Prospective Randomized Controlled Clinical Study to Compare Abciximab-bolus i.v. Versus i.c. in Primary PCI in Patients With Acute ST-elevation Myocardial Infarction

In patients with acute ST-elevation myocardial infarction (STEMI) primary percutaneous coronary intervention (PCI) is the preferred reperfusion regimen, if performed by experienced operators in a timely manner. Nevertheless, myocardial damage is not immediately terminated after successful epicardial reperfusion by primary PCI. Current strategies are directed to improve myocardial tissue perfusion, which is impaired in approximately 50% of patients and which has prognostic impact. Adjunctive intravenous abciximab administration is an established therapy to improve coronary microcirculation and reduce major cardiac adverse events.5-10 In randomized clinical trials intravenous abciximab administration has been studied. Clinical trials have shown that earlier administration results in higher preinterventional TIMI-flow with subsequent improved perfusion post PCI. However, in a pooled analysis there was no effect on mortality. As door-to-balloon-times getting shorter in current trials, earlier abciximab administration requires treatment in the prehospital setting, which poses substantial logistic obstacles. Another option might be intracoronary abciximab bolus administration which results in very high local platelet inhibitor concentrations. This might be favorable in dissolution of thrombi and microemboli with subsequent improved myocardial microcirculation, reduction of no-reflow, and infarct size. Currently, there is only limited clinical experience on the efficacy of intracoronary abciximab administration mainly restricted to case reports, retrospective registries or small randomized trials. In a recently published randomized clinical trial, we were able to show that intracoronary versus intravenous abciximab bolus administration has beneficial effects on the occurrence of no-reflow and infarct size assessed by contrast-enhancement magnetic resonance imaging. This led to a trend towards improved clinical outcome. The composite major adverse cardiac event rate, defined as death, reinfarction, target vessel revascularization, and new congestive heart failure, at 30 day follow-up was 15.6% after intravenous and 5.2% after intracoronary abciximab administration (relative risk 3.00; 95% confidence intervals 0.94-10.80; p=0.06).

Currently, there is no adequately powered clinical trial to assess the effects of intracoronary bolus in comparison to standard intravenous abciximab administration. Due to its general availability and its ease of intracoronary administration this treatment has overwhelming potential in clinical practice, which is much easier to achieve than a logistically cumbersome prehospital or interhospital transfer administration.

In the era of evidence-based medicine, such a trial is of paramount importance to achieve a break-through in abciximab use and a reduction of the high associated morbidity and mortality of STEMI patients.