Impact of pretreatment with clopidogrel on initial patency and outcome in patients treated with primary percutaneous coronary intervention for ST-segment elevation myocardial infarction: a systematic review

Prehospital triage of patients with suspected non-ST-segment elevation acute coronary syndrome: Rationale and design of the TRIAGE-ACS study

BACKGROUND

Patients with suspected non-ST-segment elevation acute coronary syndrome (NSTE-ACS) are currently transported and admitted to the nearest emergency department (ED) for risk stratification, diagnostic workup and treatment. Although such patients with NSTE-ACS can benefit from direct transfer to a PCI center for early invasive treatment, no reliable prehospital triage tools are available. Recently, the PreHEART score has been validated in the PreHEART study for prehospital triage of patients with suspected NSTE-ACS.

METHODS

The primary objective of the TRIAGE-ACS study, a prospective cohort study, is to determine whether prehospital triage using the PreHEART score can significantly reduce time from first medical contact to final diagnostics and revascularization in patients in need of coronary revascularization. The first cohort (control cohort; n = 500) is observatory and is used as a reference group for the second cohort. In the second cohort (interventional cohort; n = 500) patients are stratified in the ambulance for direct transfer to either a PCI or a non-PCI center, based on the PreHEART score. These two cohorts will be compared with each other. In total, 1000 patients will be included. Follow-up for endpoints will be performed by reviewing the medical record after 30 days, 1 year, and 2 years.

CONCLUSION

The TRIAGE-ACS study is the first prospective study to investigate the impact of prehospital triage using the PreHEART score on time to final invasive diagnostics and treatment in patients with NSTE-ACS in need of revascularization by transferring high risk patients directly to a PCI center and patients at a low risk of having an NSTE-ACS to a non-PCI center. Such triage strategy could potentially result in optimization of regional care for all ACS patients.

Bivalirudin Versus Heparin During Percutaneous Coronary Intervention in Patients With Acute Myocardial Infarction

Background

The aim of the study was to compare the efficacy and safety of bivalirudin versus unfractionated heparin (UFH) in patients with acute myocardial infarction who undergo percutaneous coronary intervention (PCI). Earlier trials comparing bivalirudin and UFH during PCI demonstrated that bivalirudin caused less bleeding with more stent thrombosis. Since then, adjunct antiplatelet strategies have evolved. Improved upstream platelet inhibition with potent P2Y12 inhibitors decreased the need for routine glycoprotein IIb/IIIa inhibitor (GPI), resulting in similar outcomes among UFH and bivalirudin. Therefore, the role of bivalirudin in modern PCI practices is questionable.

Methods

We utilized Cochrane Review Manager (RevMan) 5.3 to perform a meta-analysis of seven randomized controlled trials (RCTs) with 22,844 patients to compare bivalirudin to UFH in patients with acute myocardial infarction requiring revascularization.

Results

There was no difference between bivalirudin and UFH regarding major adverse cardiac events (MACE), risk ratio (RR) 0.99, 95% confidence interval (CI) 0.87 - 1.12; P = 0.83) or cardiovascular mortality (RR 0.87, 95% CI 0.71 - 1.07; P = 0.18). Bivalirudin increased acute stent thrombosis (RR 2.77, 95% CI 1.49 - 5.13; P = 0.001), which was only significant among ST-elevation myocardial infarction (STEMI) only trials. Bivalirudin caused less major bleeding (RR 0.66, 95% CI 0.49 - 0.90; P = 0.007), which was negated when GPI was used provisionally (RR 0.93, 95% CI 0.64 - 1.33; P = 0.67).

Conclusions

Among patients with acute myocardial infarction who underwent PCI, bivalirudin and UFH demonstrated similar MACE and cardiovascular mortality. Bivalirudin increased acute stent thrombosis, which was more remarkable among STEMI. Bivalirudin decreased major bleeding, but this benefit was negated when GPI was used provisionally.

Safety of Ticagrelor Compared to Clopidogrel after Prehospital Initiation of Treatment

Objectives  The objective of this registry was to study the safety of prehospital initiation of ticagrelor compared with clopidogrel. Background  Ticagrelor has replaced clopidogrel in many hospitals as the routinely used antiplatelet drug in patients with ST-segment elevation myocardial infarction (STEMI). Nevertheless, in the PLATelet inhibition and patient Outcomes (PLATO) trial, ticagrelor was associated with an increase in non-CABG (non-coronary artery bypass grafting)-related major bleeding. Data comparing the safety of ticagrelor and clopidogrel after prehospital initiation of treatment are not available. Methods  A retrospective, multicenter registry was performed. Selection criteria were the administration of a prehospital loading dose of ticagrelor or clopidogrel according to the ambulance STEMI treatment protocol and the presentation to a percutaneous coronary intervention-capable hospital in our region between January 2011 and December 2012. Follow-up was performed using the electronic patient files for the time period between the antiplatelet loading dose and hospital discharge. The data were analyzed using a primary bleeding end point (any bleeding) and a secondary thrombotic end point (all-cause mortality, spontaneous myocardial infarction, definite stent thrombosis, stroke, or transient ischemic attack). Results  Data of 304 clopidogrel-treated and 309 ticagrelor-treated patients were available for analysis. No significant difference in bleeding rate was observed between both groups, using univariate (17.8 vs. 20.1%; p  = 0.47; odds ratio, 1.16 [95% confidence interval, 0.78-1.74]) and multivariate ( p  = 0.42) analysis. Also for the secondary thrombotic end point (6.3 vs. 4.9%, p  = 0.45), no significant differences were observed. Conclusion  In this real-world registry, no significant differences in bleeding or thrombotic event rate were found between ticagrelor and clopidogrel after prehospital initiation of treatment.

Early ambulance initiation versus in-hospital initiation of high dose clopidogrel in ST-segment elevation myocardial infarction

Pre-hospital infarct diagnosis gives the opportunity to start anti-platelet and anti-thrombotic agents before arrival at the PCI centre. However, more evidence is necessary to demonstrate whether high dose (HD) clopidogrel (600 mg) administered in the ambulance is associated with improved initial patency of the infarct related vessel (IRV) and/or clinical outcome compared to in-hospital initiation of HD clopidogrel. From 2001 until 2009 all consecutive ST-Segment Elevation Myocardial Infarction (STEMI) patients who underwent pre-hospital diagnosis and therapy in the ambulance were prospectively included in our single-centre cohort study. We compared initial patency of the IRV and clinical outcome in patients treated from 2001 until June 2006 (in-hospital HD clopidogrel) with patients treated from July 2006 until 2009 (ambulance HD clopidogrel). A total of 2,475 patients with STEMI were registered; of these 1,110 (44.8%) received in-hospital HD clopidogrel and 1,365 (55.2%) received ambulance HD clopidogrel. Ambulance HD clopidogrel was not independently associated with initial patency (TIMI-2/3-flow pre-PCI (odds ratio: 1.18, 95% confidence interval [CI] 0.96–1.44); however, it was associated with fewer recurrent myocardial infarctions at 30 days (hazard ratio [HR]: 0.45, 95% CI 0.22–0.93) and at one year (HR: 0.45, 95% CI 0.25–0.80). No difference in TIMI 2/3 flow post-PCI, major bleeding, mortality, MACE – and the combination of mortality and recurrent myocardial infarction at 30-days and at one year was present between the two groups. In conclusion, early in-ambulance as compared to in-hospital initiation of HD clopidogrel in STEMI patients did not improve initial patency of the IRV or clinical outcome, except for a reduction of recurrent myocardial infarction. Therefore, early administration of HD clopidogrel seems to have net clinical benefit for these patients .

Impact of acute infarct-related artery patency before percutaneous coronary intervention on 30-day outcomes in patients with ST-segment elevation myocardial infarction treated with primary percutaneous coronary intervention in the EUROMAX trial

AIMS

Early infarct-related artery patency has been associated with improved outcomes in patients with ST-segment elevation myocardial infarction treated with primary percutaneous coronary intervention. However, it is unknown whether this relationship persists in contemporary practice with pre-hospital initiation of treatment, use of novel P2Y₁₂ inhibitors and frequent use of drug-eluting stents. The purpose of the study was to determine the impact of early infarct-related artery patency on outcomes in the contemporary EUROMAX trial.

METHODS AND RESULTS

A total of 2218 patients were enrolled. The current analysis was done on 1863 patients who underwent percutaneous coronary intervention and had infarct-related artery patency data. Thirty-day outcomes were compared according to infarct-related artery flow before percutaneous coronary intervention (Thrombolysis in Myocardial Infarction (TIMI) flow 0/1 vs. TIMI flow 2/3), and interaction with antithrombotic strategy was examined. A patent infarct-related artery (TIMI flow 2/3) was present in 707 patients (37.9%) and was associated with a higher rate of final TIMI 3 flow grade (98.9 vs. 92.6%; p<0.001). At 30 days, a patent infarct-related artery was associated with lower rates of cardiac death (1.3% vs. 2.9%; p=0.026) and the composite of death or myocardial infarction (2.7% vs. 4.6%; p=0.039). There were no interactions between antithrombotic treatment and the impact of infarct-related artery patency on cardiac death, myocardial infarction, or the composite of death or myocardial infarction (Breslow-Day interaction p-values of 0.21, 0.33 and 0.46, respectively).

CONCLUSION

Despite evolution in primary percutaneous coronary intervention strategies, early infarct-related artery patency is still associated with higher procedural success and improved clinical outcomes. The choice of antithrombotic strategy did not interact with the benefits of a patent infarct-related artery at presentation.

Clinical pathways and management of antithrombotic therapy in patients with acute coronary syndrome (ACS): a Consensus Document from the Italian Association of Hospital Cardiologists (ANMCO), Italian Society of Cardiology (SIC), Italian Society of Emergency Medicine (SIMEU) and Italian Society of Interventional Cardiology (SICI-GISE)

Antiplatelet therapy is the cornerstone of the pharmacologic management of patients with acute coronary syndrome (ACS). Over the last years, several studies have evaluated old and new oral or intravenous antiplatelet agents in ACS patients. In particular, research was focused on assessing superiority of two novel platelet ADP P2Y12 receptor antagonists (i.e., prasugrel and ticagrelor) over clopidogrel. Several large randomized controlled trials have been undertaken in this setting and a wide variety of prespecified and post-hoc analyses are available that evaluated the potential benefits of novel antiplatelet therapies in different subsets of patients with ACS. The aim of this document is to review recent data on the use of current antiplatelet agents for in-hospital treatment of ACS patients. In addition, in order to overcome increasing clinical challenges and implement effective therapeutic interventions, this document identifies all potential specific care pathway for ACS patients and accordingly proposes individualized therapeutic options.

Distance-related Differences in Critical Times, Protocol Activation and Mortality in a Regional STEMI Network

Introduction: The aim of the study was to assess the differences in critical network times and mortality in STEMI patients presenting to hospitals in the same STEMI network, but located at different distances from the pPCI center.

Methods: Four-hundreed sixteen patients with STEMI were studied. Group 1: 101 patients presenting to any of the six regional hospitals in the network located at less than 70 km from the pPCI center, with a maximum transport time of 30 minutes. Group 2: 81 patients presenting to any of the three territorial hospitals in the network located at 70–150 km from the pPCI center, with a transport time between 30 and 70 minutes. Group 3: 93 patients presenting to any of the four territorial hospitals in the network located at 150–250 km from the pPCI center, with a transport time between 70 and 150 minutes. Group 4: 141 patients presenting directly to the emergency room of the pPCI center. The following time intervals were recorded: presentation time (PT), from the onset of symptoms to arrival at the pPCI center; protocol initiation time (PIT), from arrival at the pPCI center to STEMI protocol initiation; ischemic time (IT), from the onset of symptoms to repermeabilisation; door to balloon time (DTB), from arrival in the pPCI center to balloon.

Results: PT showed no significant difference between the groups – 183.08 ± 25.2 minutes vs. 199.1 ± 32.4 minutes vs. 166.7 ± 42.5 minutes vs. 161.91 ± 36.8 minutes, respectively (p=0.4). PIT was significantly lower in Group 3 (61.66 ± 15.4 minutes in Group 3 vs. 92 ± 11.5 minutes in Group 2 vs. 107.4 ± 12.5 minutes in Group 1, p = 0.002). DTB time was significantly longer for patients presenting directly to the pPCI center compared to those arriving from Zone 1, 2 or 3 hospitals, 86.96 ± 11.6 minutes vs. 52.27 ± 11.2 minutes vs. 39.94 ± 10.3 minutes vs. 43.9 ± 5.3 minutes, p <0.001). Despite the differences in distance to the pPCI center, there was no significant difference in total IT between the groups (Group 1, 344.6 ± 53.4 minutes; Group 2, 369.3 ± 42.6 minutes; Group 3, 366.65 ± 36.4 minutes; and 340.2 ± 26.9 minutes in the pPCIcenter, p = 0.2), and this was reflected in similar rates of mortality (Group 1, 3.9%; Group 2, 3.7%; Group 3, 3.2%; and 3.5% in the pPCI center).

Conclusion: A well organized STEMI network can shorten protocol initiation and DTB times, achieving similar ischemic times and resulting in similar mortality rates with the centers located closer to the pPCI center. Early activation of the STEMI protocol could lead to superior results even in areas situated at longer distances from the pPCI center.

Factors Associated With Infarct-Related Artery Patency Before Primary Percutaneous Coronary Intervention for ST-Elevation Myocardial Infarction (from the FAST-MI 2010 Registry)

Early infarct-related artery (IRA) patency is associated with better clinical outcomes in patients with ST-elevation myocardial infarction (STEMI). Using the French Registry of ST-elevation and non-ST-elevation Myocardial Infarction (FAST-MI) 2010 registry, we investigated factors related to IRA patency (thrombolysis in myocardial infarction [TIMI] 2/3 flow) at the start of procedure in patients admitted for primary percutaneous coronary intervention. FAST-MI 2010 is a nationwide French registry including 4,169 patients with acute MI. Of 1,452 patients with STEMI with primary percutaneous coronary intervention, 466 (32%) had TIMI 2/3 flow of IRA before the procedure. Mean age (62 ± 14 years in both groups), Global Registry of Acute Coronary Event score (141 ± 31 vs 142 ± 34), and time from onset to angiography (472 ± 499 vs 451 ± 479 minutes) did not differ according to IRA patency (TIMI 2/3 vs TIMI 0/1). Using multivariate logistic regression analysis, IRA patency was more frequently found in patients having called earlier (time from onset to electrocardiogram [ECG] <120 minutes; odds ratio [OR] 1.49; 95% confidence interval [CI] 1.17 to 1.89), or receiving rapid-onset of action (prasugrel or glycoprotein IIb-IIIa) antiplatelet therapy in the prehospital setting (OR 1.59, 95% CI 1.14 to 2.21). Increasing time from diagnostic ECG to angiography was also associated with IRA patency (>90 minutes; OR 1.37, 95% CI 1.08 to 1.75). In conclusion, preprocedural IRA patency is observed in one third of patients with STEMI, it is more frequently found in patients having received fast-acting antiplatelet therapy before angiography, and in patients having called early. Higher IRA patency with increasing time delays from qualifying ECG to angiography suggests an additional role of spontaneous or medication-mediated fibrinolysis.

Ticagrelor, prasugrel, or clopidogrel in ST-segment elevation myocardial infarction: which one to choose?

INTRODUCTION

Clopidogrel, prasugrel, and ticagrelor are the currently available oral P2Y12 inhibitors for the treatment of ST-segment elevation myocardial infarction (STEMI), in association with aspirin. These agents bind the P2Y12 platelet receptor and thus inhibit platelet aggregation. Large randomized clinical trials have provided efficacy and safety data on P2Y12 inhibitors in STEMI patients.

AREAS COVERED

This review focuses on key pharmacologic and clinical aspects of clopidogrel, prasugrel, and ticagrelor, highlighting their differences. Results from the main clinical trials are discussed, as well as the current STEMI guideline recommendations, to help inform agent selection for patients presenting with STEMI.

EXPERT OPINION

Clinical trials studying newer P2Y12 inhibitors with increased potency have shown further reduction of cardiovascular events compared with clopidogrel, therefore suggesting the use of ticagrelor or prasugrel as a first-line agent for STEMI treatment. There are still clinical situations - such as fibrinolysis, high risk of bleeding, use of oral anticoagulant, and financial hurdles - in which clopidogrel maintains a role in the treatment of STEMI.

A pharmacodynamic comparison of 5 anti-platelet protocols in patients with ST-elevation myocardial infarction undergoing primary PCI

Background

Despite advances in anti-platelet treatments, there still exists an early increase in both ischemic as well as bleeding events following primary PCI in patients with ST-elevation myocardial infarction (STEMI). Platelet inhibition data of different anti-platelet treatments in the acute phase of a myocardial infarction might offer some insight into these problems. The aim of this study was to evaluate the pharmacodynamic profile of 5 different anti-platelet treatments in the acute phase of STEMI in patients undergoing primary PCI.

Methods

A total of 223 STEMI patients undergoing primary PCI were prospectively included. Patients received either pre-hospital clopidogrel only, pre-hospital clopidogrel followed by prasugrel switch in the cath lab, prasugrel treatment only, pre-hospital clopidogrel followed by ticagrelor switch in the cath lab or pre-hospital ticagrelor only. Platelet reactivity was measured serially using vasodilator-stimulated phosphoprotein (VASP).

Results

Patients receiving pre-hospital clopidogrel followed by prasugrel switch showed similar platelet inhibition data as patients receiving prasugrel only, with more than 90% being good responders the day after PCI. Average time from prasugrel administration to a VASP value of <50% was 1.5 hours. In patients receiving pre-hospital ticagrelor, 50% were good responders at completion of PCI and average time to a VASP-value of <50% was 2.3 hours. Only 32% of patients receiving clopidogrel only were responders the day after PCI.

Conclusions

Switching from an upstream bolus dose of clopidogrel to prasugrel at the time of PCI, appeared as a safe and feasible option with no tendency for overshoot or attenuation of platelet inhibition. Pre-hospital administration of ticagrelor was associated with a 50% good responder rate at completion of PCI.

[Antiplatelet therapy in acute coronary syndrome. Prehospital phase: nothing, aspirin or what?]

In most cases of ST segment elevation myocardial infarction (STEMI) a major coronary vessel is occluded by a thrombus. This is why early and effective antiplatelet therapy plays a key role. The current guidelines recommend the administration of dual antiplatelet therapy as early as possible. Despite the lack of convincing clinical evidence, prehospital administration appears reasonable, primarily because of pharmacokinetic considerations. Ticagrelor should be preferentially administered because the largest amount of evidence is available and it appears to be safe. In high-risk patients undergoing transfer to a catheterization laboratory, upstream use of a glycoprotein (GP) IIb/IIIa receptor antagonist (tirofiban) may be considered. Acute coronary syndrome without ST segment elevation (NSTE-ACS) represents a clinically heterogeneous group. Current guidelines recommend that antiplatelet therapy should be initiated as early as possible when the diagnosis of NSTE-ACS is made. If there is high clinical suspicion of NSTE-ACS acetylsalicylic acid (ASA) should be given before hospital admission. In high-risk patients prehospital administration of ticagrelor may be considered.

Efficacy of pre-hospital use of glycoprotein IIb/IIIa inhibitors in ST-segment elevation myocardial infarction before mechanical reperfusion in a rapid-transfer network (from the Acute Myocardial Infarction Registry of Brittany)

Previous studies investigating prehospital use of glycoprotein IIb/IIIa inhibitors (GPIs) in patients with ST-segment elevation myocardial infarction reached conflicting conclusions. The benefit of this strategy in addition to in-ambulance loading of dual-antiplatelet therapy remains controversial. The aim of this study was to analyze data from a prospective registry of patients with ST-segment elevation myocardial infarctions admitted <24 hours after symptom onset (July 2006 to May 2012). A total of 2,052 patients managed in a physician-staffed mobile intensive care unit (MICU)<12 hours after symptom onset and scheduled for primary percutaneous coronary intervention (PPCI) were retrospectively included. Patients who received GPIs in the MICU were compared with those who did not. The primary end point was infarct-related artery patency, defined as pre-PPCI Thrombolysis In Myocardial Infarction (TIMI) flow grade 3. GPIs were administered in the MICU to 737 patients (36%), including 430<2 hours after symptom onset, and 1,315 patients (64%) did not received prehospital GPIs. Pre-PPCI TIMI flow grade 3 rate was lower in patients treated in the MICU (17.2% vs 21.3%, p=0.03) because of patients treated >2 hours after symptom onset, of whom only 12.7% reached the primary end point. There was no significant difference between groups in the rate of in-hospital major adverse cardiac events. In conclusion, prehospital GPI use in patients with ST-segment elevation myocardial infarctions<12 hours after symptom onset scheduled for PPCI neither improved pre-PPCI infarct-related artery patency nor reduced in-hospital major adverse cardiac events.

Timely reperfusion for ST-segment elevation myocardial infarction: Effect of direct transfer to primary angioplasty on time delays and clinical outcomes

Primary percutaneous coronary intervention (PPCI) is the preferred reperfusion therapy for patients presenting with ST-segment elevation myocardial infarction (STEMI) when it can be performed expeditiously and by experienced operators. In spite of excellent clinical results this technique is associated with longer delays than thrombolysis and this fact may nullify the benefit of selecting this therapeutic option. Several strategies have been proposed to decrease the temporal delays to deliver PPCI. Among them, prehospital diagnosis and direct transfer to the cath lab, by-passing the emergency department of hospitals, has emerged as an attractive way of diminishing delays. The purpose of this review is to address the effect of direct transfer on time delays and clinical events of patients with STEMI treated by PPCI.

The quality of antiplatelet and anticoagulant medication administration among ST-segment elevation myocardial infarction patients transferred for primary percutaneous coronary intervention

BACKGROUND

Timely and appropriate use of antiplatelet and anticoagulant therapies has been shown to improve outcomes among ST-segment elevation myocardial infarction (STEMI) patients but has not been well described in patients transferred for primary percutaneous coronary intervention (PCI).

METHODS

We examined 16,801 (26%) transfer and 47,329 direct-arrival STEMI patients treated with primary PCI at 441 Acute Coronary Treatment and Intervention Outcomes Network Registry-Get With The Guidelines hospitals. Medication use was compared between transfer and direct-arrival patients to determine if these therapies were delayed or dosed in excess.

RESULTS

Although transfer patients were more likely to receive antiplatelet and anticoagulant therapies before catheterization, they had longer delays to initiation of heparin (35 vs. 25 minutes), clopidogrel (119 vs. 84 minutes), and glycoprotein IIb/IIIa inhibitor (107 vs. 60 minutes, P < .0001 for both). Administration of low-molecular-weight heparin and glycoprotein IIb/IIIa inhibitor at the STEMI-referring hospital was associated with longer delays to reperfusion compared with deferred administration at the STEMI-receiving hospital, whereas early use of unfractionated heparin was not. Among treated patients, those transferred were more likely to receive excess heparin dosing (adjusted odds ratio [OR] 1.28 [95% CI 1.04-1.58] for unfractionated heparin, adjusted OR 1.54 [95% CI 1.09-2.18] for low-molecular-weight heparin) and are associated with higher risks of major bleeding complications (adjusted OR 1.10, 95% CI 1.03-1.17).

CONCLUSIONS

ST-segment elevation myocardial infarction patients transferred for primary PCI in community practice are at risk for delayed and excessively dosed antithrombotic therapy, highlighting the need for continued quality improvement to maximize the appropriate use of these important adjunctive therapies.

Antiplatelet effect of thienopyridine (clopidogrel or prasugrel) pretreatment in patients undergoing primary percutaneous intervention for ST elevation myocardial infarction

Although previous retrospective studies have suggested the clinical benefits of clopidogrel pretreatment in patients with ST-segment elevation myocardial infarction (STEMI) undergoing primary percutaneous coronary intervention (PPCI), the antiplatelet effect of thienopyridines during a narrow door-to-balloon time frame has not been evaluated. Seventy-nine consecutive patients with STEMI were treated with either 600 mg of clopidogrel (n = 49) or 60 mg of prasugrel (n = 30) loading on admission. All patients underwent PPCI with a door-to-balloon time of 48 ± 20 minutes. Adenosine diphosphate (ADP)-induced platelet aggregation (PA) was determined by light transmission aggregometry before thienopyridine loading, at PPCI, and after 72 hours. Baseline ADP-induced PA was comparable in clopidogrel- and prasugrel-treated patients (79 ± 10% vs 76 ± 9%, p = 0.2). Although ADP-induced PA was reduced significantly in both clopidogrel- and prasugrel-treated patients (p <0.01 for both), it was significantly lesser in prasugrel-treated patients (63 ± 18% vs 74 ± 12%, p = 0.002). Yet, <50% of the prasugrel-treated patients achieved adequate platelet inhibition (ADP-induced PA <70%) at PPCI. Prasugrel-treated patients, compared with clopidogrel-treated patients, were more likely to have Thrombolysis In Myocardial Infarction myocardial perfusion grade of ≥2 (79% vs 49%, p = 0.01), lower Thrombolysis In Myocardial Infarction frame count (10.2 ± 5.7 vs 13.6 ± 7.2, p = 0.03), and a numerically greater incidence of early ST-segment resolution >50% (26 of 30 [87%] vs 35 of 49 [71%], p = 0.1), suggesting better myocardial reperfusion. In conclusion, overall, prasugrel compared with clopidogrel pretreatment resulted in greater platelet inhibition at PPCI, but even with prasugrel, only <50% of the patients achieved early adequate platelet response.

Clopidogrel pretreatment in primary percutaneous coronary intervention: prevalence of high on-treatment platelet reactivity and impact on preprocedural patency of the infarct-related artery

To date, there is limited data on levels of platelet inhibition achieved in patients with ST-elevation myocardial infarction (STEMI) who are loaded with clopidogrel and aspirin (ASA) prior to undergoing primary percutaneous coronary intervention (P-PCI). The aim of this investigation was to evaluate the percentage of STEMI patients with high on-treatment platelet reactivity (HPR) to clopidogrel at the time of initiating P-PCI and its association with the initial patency of the infarct-related artery (IRA). This prospective pharmacodynamic study included 50 STEMI patients, previously naïve to oral antiplatelet agents, who received 500-mg ASA and 600-mg clopidogrel loading doses prior to P-PCI. Platelet function assessment was performed at the beginning of the procedure using various assays, including VerifyNow™ system (primary endpoint), light transmission aggregometry and multiple electrode aggregometry. The percentage of patients with suboptimal response to clopidogrel and ASA assessed with the VerifyNow™ system was 88.0% and 28.6%, respectively. Similar results were obtained with the other assays used. A higher percentage of patients with initial patency of the IRA was observed among those patients without HPR compared with those with HPR to clopidogrel (66.7% vs 15.9%; p=0.013), while no differences were observed regarding postprocedural angiographic or electrocardiographic outcomes. In conclusion, this study shows that a high percentage of STEMI patients have inadequate levels of clopidogrel-induced and, to a lesser extent, aspirin-mediated platelet inhibition when starting a P-PCI procedure, and suggests that a poor response to clopidogrel might be associated with impaired initial TIMI flow in the IRA.

Ambulance or in-catheterization laboratory administration of ticagrelor for primary percutaneous coronary intervention for ST-segment elevation myocardial infarction: rationale and design of the randomized, double-blind Administration of Ticagrelor in the cath Lab or in the Ambulance for New ST elevation myocardial Infarction to open the Coronary artery (ATLANTIC) study

Primary percutaneous coronary intervention (PCI) is the treatment of choice for patients presenting with acute ST-segment elevation myocardial infarction (STEMI). However, if catheterization facilities are not immediately available, the effectiveness of PCI can be affected by delays in transfer. Evidence suggests that antiplatelet therapy administered early, preferably in the ambulance during transfer, may provide better and earlier perfusion. Ticagrelor, a direct platelet P2Y12 receptor inhibitor, is indicated for the management of patients with acute coronary syndromes. The ATLANTIC study (NCT01347580; EudraCT 2011-000214-19) is a 30-day international, randomized, parallel-group, placebo-controlled study in male and female patients (aged ≥18 years) who are diagnosed as having STEMI, with intended primary PCI. In total, 1770 patients will be randomized immediately after diagnosis to prehospital administration of ticagrelor 180 mg followed by matching placebo administered in hospital, or prehospital administration of placebo followed by ticagrelor 180 mg administered in hospital. All patients will then receive ticagrelor 90 mg twice daily for 30 days. The coprimary end point is the percentage of patients reaching thrombolysis in myocardial infarction flow grade 3 in the infarct-related artery at initial angiography or achieving ≥70% ST-segment elevation resolution pre-PCI. The primary safety end point is major, life-threatening, or minor bleeding after ticagrelor administration. The results of this study may have an impact on future recommendations for treatment for patients with STEMI.

Prehospital treatment of ST-segment elevated myocardial infarction patients

Providing optimal care to patients with ST-segment elevated myocardial infarction is challenging. If a patient experiences chest pain and calls the emergency number, a cascade of actions is initiated that should lead to a diagnosis, start of treatment and reperfusion of the infarcted myocardium. This should all happen within 90 min after first medical contact, irrespective of the location of the patient or the time of day. The complex organization that is needed to achieve this goal in every ST-segment elevated myocardial infarction patient accounts for a fascinating interplay between prehospital and in-hospital care, in a situation when every minute counts. State-of-the-art care should be provided according to the latest insights and guidelines.

Quantitative analysis of the impact of total ischemic time on myocardial perfusion and clinical outcome in patients with ST-elevation myocardial infarction

Early reperfusion of the infarct-related coronary artery is an important issue in improvement of outcomes after ST-segment elevation myocardial infarction (STEMI). In this study, the clinical significance of total ischemic time on myocardial reperfusion and clinical outcomes was evaluated in patients with STEMI treated with primary percutaneous coronary intervention and thrombus aspiration and additional triple-antiplatelet therapy. Total ischemic time was defined as time from symptom onset to first intracoronary therapy (first balloon inflation or thrombus aspiration). All patients with STEMI treated with primary percutaneous coronary intervention with total ischemic times ≥30 minutes and <24 hours from 2005 to 2008 were selected. Ischemic times were available in 1,383 patients, of whom 18.4% presented with total ischemic times ≤2 hours, 31.2% >2 to 3 hours, 26.8% >3 to 5 hours, and 23.5% >5 hours. Increased ischemic time was associated with age, female gender, hypertension, and diabetes. Patients with total ischemic times <5 hours more often had myocardial blush grade 3 (40% to 45% vs 22%, p <0.001) and complete ST-segment resolution (55% to 60% vs 42%, p = 0.002) than their counterparts with total ischemic times >5 hours. In addition, patients with total ischemic times ≤5 hours had lower 30-day mortality (1.5% vs 4.0%, p = 0.032) than patients with total ischemic times >5 hours. In conclusion, in this contemporary cohort of patients with STEMI treated with primary percutaneous coronary intervention, triple-antiplatelet therapy, and thrombus aspiration, short ischemic time was associated with better myocardial reperfusion and decreased mortality. After a 5-hour period in which outcomes remain relatively stable, myocardial reperfusion becomes suboptimal and mortality increases.

Use of early clopidogrel by reperfusion strategy among patients presenting with ST-segment elevation myocardial infarction

BACKGROUND

The 2007 update of the ACC/AHA guidelines for STEMI patients recommended addition of clopidogrel to aspirin regardless of reperfusion strategy, with a bolus dose in patients <75 years of age.

METHODS AND RESULTS

We evaluated use and dose of early clopidogrel among 52,140 STEMI patients enrolled in 368 hospitals participating in NCDR's ACTION Registry®--Get with the Guidelines (GWTG™) from January 2007-September 2009. Patients were stratified by reperfusion strategy: primary percutaneous coronary intervention (PCI, n=37,108), fibrinolysis (n=5805), or no-reperfusion (n=9227), and by age (<75 or ≥75 years). Adjusted odds for in-hospital outcomes are reported by clopidogrel use across reperfusion strategies. Clopidogrel was administered early to 97% of primary PCI, 18% of fibrinolytic, and 6% of non-reperfused patients. Among patients receiving clopidogrel, a loading dose (≥300 mg) was often used in primary PCI (91%) but less frequently among fibrinolysis-treated (83%) and non-reperfused patients (74%). A positive time trend from Q1 2007-Q3 2009 in overall clopidogrel use was observed only in fibrinolytic patients (15-20%) Use of clopidogrel was associated with a significant increase in major bleeding only among older patients in the no-reperfusion group (21.9% vs. 13.2%; OR 2.19; 95% CI 1.47-3.27). A significantly lower risk of in-hospital death was associated with clopidogrel use across all reperfusion strategies (OR [95% CI], primary PCI: 0.15 [0.13-0.19]; fibrinolysis: 0.26 [0.12-0.57]; no reperfusion: 0.42 [0.27-0.65]).

CONCLUSION

Early clopidogrel use has not yet extended to the routine care of STEMI patients treated with fibrinolysis or those not receiving reperfusion as recommended in the guideline update.

Clopidogrel pre-treatment is associated with reduced in-hospital mortality in primary percutaneous coronary intervention for acute ST-elevation myocardial infarction

AIMS Pre-treatment with clopidogrel results in a reduction of ischaemic events in non-ST-elevation acute coronary syndromes. Data on upstream clopidogrel in the setting of primary percutaneous coronary intervention (PCI) are limited. The aim of this study was to investigate whether clopidogrel loading before arrival at the PCI centre may result in an improved outcome of primary PCI for ST-elevation myocardial infarction (STEMI). METHODS AND RESULTS In a multicentre registry of acute PCI, 5955 patients undergoing primary PCI in Austria between January 2005 and December 2009 were prospectively enrolled. The patients consisted of two groups, a clopidogrel pre-treatment group (n = 1635 patients) receiving clopidogrel before arrival at the PCI centre and a peri-interventional clopidogrel group (n = 4320 patients) receiving clopidogrel at a later stage. Multiple logistic regression analysis including major confounding factors stratified by the participating centres was applied to investigate the effect of pre-treatment with clopidogrel on the in-hospital mortality. Additionally, two subgroups, with or without the use of GP IIb/IIIa antagonist therapy in the catheterization laboratory, were analysed. On univariate analysis, clopidogrel pre-treatment was associated with a reduced in-hospital mortality (3.4 vs. 6.1%, P< 0.01) after primary PCI. On multivariate analysis, clopidogrel pre-treatment remained an independent predictor of in-hospital mortality [odds ratio (OR) = 0.60, 95% confidence interval (CI) 0.35-0.99; P =0.048], especially in patients receiving additional GP IIb/IIIa antagonist therapy in the catheterization laboratory (OR = 0.40, 95% CI 0.19-0.83; P =0.01). CONCLUSION Clopidogrel pre-treatment before arrival at the PCI centre is associated with reduced mortality in a real world setting of primary PCI. These results strongly support the recommendation of clopidogrel treatment 'as soon as possible' in patients with STEMI undergoing pimary PCI.

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.

Patent coronary artery and myocardial infarction in the era of primary angioplasty: assessment of an old problem in a new setting with data from the Swedish Coronary Angiography and Angioplasty Registry (SCAAR)

AIMS

The purpose of this study was to evaluate factors that contribute to a patent IRA (infarct - related artery) and the prognostic impact of a patent IRA in patients with ST-elevation myocardial infarction.

METHODS AND RESULTS

Using the Swedish angiography and angioplasty registry (SCAAR) we included all patients with STEMI and one-vessel coronary artery disease who underwent primary PCI of the culprit lesion only from May 2005 to December 2007. A patent IRA was found in 1,104 of 3,284 patients. Patients with an occluded IRA had significantly increased 7-day mortality (HR, 3.03, 95% CI 1.68-5.46, P<0.001). The incidence of an occluded IRA increased with higher age, in patients over 80 years of age (OR, 1.23, 95% CI; 0.92-1.64), lower in patients on lipid-lowering drugs (OR, 0.68, 95% CI; 0.54-0.86) and lower in patients pre-treated with heparin (OR 0.71, 95% CI; 0.60-0.83) or GPIIb/IIIa receptor blockade (OR 0.77, 95% CI; 0.61-0.97). Treatment with acetylsalicylic acid or clopidogrel had no effect on IRA patency.

CONCLUSIONS

IRA patency was associated with a lower 7-day mortality. Older STEMI patients and patients not taking lipid-lowering drugs or pre-treated with heparin or GPIIb/IIIa receptor blockers seem to constitute risk groups for having an occluded IRA.

Role of coronary artery bypass grafting during the acute and subacute phase of ST-elevation myocardial infarction

Background/Objectives. We aimed to investigate the incidence and clinical outcome of coronary artery bypass grafting (CABG) performed in contemporary patients with ST-elevation myocardial infarction (STEMI) within 30 days after presentation.Methods. All 1071 patients enrolled in the Thrombus Aspiration during Percutaneous coronary intervention in Acute myocardial infarction Study (TAPAS) were included in this analysis. CABG was indicated for both ischaemic and anatomical reasons according to the current treatment guidelines for STEMI. For all surgical as well as non-surgical patients, clinical outcome was assessed at both 30 days and one year. Results. CABG was performed within 30 days of presentation in 59/1071 (5.5%) patients, in 13 (22%) within 24 hours, in eight (14%) between one and three days, and in 38 (64%) between four and 30 days. Compared with non-surgical patients, surgical patients required more initial intra-aortic balloon pump support (33 vs. 5%, p<0.001) and more often had multi-vessel disease (p<0.001). Overall, rethoracotomy was performed in 9/59 (15%) patients. In patients operated within three days, the rethoracotomy rate was markedly higher than after three days (33 vs. 5%, p=0.004). Cardiac mortality at 30 days and one year was 1.7% in the surgical group and 3.2 and 5.3%, respectively, in the non-surgical group. Conclusion. STEMI patients treated with CABG within three days after presentation are at increased risk of rethoracotomy. However, despite this higher incidence of surgical complications and multiple high-risk features at presentation, surgical management during the acute and subacute phase is associated with excellent 30-day and one-year survival. (Neth Heart J 2010;18:348-54.).

An organized system of emergency care for patients with myocardial infarction: a reality?

An organized system of emergency care is an essential requirement for the modern treatment of ST-elevation acute myocardial infarction. There is a strong need to deliver reperfusion therapy as soon as possible, with primary percutaneous coronary intervention being the preferred option if performed in a timely manner and thrombolytic therapy, particularly in the prehospital setting, being a good alternative if the primary percutaneous coronary intervention-related delay exceeds the equipoise. In this situation, emergency medical services have a primary role in rescuing patients from cardiac arrest, performing prehospital diagnosis, triage and treatment and safely transporting them to the most appropriate cardiological center, including interhospital transfer. A complete reorganization of the healthcare systems in different countries is frequently needed to build an ST-elevation acute myocardial infarction system of care, focusing on fast transport, use of telemedicine and diversion protocols to skip the unsuited centers.

Clopidogrel pretreatment in ST-elevation myocardial infarction patients transferred for percutaneous coronary intervention

BACKGROUND

Pretreatment with clopidogrel reduces ischemic complications before percutaneous coronary intervention (PCI). Limited data exist regarding the effect of pretreatment for ST-segment elevation myocardial infarction (STEMI) patients undergoing primary PCI.

METHODS

Prospective data were analyzed from a regional STEMI system using rapid transfer for primary PCI in 30 community hospitals. Zone 1 community hospitals are <60 miles and Zone 2 hospitals are 60 to 210 miles away from the PCI hospital. Compared with 63 minutes in the PCI hospital, median door-to-balloon times were 94 minutes in Zone 1 and 123 minutes in Zone 2 hospitals. All patients received aspirin, unfractionated heparin, and clopidogrel 600 mg in the emergency department of the presenting hospital within 15 minutes of diagnosis.

RESULTS

From April 2003 through December 2008, 2,014 consecutive STEMI patients were pretreated with clopidogrel before PCI, with a median (25th-75th percentile) duration from pretreatment to PCI of 75 (58-93) minutes. Patients with longer pretreatment duration had significantly reduced reinfarction/reischemia at 30 days (Zone 1: 0.85%, Zone 2: 0.9%) compared with nontransferred patients (3.2%, P = .001) as well as reduced stent thrombosis (Zone 1: 0.6%, Zone 2: 0.6% vs Abbott Northwestern: 2.0%; P = .04). Similarly, pretreatment duration of >60 minutes before PCI had reduced 30-day reinfarction/reischemia (1.0% vs 2.9%, P = .003). There were no significant differences in mortality or major bleeding.

CONCLUSION

ST-segment elevation myocardial infarction patients undergoing primary PCI in a regional STEMI network who received earlier pretreatment with a 600-mg loading dose of clopidogrel had less ischemic complications without increased bleeding or mortality.

Hotlines and clinical trial updates presented at the German Cardiac Society Meeting 2010: FAIR-HF, CIPAMI, LIPSIA-NSTEMI, Handheld-BNP, PEPCAD III, remote ischaemic conditioning, CERTIFY, PreSCD-II, German Myocardial Infarction Registry, DiaRegis

This article summarizes the results of a number of clinical trials and registries in the field of cardiovascular medicine which were presented during the Hotline Sessions at the annual meeting of the German Cardiac Society, held in Mannheim, Germany, from 8th to 10th April 2010. The data were presented by leading experts in the field with relevant positions in the trials. It is important to note that unpublished reports should be considered as preliminary data, as the analysis may change in the final publications. The comprehensive summaries have been generated from the oral presentation and should provide the readers with the most comprehensive information on diagnostic and therapeutic development in cardiovascular medicine similar as previously reported (Maier et al. in Clin Res Cardiol 98:345-352, 2009; 98:413-419, 2009).

Update on antiplatelet therapy in acute coronary syndromes: what do new drugs bring into clinical practice?

The incidence of new coronary events in patients receiving dual antiplatelet therapy (e.g. cyclo-oxygenase inhibitors such as aspirin [acetylsalicylic acid; ASA]) and ADP receptor blockers (e.g. clopidogrel) is high. Therefore, it is critical to identify patients who require more intense treatment such as those with poor tolerance to existing drugs, those with genotypes that predict treatment resistance, diabetic patients, and smokers. The new ADP receptor blockers (prasugrel, cangrelor, Ticagrelor) can provide greater efficacy but it should not be associated with increased bleeding. Thrombin receptor antagonists (e.g. SCH530348) are another alternative that is currently being tested in randomized trials.