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

Prehospital tirofiban increases the rate of disrupted myocardial infarction in patients with ST-segment elevation myocardial infarction: insights from the On-TIME 2 trial

AIMS

In patients with ST-segment elevation myocardial infarction (STEMI), prehospital tirofiban significantly improved myocardial reperfusion. However, its impact on the rate of disrupted myocardial infarction (MI), particularly in the context of high-sensitivity cardiac troponin (hs-cTn) assays, is still unclear.

METHODS AND RESULTS

The On-TIME 2 (Ongoing Tirofiban In Myocardial infarction Evaluation 2) trial randomly assigned STEMI patients to prehospital tirofiban or placebo before transportation to a percutaneous coronary intervention (PCI) centre. In this post hoc analysis, we evaluated STEMI patients that underwent primary PCI and had measured hs-cTn levels. Troponin T levels were collected at 18-24 and 72-96 h after PCI. Disrupted MI was defined as peak hs-cTn T levels ≤ 10 times the upper limit of normal (≤140 ng/L). Out of 786 STEMI patients, 47 (6%) had a disrupted MI. Disrupted MI occurred in 31 of 386 patients (8.0%) in the tirofiban arm and in 16 of 400 patients (4.0%) in the placebo arm (P = 0.026). After multivariate adjustment, prehospital tirofiban remained independently associated with disrupted MI (odds ratio 2.03; 95% confidence interval 1.10-3.87; P = 0.027). None of the patients with disrupted MI died during the 1-year follow-up, compared with a mortality rate of 2.6% among those without disrupted MI.

CONCLUSION

Among STEMI patients undergoing primary PCI, the use of prehospital tirofiban was independently associated with a higher rate of disrupted MI. These results, highlighting a potential benefit, underscore the need for future research focusing on innovative pre-treatment approaches that may increase the rate of disrupted MI.

Prepercutaneous coronary intervention Zalunfiban dose-response relationship to target vessel blood flow at initial angiogram in st-elevation myocardial infarction - A post hoc analysis of the cel-02 phase IIa study

BACKGROUND

Zalunfiban (RUC-4) is a novel, subcutaneously administered glycoprotein IIb/IIIa inhibitor (GPI) designed for prehospital treatment to initiate reperfusion in the infarct-related artery (IRA) before primary percutaneous coronary intervention in patients with ST-elevation myocardial infarction (STEMI). Since GPIs have been reported to rapidly reperfuse IRAs, we assessed whether there was a dose-dependent relationship between zalunfiban treatment and angiographic reperfusion indices and thrombus grade of the IRA at initial angiogram in patients with STEMI.

METHODS

This was a post hoc analysis from the open-label Phase IIa study that investigated the pharmacodynamics, pharmacokinetics, and tolerability of three doses of zalunfiban - 0.075, 0.090 and 0.110 mg/kg - in STEMI patients. This analysis explored dose-dependent associations between zalunfiban and three angiographic indices of the IRA, namely coronary and myocardial blood flow and thrombus burden. Zalunfiban was administered in the cardiac catheterization laboratory prior to vascular access, ∼10 to 15 minutes before the initial angiogram. All angiographic data were analyzed by a blinded, independent, core laboratory.

RESULTS

Twentyfour out of 27 STEMI patients were evaluable for angiographic analysis (0.075 mg/kg [n=7], 0.090 mg/kg [n=9], and 0.110 mg/kg [n=8]). TIMI flow grade 2 or 3 was seen in 1/7 patients receiving zalunfiban at 0.075 mg/kg, in 6/9 patients receiving 0.090 mg/kg, and in 7/8 patients receiving 0.110 mg/kg (ptrend = 0.004). A similar trend was observed based on TIMI flow grade 3. Myocardial perfusion was also related to zalunfiban dose (ptrend = 0.005) as reflected by more frequent TIMI myocardial perfusion grade 3. Consistent with the dose-dependent trends in greater coronary and myocardial perfusion, TIMI thrombus ≥4 grade was inversely related to zalunfiban dose (ptrend = 0.02).

CONCLUSION

This post hoc analysis found that higher doses of zalunfiban administered in the cardiac catheterization lab prior to vascular access were associated with greater coronary and myocardial perfusion, and lower thrombus burden at initial angiogram in patients with STEMI undergoing primary percutaneous coronary intervention.

Clinical pharmacology of selatogrel for self-administration by patients with suspected acute myocardial infarction

INTRODUCTION

P2Y12 receptor antagonists (P2Y12 inhibitors) are well established for the treatment of coronary artery disease. The P2Y12 inhibitors currently commercially available present either pharmacokinetic limitations (due to delayed absorption, bioactivation requirement via CYP enzymes, or need of intravenous administration), pharmacodynamic (PD) limitations (limited % inhibition of platelet aggregation (IPA) or relevant PD interactions) or safety limitations (major bleeding in specific populations).

AREAS COVERED

Selatogrel, a 2-phenylpyrimidine-4-carboxamide analog, is a potent, reversible, and selective P2Y12 inhibitor administered subcutaneously that is under development for the treatment of acute myocardial infarction (AMI) in patients with a recent history of AMI. In this review, the authors summarize the results from preclinical, phase 1, and phase 2 trials which showed that selatogrel provides rapid, pronounced, and reversible P2Y12 receptor inhibition with a favorable safety profile.

EXPERT OPINION

These unique characteristics added to the limited potential to interact with co-medications and manageable PD interactions with other P2Y12 inhibitors provide a clear rationale for investigating the benefit of selatogrel as an emergency treatment to improve clinical outcomes in patients with AMI.

Efficacy and safety of intracoronary versus intravenous tirofiban in patients with ST-segment elevation myocardial infarction undergoing primary percutaneous coronary intervention: A meta-analysis of randomized controlled trials

Background

Effective antiplatelet therapy is critical for patients with ST-segment elevation myocardial infarction (STEMI) and receiving primary percutaneous coronary interventions (PPCI). Intracoronary (IC) and intravenous (IV) administration of tirofiban are commonly used during the procedure of PPCI. However, which is the better administration route of tirofiban have not been fully evaluated.

Methods

A comprehensive literature search of RCTs that comparing IC with IV tirofiban in STEMI patients undergoing PPCI was conducted, which were published as of May 7, 2022, in PubMed, Embase, Cochrane Library, Web of Science, Scopus and ClinicalTrials.gov. The primary efficacy endpoint was 30-day major adverse cardiovascular events (MACE) and the primary safety endpoint was in-hospital bleeding events.

Results

This meta-analysis included 9 trials involving 1177 patients. IC tirofiban significantly reduced the incidence of 30-day MACE (RR 0.65, 95% CI: 0.44 to 0.95, P = 0.028) and improved the rate of the thrombolysis in myocardial infarction (TIMI) grade 3 flow in high-dose (25 μg/kg) group (RR = 1.13, 95% CI: 0.99-1.30, P = 0.001), in-hospital (WMD 2.03, 95% CI: 1.03 to 3.02, P < 0.001), and 6-month left ventricular injection fraction (LVEF) (WMD 6.01, 95% CI: 5.02 to 6.99, P < 0.001) compared with IV. There was no significant difference in the incidences of in-hospital bleeding events (RR 0.96, 95% CI: 0.67 to 1.38, P = 0.82) and thrombocytopenia (RR 0.63, 95% CI: 0.26 to 1.57, P = 0.32) between the two groups.

Conclusions

IC tirofiban significantly improved the incidence of TIMI 3 in the high-dose group, in-hospital and 6-month LVEF, and reduced the 30-day MACE incidence without increasing the risk of bleeding compared with IV.

Prehospital treatment with zalunfiban (RUC-4) in patients with ST- elevation myocardial infarction undergoing primary percutaneous coronary intervention: Rationale and design of the CELEBRATE trial

BACKGROUND

Early and complete restoration of target vessel patency in ST-elevation myocardial infarction (STEMI) is associated with improved outcomes. Oral P2Y₁₂ inhibitors have failed to demonstrate either improved patency or reduced mortality when administered in the prehospital setting. Thus, there is a need for antiplatelet agents that achieve prompt and potent platelet inhibition, and that restore patency in the prehospital setting. Zalunfiban, a novel subcutaneously administered glycoprotein IIb/IIIa inhibitor designed for prehospital administration, has shown to achieve rapid, high-grade platelet inhibition that exceeds that of P2Y₁₂ inhibitors. Whether prehospital administration of zalunfiban can improve clinical outcome is unknown.

HYPOTHESIS

The present study is designed to assess the hypothesis that a single, prehospital injection of zalunfiban given in the ambulance, in addition to standard-of-care in patients with STEMI with intent to undergo primary percutaneous coronary intervention (PCI) will improve clinical outcome compared to standard-of-care with placebo.

STUDY DESIGN

The ongoing CELEBRATE trial (NCT04825743) is a phase 3, randomized, double-blinded, placebo-controlled, international trial. Patients with STEMI intended to undergo primary PCI will receive treatment with a single subcutaneous injection containing either zalunfiban dose 1 (0.110 mg/kg), zalunfiban dose 2 (0.130 mg/kg) or placebo, and the study drug will be administered in the ambulance before transportation to the hospital. A target of 2499 patients will be randomly assigned to one of the treatment groups in a 1:1:1 ratio, ie, to have approximately 833 evaluable patients per group. The primary efficacy outcome is a ranked 7-point scale on clinical outcomes. The primary safety outcome is severe or life-threatening bleeding according to the Global Use of Strategies to Open Occluded Coronary Arteries (GUSTO) criteria.

SUMMARY

The CELEBRATE trial will assess whether a single prehospital subcutaneous injection of zalunfiban in addition to standard-of-care in patients with STEMI with intent to undergo primary PCI will result in improved clinical outcome.

Building a Machine Learning-based Ambulance Dispatch Triage Model for Emergency Medical Services

Background

In charge of dispatching the ambulances, Emergency Medical Services (EMS) call center specialists often have difficulty deciding the acuity of a case given the information they can gather within a limited time. Although there are protocols to guide their decision-making, observed performance can still lack sensitivity and specificity. Machine learning models have been known to capture complex relationships that are subtle, and well-trained data models can yield accurate predictions in a split of a second.

Methods

In this study, we proposed a proof-of-concept approach to construct a machine learning model to better predict the acuity of emergency cases. We used more than 360,000 structured emergency call center records of cases received by the national emergency call center in Singapore from 2018 to 2020. Features were created using call records, and multiple machine learning models were trained.

Results

A Random Forest model achieved the best performance, reducing the over-triage rate by an absolute margin of 15% compared to the call center specialists while maintaining a similar level of under-triage rate.

Conclusions

The model has the potential to be deployed as a decision support tool for dispatchers alongside current protocols to optimize ambulance dispatch triage and the utilization of emergency ambulance resources.

Spontaneous Reperfusion in Patients with Transient ST-Elevation Myocardial Infarction-Prevalence, Importance and Approaches to Management

Patients with transient ST-elevation myocardial infarction (STEMI) or spontaneous resolution (SpR) of the ST-segment elevation on electrocardiogram could potentially represent a unique group of patients posing a therapeutic management dilemma. In this review, we discuss the potential mechanisms underlying SpR, its relation to clinical outcomes and the proposed management options for patients with transient STEMI with a focus on immediate versus early percutaneous coronary intervention. We performed a structured literature search of PubMed and Cochrane Library databases from inception to December 2020. Studies focused on SpR in patients with acute coronary syndrome were selected. Available data suggest that deferral of angiography and revascularization within 24-48 h in these patients is reasonable and associated with similar or perhaps better outcomes than immediate angiography. Further randomized trials are needed to elucidate the best pharmacological and invasive strategies for this cohort.

Parenteral Antiplatelet Drugs in ST-Elevation Myocardial Infarction: Current Status and Future Directions

Oral inhibitors of the platelet P2Y₁₂ receptor are indispensable in the treatment of ST-elevation myocardial infarction (STEMI), improving outcomes and even reducing mortality in some studies. However, these drugs are limited by delayed absorption and suboptimal platelet inhibition at the time of primary percutaneous coronary intervention. Despite efforts to achieve faster and more sustained platelet inhibition, strategies such as prehospital administration, higher loading doses, and crushed formulations have not led to improved coronary reperfusion. Parenteral glycoprotein IIb/IIIa inhibitors act sooner and are more potent than oral P2Y₁₂ inhibitors, but their use has been limited by the increased risk of major bleeding and thrombocytopenia. Hence, there is a clinical need to refine drugs that deliver rapid, effective, yet safe platelet inhibition in the setting of STEMI. Novel parenteral antiplatelet drugs, such as cangrelor, selatogrel, and zalunfiban, have been recently developed to achieve rapid, potent antiplatelet effects while preserving hemostasis. We provide a description of currently available parenteral antiplatelet agents and of those in clinical development for prehospital administration in STEMI patients.

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.

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 .

Effect of Ularitide on Cardiovascular Mortality in Acute Heart Failure

BACKGROUND

In patients with acute heart failure, early intervention with an intravenous vasodilator has been proposed as a therapeutic goal to reduce cardiac-wall stress and, potentially, myocardial injury, thereby favorably affecting patients' long-term prognosis.

METHODS

In this double-blind trial, we randomly assigned 2157 patients with acute heart failure to receive a continuous intravenous infusion of either ularitide at a dose of 15 ng per kilogram of body weight per minute or matching placebo for 48 hours, in addition to accepted therapy. Treatment was initiated a median of 6 hours after the initial clinical evaluation. The coprimary outcomes were death from cardiovascular causes during a median follow-up of 15 months and a hierarchical composite end point that evaluated the initial 48-hour clinical course.

RESULTS

Death from cardiovascular causes occurred in 236 patients in the ularitide group and 225 patients in the placebo group (21.7% vs. 21.0%; hazard ratio, 1.03; 96% confidence interval, 0.85 to 1.25; P=0.75). In the intention-to-treat analysis, there was no significant between-group difference with respect to the hierarchical composite outcome. The ularitide group had greater reductions in systolic blood pressure and in levels of N-terminal pro-brain natriuretic peptide than the placebo group. However, changes in cardiac troponin T levels during the infusion did not differ between the two groups in the 55% of patients with paired data.

CONCLUSIONS

In patients with acute heart failure, ularitide exerted favorable physiological effects (without affecting cardiac troponin levels), but short-term treatment did not affect a clinical composite end point or reduce long-term cardiovascular mortality. (Funded by Cardiorentis; TRUE-AHF ClinicalTrials.gov number, NCT01661634 .).

Clinical approach on challenge and desensitization procedures with aspirin in patients with ischemic heart disease and nonsteroidal anti-inflammatory drug hypersensitivity

BACKGROUND

Hypersensitivity to acetylsalicylic acid (ASA) constitutes a serious problem for subjects with coronary artery disease. In such subjects, physicians have to choose the more appropriate procedure between challenge and desensitization. As the literature on this issue is sparse, this study aimed to establish in these subjects clinical criteria for eligibility for an ASA challenge and/or desensitization.

METHODS

Collection and analysis of data on ASA challenges and desensitizations from 10 allergy centers, as well as consensus among the related physicians and an expert panel.

RESULTS

Altogether, 310 subjects were assessed; 217 had histories of urticaria/angioedema, 50 of anaphylaxis, 26 of nonimmediate cutaneous eruptions, and 17 of bronchospasm related to ASA/nonsteroidal anti-inflammatory drugs (NSAID) intake. Specifically, 119 subjects had index reactions to ASA doses lower than 300 mg. Of the 310 subjects, 138 had an acute coronary syndrome (ACS), 101 of whom underwent desensitizations, whereas 172 suffered from a chronic ischemic heart disease (CIHD), 126 of whom underwent challenges. Overall, 163 subjects underwent challenges and 147 subjects underwent desensitizations; 86 of the latter had index reactions to ASA doses of 300 mg or less. Ten subjects reacted to challenges, seven at doses up to 500 mg, three at a cumulative dose of 110 mg. The desensitization failure rate was 1.4%.

CONCLUSIONS

In patients with stable CIHD and histories of nonsevere hypersensitivity reactions to ASA/NSAIDs, an ASA challenge is advisable. Patients with an ACS and histories of hypersensitivity reactions to ASA, especially following doses lower than 100 mg, should directly undergo desensitization.

Rationale for and design of the TRUE-AHF trial: the effects of ularitide on the short-term clinical course and long-term mortality of patients with acute heart failure

The TRUE-AHF is a randomized, double-blind, parallel-group, placebo-controlled trial which is evaluating the effects of a 48-h infusion of ularitide (15 ng/kg/min) on the short- and long-term clinical course of patients with acute heart failure. Noteworthy features of the study include the early enrolment of patients following their initial clinical presentation (within 12 h), and entry blood pressure criteria and thresholds for the adjustment of drug infusion rates, which aim to minimize the risk of hypotension. The trial has two primary endpoints: (i) cardiovascular mortality during long-term follow-up; and (ii) the clinical course of patients during their index hospitalization. Cardiovascular mortality is evaluated in this event-driven trial by following all randomized patients for the occurrence of death until the end of the entire study without truncation at an arbitrarily determined early time point. The clinical course during the index hospitalization is evaluated using the hierarchical clinical composite endpoint, which combines information regarding changes in symptoms and the occurrence of in-hospital worsening heart failure events and death into a single ranked metric that captures interval clinical events and minimizes the likelihood of missing data and confounding due to intensification of background therapy. The design of the TRUE-AHF trial capitalizes on lessons learned from earlier trials and aims to evaluate definitively the potential benefit of ularitide in patients with acute heart failure.

TRIAL REGISTRATION

NCT01661634.

Antithrombotic therapy before, during and after emergency angioplasty for ST elevation myocardial infarction

The first three hours after symptom onset hold the maximum potential for myocardial reperfusion and salvage in ST-elevation myocardial infarction (STEMI) patients. During this period timely primary percutaneous coronary intervention (PPCI) or, when PPCI is not promptly feasible, pre-hospital administration of fibrinolyis or a glycoprotein IIb/IIIa-inhibitor (GPI) have been shown to restore coronary patency and reperfusion and even result in myocardial infarction (MI) abortion. On the other hand, oral antiplatelet therapy may not yet guarantee sufficient platelet inhibition. Patients presenting after this golden time have less, if any, benefit from an aggressive antithrombotic treatment prior to PPCI. Antithrombotic treatment during primary angioplasty should be tailored on the basis of the coronary thrombotic burden, vascular approach and the patient's risk of bleeding complications. A GPI-based approach may be favourable in patients presenting early with large MI and high thrombus burden, whereas a bivalirudin-based approach without GPI may be preferred in patients with higher bleeding risk. There are no data to support the use of GPI in bailout conditions. The powerful oral P2Y₁₂ inhibitors, prasugrel and ticagrelor, have been clearly shown to prevent stent thrombosis and recurrent ischaemic events after emergency percutaneous coronary intervention in STEMI patients. Open issues remaining are the treatment of patients with high bleeding risk, such as the elderly and those requiring anticoagulation, as well as the duration of dual antiplatelet therapy after STEMI.

Pre-angiography total ST-segment resolution is not a reliable predictor of an open infarct-related artery

BACKGROUND

While the cutoffs of predictive value for ST-segment elevations resolution (STSR) following thrombolysis and/or primary PCI were well documented, the impact of pre-angiography STSR has not been established yet.

OBJECTIVES

The aim of this study is to assess prognostic utility of pre-angiography STSR to predict pre-procedural TIMI flow in the infarct-related artery (IRA) and infarct size in STEMI patients undergoing primary PCI.

METHODS

A prospective study was performed, including 310 patients, admitted within 12h of symptom onset and who underwent primary PCI. ST-segment elevations were measured in: (1) qualifying ECG, (2) ECG before angiography, and (3) ECG post PCI. STSR was defined as: total (≥70%), partial (between 70% and 30%) and none (<30%). Relationships between pre-angiography STSR, initial TIMI flow and troponin T level (TnT) were analyzed.

RESULTS

Pre-angiography STSR correlated with initial TIMI flow in the IRA (rS=0.619; p<0.001). Pre-angiography total STSR was observed in 23.2% patients. It was noted in 79.2% of patients with pre-procedural TIMI flow ≥2 and in 20.8% with TIMI flow ≤1 (p<0.001). Although the sensitivity of pre-angiography total STSR to detect pre-procedural TIMI flow ≥2 was 93%, its specificity was only 56% and the likelihood ratio was 2.1. Pre-angiography total STSR was associated with lower peak TnT level (2.2±2.5ng/ml vs. 6.4±5.0ng/ml, p<0.0001) when compared to the remaining patients.

CONCLUSIONS

1. Pre-angiography STSR correlates with preprocedural TIMI flow. 2. The sensitivity of pre-angiography total STSR in detection of pre-procedural TIMI flow ≥2 is high, but low specificity of only 56% makes it an unreliable predictor of an open IRA.

[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.

The effect of hospital care on early survival after penetrating trauma

Background

The effectiveness of emergency medical interventions can be best evaluated using time-to-event statistical methods with time-varying covariates (TVC), but this approach is complicated by uncertainty about the actual times of death. We therefore sought to evaluate the effect of hospital intervention on mortality after penetrating trauma using a method that allowed for interval censoring of the precise times of death.

Methods

Data on persons with penetrating trauma due to interpersonal assault were combined from the 2008 to 2010 National Trauma Data Bank (NTDB) and the 2004 to 2010 National Violent Death Reporting System (NVDRS). Cox and Weibull proportional hazards models for survival time (t_SURV) were estimated, with TVC assumed to have constant effects for specified time intervals following hospital arrival. The Weibull model was repeated with t_SURV interval-censored to reflect uncertainty about the precise times of death, using an imputation method to accommodate interval censoring along with TVC.

Results

All models showed that mortality was increased by older age, female sex, firearm mechanism, and injuries involving the head/neck or trunk. Uncensored models showed a paradoxical increase in mortality associated with the first hour in a hospital. The interval-censored model showed that mortality was markedly reduced after admission to a hospital, with a hazard ratio (HR) of 0.68 (95% CI 0.63, 0.73) during the first 30 min declining to a HR of 0.01 after 120 min. Admission to a verified level I trauma center (compared to other hospitals in the NTDB) was associated with a further reduction in mortality, with a HR of 0.93 (95% CI 0.82, 0.97).

Conclusions

Time-to-event models with TVC and interval censoring can be used to estimate the effect of hospital care on early mortality after penetrating trauma or other acute medical conditions and could potentially be used for interhospital comparisons.

Electronic supplementary material

The online version of this article (doi:10.1186/s40621-014-0024-1) contains supplementary material, which is available to authorized users.

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.

Estimating the effect of emergency care on early survival after traffic crashes

INTRODUCTION

Traffic crash mortality is higher in rural areas, but it is unclear whether this is due to greater injury severity, time delays, or Emergency Medical Services (EMS) deficiencies.

METHODS

Data from 2002-2003 were combined from the Fatality Analysis Reporting System (FARS) and an "expanded version" of the National Automotive Sampling System (NASS) Crashworthiness Data System (CDS). Weighted Cox and Weibull models for survival time (tSURV) were estimated, with time-varying covariates (TVC) having constant effects for specified time intervals following EMS arrival time (tEMS) and hospital arrival time (tHOS). The Weibull model was repeated with tSURV interval-censored to reflect uncertainty about the exact time of death, using an imputation method to accommodate interval censoring along with TVC.

RESULTS

FARS contained records for 92,718 persons with fatal or incapacitating injuries, and NASS/CDS contained 5517 (weighted population of 642,716) with incapacitating injuries. All models associated mortality with increasing age, male sex, belt nonuse, higher speeds, and vehicle rollover. The interval-censored model associated EMS intervention with a beneficial effect until tEMS+30 min, but not thereafter; hospital intervention was associated with a strongly beneficial effect that increased with time. Rural location was associated with a higher baseline hazard; a 50% reduction in rural prehospital time would theoretically reduce 4-h mortality by about 7%.

CONCLUSION

Rural/urban disparity in crash mortality is mostly independent of time delays and EMS effects. However, survival models with TVC support clinical intuition of a "golden hour" in EMS care, and the importance of timely transport to a hospital.

High Bolus Tirofiban vs Abciximab in Acute STEMI Patients Undergoing Primary PCI - The Tamip Study

BACKGROUND

Primary percutaneous coronary intervention (PCI) has been shown to be an effective therapy for patients with acute myocardial infarction (MI). Glycoprotein (GP) IIb/IIIa receptor blockers reduce thrombotic complications in patients undergoing PCI. Most available data relate to Reopro, which has been registered for this indication. GP IIb/IIIa reduce unfavorable outcome in U/A and non ST-elevation myocardial infarction (STEMI) patients. Only few studies focused on high dose Aggrastat for STEMI patients in the emergency department (ED) before PCI. The aim is to increase the patency during the time awaiting coronary angioplasty in patients with acute MI.

OBJECTIVES

To study the effect of upfront high bolus dose (HDR) of tirofiban on the extent of residual ST segment deviation 1 hour after primary PCI and the incidence of TIMI 3 flow of the infarct-related artery (IRA).

MATERIALS AND METHODS

A randomized, open label, single center study in the ED. A total of 90 patients with acute ST-elevation MI, diagnosed clinically by ECG criteria (ST segment elevation of >2 mm in two adjacent ECG leads), and with an expectation that a patient will undergo primary PCI. Patients were aged 21-85 years and all received heparin 5000 u, aspirin 160 mg, and Plavix 600 mg. Patients were divided in two groups (group I: triofiban high bolus vs group II: Reopro) with 45 patients in each group. In group I, high bolus triofiban 25 mcg/kg over 3 min was started in the ED with maintenance infusion of 0.15 mcg/ kg/min continued for 12 hours and transferred to cath lab for PCI. Patients in group II were transferred to cath lab, where a standard dose of Reopro was given with a bolus of 0.25 mcg/kg and maintenance infusion of 0.125 mcg/kg/min over 12 hours.

RESULTS

ST segment resolution and TIMI flow were evaluated in both groups before and after PCI. Thirty-five patients (78%) enrolled in group I and 29 patients (64%) in group II had resolution of ST segment (P-value 0.24). Twenty-one patients (47% group I) vs 23 patients (51% group II) with P-value 0.83 achieved TIMI 0 flow. Twenty-four patients (53% group I) compared with 22 patients (49% group II) with P-value 0.83 had TIMI 1 to 3 flow before PCI. TIMI 3 flow was achieved in 40 patients (89% group I) compared with 38 patients (84% group II) with P-value 0.76.

CONCLUSION

In this study there was a trend toward better ST segment resolution and patency of IRA (i.e., improved TIMI flow) in patients given high bolus dose Aggrastat in the ED. Larger studies are needed to confirm this finding.

Pre PCI hospital antithrombotic therapy for ST elevation myocardial infarction: striving for consensus

Strong evidence exists in favor of rapid transfer of a patient suffering an ST-elevation myocardial infarction (STEMI) to the nearest hospital with primary percutaneous coronary intervention (PCI) capability, assuming the time from first medical contact to balloon inflation can be achieved in less than 90 min. In many areas, PCI hospitals have successfully collaborated with regional non-PCI hospitals to provide primary PCI for STEMI; however, significant variations exist in how these programs are executed. For example, the pre PCI hospital administration of antithrombotic agents by emergency medical personnel can include aspirin, clopidogrel, unfractionated heparin, low molecular weight heparin, partial or full dose fibrinolytics or combinations thereof. There is little consensus on the optimal cocktail, dose and route of administration. Standardizing the pre PCI antithrombotic regimen across hospital systems may be one approach to improve timely administration of these therapies, and potentially improve STEMI outcomes.

Beneficial effects of intracoronary tirofiban bolus administration following upstream intravenous treatment in patients with ST-elevation myocardial infarction undergoing primary percutaneous coronary intervention: the ICT-AMI study

BACKGROUND

We investigated whether an additional intracoronary tirofiban bolus administration following upstream intravenous treatment could further improve myocardial reperfusion and clinical outcome in patients with ST-elevation myocardial infarction (STEMI) undergoing primary percutaneous coronary intervention (PCI).

METHODS

A total of 453 eligible STEMI patients were randomly allocated to intracoronary bolus administration of tirofiban (10 μg/kg; n=229) or saline (10 mL; n=224) during primary PCI, followed by intravenous tirofiban infusion (0.15 μg/kg/min) for 24-36 h. Serum levels of P-selectin, vWF, CD40L and serum amyloid A (SAA) in the coronary sinus were measured before and after intracoronary bolus administration. The primary endpoint was ST-segment resolution (STR) at 90 min after the procedure. Second endpoints included corrected TIMI frame count (cTFC), left ventricular volumes and ejection fraction (EF), and major adverse cardiac events (MACE) at 30-day and 6-month follow-up.

RESULTS

Intracoronary tirofiban administration resulted in a higher rate of completed STR (59.0% vs. 44.6%, P=0.002), lower cTFC (21.6±5.4 vs. 23.7±7.8, P=0.048), and significantly reduced coronary sinus levels of P-selectin, vWF, CD40L and SAA. Patients treated with intracoronary tirofiban had a trend toward less MACE at 30 days (3.1% vs. 6.7%, P=0.072). At 6 months, left ventricular end-systolic volume was smaller, EF was higher and MACE-free survival was improved (96.1% vs. 90.6%, P=0.020) in the intracoronary tirofiban group.

CONCLUSIONS

An additional intracoronary tirofiban bolus administration following upstream intravenous treatment reduces coronary circulatory platelet activation and inflammatory process, and significantly improves myocardial reperfusion and left ventricular function as well as 6-month MACE-free survival for STEMI patients undergoing primary PCI.