Combined accelerated tissue-plasminogen activator and platelet glycoprotein IIb/IIIa integrin receptor blockade with Integrilin in acute myocardial infarction. Results of a randomized, placebo-controlled, dose-ranging trial. IMPACT-AMI Investigators

A dual-center analysis of conservative versus liberal glycoprotein IIb-IIIa antagonist strategies in the treatment of ST-elevation myocardial infarction

While the efficacy of GpIIb-IIIa-inhibitors during primary PCI (pPCI) for ST-elevated myocardial infarction (STEMI) has previously been demonstrated, its ongoing role and safety in combination with newer P2Y12-inhibitors is unclear. We therefore sought to compare outcomes between two centers with divergent approaches to the use of GpIIbIIIa antagonists in pPCI. We performed a retrospective chart review of all-comer STEMI patients treated with pPCI at two high-volume Montreal academic tertiary care centers. One center tended to use GpIIb-IIIa-inhibitors up-front in a large proportion of patients (liberal strategy) and the other preferring a bail-out approach (conservative strategy). Baseline patient characteristics and procedural data were compared between the two groups. The main efficacy outcome was rate of no-reflow/slow-reflow and the main safety outcome was BARC ≥ 2 bleeding events. A total of 459 patients were included, of whom 167 (36.5%) were exposed to a GpIIb-IIIa-antagonist. There was a significant overall difference in use of GpIIb-IIIa-antagonist between the two centers (60.5% vs. 16.1%, p < 0.01). Rate of no-reflow/slow-reflow was similar between groups (2.6% vs. 1.4%, p = 0.22). In-hospital rates of unplanned revascularization, stroke and death were also not different between groups. Use of a liberal GpIIb--IIIa-antagonist strategy was however associated with a higher risk of bleeding (OR 3.16, 95% CI 1.57-6.37, p < 0.01), which persisted after adjustment for covariables (adjusted OR 2.85, 95% CI 1.40-5.81, p < 0.01). In this contemporary retrospective cohort, a conservative, bail-out only GpIIb--IIIa-antagonist strategy was associated with a lower incidence of clinically relevant bleeding without any signal for an increase in no-reflow/slow-reflow or ischemic clinical events.

Antiplatelet Agents in Acute ST Elevation Myocardial Infarction

Platelet aggregation and thrombus formation represent the basic mechanism for clinical, electrocardiographic, and biomarker changes consistent with acute coronary syndrome. Various oral and intravenous formulations of platelet function inhibitors have been developed to help decrease platelet aggregation due to acute atherosclerotic plaque rupture. In this article, we review the various mechanisms, pharmacokinetics/pharmacodynamics, and the key clinical trials related to the platelet inhibitors that form the basis for current recommendations of their use in the ST elevation myocardial infarction guidelines by the American College of Cardiology/American Heart Association.

Targeting the RT loop of Src SH3 in Platelets Prevents Thrombosis without Compromising Hemostasis

Conventional antiplatelet agents indiscriminately inhibit both thrombosis and hemostasis, and the increased bleeding risk thus hampers their use at more aggressive dosages to achieve adequate effect. Blocking integrin αIIbβ3 outside-in signaling by separating the β3/Src interaction, yet to be proven in vivo, may nonetheless resolve this dilemma. Identification of a specific druggable target for this strategy remains a fundamental challenge as Src SH3 is known to be responsible for binding to not only integrin β3 but also the proteins containing the PXXP motif. In vitro and in vivo mutational analyses show that the residues, especially E97, in the RT loop of Src SH3 are critical for interacting with β3. DCDBS84, a small molecule resulting from structure-based virtual screening, is structurally validated to be directed toward the projected target. It specifically disrupts β3/Src interaction without affecting canonical PXXP binding and thus inhibits the outside-in signaling-regulated platelet functions. Treatment of mice with DCDBS84 causes a profound inhibition of thrombosis, equivalent to that induced by extremely high doses of αIIbβ3 antagonist, but does not compromise primary hemostasis. Specific targets are revealed for a preferential inhibition of thrombosis that may lead to new classes of potent antithrombotics without hemorrhagic side effects.

Reflection on the Past, Present, and Future of Thrombolytic Therapy for Acute Ischemic Stroke

More than 25 years have passed since the US Food and Drug Administration approved IV recombinant tissue plasminogen activator (alteplase) for the treatment of acute ischemic stroke. This landmark decision brought a previously untreatable disease into a new therapeutic landscape, providing inspiration for clinicians and hope to patients. Since that time, the use of alteplase in the clinical setting has become standard of care, continually improving with quality measures such as door-to-needle times and other metrics of specialized stroke unit care. The past decade has seen more widespread use of alteplase in the prehospital setting with mobile stroke units and telestroke and beyond initial time windows via the use of CT perfusion or MRI. Simultaneously, the position of alteplase is being challenged by new lytics and by the concept of its bypass altogether in the era of endovascular therapy. We provide an overview of alteplase, including its earliest trials and how they have shaped the current therapeutic landscape of ischemic stroke treatment, and touch on new frontiers for thrombolytic therapy. We highlight the critical role of thrombolytic therapy in the past, present, and future of ischemic stroke care.

Alteplase and Adjuvant Therapies for Acute Ischemic Stroke

Acute ischemic stroke (AIS) is a time sensitive medical emergency and a leading cause of morbidity and mortality worldwide. Intravenous (IV) recombinant tissue plasminogen activator (IV alteplase) is currently the only proven effective medication for the treatment of AIS with promising adjuvant medications currently under investigation. Recent advances in endovascular thrombectomy have broadened therapeutic options in specific patient populations, with modern treatment strategies utilizing advanced imaging modalities to extend the window for treatment. In all cases, rapid treatment remains a priority. The future of IV alteplase and the changing standard for treatment of AIS remain unwritten with the increasing evidence for imaging selection for both endovascular thrombectomy and IV alteplase, while novel adjuncts are under investigation. In this article, we review the history of IV alteplase investigations for stroke, evidence for thrombectomy as an adjunct to IV alteplase, and the potential of novel adjuvant therapeutics currently under investigation.

Efficacy and Safety of Abbreviated Eptifibatide Treatment in Patients With ST-Segment Elevation Myocardial Infarction Undergoing Primary Percutaneous Coronary Intervention

The glycoprotein IIb/IIIa inhibitor eptifibatide, administered as bolus followed by infusion, is an adjunctive antithrombotic treatment during primary percutaneous coronary intervention (PCI) in selected patients with ST-segment elevation myocardial infarction (STEMI). Whether both bolus and infusion are necessary to improve outcomes is unknown. We hypothesized that primary PCI with eptifibatide bolus only is non-inferior to the conventional treatment (bolus and infusion) with regard to infarct size, while reducing bleeding complications. We analyzed 720 consecutive STEMI patients receiving eptifibatide bolus only or conventional treatment in an observational case-control study utilizing propensity score matching of clinical and intervention-specific confounders. Infarct size was estimated based on myocardial bound creatine kinase, creatine kinase (CK), and CK area under the curve values, with a prespecified non-inferiority margin of 20%. Major bleeding was defined as type 2, 3, or 5 on the Bleeding Academic Research Consortium classification. Eptifibatide bolus only was administered to 147 patients (20%), which were matched 1:1 to patients receiving conventional treatment. Based on peak myocardial bound creatine kinase, CK and CK area under the curve values, infarct size was -8.4% (95% CI [-31.2%, 14.4%]), -11.6% (95% CI [-33.5%, 10.3%]), and -13.9% (95% CI [-34.1%, 6.2%]) after eptifibatide bolus, respectively, reaching prespecified noninferiority compared with conventional treatment. Bolus treatment significantly reduced major bleeding complications (OR 0.48, 95% CI [0.30, 0.79]). In conclusion, eptifibatide given as abbreviated bolus only to selected STEMI patients who underwent primary PCI was noninferior regarding infarct size and resulted in less bleeding complications compared with conventional bolus and infusion treatment.

Comparing efficacy of receiving different dosages of eptifibatide in bleeding after percutaneous coronary intervention in patients with myocardial infarction

BACKGROUND

Acute coronary syndrome (ACS) is a common condition that needs appropriate treatment like percutaneous coronary intervention (PCI). Glycoprotein IIb/IIIa inhibitors (GPI) like eptifibatide prevent procedural ischemic complications after PCI. Eptifibatide has increased the risk of bleeding complications, although it is effective in reducing mortality and morbidity. Eptifibatide is routinely used in bolus and infusion forms and the aim of this study is to evaluate the efficacy of bolus-only dose and bolus + infusion strategy for administrating eptifibatide in bleeding complications and consequences after PCI.

METHODS

This randomized clinical trial was conducted on subjects who experienced PCI after incidence of myocardial infarction (MI). Patients were randomly divided into two groups who received bolus-only dose (n = 51) or bolus + infusion form of eptifibatide (n = 50). Then, PCI blood pressure, mean time duration of hemostasis after arterial sheath removal, laboratory data, need for blood transfusion, and presence of bleeding complications were evaluated. After 6 months, patients were followed for needs for additional coronary interventions.

RESULTS

The mean age of participants was 61.68 ± 1.50 years. The prevalence of men was 70.29%. There was no significant difference in mean of systolic blood pressure (SBP) and diastolic blood pressure (DBP) during hospitalization (P > 0.050). The mean time duration of hemostasis was 8.13 ± 0.45 minutes in the bolus-only group and 16.46 ± 0.71 minutes in the bolus + infusion group (P < 0.001). There was no significant difference in the hemoglobin (Hb) level, platelet count, white blood cell (WBC), blood urea nitrogen (BUN), and creatinine level (P > 0.050).

CONCLUSION

The results of this study suggested that bolus-only dose of eptifibatide before PCI could be able to decrease significantly bleeding complication and other clinical and cardiovascular outcomes.

A Review of Antiplatelet Activity of Traditional Medicinal Herbs on Integrative Medicine Studies

Thrombotic events mainly occurred by platelet activation and aggregation. The vascular occlusion causes serious disease states such as unstable angina, ischemic stroke, and heart attack. Due to the pervading of thrombotic diseases, new antiplatelet drugs are necessary for preventing and treating arterial thrombosis without adverse side effects. Traditional medicinal herbs have been used for the treatment of human ailments for a long time. The clinically useful and safe products from traditional medicinal herbs were identified and developed in numerous pharmacological approaches. A complementary system of traditional medicinal herbs is a good candidate for pharmacotherapy. However, it still has a limitation in its function and efficacy. Thus, it is necessary to study the mode of action of traditional medicinal herbs as alternative therapeutic agents. In this review, we focused on our current understanding of the regulatory mechanisms of traditional medicinal herbs in antiplatelet activity and antithrombotic effect of traditional medicinal herbs on platelet function.

Update in the Early Management and Reperfusion Strategies of Patients with Acute Ischemic Stroke

Acute ischemic stroke (AIS) remains a leading cause of death and long-term disability. The paradigms on prehospital care, reperfusion therapies, and postreperfusion management of patients with AIS continue to evolve. After the publication of pivotal clinical trials, endovascular thrombectomy has become part of the standard of care in selected cases of AIS since 2015. New stroke guidelines have been recently published, and the time window for mechanical thrombectomy has now been extended up to 24 hours. This review aims to provide a focused up-to-date review for the early management of adult patients with AIS and introduce the new upcoming areas of ongoing research.

Comparative efficacy and safety of reperfusion therapy with fibrinolytic agents in patients with ST-segment elevation myocardial infarction: a systematic review and network meta-analysis

BACKGROUND

Fibrinolytic therapy offers an alternative to mechanical reperfusion for ST-segment elevation myocardial infarction (STEMI) in settings where health-care resources are scarce. Comprehensive evidence comparing different agents is still unavailable. In this study, we examined the effects of various fibrinolytic drugs on clinical outcomes.

METHODS

We did a network meta-analysis based on a systematic review of randomised controlled trials comparing fibrinolytic drugs in patients with STEMI. Several databases were searched from inception up to Feb 28, 2017. We included only randomised controlled trials that compared fibrinolytic agents as a reperfusion therapy in adult patients with STEMI, whether given alone or in combination with adjunctive antithrombotic therapy, against other fibrinolytic agents, a placebo, or no treatment. Only trials investigating agents with an approved indication of reperfusion therapy in STEMI (streptokinase, tenecteplase, alteplase, and reteplase) were included. The primary efficacy outcome was all-cause mortality within 30-35 days and the primary safety outcome was major bleeding. This study is registered with PROSPERO (CRD42016042131).

FINDINGS

A total of 40 eligible studies involving 128 071 patients treated with 12 different fibrinolytic regimens were assessed. Compared with accelerated infusion of alteplase with parenteral anticoagulants as background therapy, streptokinase and non-accelerated infusion of alteplase were significantly associated with an increased risk of all-cause mortality (risk ratio [RR] 1·14 [95% CI 1·05-1·24] for streptokinase plus parenteral anticoagulants; RR 1·26 [1·10-1·45] for non-accelerated alteplase plus parenteral anticoagulants). No significant difference in mortality risk was recorded between accelerated infusion of alteplase, tenecteplase, and reteplase with parenteral anticoagulants as background therapy. For major bleeding, a tenecteplase-based regimen tended to be associated with lower risk of bleeding compared with other regimens (RR 0·79 [95% CI 0·63-1·00]). The addition of glycoprotein IIb or IIIa inhibitors to fibrinolytic therapy increased the risk of major bleeding by 1·27-8·82-times compared with accelerated infusion alteplase plus parenteral anticoagulants (RR 1·47 [95% CI 1·10-1·98] for tenecteplase plus parenteral anticoagulants plus glycoprotein inhibitors; RR 1·88 [1·24-2·86] for reteplase plus parenteral anticoagulants plus glycoprotein inhibitors).

INTERPRETATION

Significant differences exist among various fibrinolytic regimens as reperfusion therapy in STEMI and alteplase (accelerated infusion), tenecteplase, and reteplase should be considered over streptokinase and non-accelerated infusion of alteplase. The addition of glycoprotein IIb or IIIa inhibitors to fibrinolytic therapy should be discouraged.

FUNDING

None.

Optimal Antiplatelet Therapy in ST-Segment Elevation Myocardial Infarction

Cardiovascular disease is the leading cause of death worldwide. Case-fatality rates for myocardial infarction (MI) in the United States have decreased over the past decades, in large part due to advances in the treatment of acute MI and secondary preventive therapy after MI. Antiplatelet therapy remains the cornerstone of treatment of MI. This article reviews the current state of antiplatelet therapy in ST-segment elevation MI.

Platelets and Cardiovascular Disease

Platelets play an important, but often under-recognized role in cardiovascular disease. For example, the normal response of the platelet can be altered, either by increased pro-aggregatory stimuli or by diminished anti-aggregatory substances to produce conditions of increased platelet activation/aggregation and occur in active cardiovascular disease states both on a chronic (e.g. stable angina pectoris) and acute basis (e.g. acute myocardial infarction). In addition, platelet hyperaggregability is also associated with the risk factors for coronary artery disease (e.g. smoking, hypertension, and hypercholesterolaemia). Finally, the utility of an increasing range of anti-platelet therapies in the management of the above disease states further emphasizes the pivotal role platelets play in the pathogenesis of cardiovascular disease. This paper provides a comprehensive overview of the normal physiologic role of platelets in maintain homeostasis, the pathophysiologic processes that contribute to platelet dysfunction in cardiovascular disease and the associated role and benefits of anti-platelet therapies.

Changing Management of Acute Ischaemic Stroke: the New Treatments and Emerging Role of Endovascular Therapy

OPINION STATEMENT

Urgent reperfusion of the ischaemic brain is the aim of stroke treatment, and the last two decades have seen a rapid advancement in the medical and endovascular treatment of acute ischaemic stroke. Intravenous tissue plasminogen activator (tPA) was first introduced as a safe and effective thrombolytic agent followed by the introduction of newer thrombolytic agents as well as anticoagulant and antiplatelet agents, proposed as potentially safer drugs with more favourable interaction profiles. In addition to chemo-thrombolysis, other techniques including transcranial sonothrombolysis and microbubble cavitation have been introduced which are showing promising results, but await large-scale clinical trials. These developments in medical therapies which are undoubtedly of great importance due to their potential widespread and immediate availability are paralleled with gradual but steady improvements in endovascular recanalisation techniques which were initiated by the introduction of the MERCI (Mechanical Embolus Removal in Cerebral Ischemia) and Penumbra systems. The introduction of the Solitaire device was a significant achievement in reliable and safe endovascular recanalisation and was followed by further innovative stent retrievers. Initial trials failed to show a solid benefit in endovascular intervention compared with IV-tPA alone. These counterintuitive results did not last long, however, when a series of very well-designed randomised controlled trials, pioneered by MR-CLEAN, EXTEND-IA and ESCAPE, emerged, confirming the well-believed daily anecdotal evidence. There have now been seven positive trials of endovascular treatment for acute ischaemic stroke. Now that level I evidence regarding the superiority of endovascular recanalisation is abundantly available, the clinical challenge is how to select patients suitable for intervention and to familiarise and educate stroke care providers with this recent development in stroke care. It is important for the interventional services to be provided only in comprehensive stroke centres and endovascular interventions attempted by experienced well-trained operators, at this stage as an adjunct to the established medical treatment of IV-tPA, if there are no contraindications.

Adhesion Molecules: Master Controllers of the Circulatory System

This manuscript will review our current understanding of cellular adhesion molecules (CAMs) relevant to the circulatory system, their physiological role in control of vascular homeostasis, innate and adaptive immune responses, and their importance in pathophysiological (disease) processes such as acute lung injury, atherosclerosis, and pulmonary hypertension. This is a complex and rapidly changing area of research that is incompletely understood. By design, we will begin with a brief overview of the structure and classification of the major groups of adhesion molecules and their physiological functions including cellular adhesion and signaling. The role of specific CAMs in the process of platelet aggregation and hemostasis and leukocyte adhesion and transendothelial migration will be reviewed as examples of the complex and cooperative interplay between CAMs during physiological and pathophysiological processes. The role of the endothelial glycocalyx and the glycobiology of this complex system related to inflammatory states such as sepsis will be reviewed. We will then focus on the role of adhesion molecules in the pathogenesis of specific disease processes involving the lungs and cardiovascular system. The potential of targeting adhesion molecules in the treatment of immune and inflammatory diseases will be highlighted in the relevant sections throughout the manuscript.

Imaging of prehospital stroke therapeutics

Despite significant quality improvement efforts to streamline in-hospital acute stroke care in the conventional model, there remain inherent layers of treatment delays, which could be eliminated with prehospital diagnostics and therapeutics administered in a mobile stroke unit. Early diagnosis using telestroke and neuroimaging while in the ambulance may enable targeted routing to hospitals with specialized care, which will likely improve patient outcomes. Key clinical trials in telestroke, mobile stroke units with prehospital neuroimaging capability, prehospital ultrasound and co-administration of various classes of neuroprotectives, antiplatelets and antithrombin agents with intravenous thrombolysis are discussed in this article.

Early P2Y12 inhibition in ST-segment elevation myocardial infarction: Bridging the gap

Rapid and consistent platelet inhibition represents the cornerstone of pharmacologic treatment in the early hours of ST-segment elevation myocardial infarction (STEMI). Oral P2Y12 inhibitors are recommended to be administered as early as possible in patients with STEMI undergoing primary percutaneous coronary intervention. However, a delay in the onset of antiplatelet agent effects has been recently described in the first several hours after oral administration of clopidogrel, prasugrel, and ticagrelor. As a result, primary percutaneous coronary intervention is performed in most cases with P2Y12 inhibition that may be inadequate. Several strategies may be applied in order to "bridge the gap" in platelet inhibition after oral P2Y12 inhibitors in STEMI, such as upstream administration of P2Y12 inhibitors, loading dose modification, use of an intravenous P2Y12 inhibitor, or glycoprotein IIb/IIIa inhibitors' administration. These strategies may further improve clinical outcomes in this high-risk "golden window."

Advances in medical revascularisation treatments in acute ischemic stroke

Urgent reperfusion of the ischaemic brain is the aim of stroke treatment and there has been ongoing research to find a drug that can promote vessel recanalisation more completely and with less side effects. In this review article, the major studies which have validated the use and safety of tPA are discussed. The safety and efficacy of other thrombolytic and anticoagulative agents such as tenecteplase, desmoteplase, ancrod, tirofiban, abciximab, eptifibatide, and argatroban are also reviewed. Tenecteplase and desmoteplase are both plasminogen activators with higher fibrin affinity and longer half-life compared to alteplase. They have shown greater reperfusion rates and improved functional outcomes in preliminary studies. Argatroban is a direct thrombin inhibitor used as an adjunct to intravenous tPA and showed higher rates of complete recanalisation in the ARTTS study with further studies which are now ongoing. Adjuvant thrombolysis techniques using transcranial ultrasound are also being investigated and have shown higher rates of complete recanalisation, for example, in the CLOTBUST study. Overall, development in medical therapies for stroke is important due to the ease of administration compared to endovascular treatments, and the new treatments such as tenecteplase, desmoteplase, and adjuvant sonothrombolysis are showing promising results and await further large-scale clinical trials.

Platelet glycoprotein IIb/IIIa blockers during percutaneous coronary intervention and as the initial medical treatment of non-ST segment elevation acute coronary syndromes

BACKGROUND

During percutaneous coronary intervention (PCI), and in non-ST segment elevation acute coronary syndromes (NSTEACS), the risk of acute vessel occlusion by thrombosis is high. Glycoprotein IIb/IIIa blockers strongly inhibit platelet aggregation and may prevent mortality and myocardial infarction. This is an update of a Cochrane review first published in 2001, and previously updated in 2007 and 2010.

OBJECTIVES

To assess the efficacy and safety effects of glycoprotein IIb/IIIa blockers when administered during PCI, and as initial medical treatment in patients with NSTEACS.

SEARCH METHODS

We updated the searches of the Cochrane Central Register of Controlled Trials (CENTRAL) on The Cochrane Library (Issue 12, 2012), MEDLINE (OVID, 1946 to January Week 1 2013) and EMBASE (OVID, 1947 to Week 1 2013) on 11 January 2013.

SELECTION CRITERIA

Randomised controlled trials comparing intravenous IIb/IIIa blockers with placebo or usual care.

DATA COLLECTION AND ANALYSIS

Two authors independently selected studies for inclusion, assessed trial quality and extracted data. We collected major bleeding as adverse effect information from the trials. We used odds ratios (OR) and 95% confidence intervals (CI) for effect measures.

MAIN RESULTS

Sixty trials involving 66,689 patients were included. During PCI (48 trials with 33,513 participants) glycoprotein IIb/IIIa blockers decreased all-cause mortality at 30 days (OR 0.79, 95% CI 0.64 to 0.97) but not at six months (OR 0.90, 95% CI 0.77 to 1.05). All-cause death or myocardial infarction was decreased both at 30 days (OR 0.66, 95% CI 0.60 to 0.72) and at six months (OR 0.75, 95% CI 0.64 to 0.86), although severe bleeding was increased (OR 1.39, 95% CI 1.21 to 1.61; absolute risk increase (ARI) 8.0 per 1000). The efficacy results were homogeneous for every endpoint according to the clinical condition of the patients, but were less marked for patients pre-treated with clopidogrel, especially in patients without acute coronary syndromes.As initial medical treatment of NSTEACS (12 trials with 33,176 participants), IIb/IIIa blockers did not decrease mortality at 30 days (OR 0.90, 95% CI 0.79 to 1.02) or at six months (OR 1.00, 95% CI 0.87 to 1.15), but slightly decreased death or myocardial infarction at 30 days (OR 0.91, 95% CI 0.85 to 0.98) and at six months (OR 0.88, 95% CI 0.81 to 0.96), although severe bleeding was increased (OR 1.29, 95% CI 1.14 to 1.45; ARI 1.4 per 1000).

AUTHORS' CONCLUSIONS

When administered during PCI, intravenous glycoprotein IIb/IIIa blockers reduce the risk of all-cause death at 30 days but not at six months, and reduce the risk of death or myocardial infarction at 30 days and at six months, at a price of an increase in the risk of severe bleeding. The efficacy effects are homogeneous but are less marked in patients pre-treated with clopidogrel where they seem to be effective only in patients with acute coronary syndromes. When administered as initial medical treatment in patients with NSTEACS, these agents do not reduce mortality although they slightly reduce the risk of death or myocardial infarction.

Platelet glycoprotein IIb/IIIa blockers during percutaneous coronary intervention and as the initial medical treatment of non-ST segment elevation acute coronary syndromes

BACKGROUND

During percutaneous coronary intervention (PCI), and in non-ST segment elevation acute coronary syndromes (NSTEACS), the risk of acute vessel occlusion by thrombosis is high. Glycoprotein IIb/IIIa blockers strongly inhibit platelet aggregation and may prevent mortality and myocardial infarction. This is an update of a Cochrane review first published in 2001, and previously updated in 2007 and 2010.

OBJECTIVES

To assess the efficacy and safety effects of glycoprotein IIb/IIIa blockers when administered during PCI, and as initial medical treatment in patients with NSTEACS.

SEARCH METHODS

We updated the searches of the Cochrane Central Register of Controlled Trials (CENTRAL) on The Cochrane Library (Issue 12, 2012), MEDLINE (OVID, 1946 to January Week 1 2013) and EMBASE (OVID, 1947 to Week 1 2013) on 11 January 2013.

SELECTION CRITERIA

Randomised controlled trials comparing intravenous IIb/IIIa blockers with placebo or usual care.

DATA COLLECTION AND ANALYSIS

Two authors independently selected studies for inclusion, assessed trial quality and extracted data. We collected major bleeding as adverse effect information from the trials. We used odds ratios (OR) and 95% confidence intervals (CI) for effect measures.

MAIN RESULTS

Sixty trials involving 66,689 patients were included. During PCI (48 trials with 33,513 participants) glycoprotein IIb/IIIa blockers decreased all-cause mortality at 30 days (OR 0.79, 95% CI 0.64 to 0.97) but not at six months (OR 0.90, 95% CI 0.77 to 1.05). All-cause death or myocardial infarction was decreased both at 30 days (OR 0.66, 95% CI 0.60 to 0.72) and at six months (OR 0.75, 95% CI 0.64 to 0.86), although severe bleeding was increased (OR 1.39, 95% CI 1.21 to 1.61; absolute risk increase (ARI) 8.0 per 1000). The efficacy results were homogeneous for every endpoint according to the clinical condition of the patients, but were less marked for patients pre-treated with clopidogrel, especially in patients without acute coronary syndromes.As initial medical treatment of NSTEACS (12 trials with 33,176 participants), IIb/IIIa blockers did not decrease mortality at 30 days (OR 0.90, 95% CI 0.79 to 1.02) or at six months (OR 1.00, 95% CI 0.87 to 1.15), but slightly decreased death or myocardial infarction at 30 days (OR 0.91, 95% CI 0.85 to 0.98) and at six months (OR 0.88, 95% CI 0.81 to 0.96), although severe bleeding was increased (OR 1.29, 95% CI 1.14 to 1.45; ARI 1.4 per 1000).

AUTHORS' CONCLUSIONS

When administered during PCI, intravenous glycoprotein IIb/IIIa blockers reduce the risk of all-cause death at 30 days but not at six months, and reduce the risk of death or myocardial infarction at 30 days and at six months, at a price of an increase in the risk of severe bleeding. The efficacy effects are homogeneous but are less marked in patients pre-treated with clopidogrel where they seem to be effective only in patients with acute coronary syndromes. When administered as initial medical treatment in patients with NSTEACS, these agents do not reduce mortality although they slightly reduce the risk of death or myocardial infarction.

Integrin αIIbβ3: from discovery to efficacious therapeutic target

From the initial description of platelets in 1882, their propensity to aggregate and to contribute to thrombosis was apparent. Indeed, excessive platelet aggregation is associated with myocardial infarction and other thrombotic diseases whereas Glanzmann thrombasthenia, in which platelet aggregation is reduced, is a bleeding syndrome. Over the last half of the 20th century, many investigators have provided insights into the cellular and molecular basis for platelet aggregation. The major membrane protein on platelets, integrin αIIbβ3, mediates this response by rapidly transiting from its resting to an activated state in which it serves as a receptor for ligands that can bridge platelets together. Monoclonal antibodies, natural products, and small peptides were all shown to inhibit αIIbβ3 dependent platelet aggregation, and these inhibitors became the forerunners of antagonists that proceeded through preclinical testing and into large patient trials to treat acute coronary syndromes, particularly in the context of percutaneous coronary interventions. Three such αIIbβ3 antagonists, abciximab, eptifibatide, and tirofiban, received Food and Drug Administration approval. Over the past 15 years, millions of patients have been treated with these αIIbβ3 antagonists and many lives have been saved by their administration. With the side effect of increased bleeding and the development of new antithrombotic drugs, the use of αIIbβ3 antagonists is waning. Nevertheless, they are still widely used for the prevention of periprocedural thrombosis during percutaneous coronary interventions. This review focuses on the biology of αIIbβ3, the development of its antagonists, and some of the triumphs and shortcomings of αIIbβ3 antagonism.

Appropriate anti-thrombotic/anti-thrombin therapy for thrombotic lesions

Managing coronary thrombus is a challenging task and requires adequate knowledge of the various antithrombotic agents available. In this article, we will briefly analyze the risk-benefit profile of antithrombotic agents, with critical analysis of the scientific evidence available to support their use. Since thrombus consists of platelets and coagulation cofactors, an effective antithrombotic strategy involves using one anticoagulant with two or more antiplatelet agents. Unfractionated heparin traditionally has been the most commonly used anticoagulant but is fast being replaced by relatively newer agents like LMWH, direct thrombin inhibitors, and Factor Xa inhibitors.

In recent years, the antiplatelet landscape has changed significantly with the availability of more potent and rapidly acting agents, like prasugrel and ticagrelor. These agents have demonstrated a sizeable reduction in ischemic outcomes in patients with ACS, who are treated invasively or otherwise, with some concern for an increased bleeding risk. Glycoprotein IIb/IIIa inhibitors have an established role in high risk NSTE ACS patients pretreated with dual antiplatelets, but its role in STEMI patients, treated with invasive approach and dual antiplatelets, has not been supported consistently across the studies. Additionally, in recent years, its place as a directly injected therapy into coronaries has been looked into with mixed results. In conclusion, a well-tailored antithrombotic strategy requires taking into account each patient’s individual risk factors and clinical presentation, with an effort to strike balance between not only preventing ischemic outcomes but also reducing bleeding complications.

Cost-effectiveness of adjunctive eptifibatide in patients undergoing coronary stenting in Germany

OBJECTIVE

To determine the cost-effectiveness of adding eptifibatide to the standard treatment for selected high-risk patients undergoing coronary stenting in Germany. Furthermore, to investigate the impact of several extrapolation methods on the results.

METHODS

A Markov model was developed to reflect the clinical events in this specific patient population, including target vessel revascularization, myocardial infarction, and death. To extrapolate clinical data beyond 1 year, a linear, an exponential, and a Weibull survival curves were estimated. Patient characteristics and transition probabilities were derived from a high-risk subgroup of the ESPRIT trial; patient-level utility data came from a published Dutch study. Costs were calculated from a hospital and from a third-party payer perspective.

RESULTS

For both perspectives, the additional treatment with eptifibatide is the considered dominant alternative. The incremental net benefit of its use exceeds €10,000 for both perspectives. Results proved stable in probabilistic sensitivity analysis as well as under the different extrapolation scenarios.

CONCLUSIONS

Eptifibatide is likely to be dominant strategy with 77.7 and 96.7% of the simulations leading to QALYs gained and generating cost savings from both the hospital and the third-party payer perspective. Eptifibatide offsets its additional treatment costs by avoiding costly repeat procedures and leads to positive QALY gains by preventing cardiovascular events lending themselves to transient or permanent lower quality of life. The method used to extrapolate the short-term risks did not impact on results, mainly due to similar clinical risk profiles between the two treatment groups in the long term.

Treatment with tirofiban for acute coronary syndrome (ACS): a systematic review and network analysis

OBJECTIVE

To assess the efficacy of tirofiban in comparison to usual care or other GPIIb/IIIa antagonists (eptifibatide and abciximab). Results were analysed by drug administration with planned percutaneous coronary intervention (PCI) or as medical management without planned PCI, and separately for STEMI or NSTE ACS patients.

RESEARCH DESIGN AND METHODS

A systematic review was performed of randomized controlled trials of tirofiban, abciximab, eptifibatide or usual care given to patients with acute coronary syndrome. Nine databases were searched up to March 2010. Pair-wise meta-analysis was used to combine all available direct comparisons; indirect comparisons and network analysis were performed when this was not possible. The primary outcome was MACE (major adverse cardiac event).

RESULTS

The search yielded 8, 119 records and 50 trials were included (total number of patients = 52,958). Compared to usual care, high and medium-dose tirofiban (25 and 10 µg/kg/min) administered with planned PCI reduced MACE at 30 days for patients with STEMI (RR 0.67, 95% CI 0.45, 0.99; RR 0.28, 95% CI 0.10, 0.80), but was not effective as a medical management. Medium-dose tirofiban (10 µg/kg/min) administered with planned PCI or low dose (0.4 µg/kg/min) as medical management reduced the risk of MACE for patients with NSTE ACS (RR 0.39, 95% CI 0.21, 0.75; RR 0.58, 95% CI 0.41, 0.83) in comparison to usual care, but at the expense of increased thrombocytopenia (RR 3.26, 95% CI 1.31, 8.13). Evidence from RCTs and network analysis indicated tirofiban and abciximab were equally effective and safe. Comparing tirofiban and eptifibatide treatment by indirect and network analysis produced inconclusive results.

CONCLUSIONS

Tirofiban was more effective than usual care for STEMI and NSTE ACS patients receiving planned PCI, and NSTE ACS patients receiving medical management. Tirofiban and abciximab were equally effective. Comparisons of tirofiban and eptifibatide were inconclusive.

Adjunctive and alternative approaches to current reperfusion therapy

BACKGROUND AND PURPOSE

Current ischemic stroke reperfusion therapy consists of intravenous thrombolysis given in eligible patients after review of a noncontrast CT scan and a time-based window of opportunity. Rapid clot lysis has a strong association with clinical improvement but remains incomplete in many patients. This review appraises novel adjunctive or alternative approaches to current reperfusion strategies being tested in all trial phases. Summary of Review- Alternative approaches to current reperfusion therapy can be separated into 4 main categories: (1) combinatory approaches with other drugs or devices; (2) novel systemic thrombolytic agents; (3) endovascular medical or mechanical reperfusion treatments; and (4) noninvasive or minimally invasive methods to augment cerebral blood flow and alleviate intracranial blood flow steal.

CONCLUSIONS

Reperfusion treatments must be provided as fast as possible in patients most likely to benefit. Patients who fail to rapidly reperfuse may benefit from other strategies that maintain collateral flow or protect tissue at risk.

Safety and feasibility of intraarterial eptifibatide as a revascularization tool in acute ischemic stroke

OBJECT

Experience with the use of platelet glycoprotein (GP) IIb-IIIa inhibitor eptifibatide in patients with ischemic stroke is limited. The authors report the off-label use of intraarterial eptifibatide during endovascular ischemic stroke revascularization procedures for reocclusion after documented recanalization or formed fresh thrombi in distal vessels that were inaccessible to endovascular devices.

METHODS

Patients who received intraarterial eptifibatide were identified from a prospectively collected database of patients in whom endovascular revascularization for acute ischemic stroke was attempted between 2005 and 2008. Data were analyzed retrospectively. The intraarterial eptifibatide dose was a single-bolus dose of 180 μg/kg body weight. Primary outcome measures were angiographic recanalization (Thrombolysis in Myocardial Infarction Grade 2 or 3), symptomatic intracranial hemorrhage rate, overall mortality rate, and favorable 3-month modified Rankin Scale score (≤ 2).

RESULTS

The study included 35 patients (mean age 62 years, range 18-85 years). The median presenting National Institutes of Health Stroke Scale score was 13. Two patients received intravenous tissue plasminogen activator before endovascular therapy. The median time from symptom onset to therapy initiation was 230 minutes (range 90-1370 minutes). Twelve patients (34%) received intraarterial tissue plasminogen activator without mechanical measures. Mechanical revascularization measures used were Merci retriever in 19 (54%), Penumbra device in 1 (3%), balloon angioplasty in 15 (43%), and stent placement in 22 (63%) patients. The mean dose of intraarterial eptifibatide was 11.6 mg (range 5-16.6 mg). Partial-to-complete recanalization (Thrombolysis in Myocardial Infarction Grade 2 or 3) was achieved in 27 patients (77%). Postprocedure intracranial hemorrhage occurred in 13 patients (37%), causing symptoms in 5 (14%). In the 5 symptomatic intracranial hemorrhage cases, all patients but one presented more than 8 hours after symptom onset and all received intraarterial recombinant tissue plasminogen activator. The median discharge National Institutes of Health Stroke Scale score was 7 (range 0-17). At 3 months postprocedure, 21 patients (60%) had a modified Rankin Scale score ≤ 2, and 8 patients (23%) had died.

CONCLUSIONS

Adjunctive intraarterial eptifibatide is a feasible option for salvage of reocclusion and thrombolysis of distal inaccessible thrombi during endovascular stroke revascularization. Its safety and efficacy need to be studied further in larger, multicenter, controlled studies.

Platelet glycoprotein IIb/IIIa blockers during percutaneous coronary intervention and as the initial medical treatment of non-ST segment elevation acute coronary syndromes

BACKGROUND

During percutaneous coronary intervention (PCI), and in non-ST segment elevation acute coronary syndromes (NSTEACS), the risk of acute vessel occlusion by thrombosis is high. IIb/IIIa blockers strongly inhibit platelet aggregation and may prevent mortality and myocardial infarction (MI). This is an update of a Cochrane review first published in 2001, and previously updated in 2007.

OBJECTIVES

To assess the effects and safety of IIb/IIIa blockers when administered during PCI, and as initial medical treatment in patients with NSTEACS.

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) on The Cochrane Library (Issue 3, 2009), MEDLINE (1966 to October 2009), and EMBASE (1980 to October 2009).

SELECTION CRITERIA

Randomised controlled trials comparing intravenous IIb/IIIa blockers with placebo or usual care.

DATA COLLECTION AND ANALYSIS

Two authors independently selected studies for inclusion, assessed trial quality and extracted data. We collected major bleeding as adverse effect information from the trials. Odds ratios (OR) and 95% confidence intervals (CI) were used for effect measures.

MAIN RESULTS

Forty-eight trials involving 62,417 patients were included. During PCI, IIb/IIIa blockers decreased mortality at 30 days (OR 0.76, 95% CI 0.62 to 0.95) and at six months (OR 0.84, 95% CI 0.71 to 1.00). Death or MI was decreased both at 30 days (OR 0.65, 95% CI 0.60 to 0.72), and at 6 months (OR 0.70, 95% CI 0.61 to 0.81), although severe bleeding was increased (OR 1.38, 95% CI 1.20 to 1.59; absolute risk increase (ARI) 8.0 per 1000). The efficacy results were homogeneous for every endpoint according to the clinical condition of the patients, but were less marked for patients pre-treated with clopidogrel, especially in patients without ACS.As initial medical treatment of NSTEACS, IIb/IIIa blockers did not decrease mortality at 30 days (OR 0.91, 95% CI 0.80 to 1.03) or at six months (OR 1.00, 95% CI 0.87 to 1.15), but slightly decreased death or MI at 30 days (OR 0.92, 95% CI 0.86 to 0.99) and at six months (OR 0.88, 95% CI 0.81 to 0.96), although severe bleeding was increased (OR 1.27, 95% CI 1.12 to 1.43; ARI 1.4 per 1000).

AUTHORS' CONCLUSIONS

When administered during PCI, intravenous IIb/IIIa blockers reduce the risk of death and of death or MI at 30 days and at six months, at a price of an increase in the risk of severe bleeding. The efficacy effects are homogeneous but are less marked in patients pre-treated with clopidogrel where they seem to be effective only in patients with ACS. When administered as initial medical treatment in patients with NSTEACS, these agents do not reduce mortality although they slightly reduce the risk of death or MI.

Making the right choice: optimizing rt-PA and eptifibatide lysis, an in vitro study

INTRODUCTION

Recombinant tissue plasminogen activator (rt-PA) is the only FDA approved lytic therapy for acute ischemic stroke. However, there can be complications such as intra-cerebral hemorrhage. This has led to interest in adjuncts such as GP IIb-IIIa inhibitors. However, there is little data on combined therapies. Here, we measure clot lysis for rt-PA and eptifibatide in an in vitro human clot model, and determine the drug concentrations maximizing lysis. A pharmacokinetic model is used to compare drug concentrations expected in clinical trials with those used here. The hypothesis is that there is a range of rt-PA and eptifibatide concentrations that maximize in vitro clot lysis.

MATERIALS AND METHODS

Whole blood clots were made from blood obtained from 28 volunteers, after appropriate institutional approval. Sample clots were exposed to rt-PA and eptifibatide in human fresh-frozen plasma; rt-PA concentrations were 0, 0.5, 1, and 3.15 μg/ml, and eptifibatide concentrations were 0, 0.63, 1.05, 1.26 and 2.31 μg/ml. All exposures were for 30 minutes at 37 C. Clot width was measured using a microscopic imaging technique and mean fractional clot loss (FCL) at 30 minutes was used to determine lytic efficacy. On average, 28 clots (range: 6-148) from 6 subjects (3-24) were used in each group.

RESULTS AND CONCLUSIONS

FCL for control clots was 14% (95% Confidence Interval: 13-15%). FCL was 58% (55-61%) for clots exposed to both drugs at all concentrations, except those at an rt-PA concentration of 3.15 μg/ml, and eptifibatide concentrations of 1.26 μg/ml (Epf) or 2.31 μg/ml. Here, FCL was 43% (36-51) and 35% (32-38) respectively. FCL is maximized at moderate rt-PA and eptifibatide concentration; these values may approximate the average concentrations used in some rt-PA and eptifibatide treatments.

A multicenter randomized study to evaluate intracoronary abciximab with the ClearWay catheter to improve outcomes with Lysis (IC ClearLy): trial study design and rationale

BACKGROUND

Percutaneous coronary intervention (PCI) is a highly effective therapy for acute ST-elevation myocardial infarction. Adjunctive therapy with platelet glycoprotein (GP) IIb/IIIa inhibitor can result in increased vessel patency and improved outcomes in ST-elevation myocardial infarction patients undergoing PCI. The investigation of novel dosing and delivery strategies of this therapy may help to further improve outcomes.

METHODS

IC-Clearly is a randomized, open-label, multicenter trial, with the purpose of evaluating the effectiveness of an intracoronary bolus dose of abciximab delivered using the ClearWay RX catheter vs. an intravenous bolus of abciximab for ST-elevation myocardial infarction with angiographically visible thrombus (thrombus grade >or=2). A total of 150 patients will be randomized 1: 1 to treatment of the culprit artery with intracoronary abciximab (75 patients) or intravenous abciximab (75 patients) in addition to a maintenance infusion regimen of abciximab administered intravenously for 12 h after PCI. The number of patients included in this study is based on the estimation of sample size needed to identify a statistically significant difference in the primary endpoints between the two groups. The primary endpoint chosen to evaluate this hypothesis is infarct size assessed by cardiac magnetic resonance. Clinical outcomes will be assessed for each patient through hospital discharge and at 30-day follow-up.

CONCLUSION

The purpose of this study is to evaluate whether an intracoronary bolus of abciximab delivered with the ClearWay RX catheter prior to the 12 h post-PCI intravenous infusion regimen of abciximab will result in significant additional clot resolution in vivo and improved myocardial perfusion when compared with an intravenous bolus of abciximab on top of the 12 h post-PCI intravenous infusion regimen of abciximab as per standard practice. The primary endpoint chosen to evaluate this hypothesis is infarct size as assessed by cardiac magnetic resonance.

Eptifibatide: The evidence for its role in the management of acute coronary syndromes

Introduction:

Acute coronary syndromes and non-Q-wave myocardial infarction are often initiated by platelet activation. Eptifibatide is a cyclic heptapeptide and is the third inhibitor of glycoprotein (Gp) IIb/IIIa that has found broad acceptance after the specific antibody abciximab and the nonpeptide tirofiban entered the global market. Gp IIb/IIIa inhibitors act by inhibiting the final common pathway of platelet aggregation, and play an important role in the management of acute coronary syndromes.

Aims:

This review assesses the evidence for therapeutic value of eptifibatide as a Gp IIb/IIIa inhibitor in patients with acute coronary syndromes.

Evidence review:

Several large, randomized controlled trials show that eptifibatide as adjunctive therapy to standard care in patients with non-ST segment elevation acute coronary syndrome is associated with a significant reduction in the incidence of death or myocardial infarction. Data are limited regarding the use of eptifibatide in patients with ST segment elevation myocardial infarction. Cost-effectiveness analysis indicates that eptifibatide is associated with a favorable cost-effectiveness ratio relative to standard care. According to US cost-effectiveness analysis about 70% of the acquisition costs of eptifibatide are offset by the reduced medical resource consumption during the first year. Eptifibatide was well tolerated in most of the trials. Bleeding is the most commonly reported adverse event, with most major bleeding episodes occurring at the vascular access site. Major intracranial bleeds, stroke, or profound thrombocytopenia rarely occurred during eptifibatide treatment.

Place in therapy:

Eptifibatide has gained widespread acceptance as an adjunct to standard anticoagulation therapy in patients with acute coronary syndromes, and may be particularly useful in the management of patients with elevated troponin or undergoing percutaneous coronary interventions.

In vivo models for the evaluation of antithrombotics and thrombolytics

The development and application of animal models of thrombosis have played a crucial role in the discovery and validation of novel drug targets and the selection of new agents for clinical evaluation, and have informed dosing and safety information for clinical trials. These models also provide valuable information about the mechanisms of action/interaction of new antithrombotic agents. Small and large animal models of thrombosis and their role in the discovery and development of novel agents are described. Methods and major issues regarding the use of animal models of thrombosis, such as positive controls, appropriate pharmacodynamic markers of activity, safety evaluation, species specificity, and pharmacokinetics, are highlighted. Finally, the use of genetic models of thrombosis/hemostasis and how these models have aided in the development of therapies that are presently being evaluated clinically are presented.

Reperfusion revisited: beyond TIMI 3 flow

Therapy for acute myocardial infarction has advanced dramatically since the early 1980s with the use of early intravenous fibrinolytic therapy. Combining low-dose fibrinolysis and platelet lysis appears to provide an additional increase in infarct-related artery (IRA) patency, but the large-scale mortality reduction trials evaluating this strategy are just getting under way. Recently, considerable attention has shifted away from the epicardial arteries to the microvasculature. Contemporary evidence suggests that epicardial patency does not necessarily translate to actual perfusion at the myocardial level. Techniques to evaluate beyond thrombolysis in myocardial infarction (TIMI) epicardial flow are now available and validated. In addition, there are promising treatments for the prevention or alleviation of certain forms of microvascular obstruction. This review attempts to clarify the confusion surrounding epicardial flow and "myocardial malperfusion" and to provide some insight into the next direction in acute myocardial infarction therapeutics.

Coronary cyclic flow variations following primary angioplasty is associated with poor short-term prognosis

AIMS

Recent studies have shown that coronary cyclic flow variations (CCFV) is a platelet-related phenomenon that occurred following reperfusion. Although CCFV predicts acute complications following thrombolytic therapy, its impact following percutaneous coronary interventions (PCI) has not been evaluated yet.

METHODS AND RESULTS

One hundred and thirty-one patients with ST-segment Elevation Myocardial Infarction (STEMI) who underwent PCI were included in the analysis. All patients have 24-hour ST-segment monitoring. The development of CCFV was defined as > or = 3 ST-segment transitions (> or =150 microV). We divided the population in two groups according to the presence (n=14, 10.6%) or absence (n=117) of CCFV. The relation between CCFV and 30-day major adverse cardiac events (MACE) was analyzed using a multivariate logistic regression model adjusting for age, sex, diabetes, smoking, anterior infarct, Killip class, and final TIMI flow grade. Clinical and angiographic characteristics were similar between the two groups. Higher 30-day mortality (21.4 vs. 3.8%, p=0.022) and MACE rates (42.9 vs. 10.7%, p=0.005) were seen in the CCFV group. Multivariate regression analysis revealed that patients with CCFV were at increased risk of 30-day MACE (adjusted RR 5.09; 95% CI 1.3-19.1; p=0.0016).

CONCLUSION

The presence of CCFV altered primary PCI may provide an early indication of insufficient myocardial perfusion and impending catastrophic outcome.

A review of clinical trials with eptifibatide in cardiology

Glycoprotein (GP) IIb/IIIa receptor antagonists inhibit the binding of ligands to activated platelet GP IIb/IIIa receptors and, therefore, prevent the formation of platelet thrombi. Additional antithrombin therapy should be given in connection with GP IIb/IIIa administration. Eptifibatide is a small heptapeptide, which is highly selective and rapidly dissociates from its receptor after cessation of therapy. In clinical trials (IMPACT-II and ESPRIT) concomitant administration of eptifibatide to patients undergoing percutaneous coronary intervention (PCI) reduced thrombotic complications. In the PURSUIT trial, in patients with non-ST-elevation acute coronary syndromes, eptifibatide, compared to placebo, significantly reduced the primary endpoint of death and nonfatal myocardial infarction at 30 days. In patients with STEMI eptifibatide has been studied as an adjunct to fibrinolysis and primary PCI; it improved epicardial flow and tissue reperfusion. Current studies are evaluating eptifibatide as upstream therapy in high-risk patients with NSTE-ACS, in the EARLY-ACS and in comparison with abciximab in patients with primary PCI in the EVA-AMI trial.

Preliminary experience with intravenous P2Y12 platelet receptor inhibition as an adjunct to reduced-dose alteplase during acute myocardial infarction: results of the Safety, Tolerability and Effect on Patency in Acute Myocardial Infarction (STEP-AMI) angiographic trial

BACKGROUND

Fibrinolytic therapy for acute myocardial infarction (AMI) results in normal flow in only about half of patients. Adjunctive treatment with potent antiplatelet and antithrombin agents increases arterial patency but is associated with excessive bleeding. Cangrelor (formerly AR-C69931MX) is a rapidly acting, specific antagonist of platelet aggregation via binding to the adenosine diphosphate P2Y12 receptor subtype. The aim of this study was to assess the safety and coronary artery patency of cangrelor as an adjunct to alteplase (tissue plasminogen activator [t-PA]).

METHODS

Patients with AMI received aspirin, heparin, and an intravenous infusion of either cangrelor alone, full-dose t-PA alone, or 1 of 3 doses of cangrelor along with half-dose t-PA. The primary end point was Thrombolysis in Myocardial Infarction (TIMI) grade 3 flow at 60 minutes. Secondary end points included TIMI frame count, TIMI myocardial perfusion grade, extent of ST-segment resolution, composite clinical events, and bleeding.

RESULTS

Ninety-two of planned 180 patients were enrolled. The combination of cangrelor and half-dose t-PA resulted in similar 60-minute patency as full-dose t-PA alone (55% vs 50%, P = not significant) and greater patency than with cangrelor alone (55% vs 18%, P < .05). The percentage of patients achieving >70% ST-segment resolution at 60 minutes tended to be greater with combination therapy than with either cangrelor or t-PA alone (28% vs 13%, P = .13 and 28% vs 14%, P = .30, respectively). Bleeding and adverse clinical events were comparable among the groups.

CONCLUSION

This first experience with the intravenous P2Y12 receptor inhibitor, cangrelor, suggests the potential of this compound as an adjunct to fibrinolysis during treatment of AMI.

Reperfusion strategies in acute ST-segment elevation myocardial infarction: a comprehensive review of contemporary management options

There are an estimated 500,000 ST-segment elevation myocardial infarction (STEMI) events in the U.S. annually. Despite improvements in care, up to one-third of patients presenting with STEMI within 12 h of symptom onset still receive no reperfusion therapy acutely. Clinical studies indicate that speed of reperfusion after infarct onset may be more important than whether pharmacologic or mechanical intervention is used. Primary percutaneous coronary intervention (PCI), when performed rapidly at high-volume centers, generally has superior efficacy to fibrinolysis, although fibrinolysis may be more suitable for many patients as an initial reperfusion strategy. Because up to 70% of STEMI patients present to hospitals without on-site PCI facilities, and prolonged door-to-balloon times due to inevitable transport delays commonly limit the benefit of PCI, the continued role and importance of the prompt, early use of fibrinolytic therapy may be underappreciated. Logistical complexities such as triage or transportation delays must be considered when a reperfusion strategy is selected, because prompt fibrinolysis may achieve greater benefit, especially if the fibrinolytic-to-PCI time delay associated with transfer exceeds approximately 1 h. Selection of a fibrinolytic requires consideration of several factors, including ease of dosing and combination with adjunctive therapies. Careful attention to these variables is critical to ensuring safe and rapid reperfusion, particularly in the prehospital setting. The emerging modality of pharmacoinvasive therapy, although controversial, seeks to combine the benefits of mechanical and pharmacologic reperfusion. Results from ongoing clinical trials will provide guidance regarding the utility of this strategy.

Early management of ST elevation myocardial infarction: a review of practice

The last two decades of the 20th century witnessed continuous evolution in the understanding of the pathophysiology of ST elevation myocardial infarction. In parallel, the management of these patients developed steadily throughout this time and into the early years of the 21st century. From humble beginnings involving oxygen therapy, bed rest and analgesia, the relative merits of different strategies to open 'infarct-related arteries' (IRAs) are now being debated: pharmacological reperfusion, mechanical reperfusion or a combination of both these modalities. The current understanding of the process of thrombotic occlusion of the coronary artery has led to the appreciation of the importance of not simply opening the IRA, but also maintaining its patency once opened. Considerable attention is now being afforded to the significant minority of patients who do not achieve early, complete myocardial reperfusion, despite restoration of adequate flow down the epicardial IRA. Those patients who fail to achieve myocardial reperfusion, either due to late presentation or failure of reperfusion therapy, and are left with permanent myocardial scarring can now be considered. This article critically appraises the recent and emerging evidence and clinical implications of the contemporary management of ST elevation myocardial infarction.

Experimental treatments for acute ischaemic stroke

Treatments for acute ischaemic stroke continue to evolve. Experimental approaches to restore cerebral perfusion include techniques to augment recanalising therapies, including combination of antiplatelet agents with intravenous thrombolysis, bridging therapy of combining intravenous with intra-arterial thrombolysis, and trials of new thrombolytic agents. Trials with MRI selection criteria are underway to expand the window of opportunity for thrombolysis. Sonothrombolysis and novel endovascular mechanical devices to retrieve or dissolve acute cerebral occlusions are being tested. Approaches to improve cerebral perfusion with other devices and induced hypertension are also being considered. Although numerous neuroprotective agents have not shown benefit, trials of hypothermia, magnesium, caffeinol, high doses of statins, and albumin are continuing. The findings of these randomised trials are anticipated to allow improved treatment of patients with acute stroke.

Early initiation of eptifibatide in the emergency department before primary percutaneous coronary intervention for ST-segment elevation myocardial infarction: results of the Time to Integrilin Therapy in Acute Myocardial Infarction (TITAN)-TIMI 34 trial

BACKGROUND

Early restoration of epicardial flow before primary percutaneous coronary intervention (PCI) for ST-segment elevation myocardial infarction (STEMI) has been associated with improved clinical outcomes.

METHODS

We hypothesized that early administration of the glycoprotein IIb/IIIa inhibitor eptifibatide in the emergency department (ED) would yield superior epicardial flow and myocardial perfusion before primary PCI compared with initiating eptifibatide after diagnostic angiography in the cardiac catheterization laboratory (CCL). Three hundred forty-three patients with STEMI were randomized to either early ED eptifibatide (n = 180) or CCL eptifibatide (n = 163).

RESULTS

The primary end point (pre-PCI corrected TIMI frame count) was significantly lower (faster flow) with early eptifibatide (77.5 +/- 32.2 vs 84.3 +/- 30.7, P = .049). The incidence of normal pre-PCI TIMI myocardial perfusion was increased among patients treated in the ED versus CCL (24% vs 14%, P = .026). There was no excess of TIMI major or minor bleeding among patients treated in the ED versus CCL (6.9% [12/174] vs 7.8% [11/142], P = NS).

CONCLUSION

A strategy of early initiation of eptifibatide in the ED before primary PCI for STEMI yields superior pre-PCI TIMI frame counts, reflecting epicardial flow, and superior TIMI myocardial perfusion compared with a strategy of initiating eptifibatide in the CCL without an increase in bleeding risk.

Role of abciximab in the treatment of coronary artery disease

Glycoprotein IIb/IIIa complex is a crucial membrane receptor for platelet aggregation, binding platelets to fibrinogen and establishing interplatelet bridges. This receptor is the common end point of the multiple activation pathways of a platelet. Antiplatelet agents, such as aspirin or thienopyridines, including ticlopidine and clopidogrel, inhibit one or more but not all, of these pathways. Inhibitors of the receptor are powerful platelet antiaggregants and include two groups of agents: non-competitive receptor blockers, such as abciximab, and competitive antagonists, such as tirofiban and eptifibatide. Abciximab is a monoclonal antibody that binds to the glycoprotein IIb/IIIa complex, thus blocking the interaction with fibrinogen. It is used for treatment of coronary artery disease, being well-studied in the setting of acute coronary syndromes and percutaneous coronary intervention, in which a rapid and effective antiaggregation is clinically important.

Initial Appraisal of Acute Coronary Syndromes

Acute coronary syndrome remains a daunting health care problem in the United States. One third of emergency department patients with chest pain will eventually have a diagnosis of acute coronary syndrome. During the past decade, there have been many advances in the treatment of acute coronary syndrome as well as a widespread movement in emergency medicine to streamline the process of its treatment. Goals of emergency department care include rapid identification of patients with acute myocardial infarction, exclusion of causes of nonischemic chest pain, stratification of patients with acute coronary ischemia into low-risk and high-risk groups, and initiation of pharmacologic treatments. These goals will be discussed in this review, with particular emphasis on pharmacologic treatments.

Antiplatelet Therapy in Neuroendovascular Therapeutics

Our understanding of the pharmacology of antiplatelet therapy continues to evolve rapidly. Although the existing data are primarily generated in the setting of interventional and preventative cardiology studies, these data may be extrapolated to guide the rational application of these agents in neuroendovascular procedures. Platelet function testing represents an increasingly available and practical method by which to verify the adequacy of therapy and guide clinical decision making. The optimal application of these agents will undoubtedly improve the risk profile of neuroendovascular procedures, increase the success rate of acute stroke intervention, and facilitate more effective secondary stroke prevention.