Impact of early abciximab administration on myocardial reperfusion in patients with ST-segment elevation myocardial infarction pretreated with 600 mg of clopidogrel before percutaneous coronary intervention

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.

Efficacy and safety of a routine early invasive strategy after fibrinolysis stratified by glycoprotein IIb/IIIa inhibitor use during percutaneous coronary intervention: a pre-specified subgroup analysis of the TRANSFER-AMI randomised controlled trial

OBJECTIVE

We evaluated the efficacy and safety of an early invasive strategy post-fibrinolysis in relation to glycoprotein (GP) IIb/IIIa inhibitor use.

METHODS

The Trial of Routine Angioplasty and Stenting after Fibrinolysis to Enhance Reperfusion in Acute Myocardial Infarction (TRANSFER-AMI) randomised 1059 ST elevation myocardial infarction patients to an early invasive strategy or standard therapy post-fibrinolysis. The primary end point was the composite of death, reinfarction, recurrent ischaemia, new or worsening heart failure, or cardiogenic shock at 30 days. In this pre-specified analysis, we examined efficacy and safety outcomes of an early invasive strategy after stratification by GPIIb/IIIa inhibitor use, which was permitted during percutaneous coronary intervention (PCI) at the discretion of the treating physician.

RESULTS

A total of 695 patients (65.6%) received GPIIb/IIIa inhibitors. There was significant heterogeneity (p<0.001) in the efficacy of an early invasive strategy compared to standard therapy, between the strata with GPIIb/IIIa inhibitor use (primary end point 9.6% vs 22.3% respectively, p<0.001) and without GPIIb/IIIa inhibitor use (primary end point 14.8% vs 10.4% respectively, p=0.21). Patients who received GPIIb/IIIa inhibitors had lower Global Registry of Acute Coronary Events (GRACE) risk scores compared to those without GPIIb/IIIa inhibitor use (median 121 vs 130, p<0.001). After adjusting for the interaction between GRACE risk score and treatment assignment, the heterogeneity in the efficacy of an early invasive strategy with respect to GPIIb/IIIa inhibitor use was no longer significant (p interaction=0.08).

CONCLUSIONS

The apparent difference in the efficacy of an early invasive strategy between GPIIb/IIIa inhibitor strata likely reflects an association between GPIIb/IIIa inhibitor use and baseline risk. GPIIb/IIIa inhibitor use during PCI at the discretion of the treating physician does not appear to modulate the efficacy of an early invasive strategy post-fibrinolysis.

CLINICAL TRIAL REGISTRATION

http://www.clinicaltrials.gov/ct2/show/NCT00164190, NCT00164190.

Influence of abciximab on evolution of left ventricular function in patients with non-ST-segment elevation acute coronary syndromes undergoing PCI after clopidogrel pretreatment: lessons from the ISAR-REACT 2 trial

BACKGROUND

Abciximab reduced the combined endpoint of death, myocardial infarction (MI) and target vessel revascularization in patients with non-ST-segment elevation acute coronary syndromes (NSTE-ACS) undergoing percutaneous coronary intervention (PCI) with stent implantation after a 600-mg loading dose of clopidogrel. The aim of the present study was to investigate the impact of abciximab on the evolution of left ventricular ejection fraction (LVEF) in these patients.

METHODS

The current study included 1,158 patients enrolled in the randomized, double-blind ISAR-REACT 2 (the Intracoronary Stenting and Antithrombotic Regimen: Rapid Early Action for Coronary Treatment) trial who had paired angiograms obtained at baseline and 6-8 months after randomization. Of them, 586 patients received abciximab and 572 patients received placebo. The primary outcome analysis was LVEF at 6-8-month follow-up.

RESULTS

Baseline LVEF was comparable in patients assigned to abciximab or placebo (53.2 ± 12.6 vs. 53.7 ± 12.1%; P = 0.393). At 6-8-month follow-up angiography, there was no difference in LVEF between the abciximab and placebo groups (55.4 ± 11.5 vs. 55.8 ± 11.2%; P = 0.743). Subgroup analysis of patients with elevated baseline troponin (>0.03 μg/L) also revealed comparable LVEF at follow-up in both treatment groups (P = 0.527). The multivariate analysis identified age, arterial hypertension, prior MI, prior coronary artery bypass graft surgery, baseline LVEF, MI at 30 days and repeat PCI as independent correlates of follow-up LVEF.

CONCLUSION

Although abciximab reduced the 30-day and 1-year incidence of major adverse cardiac events in patients with NSTE-ACS undergoing primary PCI after pre-treatment with a 600-mg loading dose of clopidogrel, the agent did not improve or impact on the evolution of LVEF over 6-8 months of follow-up.