelial dysfunction. The purposes of this review are to examine the current state of understanding of ischemia-reperfusion injury, as well as to highlight recent interventions aimed at this heretofore elusive target. In conclusion, despite its complexity our ongoing efforts to mitigate this form of injury should not be deterred, because nearly 2 million patients annually undergo either spontaneous (in the form of acute myocardial infarction) or iatrogenic (in the context of cardioplegic arrest) ischemia-reperfusion.

Postconditioning: from experimental proof to clinical concept

The therapeutic strategies for acute myocardial infarction in the last decade have, among other therapeutic targets, focused on myocardial reperfusion injury, which accounts for a significant part of the final infarct size. Although several experiments in the last 20 years have reported that pharmacological interventions at reperfusion might reduce myocardial reperfusion injury, this could not be consistently confirmed in animal models or human studies. An alternative to chemical modifiers, postconditioning (brief repeated periods of ischemia applied at the onset of reperfusion) is the first method proven to be efficient in different animal models and to be confirmed in a recent human study. This simple method, applied in the first minute of reperfusion, reduces the final infarct size by 30–50%. This review will focus on the postconditioning technique and show how the data from different animal models and experimental settings have advanced our understanding of both the mechanisms and the definition of an accurate protocol that is easily applicable in human patients in the setting of acute myocardial infarction.

Cardiac stunning in the clinic: the full picture

Cardiac stunning refers to different dysfunctional levels occurring after an episode of acute ischemia, despite blood flow is near normal or normal. The phenomenon was initially identified in animal models, where it has been very well characterized. After being established in the experimental setting, it remained unclear, whether a similar syndrome occurs in humans. In addition, it remained controversial, whether stunning was of any clinical relevance as it is spontaneously reversible. Hence, many studies continue to focus on the properties and mechanisms of stunning, although therapies seem more relevant for attenuating and treating myocardial ischemia/reperfusion (I/R) injury, i.e. to bridge until recovery. This article reviews the different facets of cardiac stunning, i.e. myocardial, vascular/microvascular/endothelial, metabolic, neural/neuronal, and electrical stunning. This review also displays where these facets exist and which clinical relevance they might have. Particular attention is directed to the different therapeutic interventions that the various facets of this I/R-induced cardiac injury might require. A final outlook considers possible alternatives to further reduce the detrimental consequences of brief episodes of ischemia and reperfusion.

Treatment with amlodipine and atorvastatin has additive effect on blood and plaque inflammation in hypertensive patients with carotid atherosclerosis

Since previous studies have reported a beneficial effect of amlodipine and atorvastatin treatment in experimental atherosclerosis, we aimed to investigate the effect of the combination of both drugs on blood and plaque inflammation in patients with carotid stenosis. For that purpose, twenty six hypertensive patients undergoing carotid endarterectomy were randomized to receive either atorvastatin 20 mg/day alone (ATV, n=12) or in combination with amlodipine 20 mg/day (ATV+AML, n=14) before scheduled carotid endarterectomy. At the end of follow-up (4-6 weeks), there was a significant decrease in total and LDL-cholesterol levels, but not in blood pressure levels. In contrast, decreased MCP-1 plasma levels, NF-kappaB activation (EMSA) and MCP-1 mRNA expression (quantitative PCR) was only observed in blood from ATV+AML treated-patients. Moreover, carotid atherosclerotic plaques from ATV+AML group demonstrated a significant reduction in macrophage infiltration in relation to ATV group (immunohistochemistry). Our results suggest that combined treatment with atorvastatin and amlodipine decreases inflammatory status of atherosclerotic patients more than atorvastatin treatment alone, suggesting that co-administration of both drugs could have beneficial additive effects.

Post-myocardial infarction beta-blocker therapy: the bradycardia conundrum. Rationale and design for the Pacemaker & beta-blocker therapy post-MI (PACE-MI) trial

Multiple clinical trials have demonstrated beta-blockers improving survival after myocardial infarction (MI). Patients with "bradycardia-related" contraindications to beta-blockers, such as those with asymptomatic bradycardia or AV conduction abnormalities, have been excluded from clinical trials of beta-blockers and continue to be excluded from post-MI beta-blocker therapy in routine clinical practice. These patients tend to be elderly and have a high 1-year mortality. If beta-blockers provide benefit to the post-MI patient independent of their heart rate-lowering effect, then these patients could benefit substantially from initiation of beta-blocker therapy. However, in this particular group of patients, beta-blockers can be safely initiated only if more severe or significant bradycardia can be prevented by pacemaker implantation. It is unclear whether adverse effects related to pacemaker implantation could also negate some or all of the hypothesized benefit of beta-blocker therapy. Although beta-blockers are particularly effective in the elderly, the benefit of beta-blocker therapy in patients with bradycardia-related contraindications to beta-blockers has not been established. The PACE-MI trial is a randomized controlled trial that will address whether beta-blocker therapy enabled by pacemaker implantation is superior to no beta-blocker and no pacemaker therapy after MI in patients with rhythm contraindications to beta-blockers or in those who have developed symptomatic bradycardia due to beta-blockers. The trial will randomize 1124 patients to standard therapy (not to include beta-blockers as patients must have a contraindication to be enrolled) or standard therapy plus pacemaker implantation and beta-blocker. The primary end point is the composite end point of total mortality plus nonfatal reinfarction.

Time to reperfusion in acute myocardial infarction. It is time to reduce it!

BACKGROUND AND OBJECTIVES

Mortality from ST-segment elevation myocardial infarction remains high, with most deaths occurring before hospital admission. Despite effective pre- and in-hospital reperfusion strategies becoming standard over the past 2 decades, time-to-admission and time-to-treatment remain prolonged. We reviewed temporal trends in these times in published clinical trials.

METHODS

All major randomized clinical trials reporting on reperfusion strategies for acute myocardial infarction published between 1993 and 2003 were evaluated. Strategies included pre- and in-hospital thrombolysis, primary percutaneous coronary intervention (pPCI) with or without transfer, and "facilitated" PCI. We generated overall estimates of time-to-admission, time-to-treatment, door-to-balloon (DTB), and door-to-needle (DTN) times and evaluated temporal trends in the length of time-to-admission and time-to-treatment.

RESULTS

In studies that evaluated only in-hospital thrombolysis, the time-to-admission was 149 +/- 45 minutes; the mean time-to-treatment was 181 +/- 29 minutes. In studies that considered only in-hospital pPCI (without transfer), the mean time-to-admission was 153 +/- 41 minutes; the mean time-to-treatment was 234 +/- 43 minutes. In studies that compared in-hospital pPCI with in-hospital thrombolytic therapy, the mean time-to-admission was 155 +/- 47 and 150 +/- 48 minutes, respectively. The DTN time was 65 +/- 10 minutes, whereas DTB time was 81 +/- 39 minutes. In other trials evaluating in-hospital thrombolysis and pPCI with transfer to a referral center, the time-to-admission in subjects treated with thrombolysis (n = 1345) was 127 +/- 32 minutes vs 131 +/- 36 minutes for pPCI (n = 1528). For in-hospital thrombolysis, time-to-treatment was 151 +/- 23 minutes vs 203 +/- 15 minutes for pPCI patients with transfer. The DTN time in the thrombolysis group was 44 +/- 28 minutes as compared with DTB time of 78 +/- 38 minutes in the pPCI group. Throughout the last decade, time-to-admission decreased significantly (P = .02) but time-to-treatment remained unchanged (P = .38) for patients undergoing thrombolysis. In the pPCI arm, time-to-admission remained unchanged (P = .11) but a insignificant trend toward reduction was demonstrated in time-to-treatment (P = .11).

CONCLUSION

Time-to-admission and time-to-treatment for ST-segment elevation myocardial infarction are still prolonged. Resources should be directed to early recognition of the acute myocardial infarction, improved utilization of emergency services for transportation, and prehospital diagnosis and triaging. Ambulances equipped with wireless capability to transmit electrocardiograms to the on-call cardiologist seem to be promising tools to achieve earlier diagnosis and triaging with high diagnostic sensitivity and specificity.

Vascular Protection of Dual Therapy (Atorvastatin-Amlodipine) in Hypertensive Patients

Hypertension frequently coexists with other cardiovascular risk factors, such as hypercholesterolemia, and their combination is associated with a greater rate of cardiovascular events. Recent clinical data support that treatment of hypertensive patients with a combination of antihypertensive and lipid-lowering therapies leads to a higher reduction in the incidence of cardiovascular events. In the Anglo-Scandinavian Cardiac Outcomes Trial-Blood Pressure Lowering Arm (ASCOT-BPLA), an optimal prevention of cardiovascular events was reached in patients who were randomly assigned to atorvastatin and the amlodipine treatment. However, the potential underlying mechanisms of these vascular protective effects are not fully elucidated. Because experimental studies have shown that statins and calcium channel blockers have antiatherosclerotic effects, the effect of atorvastatin alone or in combination with amlodipine was analyzed in the protein secretion profile of atherosclerotic plaques that were cultured ex vivo. In this respect, the addition of atorvastatin and amlodipine to atherosclerotic plaques normalized the levels of the different released proteins to that obtained from healthy arteries. This review highlights recent clinical and experimental studies that support that a combined treatment of hypertensive patients with both statins and calcium channel blockers could promote a higher reduction in their global cardiovascular risk profile and associated mortality. As an example, the application of a proteomic approach to assess the modulation by atorvastatin alone or in combination with amlodipine on the proteins that are released by atherosclerotic plaques has allowed the identification of novel therapeutic targets by which these drugs could promote their additive/synergic effects.

Management of Coronary Heart Disease: Stable Angina, Acute Coronary Syndrome, Myocardial Infarction

Stable angina should first be treated medically, particularly with aspirin and beta-blockers. Diagnostic stress tests are used in patients who have intermediate probability of CHD to further assess the likelihood of disease,with catheterization reserved for patients who have symptoms despite optimal medical therapy or are at risk for multivessel CHD. The work-up for low-risk unstable angina can involve medical management followed by stress testing. Moderate-to-high risk unstable angina and NSTEMI should be treated with an integrated approach, using medical therapy, cardiac catheterization, and revascularization. Patients who have STEMI require urgent reperfusion either with thrombolytic agents or primary angioplasty. Follow-ing a diagnosis of CHD, patients should undergo intense coronary risk-fac-tor modification to reduce the risk of future events.

Drug Therapy for Prevention of Recurrent Myocardial Infarction

OBJECTIVE

To provide an evidence-based overview of drug treatment for long-term secondary prevention of myocardial infarction (MI).

DATA SOURCES

We conducted searches of MEDLINE (1966-August 2002), the Cochrane Controlled Trial Register, and the reference list of each identified study.

STUDY SELECTION/DATA EXTRACTION

Trials and meta-analyses were included using the following criteria: (1) randomized trials, (2) description of identification procedure, inclusion criteria, outcome measures, and statistical methods, (3) confirmed MIs, (4) treatment continued for at least 1 month, and (5) all-cause mortality as primary outcome; other events as secondary outcomes. All authors interpreted the results from trials that met the inclusion criteria.

DATA SYNTHESIS

In randomized clinical trials, low-dose aspirin, high-intensity oral anticoagulants, beta-blockers, angiotensin-converting enzyme (ACE) inhibitors, and statins decreased the risk of mortality and reinfarction after MI. Randomized clinical trials using calcium-channel blockers, antiarrhythmics, and hormone replacement therapy did not show benefits in patients with prior MI. Effects of the combined use of aspirin or oral anticoagulants with beta-blockers or ACE inhibitors plus statins must be derived from subgroup analysis of trials, but seem to be beneficial.

CONCLUSIONS

The use of at least aspirin or an oral anticoagulant, a beta-blocker or an ACE inhibitor, plus a statin should be incorporated in the treatment routine. Clopidogrel treatment might be an alternative to aspirin. Standard addition of a beta-blocker to ACE inhibitor-treated patients without reduced left-ventricular ejection fraction seems to be untimely.

Planning and monitoring of placebo-controlled survival trials: comparison of the triangular test with usual interim analyses methods

AIMS

For ethical and economic reasons, interim analysis of phase III clinical trials is essential. This study was conducted to compare the efficiency of two interim analysis procedures, which could be used to allow early termination of a clinical trial.

METHODS

We made a post hoc application of two interim analysis methods (Lan & DeMets with O'Brien-Flemming modification, and the triangular test according to Whitehead) by using individual patient data from four published placebo-controlled survival trials. We determined the date the trial would have been stopped had each method been used, and we estimated consequent results in terms of events and patient numbers included in the trial, the duration of the trial, and on treatment effect.

RESULTS

The triangular test provided the lowest number of events required to reach a conclusion of the trials while providing an accurate estimate of experimental treatment effects. The triangular test thus indicated the smallest number of patients that would have been enrolled, and the shortest trial duration. The difference between the methods was most important with a detrimental effect of experimental treatment: the number of required events was reduced by 75% and the trial duration was shortened by 48% with the triangular test compared to the Lan & DeMets method.

CONCLUSIONS

Stopping a trial early must depend on the clinical context. It is most important to stop a placebo-controlled trial as soon as possible when the experimental treatment can be shown deleterious. In such a situation the triangular test is more appropriate than the Lan & DeMets method. When a treatment effect is no different from, or better than, placebo the triangular test is also superior but the importance of premature termination of the trial in such cases has to be balanced against the inevitable reduction of information that the trial can provide.

Heart rate-lowering and -regulating effects of once-daily sustained-release diltiazem

BACKGROUND

Epidemiologic evidence suggests that an elevated heart rate (HR) is an adverse and independent prognostic factor in arterial hypertension and other cardiovascular diseases. Although diltiazem is characterized as an HR-lowering calcium antagonist, no studies have quantified the magnitude of HR changes in patients with angina or hypertension.

HYPOTHESIS

The study was undertaken to explore the magnitude of proportional HR reduction at varying levels of resting HR with the sustained-release formulation of diltiazem (SR diltiazem) at the usual clinical doses of 200 or 300 mg once daily.

METHODS

This meta-analysis was conducted on six comparative double-blind studies including 771 patients with angina or hypertension in which SR diltiazem 200-300 mg once daily was compared either with placebo or with other agents known not to influence HR (angiotensin-converting enzyme inhibitors, diuretics). Sustained-release diltiazem decreases elevated baseline HR, with an increasing effect at higher initial rates.

RESULTS

Multiple comparisons by baseline HR category showed a significant difference between both groups for baseline HR of 74-84 beats/min and > or = 85 beats/min (p = 0.001). Sustained-release diltiazem had no significant HR-decreasing effect on baseline HR < or =74 beats/min but appears to have a genuine regulating effect on HR: it reduces tachycardia without inducing excessive bradycardia. These findings are in contrast to those with dihydropyridine calcium antagonists, which tend to increase HR and have been associated with an adverse outcome in acute cardiovascular conditions. At the same time, there is evidence to suggest that HR-lowering calcium-channel blockers decrease cardiovascular event rates following myocardial infarction.

CONCLUSION

When calcium antagonists are indicated for use in patients with angina or hypertension, an HR-lowering agent, that is, diltiazem rather than dihydropyridine, should be recommended.

Current status of safety and efficacy of calcium channel blockers in cardiovascular diseases: a critical analysis based on 100 studies

Recently, serious concerns have been expressed about the long-term safety of the calcium channel blockers (CCBs) as a group. Safety and efficacy are, however, ultimately linked to each other; therefore both must be evaluated especially in the therapy of angina and hypertension, the main clinical indications for CCBs. The structural, functional, and pharmacokinetic heterogeneity of CCBs means that the efficacy and dangers of one subclass, such as the short-acting dihydropyridines (DHPs), in one situation, such as unstable angina, do not necessarily apply in other clinical situations. One hundred studies are reviewed according to their methods of data collection: case series, case control, cohort, randomized controlled trials (RCTs), and meta-analyses. Large, well-designed RCTs and the meta-analyses based on these trials remain the gold standard. Observational studies, though potentially less reliable sources of information because of selection bias, may nevertheless produce hypotheses that must then be tested in RCTs. Regarding safety, both observational studies and RCTs suggest that adverse effects of CCBs may be linked to short-acting agents, specifically short-acting nifedipine. Two good studies favor the safety of verapamil, even in short-acting form. Incomplete but increasing overall evidence favors the safety of longer-acting DHPs. Heart failure remains a class contraindication to the use of all CCBs, with some exceptions. Regarding efficacy, there are positive results of RCTs with CCBs in 2 specific clinical situations, namely, verapamil in postinfarct protection in the absence of pre-existing heart failure, and 2 outcome studies on hypertension with longer acting DHPs. These results cannot automatically be applied to other clinical situations and to other CCBs. For example, there is no evidence for the safety or efficacy of DHPs used without beta blockers in postinfarct patients. In diabetic hypertensives, 2 relatively large RCTs show that the blood pressure can be reduced by DHP-based therapy in diabetics, with a reduction in hard end points. To achieve current blood pressure goals, combination therapy is almost always necessary, and in diabetics there is strong evidence that 1 essential component should be an angiotensin converting enzyme inhibitor. The future aim with CCBs must be to obtain a large database gathered from RCTs, which will give the same certainty about efficacy and safety that already holds for use of the diuretics in hypertension, beta-blockers in postmyocardial infarction patients, and the angiotensin converting enzyme inhibitors in heart failure.