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

Prehospital study of survival outcomes from out-of-hospital cardiac arrest in ST-elevation myocardial infarction in Queensland, Australia (the PRAISE study)

AIM

Patients that experience an out-of-hospital cardiac arrest in the context of a paramedic-identified ST-segment elevation myocardial infarction are a unique cohort. This study identifies the survival outcomes and determinants of survival in these patients.

METHODS

A retrospective analysis was undertaken of all patients, attended between 1 January 2013 and 31 December 2017 by the Queensland Ambulance Service, who had a ST-segment elevation myocardial infarction identified by the attending paramedic prior to deterioration into out-of-hospital cardiac arrest. We described the 'survived event' and 'survived to discharge' outcomes of patients and performed univariate analysis and multivariate logistic regression to identify factors associated with survival.

RESULTS

In total, 287 patients were included. Overall, high rates of survival were reported, with 77% of patients surviving the initial out-of-hospital cardiac arrest event and 75% surviving to discharge. Predictors of event survival were the presence of an initial shockable rhythm (adjusted odds ratio 8.60, 95% confidence interval (CI) 4.16-17.76; P < 0.001) and the administration of prehospital medication for subsequent primary percutaneous coronary intervention (adjusted odds ratio 2.54, 95% CI 1.17-5.50; P = 0.020). These factors were also found to be associated with survival to hospital discharge, increasing the odds of survival by 13.74 (95% CI 6.02-31.32; P < 0.001) and 6.96 (95% CI 2.50-19.41; P < 0.001) times, respectively. The administration of prehospital fibrinolytic medication was also associated with survival in a subgroup analysis.

CONCLUSION

This subset of out-of-hospital cardiac arrest patients was found to be highly salvageable and responsive to resuscitative measures, having arrested in the presence of paramedics and presented with an identified reversible cause.

COMPARison of pre-hospital CRUSHed vs. uncrushed Prasugrel tablets in patients with STEMI undergoing primary percutaneous coronary interventions: Rationale and design of the COMPARE CRUSH trial

BACKGROUND

Dual antiplatelet therapy constitutes the cornerstone of medical treatment in patients with ST elevation myocardial infarction (STEMI). However, oral antiplatelet agents, such as prasugrel or ticagrelor, are characterized by slow gastrointestinal drug absorption in the acute phase of STEMI, leading to decreased bioavailability and therefore delayed onset of platelet inhibition. Evidence suggests that administration of crushed tablets of the P2Y₁₂ inhibitor prasugrel improves drug absorption and achieves earlier antiplatelet effects in STEMI patients undergoing primary percutaneous coronary intervention (PCI). However, the clinical implications of these pharmacokinetic and pharmacodynamic findings are unknown.

HYPOTHESIS

The present study is designed to test the hypothesis that patients presenting with STEMI planned for primary PCI will have improved markers of optimal reperfusion and clinical outcomes by prehospital administration of crushed tablets of prasugrel loading dose.

STUDY DESIGN

COMPARE CRUSH (NCT03296540) is a randomized trial in a regionally organized ambulance care setting evaluating the efficacy and safety of pre-hospital loading dose with prasugrel crushed tablets versus integral tablets in approximately 674 patients presenting with STEMI planned for primary PCI. The independent primary endpoints are percentage of patients reaching thrombolysis in myocardial infarction (TIMI) flow grade 3 in the infarct-related artery at initial angiography, or achieving ≥70% ST-segment elevation resolution at 1 hour post-PCI. Secondary clinical endpoints are death, myocardial infarction, revascularization, and stent thrombosis followed up to 1 year. Moreover, the primary safety endpoint is bleeding events assessed at 48 hours.

CONCLUSIONS

The COMPARE CRUSH trial will assess whether prehospital administration of loading dose prasugrel in form of crushed tablets - which is expected to provide faster platelet inhibition compared to standard treatment with integral tablets - results in improved reperfusion and clinical outcomes. RCT# NCT03296540.

Impact of preprocedural TIMI flow on clinical outcome in low-risk patients with ST-elevation myocardial infarction: Results from the ATLANTIC study

OBJECTIVES

This study sought to analyze the impact of the preprocedural thrombolysis in myocardial infarction (TIMI) flow on clinical outcome in patients with ST-elevation myocardial infarction (STEMI).

BACKGROUND

Previous studies have shown that the TIMI flow 0/1 prior to primary percutaneous coronary intervention (PCI) is associated with a poor clinical outcome. However, it is unclear whether the same is true in patients with ongoing STEMI of less than 6 hr duration, rapid reperfusion, and modern guideline-adherent therapy.

METHODS

The ATLANTIC study compared prehospital versus inhospital treatment with ticagrelor in patients with acute STEMI. For this analysis, patients were divided into three groups according to the preprocedural TIMI flow grade of the infarct vessel: TIMI 0/1, TIMI 2, and TIMI 3.

RESULTS

From a total of 1,680 patients, 1,113 had TIMI 0/1, 279 TIMI 2, and 288 TIMI 3 flow before primary PCI. At 30 days, the composite ischemic endpoint (5.5, 2.9, and 2.1%, p < .05) and all-cause death (3.0, 1.4, and 2.1%, p = .30) were highest in patients with TIMI flow 0/1. After adjustment, preprocedural TIMI flow <3 (versus 3) was not an independent predictor of major adverse ischemic events within 30 days (odds ratio 1.89, 95% confidence interval 0.74-4.85). However, definite stent thrombosis occurred only in patients with initial TIMI flow 0/1 (1.0%). Among these patients, those with prehospital administration of ticagrelor were less often affected (0.3% vs. 1.3%, p < .05).

CONCLUSION

In this post-hoc analysis, preprocedural TIMI flow was not independently associated with a higher rate of adverse ischemic events.

Morphine and Ticagrelor Interaction in Primary Percutaneous Coronary Intervention in ST-Segment Elevation Myocardial Infarction: ATLANTIC-Morphine

BACKGROUND

Morphine adversely impacts the action of oral adenosine diphosphate (ADP)-receptor blockers in ST-segment elevation myocardial infarction (STEMI) patients, and is possibly associated with differing patient characteristics. This retrospective analysis investigated whether interaction between morphine use and pre-percutaneous coronary intervention (pre-PCI) ST-segment elevation resolution in STEMI patients in the ATLANTIC study was associated with differences in patient characteristics and management.

METHODS

ATLANTIC was an international, multicenter, randomized study of treatment in the acute ambulance/hospital setting where STEMI patients received ticagrelor 180 mg ± morphine. Patient characteristics, cardiovascular history, risk factors, management, and outcomes were recorded.

RESULTS

Opioids (97.6% morphine) were used in 921 out of 1862 patients (49.5%). There were no significant differences in age, sex or cardiovascular history, but more morphine-treated patients had anterior myocardial infarction and left-main disease. Time from chest pain to electrocardiogram and ticagrelor loading was shorter with morphine (both p = 0.01) but not total ischemic time. Morphine-treated patients more frequently received glycoprotein IIb/IIIa inhibitors (p = 0.002), thromboaspiration and stent implantation (both p < 0.001). No significant difference between the two groups was found regarding pre-PCI ≥ 70% ST-segment elevation resolution, death, myocardial infarction, stroke, urgent revascularization and definitive acute stent thrombosis. More morphine-treated patients had an absence of pre-PCI Thrombolysis in Myocardial Infarction (TIMI) 3 flow (85.8% vs. 79.7%; p = 0.001) and more had TIMI major bleeding (1.1% vs. 0.1%; p = 0.02).

CONCLUSIONS

Morphine-treatment was associated with increased GP IIb/IIIa inhibitor use, less pre-PCI TIMI 3 flow, and more bleeding. Judicious morphine use is advised with non-opioid analgesics preferred for non-severe acute pain.

TRIAL REGISTRATION

clinicaltrials.gov identifier: NCT01347580.

Effect of preoperative loading dose ticagrelor and clopidogrel on no-reflow phenomenon during intervention in patients with ST-segment elevation myocardial infarction undergoing primary percutaneous coronary intervention: a systematic review and meta-analysis

BACKGROUND

Previous studies have shown that ticagrelor is more effective than clopidogrel in platelet inhibition. However, this conclusion remains controversial. Therefore, we performed this meta-analysis to assess the effect of preoperative loading dose ticagrelor and clopidogrel on no-reflow (NRF) during intervention in patients with ST-segment elevation myocardial infarction undergoing primary percutaneous coronary intervention (PPCI).

MATERIALS AND METHODS

Randomized controlled trials and observational studies were reviewed. The retrieval time was limited from inception to October 1, 2017. The retrieved databases included PubMed, Embase, the Cochrane Library, Web of Science, CBM, CNKI, the VIP database, and the Wang Fang database. RevMan 5.3 software was used for data analysis.

RESULTS

Fourteen randomized controlled trials and one observational study, including 4,162 patients, were included. In these articles, 1,521 patients were in the ticagrelor group (180 mg) and 2,641 patients were in the clopidogrel group (600 mg). The meta-analysis showed that compared with clopidogrel group, preoperative loading dose ticagrelor: 1) significantly reduced the incidence of NRF during PPCI (95% confidence interval [CI]: 0.15, 0.39, P<0.05) as well as the level of postoperative corrected thrombolysis in myocardial infarction frame count (95% CI: -8.89, -6.91, P<0.05); 2) significantly reduced the incidence of major adverse cardiovascular events during hospitalization, including 30 and 180 days after PPCI (95% CI: 0.41, 0.82, P<0.05; 95% CI: 0.15, 0.46, P<0.05, respectively); and 3) significantly improved thrombolysis in myocardial infarction flow after PPCI (95% CI: 1.40, 2.45, P<0.05). No significant difference was observed in terms of bleeding events within 30 and 180 days after PPCI (95% CI: 0.71, 1.54, P=0.82; 95% CI: 0.81, 3.19, P=0.18, respectively).

CONCLUSION

Compared with clopidogrel, loading dose ticagrelor effectively reduced both the occurrence of NRF during PPCI and the incidence of major adverse cardiovascular event in patients with ST-segment elevation myocardial infarction undergoing PPCI. Furthermore, it did not increase the risk of bleeding after PPCI.

P2Y12 receptor inhibition and effect of morphine in patients undergoing primary PCI for ST-segment elevation myocardial infarction

PRIVATE-ATLANTIC (P2Y12 Receptor Inhibition with VASP Testing using Elisa kit during the ATLANTIC study) is a pre-specified substudy of the randomised, double-blind ATLANTIC trial in patients with ST-segment elevation myocardial infarction, designed to help interpret the main trial results. The primary objective of ATLANTIC was to assess coronary reperfusion prior to percutaneous coronary intervention (PCI) with pre- vs in-hospital ticagrelor 180 mg loading dose (LD). PRIVATE-ATLANTIC assessed platelet inhibition in 37 patients by measurement of vasodilator-associated stimulated phosphoprotein (VASP) platelet reactivity index (PRI) and VerifyNow platelet reactivity units (PRU) before angiogram (T1), immediately after PCI (T2), 1 (T3), and 6 (T4) hours (h) after PCI, and before next study drug administration (T5). The median time difference between the two ticagrelor LD was 41 minutes. Platelet reactivity was unaffected at T1 when measured by VASP-PRI (89.8 vs 93.9% for pre- and in-hospital ticagrelor, respectively; p = 0.18) or PRU (239 vs 241; p = 0.82). Numerical differences were apparent at T2 and maximal at T3. Morphine administration significantly delayed onset of platelet inhibition at T3 (VASP-PRI 78.2 vs 23.4% without morphine; p = 0.0116) and T4 (33.1 vs 11.0%; p = 0.0057). In conclusion, platelet inhibition in ATLANTIC was unaffected by pre-hospital ticagrelor administration at the time of initial angiogram due to the short transfer delay. The maximum difference in platelet inhibition was detected 1 h after PCI (T3). Morphine administration was associated with delayed onset of action of ticagrelor and appeared more important than timing of ticagrelor administration.

Thrombus aspiration and prehospital ticagrelor administration in ST-elevation myocardial infarction: Findings from the ATLANTIC trial

BACKGROUND

The potential interactions between prehospital (pre-H) ticagrelor administration and thrombus aspiration (TA) in patients with ST-elevation myocardial infarction (STEMI) treated with primary percutaneous coronary intervention (PCI) have never been studied. Therefore, we evaluated the potential benefit of TA and pre-H ticagrelor treatment in patients enrolled in the ATLANTIC trial (NCT01347580).

METHODS

This analysis included 1,630 patients who underwent primary PCI. Multivariate analysis was used to explore the potential association of TA and pre-H treatment to clinical outcomes. Potential interactions between TA and pre-H ticagrelor were also explored.

RESULTS

A total of 941 (57.7%) patients underwent TA. In adjusted multivariate logistic model, pre-H ticagrelor treatment was significantly associated with less frequent new MI or definite stent *thrombosis (ST) (odds ratio [OR] 0.43, 95% CI 0.20-0.92, P=.031), or definite ST (OR 0.26, 95% CI 0.07-0.91, P=.036) at 30 days. Patients treated with TA had higher frequency of Thrombolysis in Myocardial Infarction (TIMI) flow 0-1 compared with no-TA group (80.7% vs 51.9%, P<.0001). TA when also adjusted for TIMI flow 0-1 showed significant association only for higher bailout use of glycoprotein IIb/IIIa inhibitors (OR 1.72, 95% CI 1.18-2.50, P=.004) and more frequent 30-day TIMI major bleeding (OR 2.92, 95% CI 1.10-7.76, P=.032). No significant interactions between TA and pre-H ticagrelor were present for the explored end points.

CONCLUSIONS

TA when left to physicians' discretion was used in high-risk patients, was associated with bailout use of glycoprotein IIb/IIIa inhibitors and TIMI major bleeding, and had no impact on 30-day clinical outcomes. Conversely, pre-H ticagrelor treatment predicted lower 30-day rates of ST or new MI without interaction with TA.

Duration of ischemia and treatment effects of pre- versus in-hospital ticagrelor in patients with ST-segment elevation myocardial infarction: Insights from the ATLANTIC study

BACKGROUND

Among patients with STEMI in the ATLANTIC study, pre-hospital administration of ticagrelor improved post-PCI ST-segment resolution and 30-day stent thrombosis. We investigated whether this clinical benefit with pre-hospital ticagrelor differs by ischemic duration.

METHODS

In a post hoc analysis we compared absence of ST-segment resolution post-PCI and stent thrombosis at 30 days between randomized treatment groups (pre- versus in-hospital ticagrelor) stratified by symptom onset to first medical contact (FMC) duration [≤1 hour (n = 773), >1 to ≤3 hours (n = 772), and >3 hours (n = 311)], examining the interaction between randomized treatment strategy and duration of symptom onset to FMC for each outcome.

RESULTS

Patients presenting later after symptom onset were older, more likely to be female, and have higher baseline risk. Patients with symptom onset to FMC >3 hours had the greatest improvement in post-PCI ST-segment elevation resolution with pre- versus in-hospital ticagrelor (absolute risk difference: ≤1 hour, 2.9% vs. >1 to ≤3 hours, 3.6% vs. >3 hours, 12.2%; adjusted p for interaction = 0.13), while patients with shorter duration of ischemia had greater improvement in stent thrombosis at 30 days with pre- versus in-hospital ticagrelor (absolute risk difference: ≤1 hour, 1.3% vs. >1 hour to ≤3 hours, 0.7% vs. >3 hours, 0.4%; adjusted p for interaction = 0.55). Symptom onset to active ticagrelor administration was independently associated with stent thrombosis at 30 days (adjusted OR 1.89 per 100 minute delay, 95%CI 1.20-2.97, P < .01), but not post-PCI ST-segment resolution (P = .41).

CONCLUSIONS

The effect of pre-hospital ticagrelor to reduce stent thrombosis was most evident when given early within 3 hours after symptom onset, with delay in ticagrelor administration after symptom onset associated with higher rate of stent thrombosis. These findings re-emphasize the need for early ticagrelor administration in primary PCI treated STEMI patients.

Prasugrel vs clopidogrel in cardiogenic shock patients undergoing primary PCI for acute myocardial infarction

There is limited clinical data comparing different P2Y12-receptor inhibitors in patients with acute myocardial infarction (AMI) complicated by cardiogenic shock. The aim of the ISAR-SHOCK registry was to compare the clinical outcome of patients treated with clopidogrel vs prasugrel in this setting. Patients (n=145) with AMI complicated by cardiogenic shock and undergoing primary PCI in two centres (Deutsches Herzzentrum München and Klinikum rechts der Isar, Technical University Munich) between January 2009 and May 2012 were included in this registry. The use of prasugrel for patients within this registry reflected co-morbidities and platelet function testing results during the acute AMI phase. Early outcome at 30-days was reported with regard to all-cause mortality, myocardial infarction (MI), stent thrombosis (ST) and bleeding events. With regard to antiplatelet treatment in the 145 cardiogenic shock patients, 50 patients were initially treated or immediately switched to prasugrel while 95 patients were treated with clopidogrel. All-cause mortality was lower in prasugrelvs clopidogrel-treated patients (30 % vs 50.5%, HR: 0.51, 95% CI [0.29–0.92], p=0.025). No significant differences in prasugrel- vs clopidogrel-treated patients were observed for the occurrence of MI (p=0.233), ST (p=0.306) or TIMI major bleedings (p=0.571). Results of the ISAR-SHOCK registry suggest that the use of prasugrel in AMI patients complicated by cardiogenic shock might be associated with a lower mortality risk as compared to clopidogrel therapy without increasing the risk of bleeding. These findings, however, need confirmation from specifically designed randomised studies in this high-risk cohort of patients.

Association between gender and short-term outcome in patients with ST elevation myocardial infraction participating in the international, prospective, randomised Administration of Ticagrelor in the catheterisation Laboratory or in the Ambulance for New ST elevation myocardial Infarction to open the Coronary artery (ATLANTIC) trial: a prespecified analysis

OBJECTIVES

To evaluate gender differences in outcomes in patents with ST-segment elevation myocardial infarction (STEMI) planned for primary percutaneous coronary intervention (PPCI).

SETTINGS

A prespecified gender analysis of the multicentre, randomised, double-blind Administration of Ticagrelor in the catheterisation Laboratory or in the Ambulance for New ST elevation myocardial Infarction to open the Coronary artery.

PARTICIPANTS

Between September 2011 and October 2013, 1862 patients with STEMI and symptom duration <6 hours were included.

INTERVENTIONS

Patients were assigned to prehospital versus in-hospital administration of 180 mg ticagrelor.

OUTCOMES

The main objective was to study the association between gender and primary and secondary outcomes of the main study with a focus on the clinical efficacy and safety outcomes.

PRIMARY OUTCOME

the proportion of patients who did not have 70% resolution of ST-segment elevation and did not meet the criteria for Thrombolysis In Myocardial Infarction (TIMI) flow 3 at initial angiography. Secondary outcome: the composite of death, MI, stent thrombosis, stroke or urgent revascularisation and major or minor bleeding at 30 days.

RESULTS

Women were older, had higher TIMI risk score, longer prehospital delays and better TIMI flow in the infarct-related artery. Women had a threefold higher risk for all-cause mortality compared with men (5.7% vs 1.9%, HR 3.13, 95% CI 1.78 to 5.51). After adjustment, the difference was attenuated but remained statistically significant (HR 2.08, 95% CI 1.03 to 4.20). The incidence of major bleeding events was twofold to threefold higher in women compared with men. In the multivariable model, female gender was not an independent predictor of bleeding (Platelet Inhibition and Patient Outcomes major HR 1.45, 95% CI 0.73 to 2.86, TIMI major HR 1.28, 95% CI 0.47 to 3.48, Bleeding Academic Research Consortium type 3-5 HR 1.45, 95% CI 0.72 to 2.91). There was no interaction between gender and efficacy or safety of randomised treatment.

CONCLUSION

In patients with STEMI planned for PPCI and treated with modern antiplatelet therapy, female gender was an independent predictor of short-term mortality. In contrast, the higher incidence of bleeding complications in women could mainly be explained by older age and clustering of comorbidities.

CLINICAL TRIAL REGISTRATION

NCT01347580;Post-results.

Assessment of consent models as an ethical consideration in the conduct of prehospital ambulance randomised controlled clinical trials: a systematic review

BACKGROUND

We sought to understand the main ethical considerations when conducting clinical trials in the prehospital ambulance based setting.

METHODS

A systematic review of the literature on randomised controlled trials in ambulance settings was undertaken. A search of eight databases identified published studies involving recruitment of ambulance service users. Four independent authors undertook abstract and full-text reviews to determine eligibility and extract relevant data. The data extraction concentrated on ethical considerations, with any discussion of ethics being included for further analysis. The resultant data were combined to form a narrative synthesis.

RESULTS

In all, 56 papers were identified as meeting the inclusion criteria. Issues relating to consent were the most significant theme identified. Type of consent differed depending on the condition or intervention being studied. The country in which the research took place did not appear to influence the type of consent, apart from the USA where exception from consent appeared to be most commonly used. A wide range of terms were used to describe consent.

CONCLUSIONS

Consent was the main ethical consideration in published ambulance based research. A range of consent models were used ranging from informed consent to exception from consent (waiver of consent). Many studies cited international guidelines as informing their choice of consent model but diverse and sometimes confused terms were used to describe these models. This suggests that standardisation of consent models and the terminology used to describe them is warranted.

Clinical impact and predictors of complete ST segment resolution after primary percutaneous coronary intervention: A subanalysis of the ATLANTIC Trial

Background:

In the ATLANTIC (Administration of Ticagrelor in the catheterization laboratory or in the Ambulance for New ST elevation myocardial Infarction to open the Coronary artery) trial the early use of aspirin, anticoagulation, and ticagrelor coupled with very short medical contact-to-balloon times represent good indicators of optimal treatment of ST-elevation myocardial infarction and an ideal setting to explore which factors may influence coronary reperfusion beyond a well-established pre-hospital system.

Methods:

This study sought to evaluate predictors of complete ST-segment resolution after percutaneous coronary intervention in ST-elevation myocardial infarction patients enrolled in the ATLANTIC trial. ST-segment analysis was performed on electrocardiograms recorded at the time of inclusion (pre-hospital electrocardiogram), and one hour after percutaneous coronary intervention (post-percutaneous coronary intervention electrocardiogram) by an independent core laboratory. Complete ST-segment resolution was defined as ≥70% ST-segment resolution.

Results:

Complete ST-segment resolution occurred post-percutaneous coronary intervention in 54.9% ( n=800/1456) of patients and predicted lower 30-day composite major adverse cardiovascular and cerebrovascular events (odds ratio 0.35, 95% confidence interval 0.19–0.65; p<0.01), definite stent thrombosis (odds ratio 0.18, 95% confidence interval 0.02–0.88; p=0.03), and total mortality (odds ratio 0.43, 95% confidence interval 0.19–0.97; p=0.04). In multivariate analysis, independent negative predictors of complete ST-segment resolution were the time from symptoms to pre-hospital electrocardiogram (odds ratio 0.91, 95% confidence interval 0.85–0.98; p<0.01) and diabetes mellitus (odds ratio 0.6, 95% confidence interval 0.44–0.83; p<0.01); pre-hospital ticagrelor treatment showed a favorable trend for complete ST-segment resolution (odds ratio 1.22, 95% confidence interval 0.99–1.51; p=0.06).

Conclusions:

This study confirmed that post-percutaneous coronary intervention complete ST-segment resolution is a valid surrogate marker for cardiovascular clinical outcomes. In the current era of ST-elevation myocardial infarction reperfusion, patients’ delay and diabetes mellitus are independent predictors of poor reperfusion and need specific attention in the future.

Pre-hospital ticagrelor in ST-segment elevation myocardial infarction in the French ATLANTIC population

BACKGROUND

ATLANTIC was a randomized study comparing pre- and in-hospital treatment with a ticagrelor loading dose (LD) in ongoing ST-segment elevation myocardial infarction (STEMI). We sought to compare patient characteristics and clinical outcomes in France with other countries participating in ATLANTIC.

METHODS

The population comprised 1862 patients, 660 (35.4%) from France and 1202 from 12 other countries. The main endpoints were reperfusion (≥70% ST-segment elevation resolution) and TIMI flow grade 3 before (co-primary endpoints) and after percutaneous coronary intervention (PCI). Other endpoints included a composite ischaemic endpoint (death/myocardial infarction/stroke/urgent revascularization/definite stent thrombosis) and bleeding events at 30days.

RESULTS

In France, median times from first LD to angiography and between first and second LDs were 49 and 35min, respectively, and were similar to other countries. French patients were younger (mean 58.7 vs 61.9years, p<0.0001) and characterized by a higher rate of radial access (89.9% vs 54.8%, p<0.0001), more frequent use of pre-hospital glycoprotein (GP) IIb/IIIa inhibitors (14.1% vs 3.1%, p<0.0001) and intravenous enoxaparin (57.3% vs 10.1%, p<0.0001). In France, as in other countries, the co-primary endpoints did not differ between the two randomization groups. The composite ischaemic endpoint was numerically lower in France (3.3% vs 5.1%, p=0.07), with a lower mortality (1.4% vs 3.3%, p=0.01). PLATO major bleeding was numerically less frequent in France (1.8% vs 3.2%, p=0.07).

CONCLUSIONS

The French population appears to have better outcomes than the rest of the study population, and seems related to differences in demographics and management characteristics.

TRIAL REGISTRY

ClinicalTrials.gov (NCT01347580).

New approaches to inhibiting platelets and coagulation

Ischemic heart disease and stroke are major causes of death and morbidity worldwide. Coronary and cerebrovascular events are a consequence of thrombus formation caused by atherosclerotic plaque rupture or embolism, both of which result from platelet activation and aggregation and thrombin-mediated fibrin generation via the coagulation cascade. Current and emerging antiplatelet and anticoagulant agents are evolving rapidly. The use of aspirin for primary prevention continues to be controversial, as are the doses appropriate for secondary prevention. Development of new oral and intravenous adenosine diphosphate P2Y12 inhibitors and novel antiplatelet agents continues to transform the landscape of antiplatelet therapy. Oral anticoagulation has advanced with the use of direct thrombin and factor Xa inhibitors that do not require therapeutic monitoring. In this review, we discuss the pharmacology and growing clinical evidence for traditional and new antiplatelet and anticoagulant therapies.

[ESC/EACTS guidelines on myocardial revascularization : Amendments 2014]

One of the most important treatment principles in interventional cardiology relies on myocardial revascularization by percutaneous coronary intervention (PCI) or surgical placement of coronary artery bypass grafts (CABG). However, in order to apply these principles effectively, it is important to identify patients who require revascularization. Consequently, the appropriate method has to be selected to effectively restore blood flow. Patients will only benefit from the interventional or surgical procedures when those revascularization measures that can cause more harm than good are avoided. In the new European Society of Cardiology and European Association for Cardio-Thoracic Surgery (ESC/EACTS) guidelines on myocardial revascularization some new aspects will be addressed.

Pre-PCI angiographic TIMI flow in the culprit coronary artery influences infarct size and microvascular obstruction in STEMI patients

OBJECTIVE

The influence of initial-thrombolysis in myocardial infarction (i-TIMI) coronary flow in the culprit coronary artery on myocardial infarct and microvascular obstruction (MVO) size is unclear. We assessed the impact on infarct size of i-TIMI flow in the culprit coronary artery, as well as on MVO incidence and size, by contrast-enhanced cardiac magnetic resonance (ce-CMR).

METHODS

In a prospective, multicenter study, pre-percutaneous coronary intervention (PCI) coronary occlusion was defined by an i-TIMI flow ≤1, and patency was defined by an i-TIMI flow ≥2. Infarct size, as well as MVO presence and size, were measured on ce-CMR 72h after admission.

RESULTS

A total of 140 patients presenting with ST-elevated myocardial infarction referred for primary PCI were included. There was no significant difference in final post-PCI TIMI flow between the groups (2.95±0.02 vs. 2.97±0.02, respectively; p=0.44). In the i-TIMI flow ≤1 group, infarct size was significantly larger (32±17g vs. 21±17g, respectively; p=0.002), MVO was significantly more frequent (74% vs. 53%, respectively; p=0.012), and MVO size was significantly larger [1.3 IQR (0; 7.1) vs. 0 IQR (0; 1.6)], compared to in the i-TIMI ≥2 patient group.

CONCLUSION

Initial angiographic TIMI flow in the culprit coronary artery prior to any PCI predicted final infarct size and MVO size: the better was the i-TIMI flow, the smaller were the infarct and MVO size.

Ticagrelor: a review of its use in adults with acute coronary syndromes

Ticagrelor (Brilique™, Brilinta®), a cyclopentyl-triazolopyrimidine, is an orally active, reversible, and selective adenosine diphosphate (ADP) receptor antagonist indicated for use in patients with acute coronary syndromes (ACS). Ticagrelor has a faster onset of action and provides greater inhibition of platelet aggregation than clopidogrel. In the large well-designed, PLATO study in adult patients with ACS, 12 months' treatment with ticagrelor was more effective than clopidogrel in reducing the incidence of the primary composite endpoint of myocardial infarction, stroke, or cardiovascular (CV) death. Ticagrelor also reduced all-cause mortality relative to clopidogrel, although statistical significance of this was not confirmed in hierarchical testing. Benefit with ticagrelor was seen both in invasively and noninvasively managed patients. Ticagrelor was generally well tolerated and was not associated with an increased risk of major bleeding relative to clopidogrel. However, the incidences of non-coronary artery bypass grafting (CABG)-related bleeding, and major or minor bleeding, as well as some non-hemorrhagic adverse events, including dyspnea (usually of mild or moderate severity) and ventricular pauses (largely asymptomatic) were higher with ticagrelor. In addition, the ATLANTIC study showed that although pre-hospital administration of ticagrelor did not improve pre-percutaneous coronary intervention (PCI) coronary reperfusion in ACS patients relative to in-hospital administration, ticagrelor was safe in both instances, with no significant between-group differences in non-CABG-related major and minor bleeding events. Although further comparative studies with other antiplatelet agents, including prasugrel, are required to position it more definitively, current evidence indicates that ticagrelor is a useful option for the prevention of thrombotic CV events in ACS patients managed invasively or noninvasively.

[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.

Effects of baseline coronary occlusion and diabetes mellitus in patients with ST-segment elevation myocardial infarction undergoing primary percutaneous coronary intervention

Several studies have highlighted the prognostic role of preprocedural Thrombolysis In Myocardial Infarction (TIMI) flow in the infarct-related artery (IRA) in patients with ST-segment elevation myocardial infarction (STEMI). However, the impact of preprocedural IRA occlusion in patients with diabetes with STEMI has been insufficiently studied. The aim of this study was to evaluate the effects of baseline IRA occlusion and diabetic status in patients with STEMI who underwent primary percutaneous coronary intervention by using data from a pooled analysis of randomized trials comparing intracoronary with intravenous abciximab bolus administration. A total of 3,046 patients with STEMI who underwent primary percutaneous coronary intervention were included. Diabetes was present in 578 patients (19%). The primary outcome was mortality after a median follow-up period of 375 days. Secondary end points were reinfarction and stent thrombosis. In patients without diabetes, IRA occlusion versus no occlusion was not associated with increased rates of mortality (4.3% vs 2.7%, p = 0.051) and reinfarction (3.3% vs 2.5%, p = 0.33). Patients with diabetes with IRA occlusion compared with those without occlusion showed higher rates of mortality (10.6% vs 4.6%, p = 0.01) and reinfarction (5.6% vs 2.1%, p = 0.03). Baseline IRA occlusion increased the rate of stent thrombosis in the nondiabetic (2.1% vs 1.0%, p = 0.04) and diabetic (3.2% vs 0.8%, p = 0.05) cohorts. Interaction analysis demonstrated that the risk for death and reinfarction was significantly increased when diabetes and IRA occlusion occurred concomitantly. In conclusion, patients with STEMI with diabetes and baseline IRA occlusion had disproportionately higher rates of death and reinfarction. Preprocedural IRA occlusion increased the risk for stent thrombosis, irrespective of diabetic status.

Prasugrel and ticagrelor: is there a winner?

Clopidogrel is a prodrug that undergoes extensive enteric clearance and requires two-stage hepatic activation by cytochrome P450 (CYP) enzymes. This metabolic pathway is susceptible to genetic polymorphisms, resulting in a variable platelet inhibitory effect. A growing number of studies have linked poor antiplatelet response to clopidogrel to adverse clinical outcomes, particularly coronary ischemic events and stent thrombosis. This has prompted the development of new ADP receptor antagonists that inhibit platelets more effectively. Two of these agents, prasugrel and ticagrelor, have been investigated in two large randomized clinical trials, and both have shown superiority versus clopidogrel in reducing ischemic endpoints, with an increase in bleeding events, but a favorable final net clinical outcome. Since the publication of the main articles, several sub-analyses have been performed on the same data, and Guideline recommendations have largely endorsed these subgroup findings. Most clinicians have accepted the concept that we might consider approaching the patient differently, deserving a specific agent for each different settings. However, subgroup analyses of randomized trials are often post hoc, underpowered and prone to bias. Weighing efficacy and safety of the most commonly used antiplatelet agents will represent a clinical challenge over the next few years. Furthermore, individuals and organizations involved in formulary decisions will have to face economic constraints, also taking into account the availability of low-cost generic clopidogrel. In the following review, we have performed a critical appraisal of the current literature in order to outline lights and shadows on the most relevant clinical scenarios.

Prehospital ticagrelor in ST-segment elevation myocardial infarction

BACKGROUND

The direct-acting platelet P2Y12 receptor antagonist ticagrelor can reduce the incidence of major adverse cardiovascular events when administered at hospital admission to patients with ST-segment elevation myocardial infarction (STEMI). Whether prehospital administration of ticagrelor can improve coronary reperfusion and the clinical outcome is unknown.

METHODS

We conducted an international, multicenter, randomized, double-blind study involving 1862 patients with ongoing STEMI of less than 6 hours' duration, comparing prehospital (in the ambulance) versus in-hospital (in the catheterization laboratory) treatment with ticagrelor. The coprimary end points were the proportion of patients who did not have a 70% or greater resolution of ST-segment elevation before percutaneous coronary intervention (PCI) and the proportion of patients who did not have Thrombolysis in Myocardial Infarction flow grade 3 in the infarct-related artery at initial angiography. Secondary end points included the rates of major adverse cardiovascular events and definite stent thrombosis at 30 days.

RESULTS

The median time from randomization to angiography was 48 minutes, and the median time difference between the two treatment strategies was 31 minutes. The two coprimary end points did not differ significantly between the prehospital and in-hospital groups. The absence of ST-segment elevation resolution of 70% or greater after PCI (a secondary end point) was reported for 42.5% and 47.5% of the patients, respectively. The rates of major adverse cardiovascular events did not differ significantly between the two study groups. The rates of definite stent thrombosis were lower in the prehospital group than in the in-hospital group (0% vs. 0.8% in the first 24 hours; 0.2% vs. 1.2% at 30 days). Rates of major bleeding events were low and virtually identical in the two groups, regardless of the bleeding definition used.

CONCLUSIONS

Prehospital administration of ticagrelor in patients with acute STEMI appeared to be safe but did not improve pre-PCI coronary reperfusion. (Funded by AstraZeneca; ATLANTIC ClinicalTrials.gov number, NCT01347580.).

Effects of P2Y12 receptor inhibition in patients with ST-segment elevation myocardial infarction

In ST-segment elevation myocardial infarction (STEMI), an effective antiplatelet treatment adjunctive to primary percutaneous coronary intervention is of utmost importance. High dose of clopidogrel, prasugrel, or ticagrelor provides a faster, more potent, and more consistent platelet inhibition than standard clopidogrel. Oral P2Y12 inhibitors have been studied in large clinical trials and are in use in clinical practice. Intravenously administered P2Y12 inhibitors such as cangrelor have also been tested. However, statistically significant anti-ischemic superiority of stronger platelet inhibition regimens versus standard clopidogrel has not been proved exclusively in patients receiving primary percutaneous coronary intervention. Whether orally administered antiplatelet agents suffice in patients with STEMI has been recently disputed, mainly because of their delayed onset of action. Platelet reactivity variability before P2Y12 blockade and its evolution over time, genetic predisposition, antiplatelet agent used, timing, and method of platelet function testing significantly affect the rates of high on-treatment platelet reactivity. Although ominous signs of greater bleeding potential of stronger antiplatelet regimens have not appeared in STEMI, this should be carefully tested.

Southern Saskatchewan Ticagrelor Registry experience

BACKGROUND

As ticagrelor enters into clinical use for acute coronary syndrome, it is important to understand patient/physician behavior in terms of appropriate use, adherence, and event rates.

METHODS

The Southern Saskatchewan Ticagrelor Registry is a prospective, observational, multicenter cohort study that identifies consecutive patients started on ticagrelor. We aimed to evaluate both on- and off-label use, identify characteristics of patients who prematurely stop ticagrelor, and describe patient/physician behavior contributing to inappropriate stoppage of this medication.

RESULTS

From April 2012 to September 2013, 227 patients were initiated on ticagrelor, with a mean age of 62.2±12.1 years. The participants were 66% men and had a mean follow up of 157.4±111.7 days. Seventy-four patients (32.4%) had off-label indications. Forty-seven patients (20.7%) prematurely stopped ticagrelor and were more likely to be older, women, nonwhite, present with shock, and complain of dyspnea. Twenty-six of the 47 patients stopped ticagrelor inappropriately because of patient nonadherence (18 patients) and physician advice (eight patients). A composite outcome event of death from vascular causes, myocardial infarction, or stroke occurred in 8.8% of the entire cohort and was more likely to occur in those older then 65 years, those presenting with cardiogenic shock, and those who prematurely stopped ticagrelor.

CONCLUSION

In this real-world registry of patients started on ticagrelor, a third have off-label indications and a fifth prematurely stop the medication. Premature discontinuation was an independent predictor of major life-threatening bleeding and increased composite event rate of death from vascular causes, myocardial infarction, or stroke.

P2Y12-receptor-inhibiting antiplatelet strategies in acute coronary syndromes

Antiplatelet therapy in acute coronary syndromes is essential for preventing stent thrombosis and for reducing major adverse cardiovascular events. Treatment strategy has changed over the last years by frequent use of more active agents inhibiting the ADP mediated activation of platelets instead of clopidogrel, such as prasugrel and ticagrelor. Compared to clopidogrel these modern antiplatelet drugs showed a significant reduction of efficacy endpoints as well as an acceptable safety profile in large multicenter randomized trials (TRITON TIMI 38, PLATO). Going in with higher efficacy a generally higher bleeding risk of prasugrel could be reduced by optimizing the maintenance dose in elderly and underweight patients (TRILOGY-ACS). However even prasugrel and ticagrelor have shown a delayed onset of action in special patient populations (e.g. STEMI) suggesting that the optimal ADP inhibitor has not been found yet. Results of the CHAMPION PHOENIX trial indicate that cangrelor, an intravenous agent, might fulfill these high expectations of an ideal platelet inhibitor in the first hours of an ACS in special patient cohorts. This review summarizes the results of most important clinical studies investigating the novel P2Y12 receptor inhibiting antiplatelet drugs.

What is the optimum adjunctive reperfusion strategy for primary percutaneous coronary intervention?

Acute ST-segment elevation myocardial infarction (STEMI) is a dynamic, thrombus-driven event. As understanding of its pathophysiology has improved, the central role of platelets in initiation and orchestration of this process has become clear. Key components of STEMI include formation of occlusive thrombus, mediation and ultimately amplification of the local vascular inflammatory response resulting in increased vasoreactivity, oedema formation, and microvascular obstruction. Activation, degranulation, and aggregation of platelets are the platforms from which these components develop. Therefore, prompt, potent, and predictable antithrombotic therapy is needed to optimise clinical outcomes after primary percutaneous coronary intervention. We review present pharmacological and mechanical adjunctive therapies for reperfusion and ask what is the optimum combination when primary percutaneous coronary intervention is used as the mode of revascularisation in patients with STEMI.