Current and Future Roles of Glycoprotein IIb-IIIa Inhibitors in Primary Angioplasty for ST-Segment Elevation Myocardial Infarction

Acute myocardial infarction still represents the major cause of mortality in high-income countries. Therefore, considerable efforts have been focused on the treatment of myocardial infarctions in the acute and long-term phase, with special attention being paid to reperfusion strategies and adjunctive antithrombotic therapies. In fact, despite the successful mechanical recanalization of the epicardial conduit, a substantial percentage of patients still experience poor myocardial reperfusion or acute/subacute in-stent thrombosis. Due the delayed onset of action of currently available oral antiplatelet therapies, glycoprotein (GP) IIb-IIIa inhibitors could be expected to improve clinical outcomes, especially when administrated in the early phase of the infarction, due to the larger platelet composition of fresh thrombi, the dynamic nature of early thrombi, and the larger amount of viable myocardium existing in the early, as compared to a delayed, phase. Considerable evidence has accumulated regarding the benefits from GP IIb-IIIa inhibitors on mortality, especially among high-risk patients and when administered as an upstream strategy. Therefore, based on currently available data, GP IIb-IIIa inhibitors can be considered when the drug can be administered within the first 3 h of symptom onset and among high-risk patients (e.g., those with advanced Killip class or an anterior myocardial infarction). Even though it is not universally accepted, in our opinion, this strategy should be implemented in a pre-hospital setting (in an ambulance) or as soon as possible when arriving at the hospital (at the Emergency Room or Coronary Care Unit, irrespective of whether they are in spoke or hub hospitals). A new, second-generation GP IIb-IIIa inhibitor (zalunfiban) appears to be highly suitable as a pre-hospital pharmacological facilitation strategy at the time of first medical contact due to its favourable features, including its simple subcutaneous administration, rapid onset of action (15 min), and limited time of action (with a half-life of ~1 h), which is likely to minimize the risk of bleeding. The ongoing CELEBRATE trial, including 2499 STEMI patients, may potentially provide compelling data to support the upstream treatment of STEMI patients undergoing mechanical reperfusion. In fact, although the current therapeutic target of increased rates of timely reperfusion has been achieved, the future goal in myocardial infarction treatment should be to achieve the most rapid reperfusion prior to primary percutaneous coronary intervention, thus further minimizing myocardial damage, or, in some cases, even preventing it completely, and improving survival.

Modulators of Mortality Benefit From Peri-Angioplasty Adjunctive Tirofiban in Patients With ST-Elevation Myocardial Infarction Undergoing Primary Percutaneous Coronary Intervention

BACKGROUND

Studies investigating the modulators of mortality benefit conferred by peri-angioplasty glycoprotein IIb/IIIa inhibitors in ST-elevation myocardial infarction (STEMI) are still lacking.Methods and Results:A prospective database (n=1,025) of consecutive cases undergoing primary percutaneous coronary intervention for STEMI was retrospectively analyzed. For patients in Killip class I, II or III, IV, the multivariate-adjusted hazard ratios of 30-day all-cause mortality associated with adjunctive tirofiban were 3.873 (95% CI 0.504-29.745; P=0.193), 0.550 (95% CI 0.188-1.609; P=0.275), and 0.264 (95% CI 0.099-0.704; P=0.008), respectively. The P value for a linear trend was 0.032. Patients who had a body mass index (BMI) within 22.9-25.0 kg/m²had a significant benefit from tirofiban (adjusted HR 0.344; 95% CI 0.145-0.814; P=0.015) compared to other BMI groups. The P value for a quadratic trend was 0.012. A novel Killip-BMI score (KBS = 2.5 × Killip category - | BMI - 24 |) was calculated to select the beneficial population. A KBS ≥2 was associated with significant mortality benefit, whereas a KBS <0 predicted increased 30-day mortality with tirofiban use.

CONCLUSIONS

Survival benefit from peri-angioplasty tirofiban therapy for STEMI was positively correlated with the Killip class. Tirofiban should be used cautiously in either underweight or overweight patients. The novel KBS used in this study can guide peri-angioplasty use of adjunctive tirofiban in patients with STEMI undergoing primary angioplasty.

Prodromal angina and risk of 2-year cardiac mortality in patients with ST-segment elevation myocardial infarction undergoing primary percutaneous intervention

We sought to investigate the prognostic significance of prodromal angina (PA) in unselected patients with ST-segment elevation myocardial infarction (STEMI) undergoing primary percutaneous coronary intervention (PPCI) and its additive predictive value to the GRACE score.We prospectively enrolled 3015 consecutive STEMI patients undergoing PPCI. Patients were divided in 2 groups according to the presence or absence of PA. Multivariable Cox regression was used to establish the relation to 2-year cardiac mortality of PA.The mean age of the study population was 68 (±14) years; 2178 patients (72%) were male. During follow-up, 395 (13%) patients died with 278 of these (9.2%) suffering from cardiac mortality. Kaplan-Meier estimates showed a survival rate of 95% and 87% for patients with PA and no PA, respectively (log rank test < 0.001). After multivariable analysis, patients with PA had still a lower risk of 2 years' cardiac mortality compared with patients without PA (adjusted hazard ratio = 0.50; 95% confidence interval [CI] 1.06-1.81, P = .001). Evaluation of net reclassification improvement showed that reclassification improved by 0.16% in case patients, whereas classification worsened in control patients by 1.08% leading to a net reclassification improvement of -0.93% (95% CI: -0.98, -0.88).In patients with STEMI undergoing PPCI the presence of PA is independently associated with a lower risk of 2-year cardiac mortality. However, the incorporation of this variable to the GRACE score slightly worsened the classification of risk. Accordingly, it seems unlikely that the evaluation of PA may be useful in clinical practice.

Guanxinning tablet for patients who switch from dual antiplatelet therapy to aspirin alone after percutaneous coronary intervention: study protocol for a cluster randomized controlled trial

Background

One-year dual antiplatelet therapy (DAPT), generally aspirin in combination with a P2Y12 receptor inhibitor, has been a standard treatment for patients undergoing percutaneous coronary intervention (PCI). Prolonged DAPT has proven itself effective in further reducing cardiovascular events, yet with increased risk of bleeding. Thus, it is of great necessity to find an alternative drug that is as effective but safer and more economic than the P2Y12 inhibitors after termination of one-year DAPT.

Methods

We will conduct a cluster randomized controlled trial in 3600 eligible post-PCI patients from 36 tertiary hospitals (100 patients per hospital) across mainland China. The hospitals served as clusters are randomized in a 2:1 ratio to Guanxinning tablet (GXNT) plus aspirin or aspirin alone for 12 months, with other conventional treatment applied in both groups. After the treatment period, all patients will be followed up for another 12 months. The primary outcome measure is composite cardiovascular events including cardiovascular death, non-fatal myocardial infarction, stent thrombosis, revascularization, ischemic stroke, and re-admission due to unstable angina. Secondary outcome measures are all-cause mortality, each individual component of the primary outcome measure, and stopping or reducing the rate of nitroglycerin administration. Adverse events, including bleeding, will be closely monitored during the whole trial period. In addition, a cost-effectiveness study of GXNT for the study population will be conducted along with this trial.

Discussion

This trial aims to determine whether the addition of GXNT will further improve prognosis without increasing bleeding risk for patients with coronary artery disease who have switched from DAPT to aspirin alone after PCI. Completion of this clinical trial might provide a novel, promising, and safer alternative to P2Y12 inhibitors for prolonged antiplatelet therapy in post-PCI patients.

Trial registration

Chinese Clinical Trial Registry, ChiCTR-IIR-17010688. Registered on 20 February 2017.

Electronic supplementary material

The online version of this article (10.1186/s13063-017-2373-x) contains supplementary material, which is available to authorized users.

The experiences of myocardial infarction patients readmitted within six months of primary percutaneous coronary intervention

AIMS AND OBJECTIVES

To explore the experiences of patients readmitted due to potential ischaemic heart disease symptoms within six months of primary percutaneous coronary intervention.

BACKGROUND

Following myocardial infarction and primary percutaneous coronary intervention, some patients experience potential ischaemic heart disease symptoms that may lead to readmission. Symptoms may be related to cardiac ischaemia, reduced psychological health or a comorbid condition.

DESIGN

A qualitative study involving semistructured, in-depth interviews conducted once, mean 196 (50-384) days following readmission (at least six months following original ST-elevation myocardial infarction and primary percutaneous coronary intervention). This is the qualitative part of a mixed methods study.

METHODS

Participants were purposefully selected, and concurrent sampling, data collection and data analysis were performed. Data were organised using framework analysis; constant comparative analysis involving deduction and induction led to identification of cogent themes and subthemes.

RESULTS

Twenty-five participants (14 men, 27-79 years) experienced 1-4 readmissions; discharge diagnoses were cardiac, psychological, indeterminate, pulmonary and gastric. Three main themes emerged: (1) anxiety, uncertainty and inability to determine cause of symptoms, (2) fear of experiencing further myocardial infarction and (3) insufficient opportunity to validate self-construction of illness.

CONCLUSION

Fear of dying or experiencing a further myocardial infarction led to patients seeking help at the time of potential ischaemic heart disease symptoms. Participants were anxious and lacked understanding regarding symptom attribution at the time of readmission and generally following their heart attack. Additionally, original heart attack symptoms were used as a comparator for future symptoms. Participants reported feeling well immediately after primary percutaneous coronary intervention but later experiencing fatigue and debilitation often linked to potential ischaemic heart disease symptoms.

RELEVANCE TO CLINICAL PRACTICE

Increased education and information related to symptom attribution post-primary percutaneous coronary intervention and postreadmission are worthy of exploration and may lead to increased understanding and reassurance for this patient group.

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.

ST-segment resolution with bivalirudin versus heparin and routine glycoprotein IIb/IIIa inhibitors started in the ambulance in ST-segment elevation myocardial infarction patients transported for primary percutaneous coronary intervention: The EUROMAX ST-segment resolution substudy

BACKGROUND

Myocardial reperfusion after primary percutaneous coronary intervention (PCI) can be assessed by the extent of post-procedural ST-segment resolution. The European Ambulance Acute Coronary Syndrome Angiography (EUROMAX) trial compared pre-hospital bivalirudin and pre-hospital heparin or enoxaparin with or without GPIIb/IIIa inhibitors (GPIs) in primary PCI. This nested substudy was performed in centres routinely using pre-hospital GPI in order to compare the impact of randomized treatments on ST-resolution after primary PCI.

METHODS

Residual cumulative ST-segment deviation on the single one hour post-procedure electrocardiogram (ECG) was assessed by an independent core laboratory and was the primary endpoint. It was calculated that 762 evaluable patients were needed to show non-inferiority (85% power, alpha 2.5%) between randomized treatments.

RESULTS

A total of 871 participated with electrocardiographic data available in 824 patients (95%). Residual ST-segment deviation one hour after PCI was 3.8±4.9 mm versus 3.9±5.2 mm for bivalirudin and heparin+GPI, respectively ( p=0.0019 for non-inferiority). Overall, there were no differences between randomized treatments in any measures of ST-segment resolution either before or after the index procedure.

CONCLUSIONS

Pre-hospital treatment with bivalirudin is non-inferior to pre-hospital heparin + GPI with regard to residual ST-segment deviation or ST-segment resolution, reflecting comparable myocardial reperfusion with the two strategies.

Impact of time from symptom onset to drug administration on outcome in patients undergoing glycoprotein IIb-IIIa facilitated primary angioplasty (from the EGYPT cooperation)

Contrasting data have been so far reported on facilitation with glycoprotein IIb-IIIa inhibitors (GpIIbIIIa) in patients who underwent primary percutaneous coronary intervention. However, it has been demonstrated a time-dependent composition of coronary thrombus in ST-segment elevation myocardial infarction, with more platelets in the first hours. Subsequently, the benefits of early administration of GpIIbIIIa may be affected by the time from symptoms onset to GpIIbIIIa, that therefore is the aim of this study. Our population is represented by 814 patients who underwent GpIIbIIIa facilitated primary angioplasty included in the Early glycoprotein IIb-IIIa inhibitors in primary angioplasty database. Patients were divided according to quartiles of time from symptom onset to GpIIbIIIa administration (≤65 minutes; 65 to 100 minutes; 101 to 178 minutes; and >178 minutes). Myocardial perfusion was evaluated by myocardial blush grade and ST-segment resolution. Time from symptoms onset to GpIIbIIIa was linearly associated with hypertension, diabetes, hypercholesterolemia, and previous myocardial infarction but inversely associated with smoking. Abciximab was more often administrated later from symptoms onset. Time from symptoms onset to GpIIbIIIa was significantly associated with the rate of preprocedural recanalization (thrombolysis in myocardial infarction [TIMI] 2 to 3; p <0.001), postprocedural TIMI 3 flow (p <0.001), the rate of complete ST-segment resolution (p <0.001), and the rate of myocardial blush grade 2 to 3 (p <0.001) and inversely associated with the occurrence of distal embolization (p <0.001). Follow-up data were collected at a median (twenty-fifth to seventy-fifth) of 360 (30 to 1,095) days. A total of 52 patients had died. Time to GpIIbIIIa had a significant impact on mortality (hazard ratio [95% confidence interval] 1.46 [1.11 to 1.92], p = 0.007) that was confirmed after correction for baseline confounding factors (adjusted hazard ratio [95% confidence interval] 1.41 [1.02 to 2.21], p = 0.042). In conclusion, this study showed that in patients who underwent primary angioplasty with upstream GpIIbIIIa, time from symptoms onset to GpIIbIIIa strongly impacts on preprocedural recanalization, distal embolization, myocardial perfusion, and long-term survival.

Preprocedural TIMI flow and infarct size in STEMI undergoing primary angioplasty

Despite optimal epicardial recanalization, primary angioplasty for STEMI is still associated with suboptimal reperfusion in a relatively large proportion of patients. The aim the current study was to evaluate the impact of preprocedural TIMI flow on myocardial scintigraphic infarct size among STEMI undergoing primary angioplasty. Our population is represented by 793 STEMI patients undergoing primary PCI. Infarct size was evaluated at 30 days by technetium-99m-sestamibi. Poor preprocedural TIMI flow (TIMI 0-1) was observed in 645 patients (81.3%). Poor preprocedural TIMI flow was associated with more hypercholesterolemia (p = 0.012), and a trend in lower prevalence of diabetes (p = 0.081). Preprocedural TIMI flow significantly affected scintigraphic and enzymatic infarct size. Similar findings were observed in the analysis restricted to patients with postprocedural TIMI 3 flow. The impact of preprocedural TIMI flow on scintigraphic infarct size was confirmed when the analysis was performed according to the percentage of patients above the median (p < 0.001) and after adjustment for baseline confounding factors (Hypercholesterolemia and diabetes) [adjusted OR (95% CI) for pre preprocedural TIMI 3 flow = 0.59 (0.46-0.75), p < 0.001]. This study shows that among patients with STEMI undergoing primary angioplasty, poor preprocedural TIMI flow is independently associated with larger infarct size.

RUC-4: a novel αIIbβ3 antagonist for prehospital therapy of myocardial infarction

OBJECTIVE

Treatment of myocardial infarction within the first 1 to 2 hours with a thrombolytic agent, percutaneous coronary intervention, or an αIIbβ3 antagonist decreases mortality and the later development of heart failure. We previously reported on a novel small molecule αIIbβ3 antagonist, RUC-2, that has a unique mechanism of action. We have now developed a more potent and more soluble congener of RUC-2, RUC-4, designed to be easily administered intramuscularly by autoinjector to facilitate its use in the prehospital setting. Here, we report the properties of RUC-4 and the antiplatelet and antithrombotic effects of RUC-2 and RUC-4 in animal models.

APPROACH AND RESULTS

RUC-4 was ≈ 20% more potent than RUC-2 in inhibiting human ADP-induced platelet aggregation and much more soluble in aqueous solutions (60-80 mg/mL). It shared RUC-2's specificity for αIIbβ3 versus αVβ3, did not prime the receptor to bind fibrinogen, or induce changes in β3 identified by a conformation-specific monoclonal antibody. Both RUC-2 and RUC-4 prevented FeCl3-induced thrombotic occlusion of the carotid artery in mice and decreased microvascular thrombi in response to laser injury produced by human platelets infused into transgenic mice containing a mutated von Willebrand factor that reacts with human but not mouse platelets. Intramuscular injection of RUC-4 in nonhuman primates at 1.9 and 3.85 mg/kg led to complete inhibition of platelet aggregation within 15 minutes, with dose-dependent return of platelet aggregation after 4.5 to 24 hours.

CONCLUSIONS

RUC-4 has favorable biochemical, pharmacokinetic, pharmacodynamic, antithrombotic, and solubility properties as a prehospital therapy of myocardial infarction, but the possibility of increased bleeding with therapeutic doses remains to be evaluated.

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.

A prospective cohort study investigating readmission, symptom attribution and psychological health within six months of primary percutaneous coronary intervention

AIMS

Following primary percutaneous coronary intervention (PPCI) for ST-elevation myocardial infarction, some patients are readmitted with potential ischaemic heart disease symptoms. This study investigated the proportion of PPCI patients readmitted due to potential ischaemic heart disease symptoms within six months, and the cause of symptoms and associated factors.

METHODS AND RESULTS

A prospective cohort study included consecutive PPCI patients. Baseline variables incorporated the Global Registry of Acute Coronary Events, the Charlson Comorbidity Index and self-report measures ENRICHD Social Support Inventory, Seattle Angina Questionnaire (SAQ) and Hospital and Anxiety and Depression Scale (HADS). At six months, repeat SAQ, HADS and readmission data were collected. Of 202 PPCI patients (mean 59.7 years (SD 13.9), 75.7% male), 38 (18.8%; 95% confidence interval 14.0-24.8%) were readmitted due to potential ischaemic heart disease symptoms (16 cardiac events, 22 indeterminate diagnosis) at six months. Mean HADS anxiety scores were higher for the readmission compared with the non-readmission group (baseline 9.5 vs. 7.1, p=0.006; six months 9.4 vs. 6.0, p<0.001). Angina symptoms were stable and infrequent throughout for both groups. Logistic regression modelling, including predictors HADS anxiety, SAQ angina stability, SAQ angina frequency, the Global Registry of Acute Coronary Events and the Charlson Comorbidity Index, determined HADS anxiety as a predictor of readmission with adjusted odds ratio of 1.12 (95% confidence interval 1.03-1.22, p=0.008).

CONCLUSION

One in six patients were readmitted due to potential ischaemic heart disease symptoms, with the largest proportion receiving an indeterminate readmission diagnosis. Elevated levels of anxiety at baseline were predictive of readmission with potential ischaemic heart disease symptoms at six months.

Significance of antiplatelet therapy in emergency myocardial infarction treatment

Antiplatelet drugs play a crucial role in the treatment of patients with myocardial infarction, particularly in association with percutaneous coronary intervention. Their main advantage is the reduction of adverse ischemic incidents and the major disadvantage is the increase in the frequency of hemorrhages. Thus, the choice of appropriate drug depends on the right risk assessment of the development of these complications in individual patients. The aim of this article is to provide an update of antiplatelet therapy in emergency myocardial infarction treatment. Currently, the most important role in the process of platelet inhibition is played by ADP P2Y12 blockers: clopidogrel, prasugrel and ticagrelor. Clopidogrel and prasugrel belong to thienopyridines, and ticagrelor, a drug of irreversible action, is an analogue of adenosine triphosphate. By 2011 clopidogrel, alongside aspirin, had the highest recommendations of world cardiology associations for acute coronary syndrome treatment. The position on clopidogrel was changed following the publication of European Society of Cardiology guidelines for STEMI in 2012 which advocate the administration of acetylsalicylic acid (ASA) and ADP receptor blocker (in combination with ASA). It needs to be stressed that prasugrel and ticagrelor received class IB recommendation, while clopidogrel received only IC. However, the most recent studies aimed at introducing a new generation of antiplatelet drugs of high efficacy in prevention of ischemic incidents and of reversible action: cangrelor and elinogrel, which raise hopes for better prognosis for myocardial infarction patients.

Elevating local concentrations of GPIIb-IIIa antagonists counteracts platelet thrombus stability

Glycoprotein IIb-IIIa (GPIIb-IIIa) antagonists have the capacity to destabilize coronary thrombi and restore vessel patency. Antagonist concentration and residence time, which can be increased by local intracoronary (LIC) administration, and thrombus age may be key factors that influence thrombus stability. Light transmission aggregometry was used to examine the effects of exposing human platelet aggregates to extremely high local levels of GPIIb-IIIa antagonists versus conventional therapeutic levels in vitro. Freshly-formed or aged platelet aggregates were subjected to GPIIb-IIIa antagonists (abciximab, eptifibatide) or direct thrombin inhibitor bivalirudin at concentrations simulating either conventional intravenous (IV) or LIC administration. The degree of antagonist-induced disaggregation was significantly higher using elevated (LIC) doses versus conventional (IV) doses (60.1 % vs. 7.4 % for abciximab, 41.6 % or 45.3 % vs. 17.6 % for eptifibatide, p < 0.01). Bivalirudin did not promote disaggregation. Microscopy confirmed noticeably smaller, more dispersed aggregates for antagonist LIC treatments. Dosing at LIC levels also induced more disaggregation than IV levels when aggregates were aged for 30 min prior to exposure. An in vitro perfusion model was used to simulate the fluid dynamics of IV or LIC administration of abciximab using a microporous local drug delivery balloon catheter such as the Atrium ClearWay™ RX. The perfusion model resulted in more rapid thrombus clearance with LIC dosing levels compared to IV. In summary, boosting the concentration of GPIIb-IIIa antagonists enhances dispersal of human platelet aggregates in vitro. These data provide a foundation for investigating increased local concentrations of GPIIb-IIIa antagonists in patients, as with LIC administration.

Design and methods of European Ambulance Acute Coronary Syndrome Angiography Trial (EUROMAX): an international randomized open-label ambulance trial of bivalirudin versus standard-of-care anticoagulation in patients with acute ST-segment-elevation myocardial infarction transferred for primary percutaneous coronary intervention

BACKGROUND

In patients with ST-segment elevation myocardial infarction (STEMI) triaged to primary percutaneous coronary intervention (PCI), anticoagulation often is initiated in the ambulance during transfer to a PCI site. In this prehospital setting, bivalirudin has not been compared with standard-of-care anticoagulation. In addition, it has not been tested in conjunction with the newer P2Y12 inhibitors prasugrel or ticagrelor.

DESIGN

EUROMAX is a randomized, international, prospective, open-label ambulance trial comparing bivalirudin with standard-of-care anticoagulation with or without glycoprotein IIb/IIIa inhibitors in 2200 patients with STEMI and intended for primary percutaneous coronary intervention (PCI), presenting either via ambulance or to centers where PCI is not performed. Patients will receive either bivalirudin given as a 0.75 mg/kg bolus followed immediately by a 1.75-mg/kg per hour infusion for ≥30 minutes prior to primary PCI and continued for ≥4 hours after the end of the procedure at the reduced dose of 0.25 mg/kg per hour, or heparins at guideline-recommended doses, with or without routine or bailout glycoprotein IIb/IIIa inhibitor treatment according to local practice. The primary end point is the composite incidence of death or non-coronary-artery-bypass-graft related protocol major bleeding at 30 days by intention to treat.

CONCLUSION

The EUROMAX trial will test whether bivalirudin started in the ambulance and continued for 4 hours after primary PCI improves clinical outcomes compared with guideline-recommended standard-of-care heparin-based regimens, and will also provide information on the combination of bivalirudin with prasugrel or ticagrelor.

Short-term effect of upstream administration in comparison to deferred injection of tirofiban on patients with acute ST-segment elevation myocardial infarction undergoing primary percutaneous coronary intervention

BACKGROUND

High bolus dose tirofiban has been demonstrated to provide greater inhibition of platelet aggregation, but the most appropriate timing of its administration remains unknown.

OBJECTIVES

To evaluate the efficacy of upstream vs. deferred administration of tirofiban in patients with acute ST-segment elevation myocardial infarction undergoing primary percutaneous coronary intervention (PCI) on clinical outcomes.

METHODS

The 660 patients with acute ST-segment elevation myocardial infarction undergoing primary percutaneous coronary intervention were divided into upstream (n=330, administration of tirofiban to all patients in emergency room) and deferred groups (n=330, treatment of patients with large thrombus burden or no-reflow phenomenon in cardiac catheterization laboratory during PCI). The primary end-points were death, nonfatal myocardial infarction (MI), stent thrombosis (ST), revascularization of targeted vessels (TVR) or major adverse cardiac events (MACE) at 1 month and 6 months following PCI, with safety end-point at 7 days.

RESULTS

Compared with that of the deferred group, there was a significant increase of left ventricular ejection fraction (LVEF) in the upstream group within 7 days (55.5 ± 6.6% vs. 54.6 ± 7.9%, P=0.011). The rates of 7-day and 1-month MACE in the upstream group were lower than those in the deferred group (1.5% vs. 4.2%, 3.3% vs. 7.0%, P=0.037 and 0.034, respectively). However, there were higher tendencies for major and minor bleedings in the upstream group (1.8% vs. 0.9%, 2.7% vs. 1.5%, P=0.315 and 0.280, respectively).

CONCLUSION

To the Chinese patients with acute myocardial infarction undergoing primary PCI, upstream administration of tirofiban was slightly superior to deferred injection for short-term clinical outcomes.

Early glycoprotein IIb-IIIa inhibitors in primary angioplasty-abciximab long-term results (EGYPT-ALT) cooperation: individual patient's data meta-analysis

BACKGROUND

Even although time to treatment has been shown to be a determinant of mortality in primary angioplasty, the potential benefits are still unclear from early pharmacological reperfusion by glycoprotein (Gp) IIb-IIIa inhibitors. Therefore, the aim of this meta-analysis was to combine individual data from all randomized trials conducted on upstream as compared with late peri-procedural abciximab administration in primary angioplasty.

METHODS

The literature was scanned using formal searches of electronic databases (MEDLINE and EMBASE) from January 1990 to December 2010. All randomized trials on upstream abciximab administration in primary angioplasty were examined. No language restrictions were enforced.

RESULTS

We included a total of seven randomized trials enrolling 722 patients, who were randomized to early (n = 357, 49.4%) or late (n = 365, 50.6%) peri-procedural abciximab administration. No difference in baseline characteristics was observed between the two groups. Follow-up data were collected at a median (25th-75th percentiles) of 1095 days (720-1967). Early abciximab was associated with a significant reduction in mortality (primary endpoint) [20% vs. 24.6%; hazard ratio (HR) 95% confidence interval (CI) = 0.65 (0.42-0.98) P = 0.02, P(het) = 0.6]. Furthermore, early abciximab administration was associated with a significant improvement in pre-procedural thrombolysis in myocardial infarction (TIMI) 3 flow (21.6% vs. 10.1%, P < 0.0001), post-procedural TIMI 3 flow (90% vs. 84.8%, P = 0.04), an improvement in myocardial perfusion as evaluated by post-procedural myocardial blush grade (MBG) 3 (52.0% vs. 43.2%, P = 0.03) and ST-segment resolution (58.4% vs. 43.5%, P < 0.0001) and significantly less distal embolization (10.1% vs. 16.2%, P = 0.02). No difference was observed in terms of major bleeding complications between early and late abciximab administration (3.3% vs. 2.3%, P = 0.4).

CONCLUSIONS

This meta-analysis shows that early upstream administration of abciximab in patients undergoing primary angioplasty for ST-segment elevation myocardial infarction (STEMI) is associated with significant benefits in terms of pre-procedural epicardial re-canalization and ST-segment resolution, which translates in to significant mortality benefits at long-term follow-up.

Pre-hospital ECG in patients undergoing primary percutaneous interventions within an integrated system of care: reperfusion times and long-term survival benefits

AIMS

Treatment delay is a powerful predictor of survival in STEMI patients undergoing primary PCI. We investigated the effectiveness of pre-hospital triage with direct referral to PCI, alongside more conventional referral strategies.

METHODS AND RESULTS

From January 2003 to December 2007, 1,619 STEMI patients were referred for primary PCI at our cathlab through two main triage groups: i.e., 1) following pre-hospital triage (n=524), 2) via more conventional triages (n=1,095) represented by the S. Orsola-Malpighi hospital emergency department triage (hub hospital) and local hospital triage. Pre-hospital diagnosis was associated with a 76 minute reduction in pain-to-balloon time (143 [107-216] vs. 219 [149-343], p=0.001) allowing mechanical revascularisation within 90 minutes from the first medical contact in the vast majority of the patients (>80%). Clinically, pre-hospital triage showed no significant reductions in terms of adjusted long-term mortality (HR 0.81, 95% CI 0.61-1.08; p=0.16) in the overall population. However, significant adjusted survival benefits were observed in high-risk groups (i.e., cardiogenic shock, TIMI risk score >30, diabetes mellitus).

CONCLUSIONS

This study shows that pre-hospital diagnosis allows for significant reductions in primary PCI treatment delays and suggests the hypothesis that this referral strategy might provide long-term survival benefits especially in high-risk patients.

Glycoprotein IIb-IIIa inhibitors

Platelets play a pivotal role in the pathogenesis of coronary artery disease and myocardial infarction. Therefore, great interests have been focused in the last decades on improvement in antiplatelet therapies, that currently are regarded as main pillars in the prevention and treatment of coronary artery disease, with special attention to glycoprotein IIb-IIIa (GP IIb-IIIa) receptors, that mediates the final stage of platelet activation. GP IIb-IIIa inhibitors, especially abciximab, have been shown to improve clinical outcome in patients undergoing primary angioplasty for STEMI. Upstream administration cannot routinely recommended, but may potentially be considered among high-risk patients within the first 4 h from symptoms onset. In case of periprocedural administration of antithrombotic therapy, Bivalirudin should be considered, especially in patients at high risk for bleeding complications. Among high-risk patients with acute coronary syndromes, an early invasive strategy with selective downstream administration of GP IIb-IIIa inhibitors is the strategy of choice, whereas bivalirudin should be considered in patients at high risk for bleeding complications. Among patients with unstable angina GP IIb-IIIa inhibitors should be considered only in case of evidence of intracoronary thrombus or in case of thrombotic complications (as provisional use). Further, randomized trials are certainly needed in the era of new oral antiplatelet therapies, and with strategies to prevent bleeding complications such as larger use of radial approach, mechanical closure devices, bivalirudin, or postprocedural protamine administration to promote early sheat removal.

Persistent coronary no flow after wire insertion is an early and readily available mortality risk factor despite successful mechanical intervention in acute myocardial infarction: a pooled analysis from the STRATEGY (Single High-Dose Bolus Tirofiban and Sirolimus-Eluting Stent Versus Abciximab and Bare-Metal Stent in Acute Myocardial Infarction) and MULTISTRATEGY (Multicenter Evaluation of Single High-Dose Bolus Tirofiban Versus Abciximab With Sirolimus-Eluting Stent or Bare-Metal Stent in Acute Myocardial Infarction Study) trials

OBJECTIVES

These studies sought to investigate the impact on mortality of coronary flow after passage of the wire through the culprit vessel in patients with ST-segment elevation myocardial infarction (STEMI) undergoing mechanical reperfusion.

BACKGROUND

Reduced spontaneous coronary flow before percutaneous coronary intervention influences mortality in patients with STEMI. Response to vessel wiring in patients with an occluded coronary artery before intervention might further discriminate outcomes irrespective of pre- and post-intervention coronary flow.

METHODS

Data from the STRATEGY (Single High-Dose Bolus Tirofiban and Sirolimus-Eluting Stent Versus Abciximab and Bare-Metal Stent in Acute Myocardial Infarction) and MULTISTRATEGY (Multicenter Evaluation of Single High-Dose Bolus Tirofiban Versus Abciximab With Sirolimus-Eluting Stent or Bare-Metal Stent in Acute Myocardial Infarction Study) trials were pooled: of 919 index procedures, 902 films (98%) were technically adequate for core laboratory TIMI (Thrombolysis In Myocardial Infarction) flow determination.

RESULTS

TIMI flow grade 0 was present before percutaneous coronary intervention in 59% of infarct vessels, TIMI flow grade 1 to 2 was found in 21%, whereas the remainder of infarct arteries presented with TIMI flow grade 3. In 49% of patients who showed persistent TIMI flow grade 0 after wire insertion (AWI), mortality was higher at 30 days (5.3%) and 1 year (9.4%) compared with patients in whom TIMI flow grade before percutaneous coronary intervention was either >0 (0.8%; p < 0.003 and 3.6%, p < 0.008) or improved from 0 AWI (1.5%, p < 0.04 and 3.6%, p < 0.02). After correcting for multiple imbalances, including baseline and final flow, persistent TIMI flow grade 0 AWI remained associated at 30 days to 2-fold (risk ratio [RR]: 2.1, 95% confidence interval [CI]: 1.08 to 5.00; p = 0.038) and at 1 year to almost 3-fold increases of mortality (RR: 2.7, 95% CI: 1.3 to 5.6; p = 0.008).

CONCLUSIONS

STEMI patients displaying persistent no-flow AWI have a lower survival rate despite an apparently successful mechanical intervention. As an early marker for high residual mortality risk, persistent no-flow AWI may qualify STEMI patients for dedicated pharmacomechanical treatment strategies.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

An anti-von Willebrand factor aptamer reduces platelet adhesion among patients receiving aspirin and clopidogrel in an ex vivo shear-induced arterial thrombosis

The von Willebrand factor (vWF) aptamer, ARC1779 that blocks the binding of vWF A1-domain to platelet glycoprotein 1b (GPIb) at high shear, may deliver a site-specific antithrombotic effect. We investigated the efficiency of ARC1779 on platelet function in patients with coronary artery disease (CAD) on double antiplatelet therapy. Blood from patients taking aspirin and clopidogrel and from normal volunteers was treated ex vivo with ARC1779 or abciximab, either prior to perfusion (pretherapy) or 10 minutes following the initiation of perfusion (posttherapy) on damaged arteries. Under pre- but not posttherapy, platelet adhesion was significantly reduced by ARC1779 at 83 and 250 nmol/L and by abciximab (100 nmol/L) versus placebo (4.8, 3.8, and 2.9 vs 7.3 platelets × 10(6)/cm(2), P < .05). In contrast to abciximab, ARC1779 did not significantly affect platelet aggregation, P-selectin expression, and platelet-leukocyte binding. These proof-of-concept data may constitute the framework for randomized clinical investigations of this novel antiplatelet therapy among patients with CAD.

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

OBJECTIVES

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Early treatment with abciximab in patients with ST elevation myocardial infarction results in a high rate of normal or near normal blood flow in the infarct related artery

There is debate whether early treatment with GpIIb/IIIa inhibitors is of clinical benefit in primary percutaneous coronary intervention (PCI) for ST-elevation myocardial infarction (STEMI). This study explored the effects of early given abciximab on coronary blood flow and major adverse cardiac events (MACE) in patients with STEMI treated with primary PCI and adjunctive abciximab. We studied all consecutive patients from our catchment area with STEMI undergoing acute angiography with the intention of primary PCI during 2005. Abciximab was given as early pre-treatment before, (n = 133) or at the cath. lab. after a diagnostic angiography (n = 109). Pre-procedural TIMI 2-3 flow was observed in 45.9 % of patients in the early group versus 20.2 % in the cath. lab. group, P = 0.0001. Mortality rates were 3.8 % versus 3.7% inhospital and 8.3 % versus 7.3% at one year in the early respectively the cath. lab. group, both P = NS. The MACE rate (death, non fatal myocardial infarction, unplanned revascularization) at one year was 19.5 % (early group) and 26.6 % (cath. lab. group), P = 0.19.

CONCLUSION

In this single centre registry study of unselected patients with STEMI early given abciximab was associated with a significantly higher rate of TIMI 2-3 flow compared to abciximab given after the acute angiography.

Percutaneous coronary intervention following thrombolysis: for whom and when?

Primary percutaneous coronary intervention (PPCI) is the treatment of choice for patients with ST segment elevation myocardial infarction (STEMI). In the attempt to reduce the unfavourable effects of time delays before PPCI, the administration of thrombolysis has been advocated (facilitated-PCI), but this treatment was shown to be ineffective and harmful, and should be avoided in patients who can receive PPCI promptly. Fibrinolysis is still indicated when PPCI is not available within 90-120 min but 1/3 of STEMI patients undergoing fibrinolysis does not show signs of reperfusion and even when reperfusion is achieved they have a considerable risk of death and recurrent MI. Thus invasive management with early PCI could be complementary to fibrinolysis both to obtain coronary reperfusion in those patients with failed thrombolysis (rescue-PCI) and to decrease the risk of further ischaemic events in patients with successful thrombolysis. In this article we show that this synergy has been supported by modern randomized control trials and meta-analysis. It is advisable that organization model of territorial network for the treatment of STEMI patients should be expanded to provide a timely access to hospital with interventional facilities also to patients treated with fibrinolysis that need rescue-PPCI or an urgent/early invasive management.

How to reduce the time windows for primary percutaneous coronary intervention

Percutaneous coronary intervention (PCI) is an effective procedure for re-establishing coronary artery perfusion in ST-segment elevation myocardial infarction. PCI is the preferred therapeutic option when it can be performed by an experienced team within 90-120 min of the first medical contact. Time from the onset of symptoms to balloon inflation seems to correlate directly with mortality rates. We discuss both hospital strategies and territorial system networks aimed at reducing the time windows for primary PCI, thereby improving clinical outcome and survival rates.

Variability of platelet aggregate dispersal with glycoprotein IIb-IIIa antagonists eptifibatide and abciximab

BACKGROUND

Utilization of glycoprotein IIb-IIIa (GPIIb-IIIa) inhibitors improves outcomes of patients with acute coronary syndromes (ACS), including those undergoing percutaneous coronary intervention (PCI). These results may be related to the ability of the inhibitors to destabilize coronary thrombi, reduce microembolization, and restore vessel patency.

OBJECTIVE

To evaluate in vitro the ability of GPIIb-IIIa antagonists, abciximab and eptifibatide, to promote the disaggregation of platelet-rich thrombus.

METHODS

Antagonist-induced disaggregation was assayed in plasma by aggregometry, as well as in whole blood by point of care and capillary perfusion systems. Fibrinogen dissociation from the platelet surface was quantified by flow cytometry.

RESULTS

Significant disaggregation of 5 microm ADP-induced aggregates was observed after addition of either agent. The maximum extent and rate of disaggregation were significantly higher with eptifibatide than with abciximab. Both antagonists also dispersed 2 microg mL(-1) collagen-induced aggregates, again with eptifibatide having a greater effect. Eptifibatide, but not abciximab (up to 10 microg mL(-1)), was efficient at dissociating aggregates to single platelets in whole blood and dispersing aggregates that had been aged for 30 min before treatment. Eptifibatide also reduced existing thrombus burden in the perfusion model under arterial flow conditions. A key mechanism of aggregate dispersal was antagonist-induced displacement of platelet-bound fibrinogen, which was greater with eptifibatide, a competitive inhibitor of fibrinogen binding, than with the noncompetitive inhibitor, abciximab.

CONCLUSIONS

These results suggest that drug concentration and residence time, along with thrombus extent and age, may be critical determinants in promoting timely recanalization.