Prehospital initiation of tirofiban in patients with ST-elevation myocardial infarction undergoing primary angioplasty (On-TIME 2): a multicentre, double-blind, randomised controlled trial

[Myocardial infarction: Role of new antiplatelet agents]

Thienopyridines have become the cornerstone of treatment of percutaneous coronary intervention although no survival benefit has ever been shown with clopidogrel despite increasing loading doses. Newly developed P2Y(12) inhibitors are more potent, more predictable and have a faster onset of action than clopidogrel, characteristics that make them particularly attractive for high-risk PCI. Four new P2Y(12) inhibitors have been tested each of them having particular individual properties. Prasugrel is an oral prodrug leading to irreversible blockade of the P2Y(12) receptor and is approved worldwide for ACS PCI. Ticagrelor is a direct-acting and reversible inhibitor of the P2Y(12) receptor with potentially more pleiotropic effects. Cangrelor is an intravenous direct and reversible inhibitor of the P2Y(12) receptor providing the highest level of inhibition and elinogrel is an intravenous and oral P2Y(12) antagonist with a direct and reversible action. Both prasugrel and ticagrelor, opposed to clopidogrel, have shown that stronger P2Y(12) inhibition led respectively to significant 19 % and 16 % relative risk reduction of a similar primary endpoint combining cardiovascular death, nonfatal myocardial infarction, or nonfatal stroke. Both drugs showed a significant 0.6 % absolute excess of TIMI major bleeding not related to CABG surgery. The effect of these new compounds is prompt, predictable and powerful as compared to clopidogrel. Their net benefit is particularly marked in PCI for STEMI patients, in which there is no significant increase in major bleeding when compared with clopidogrel. However, because in clinical trials patients perceived to be at higher risk for bleeding usually are excluded, the risk of major and even fatal bleeding might even be higher in a "real-world" setting i.e. in the elderly patient with comorbidities.

Role of the paclitaxel-eluting stent and tirofiban in patients with ST-elevation myocardial infarction undergoing postfibrinolysis angioplasty: the GRACIA-3 randomized clinical trial

BACKGROUND

A catheter-based approach after fibrinolysis is recommended if fibrinolysis is likely to be successful in patients with acute ST-elevation myocardial infarction. We designed a 2x2 randomized, open-label, multicenter trial to evaluate the efficacy and safety of the paclitaxel-eluting stent and tirofiban administered after fibrinolysis but before catheterization to optimize the results of this reperfusion strategy.

METHODS AND RESULTS

We randomly assigned 436 patients with acute ST-elevation myocardial infarction to (1) bare-metal stent without tirofiban, (2) bare-metal stent with tirofiban, (3) paclitaxel-eluting stent without tirofiban, and (4) paclitaxel-eluting stent with tirofiban. All patients were initially treated with tenecteplase and enoxaparin. Tirofiban was started 120 minutes after tenecteplase in those patients randomly assigned to tirofiban. Cardiac catheterization was performed within the first 3 to 12 hours after inclusion, and stenting (randomized paclitaxel or bare stent) was applied to the culprit artery. The primary objectives were the rate of in-segment binary restenosis of paclitaxel-eluting stent compared with that of bare-metal stent and the effect of tirofiban on epicardial and myocardial flow before and after mechanical revascularization. At 12 months, in-segment binary restenosis was similar between paclitaxel-eluting stent and bare-metal stent (10.1% versus 11.3%; relative risk, 1.06; 95% confidence interval, 0.74 to 1.52; P=0.89). However, late lumen loss (0.04+/-0.055 mm versus 0.27+/-0.057 mm, P=0.003) was reduced in the paclitaxel-eluting stent group. No evidence was found of any association between the use of tirofiban and any improvement in the epicardial and myocardial perfusion. Major bleeding was observed in 6.1% of patients receiving tirofiban and in 2.7% of patients not receiving it (relative risk, 2.22; 95% confidence interval, 0.86 to 5.73; P=0.14).

CONCLUSIONS

This trial does not provide evidence to support the use of tirofiban after fibrinolysis to improve epicardial and myocardial perfusion. Compared with bare-metal stent, paclitaxel-eluting stent significantly reduced late loss but appeared not to reduce in-segment binary restenosis.

CLINICAL TRIAL REGISTRATION

URL: http://clinicaltrials.gov. Unique identifier: NCT00306228.

The optimal pharmacological formula for percutaneous coronary intervention

INTRODUCTION

Adjunctive pharmacotherapy is of key importance in determining the outcomes of percutaneous coronary intervention (PCI). In parallel, there has been an increasing body of evidence indicating that the aggressive management of coronary risk factors and changes in lifestyle behavior yield additional positive results in morbidity and mortality reductions. A stream of new data from randomized clinical trials has recently prompted the release of a focused update of the PCI guidelines, endorsing new recommendations on the use of antiplatelet drugs and parenteral anticoagulants.

AREAS COVERED

The aim of this manuscript is to provide an up-to-date overview of the current evidence on the use of adjunctive pharmacological therapy in patients undergoing revascularization, with focus on results of recent trials and future directions.

EXPERT OPINION

Given the availability of several pharmacological agents with different mechanisms of action, understanding whether a drug should or should not be prescribed, as well as individualizing the pharmacological formula to the patient's need and risk category, is pivotal to balance the safety and efficacy of adjunctive therapies for PCI. Studies on new antiplatelet agents and selective inhibitors of specific coagulation factors are likely to characterize the next years of research on interventional pharmacology.

[Antithrombotic treatments in acute coronary syndromes with persistent ST-segment elevation]

Pharmacological treatment is essential to limit myocardial damages of occluding thrombus feature of acute coronary syndromes with persistent ST-segment elevation. Thanks to its ease of use, it will always come first and accompany a mechanical treatment that will complement its action. Research has been very active in the last few years allowing the development of new agents, mostly oral antiplatelets and intravenous or subcutaneous antithrombins. Physicians implied in strategies of reperfusion have a responsibility to choose the most suitable combination therapy taking into account delays in care, kind of reperfusion and the patient himself. The highest level of recommendation indicative of a perfect agreement of the experts is rare in this area. Therefore, guidance is needed to help physicians. Admittedly the latest European recommendations merit of having taken positions often clear when several molecules are available in the same indication. They also underline the arrival, unexpected a few years ago, of oral treatment with rapid onset and efficacy perfectly suited to start an emergency antithrombotic treatment in acute coronary syndromes with persistent ST-segment elevation. Nevertheless, progress in terms of clinical efficacy is often modest, requiring a concomitant evaluation of each new molecule's safety, particularly the risks of bleeding.

The golden hour of prehospital reperfusion with triple antiplatelet therapy: a sub-analysis from the Ongoing Tirofiban in Myocardial Evaluation 2 (On-TIME 2) trial early initiation of triple antiplatelet therapy

BACKGROUND

It is known that the efficacy of thrombolytic therapy in ST-segment elevation myocardial infarction (STEMI) is highly time dependent with the best efficacy when given within the so-called golden hour. This analysis from the On-TIME 2 trial evaluated the efficacy of triple antiplatelet therapy on initial patency and ST-segment resolution (STR) in relation to time from symptom onset to first medical contact.

METHODS

The On-TIME 2 trial included 1,398 consecutive STEMI patients referred for primary percutaneous coronary intervention (PCI). Patients were randomized to dual (500 mg aspirin and 600 mg clopidogrel) or triple antiplatelet (500 mg aspirin, 600 mg clopidogrel, and tirofiban 25 μg/kg bolus and 0.15 μg/kg per minute maintenance infusion for 18 hours) pretreatment in the ambulance. Primary outcome of this sub-analysis was initial patency of the infarct-related vessel and STR before PCI according to time from symptom onset to first medical contact in quartiles. In addition, the incidence of aborted myocardial infarction, defined as the absence of a rise in creatinine kinase, was assessed.

RESULTS

Initial patency, STR before PCI, and the incidence of aborted myocardial infarction gradually increased with shorter time from symptom onset to first medical contact. Initial Thrombolysis in Myocardial Infarction flow was present in 21.2% in the total population and 26.2%, 21.5%, 18.1%, and 18.8% in the time quartiles, respectively (P for trend=.01). The incidence of complete STR pre-angiography was 16.6% in the total population and 23.4%, 18.2%, 14.7%, and 9.9% in the 4 quartiles, respectively (P for trend<.001). This was largely driven by the effect of triple antiplatelet therapy, which further improved initial patency and STR and led to a significantly higher incidence of aborted myocardial infarction (13.2% vs 8.7%, P=.011), especially in the patients with short duration of symptoms.

CONCLUSION

Antiplatelet pretreatment before primary PCI, including a glycoprotein IIb/IIIa blocker, seems to be most effective when given shortly after symptom onset. Further studies should be performed to test this hypothesis.

A comparison between upfront high-dose tirofiban versus provisional use in the real-world of non-selected STEMI patients undergoing primary PCI: Insights from the Zwolle acute myocardial infarction registry

BACKGROUND

Despite the proven benefit of glycoprotein IIb/IIIa blockers in patients with acute ST-segment elevation myocardial infarction (STEMI), there is still debate on the timing of administration of these drugs and whether all or only a selection of patients should be treated. We evaluated the effect of routine upfront versus provisional use of high-dose tirofiban (HDT) in a large real-world population of non-selected STEMI patients.

METHODS

Consecutive STEMI patients were registered in a single-centre dedicated database. Patients with upfront HDT therapy before first balloon inflation were compared with patients who received the drug on a provisional basis, after first balloon inflation. Initial TIMI flow of the infarct-related vessel and enzymatic infarct size and 30-day clinical outcome were assessed.

RESULTS

Out of 2679 primary PCI patients HDT was given upfront in 885 (33.0%) and provisionally in 812 (45.3%). Upfront as compared with provisional HDT showed higher initial patency (22.3 vs. 17.9%, p=0.006), smaller infarct size (1401 IU/l (IQR 609 to 2948) vs. 1620 (753 to 3132), p=0.03) and a lower incidence of death or recurrent MI at 30 days (3.3 vs. 5.1%, p=0.04) without an increase in TIMI bleeding (p=0.24). Upfront HDT independently predicted initial patency (odds ratio (OR) 1.47, 95% confidence interval (CI) 1.15 to 1.88, p=0.02), enzymatic infarct size (OR 0.70, 95% CI 0.56 to 0.86, p=0.001) and 30-day death or recurrent MI (OR 0.59, 95% CI 0.37 to 0.95, p=0.03).

CONCLUSION

Our findings support the use of upfront potent antiplatelet and antithrombotic therapy in STEMI patients and encourage further clinical investigations in this field. (Neth Heart J 2010;18:592-7.).

Prevention and treatment of microvascular obstruction-related myocardial injury and coronary no-reflow following percutaneous coronary intervention: a systematic approach

Microvascular obstruction (MVO) commonly occurs following percutaneous coronary interventions (PCI), may lead to myocardial injury, and is an independent predictor of adverse outcome. Severe MVO may manifest angiographically as reduced flow in the patent upstream epicardial arteries, a situation that is termed "no-reflow." Microvascular obstruction can be broadly categorized according to the duration of myocardial ischemia preceding PCI. In "interventional MVO" (e.g., elective PCI), obstruction typically involves myocardium that was not exposed to acute ischemia before PCI. Conversely "reperfusion MVO" (e.g., primary PCI for acute myocardial infarction) occurs within a myocardial territory that was ischemic before the coronary intervention. Interventional and reperfusion MVO have distinct pathophysiological mechanisms and may require individualized therapeutic approaches. Interventional MVO is triggered predominantly by downstream embolization of atherosclerotic material from the epicardial vessel wall into the distal microvasculature. Reperfusion MVO results from both distal embolization and ischemia-reperfusion injury within the subtended ischemic tissue. Management of MVO and no-reflow may be targeted at different levels: the epicardial artery, microvasculature, and tissue. The aim of the present report is to advocate a systematic approach to prevention and treatment of MVO in different clinical settings. Randomized clinical trials have studied strategies for prevention of MVO and no-reflow; however, the efficacy of measures for reversing MVO once no-reflow has been demonstrated angiographically is unclear. New approaches for prevention and treatment of MVO will require a better understanding of intracellular cardioprotective pathways such as the blockade of the mitochondrial permeability transition pore.

Does ST resolution achieved via different reperfusion strategies (fibrinolysis vs percutaneous coronary intervention) have different prognostic meaning in ST-elevation myocardial infarction? A systematic review

OBJECTIVE

We perform a systematic review to discern if ST resolution achieved via percutaneous coronary intervention (PCI) has a different meaning to that achieved via fibrinolysis.

BACKGROUND

Resolution of ST-segment elevation in acute myocardial infarction has been widely used as a surrogate for treatment success. A recent randomized study suggested that after primary PCI, the prognostic significance of ST resolution may have been overemphasized.

METHODS

Using the MEDLINE, COCHRANE, EMBASE, and PUBMED databases to search for the relevant papers, we analyze the data with a new ST-resolution score. ST-resolution groups of <30%, 30% to < 70%, and ≥ 70% are given scores of 1, 2, and 3 respectively, whereas ST-resolution groups reported as < 50% are scored as 1.5, and ≥ 50% scored as 2.5.

RESULTS

We identify 18 fibrinolysis cohorts (32,341 patients) and 5 PCI cohorts (1,913 patients). The mean ST-resolution score weighted for the number of patients in each cohort is 1.87 ± 0.15 for PCI and 1.66 ± 0.20 for fibrinolysis (P < .001). The raw combined 30-day mortality is 4.9% with fibrinolysis and 4.3% with PCI (P = .452 by Poisson regression). There is a linear relationship with lower 30-day mortality associated with higher ST-resolution score. The regression line for the PCI cohorts almost overlaps with that from the fibrinolysis cohorts. On multivariate regression, only ST-resolution score is significant in predicting 30-day mortality. When tested, the interaction term (treatment group × ST resolution score) is never a significant predictor (P > .25 in all models).

CONCLUSION

ST resolution after different reperfusion therapies has similar prognostic meaning.

Effectiveness and safety of glycoprotein IIb/IIIa inhibitors in patients with myocardial infarction undergoing primary percutaneous coronary intervention: a meta-analysis of observational studies

INTRODUCTION

Meta-analyses of randomized controlled trials (RCT) showed that glycoprotein IIb/IIIa inhibitors (GPI) are associated with reduced adverse events following primary percutaneous coronary revascularization (PCI). However, the external validity of RCTs is generally limited due to their restricted inclusion of patients. The objective of this study is to evaluate the effectiveness and safety of GPI, as adjuvant therapy for primary PCI in real-life patients with myocardial infarction with ST segment elevation (STEMI) from the general population.

METHODS

We identified all published peer-reviewed observational studies enrolling STEMI patients who underwent primary PCI. We performed random-effect meta-analyses to determine the association of GPI with major adverse events.

RESULTS

A total of 11 studies, enrolling 12,253 patients, were retained for this meta-analysis. GPI was associated with approximately 53% reduction in short-term mortality (odds ratio (OR): 0.47, 95% confidence intervals (CI): 0.32-0.68). There was a 62% reduction in long-term mortality associated with GPI (OR: 0.38, 95% CI: 0.30-0.50). GPI was associated with a 62% reduction in 30-day re-infarction (OR: 0.38, 95% CI: 0.24-0.60) and 42% reduction in 30-day repeat PCI (OR: 0.58, 95% CI: 0.36-0.94). A non-significant increase in major bleeding with GPI was observed with an OR of 1.55 (95% CI: 0.92-2.62).

CONCLUSIONS

GPI is associated with significant reductions in short-term mortality, re-infarction and repeat PCI, long-term mortality and an inconclusive increase in major bleeding. These results provide evidence for the safety and effectiveness of GPI as adjuvant therapy for primary PCI in real-life STEMI patients.

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.

Antithrombotic strategies in patients undergoing percutaneous coronary intervention for acute coronary syndrome

In patients undergoing percutaneous coronary intervention (PCI) for acute coronary syndrome (ACS), both periprocedural acute myocardial infarction and bleeding complications have been shown to be associated with early and late mortality. Current standard antithrombotic therapy after coronary stent implantation consists of lifelong aspirin and clopidogrel for a variable period depending in part on the stent type. Despite its well-established efficacy in reducing cardiac-related death, myocardial infarction, and stroke, dual antiplatelet therapy with aspirin and clopidogrel is not without shortcomings. While clopidogrel may be of little beneficial effect if administered immediately prior to PCI and may even increase major bleeding risk if coronary artery bypass grafting is anticipated, early discontinuation of the drug may result in insufficient antiplatelet coverage with thrombotic complications. Optimal and rapid inhibition of platelet activity to suppress ischemic and thrombotic events while minimizing bleeding complications is an important therapeutic goal in the management of patients undergoing percutaneous coronary intervention. In this article we present an overview of the literature on clinical trials evaluating the different aspects of antithrombotic therapy in patients undergoing PCI and discuss the emerging role of these agents in the contemporary era of early invasive coronary intervention. Clinical trial acronyms and their full names are provided in Table 1.

Perspectives on the 2009 focused updates on the management of ST-segment elevation myocardial infarction and percutaneous intervention

The American College of Cardiology, American Heart Association and Society of Angiography and Intervention recently published updated guidelines for management of patients with acute ST elevation myocardial infarction (STEMI) and percutaneous coronary intervention (PCI). In this article, we highlight the most important new recommendations and review the supporting data. Key aspects of these updates include guidance regarding the selection of antithrombotic therapy, caution in treating hyperglycemia with insulin, and opinion that insufficient data currently exist to recommend against concomitant administration of proton pump inhibitors and thienopyridines. New interventional recommendations include support for aspiration thrombectomy, drug eluting stents, PCI of unprotected left main disease, and use of fractional flow reserve to guide whether PCI is warranted in symptomatic patients with intermediate coronary stenoses. As these guidelines represent a synopsis of the most recently available data in the management of patients with STEMI, health care providers should familiarize themselves with these updated recommendations to ensure optimal treatment of their patients.

Upstream vs deferred administration of small-molecule glycoprotein IIb/IIIa inhibitors in primary percutaneous coronary intervention for ST-segment elevation myocardial infarction: insights from randomized clinical trials

BACKGROUND

Recent data have demonstrated similar outcomes for patients with ST-segment elevation myocardial infarction (STEMI) who undergo primary percutaneous coronary intervention (PCI) and are treated with small-molecule glycoprotein IIb/IIIa inhibitors (smGPIs) compared with those treated with abciximab. In the present study, a meta-analysis was performed to evaluate the relative safety and efficacy of upstream vs deferred administration of smGPIs in STEMI patients.

METHODS AND RESULTS

A total of 10 randomized clinical trials comparing upstream vs deferred administration of smGPIs in 2,724 patients were located in the electronic databases of the published literature. Preprocedural Thrombolysis In Myocardial Infarction Study (TIMI) grade 2 or 3 flow was present in 45.0% of the upstream group compared with 36.9% in the deferred group (odds ratio (OR) 1.40, P<0.001). However, no difference in post-procedural TIMI 3 flow (OR 0.87, P=0.25) was found between the groups. The 30-day mortality rate in the upstream group did not differ from that of the deferred group (OR 1.04, P=0.85). No significant difference was noted with respect to major bleeding complications (OR 1.25, P=0.38).

CONCLUSIONS

In STEMI patients scheduled for primary PCI, although early smGPIs treatment improved initial epicardial patency, no beneficial effect on post-procedural angiographic or 30-day clinical outcome was found. Thus, the current available data do not support the routine utilization of upstream smGPIs in STEMI patients treated with primary PCI.

Prehospital high-dose tirofiban in patients undergoing primary percutaneous intervention. The AGIR-2 study

BACKGROUND

Compared with administration in the catheterization laboratory, early treatment with glycoprotein IIb/IIIa inhibitors provides benefits to patients with ST-segment elevation myocardial infarction who undergo primary percutaneous intervention. Whether this benefit is maintained on top of a 600 mg loading dose of clopidogrel is unknown.

METHODS

In a multicentre, controlled, randomized study, 320 patients with ST-segment elevation myocardial infarction undergoing primary percutaneous coronary intervention received a high-dose bolus of tirofiban given either in the ambulance (prehospital group) or in the catheterization laboratory. The primary endpoint was a TIMI flow grade 2-3 of the infarct-related vessel at initial angiography. Secondary endpoints included ST-segment resolution 1h after percutaneous coronary intervention and peak serum troponin I concentration.

RESULTS

Tirofiban was administered 48 (95% confidence interval 21.4-75.0) min earlier in the prehospital group. At initial angiography, the combined incidence of TIMI 2-3 flow was 39.7% in the catheterization-laboratory group and 44.2% in the prehospital group (p=0.45). No difference was found on postpercutaneous intervention angiography or peak troponin concentration. Complete ST-segment resolution 60 min after the start of intervention was 55.4% in the catheterization-laboratory group and 52.6% in the prehospital group (p=0.32).

CONCLUSION

Prehospital initiation of high-dose bolus tirofiban did not improve significantly initial TIMI 2 or 3 flow of the infarct-related artery or complete ST-segment resolution after coronary intervention compared with initiation of tirofiban in the catheterization laboratory (NCT00538317).

Tirofiban for myocardial infarction

IMPORTANCE OF THE FIELD

Inhibition of platelet aggregation plays a key role in treatment of coronary artery disease.

AREAS COVERED IN THIS REVIEW

Studies on the effects of tirofiban in patients with either ST elevation or non-ST elevation myocardial infarction are reviewed.

WHAT THE READER WILL GAIN

Tirofiban is a small-molecule glycoprotein IIb/IIIa receptor inhibitor. If discontinued, the action of tirofiban is faster reversed as abciximab. The dose varied between low (bolus of 0.4 microg/kg administered over 30 min followed by an infusion of 0.10 microg/kg/min), intermediate (bolus of 10 microg/kg administered over 3 min followed by an infusion of 0.15 microg/kg/min) and high (bolus of 25 microg/kg administered over 3 min followed by an infusion of 0.15 microg/kg/min). The high-dose administration especially may be beneficial in patients with ST elevation myocardial infarction undergoing primary percutaneous coronary intervention (PCI). There is no indication for tirofiban in patients treated with thrombolysis. Patients with non-ST elevation myocardial infarction requiring PCI are most likely to benefit from tirofiban if they have ongoing ischemia and/or dynamic ECG changes. The risk of serious bleeding with tirofiban is low and there is a very low risk of thrombocytopenia.

TAKE HOME MESSAGE

Use of tirofiban for myocardial infarction is effective and has an acceptable safety profile.

Effect of early, pre-hospital initiation of high bolus dose tirofiban in patients with ST-segment elevation myocardial infarction on short- and long-term clinical outcome

OBJECTIVES

The purpose of this trial was to study the effect of a high bolus dose (HBD) of tirofiban on clinical outcome in patients undergoing primary percutaneous coronary intervention for ST-segment elevation myocardial infarction (STEMI).

BACKGROUND

The On-TIME 2 (Ongoing Tirofiban In Myocardial infarction Evaluation 2) placebo-controlled, double-blind, randomized trial showed that early administration of HBD tirofiban in the ambulance improves ST-segment resolution in patients with STEMI undergoing primary percutaneous coronary intervention. The effect of early tirofiban treatment on clinical outcome is unclear.

METHODS

The On-TIME 2 trial consisted of 2 phases: an open-label phase, followed by a double-blind, placebo-controlled phase. STEMI patients were randomized to either HBD tirofiban or no tirofiban (phase 1) or placebo (phase 2) in addition to aspirin, heparin, and high-dose clopidogrel. The protocol pre-specified a pooled analysis of the 2 study phases to assess the incidence of major adverse cardiac events at the 30-day follow-up and on total mortality at the 1-year follow-up.

RESULTS

During a 3-year period, 1,398 patients were randomized, 414 in phase 1 and 984 in phase 2. Major adverse cardiac events at 30 days were significantly reduced (5.8% vs. 8.6%, p = 0.043). There was a strong trend toward a decrease in mortality (2.2% vs. 4.1%, p = 0.051) in patients who were randomized to tirofiban pre-treatment, which was maintained during the 1-year follow-up (3.7% vs. 5.8%, p = 0.08). No clinically relevant difference in bleeding was observed.

CONCLUSIONS

Early, pre-hospital initiation of HBD tirofiban, in addition to high-dose clopidogrel, improves the clinical outcome after primary percutaneous coronary intervention in patients with STEMI. (Ongoing 2b/3a inhibition In Myocardial infarction Evaluation; ISRCTN06195297).

Utilisation of emergency medical service among Singapore patients presenting with ST-segment elevation myocardial infarction: prevalence and impact on ischaemic time

BACKGROUND

Previous studies in Western countries found that the emergency medical service (EMS) was under-used in patients with myocardial infarction.

AIM

We sought to determine the prevalence of immediate EMS utilisation among Singapore patients presenting with ST-segment elevation myocardial infarction (STEMI), and correlated the use of the EMS with the symptom-to-balloon and door-to-balloon times.

METHODS

We studied 252 patients admitted with STEMI to our institution from August 2008 to September 2009. Information regarding demographic characteristics, whether EMS was used, reperfusion procedural details and mortality rates were collected prospectively.

RESULTS

Among the recruited patients, 89 (35.3%) used the EMS (EMS group) and 163 (64.7%) did not use the EMS (non-EMS group). In the latter group, 98 (60.1%) arrived at our institution through their own transport, 56 (34.4%) first consulted general practitioners, and 9 (5.5%) initially consulted another hospital without acute medical services. Among the 245 (out of 252, 97.2%) patients who received percutaneous coronary intervention (PCI), the EMS group was more likely to undergo primary PCI (P= 0.003) while the non-EMS group was more likely to undergo non-urgent PCI (P= 0.002). In patients who underwent primary PCI, the EMS group had a shorter symptom-to-balloon time (average difference 81.6 min, P= 0.002). The door-to-balloon time was similar for both groups.

CONCLUSION

Despite the availability of a centralised EMS, 64.7% of patients with STEMI did not contact EMS at presentation. These patients were less likely to receive primary PCI and had a significantly longer symptom-to-balloon time.

ST-segment resolution prior to primary percutaneous coronary intervention is a poor indicator of coronary artery patency in patients with acute myocardial infarction

BACKGROUND

The prognostic value of ST-segment resolution (STR) after initiation of reperfusion therapy has been established by various studies conducted in both the thrombolytic and mechanic reperfusion era. However, data regarding the value of STR immediately prior to primary percutaneous coronary intervention (PCI) to predict infarct-related artery (IRA) patency remain limited. We investigated whether STR prior to primary PCI is a reliable, noninvasive indicator of IRA patency in patients with ST-segment elevation myocardial infarction (STEMI).

METHODS

The study population consisted of STEMI patients who underwent primary PCI at our institution between 2000 and 2007. STR was analyzed in 12-lead electrocardiograms recorded at first medical contact and immediately prior to primary PCI and defined as complete (> or =70%), partial (70%- 30%), or absent (<30%).

RESULTS

In 1253 patients with a complete data set, STR was inversely related to the probability of impaired preprocedural flow (P(for trend) < 0.001). Although the sensitivity of incomplete (<70%) STR to predict a Thrombolysis in Myocardial Infarction (TIMI) flow of <3 was 96%, the specificity was 23%, and the negative predictive value of incomplete STR to predict normal coronary flow was only 44%.

CONCLUSIONS

This study establishes the correlation between STR prior to primary PCI and preprocedural TIMI flow in STEMI patients treated with primary PCI. However, the negative predictive value of incomplete STR for detection of TIMI-3 flow is only 44% and therefore should not be a criterion to refrain from immediate coronary angiography in STEMI patients.

Guideline adherence for antithrombotic therapy in acute coronary syndrome: an overview in Dutch hospitals

OBJECTIVE

To assess current Dutch antithrombotic treatment strategies for acute coronary syndrome (ACS) in light of the current European Society of Cardiology (ESC) guidelines.

METHODS

For every Dutch hospital with a coronary care unit (CCU) (n = 93) a single cardiologist was interviewed concerning heparin, thienopyridine and GP IIb/IIIa inhibitor (GPI) treatment. In each hospital, we randomly approached one cardiologist assuming equal policy among physicians employed at the same hospital.

RESULTS

The response rate was 90%. In 59% of hospitals, treatment of ST-elevation myocardial infarction (STEMI) occurred according to the 2008 ESC STEMI guideline, with unfractionated heparin. In contrast, although not recommended, low-molecular-weight heparin (LMWH) was used in 39% (enoxaparin 19%, dalteparin 12%, nadroparin 8%). In non-STEMI, low-molecular-weight-heparins (LMWHs) were used in 97% of all hospitals. Fondaparinux, agent of choice in a noninvasive strategy for the treatment of non-STEMI, was applied in only 2% of hospitals. Although recommended by the ESC, dose adjustment of LMWH therapy for patients with renal failure is not applied in 71% of hospitals. Likewise, LMWH dose adjustment is not applied for patients aged over 75 years in 92% of hospitals.

CONCLUSION

To a great extent treatment of ACS in the Netherlands occurs according to ESC guidelines. Additional benefit may be achieved by routine dose adjustment of LMWH for patients with renal insufficiency and aged >75 years, since these patients are at high risk of bleeding complications secondary to antithrombotic treatment. Periodical evaluation of real-life practice may improve guideline adherence and potentially improve clinical outcome. (Neth Heart J 2010;18:291-9.).

Early administration of small-molecule glycoprotein IIb/IIIa inhibitors before primary percutaneous coronary intervention for ST-elevation myocardial infarction: insights from randomized clinical trials

BACKGROUND

Current guidelines recommend abciximab (ReoPro) as an adjunctive pharmacologic agent to primary percutaneous coronary intervention (PPCI) for patients with ST-segment elevation myocardial infarction (STEMI). However, small-molecule glycoprotein IIb/IIIa receptor inhibitors (smGPIs), such as tirofiban (aggrastat) and eptifibatide (integrilin), are more commonly used in clinical practice.

METHOD AND RESULT

We performed a meta-analysis to compare the safety and efficacy of early administration of smGPIs versus abciximab before PPCI. The literature was scanned by formal searches of electronic databases from January 1990 to April 2009. A total of 4 randomized trials meeting the prespecified criteria were analyzed, involving 2040 patients. Rates of initial Thrombolysis in Myocardial Infarction Study (TIMI) 3 flow before procedure as well as complete ST resolution after PPCI were not inferior in smGPIs group compared with abciximab group (odds ratio [OR] 1.12, P = .31; and OR 1.05, P = .66, respectively). There was no significant difference in the risk of 30-day (OR 0.83, P = .54) or 8-month mortality (OR 0.78, P = .43) between smGPI and abciximab group. With regard to the safety end points, neither the major nor the minor bleeding complications in smGPIs group differed significantly from those in abciximab group (OR 1.32, P = .43; and OR 0.82, P = .37, respectively).

CONCLUSION

This meta-analysis shows that early administration of smGPIs is as effective as abciximab in the setting of PPCI for STEMI, without an increase in bleeding complications.

[STEMI guidelines 2008--Do they influence today's myocardial infarction treatment strategies in rural areas?]

2008 new guidelines for the management of patients with ST-elevation myocardial infarction were published by the European Society of Cardiology. For daily clinical practice, changes in recommendations concerning the preferred revascularization therapy according to different time delays are of great interest. This review focuses on possible implications of these new guidelines on the choice of reperfusion strategies in rural areas.

Achieving routine sub 30 minute door-to-balloon times in a high volume 24/7 primary angioplasty center with autonomous ambulance diagnosis and immediate catheter laboratory access

BACKGROUND

In primary angioplasty (primary percutaneous coronary intervention [PPCI]) for acute myocardial infarction, institutional logistical delays can increase door-to-balloon times, resulting in increased mortality.

METHODS

We moved from a thrombolysis (TL) service to 24/7 PPCI for direct access and interhospital transfer in April 2004. Using autonomous ambulance diagnosis with open access to the myocardial infarction center catheter laboratory, we compared reperfusion times and clinical outcomes for the final 2 years of TL with the first 3 years of PPCI.

RESULTS

Comparison was made between TL (2002-2004, n = 185) and PPCI (2004-2007, n = 704); all times are medians in minutes (interquartile range): for TL, symptom to needle 153 (85-225), call to needle 58 (49-73), first professional contact (FPC) to needle 47 (39-63), door to needle 18 (12-30) (mortality: 7.6% at 30 days, 9.2% at 1 year); for interhospital transfer PPCI (n = 227), symptom to balloon 226 (175-350), call to balloon 135 (117-188), FPC to balloon 121 (102-166), first door-to-balloon 100 (80-142) (mortality: 7.0% at 30 days, 12.3% at 1 year); for direct-access PPCI (n = 477), symptom to balloon 142 (101-238), call to balloon 79 (70-93), FPC to balloon 69 (59-82), door to balloon 20 (16-29) (mortality: 4.6% at 30 days, 8.6% at 1 year). There was no difference between direct-access PPCI and TL times for symptom to needle/balloon. Direct-access PPCI was significantly quicker for the group than in-hospital thrombolysis for door to needle/balloon times due to the lack of any long wait patients (P < .001).

CONCLUSIONS

Interhospital transfer remains slow even with rapid institutional door-to-balloon times. With autonomous ambulance diagnosis and open access direct to the catheter laboratory, a median door-to-balloon time of <30 minutes day and night was achieved, and >95% of patients were reperfused within 1 hour.

Magnitude and consequences of missing the acute infarct-related circumflex artery

Emergent reperfusion strategies are integral to providing optimal patient outcomes in the setting of acute coronary artery occlusion. ST-segment elevation on the surface 12-lead electrocardiogram, although specific as a surrogate marker, is insensitive to acute posterior circulation coronary artery occlusion. Studies of non-ST-segment elevation acute coronary syndrome consistently identify patients who have epicardial vessel occlusion at the time of initial angiography, which is usually delayed for hours or days after the initial presentation. In addition, studies of ST-segment elevation myocardial infarction often divulge a disparity in identification of the infarct-related artery, with an underrepresentation of the left circumflex artery. Taken together, it is likely that many patients with left circumflex artery occlusion are "missed" during the early phases of myocardial infarction due to the electrocardiographically silent nature of the posterior territory, resulting in delayed myocardial salvage and worse cardiovascular outcomes. In this review, we report on the magnitude of missed left circumflex infarction and the consequences of this delay in diagnosis. We review the electrocardiographic findings of left circumflex occlusion and discuss strategies to enhance early identification. Heightened awareness of this clinical scenario and the available methods to avoid missing this elusive diagnosis are imperative in our quest to further improve the outcomes of patients with acute myocardial infarction.