P3700Intracoronary tenecteplase versus abciximab as adjunctive treatment during primary PCI in acute myocardial infarction of anterior location

Abstract

Background: Primary PCI is the preferred reperfusion strategy in patients with STEMI, but controversy remains about the optimal adjunctive antithrombotic therapy and its route of administration. There are no randomised trials comparing intracoronary (IC) administration of fibrinolytic agents to that of GP IIb/IIIa inhibitors during primary PCI. Our purpose was to compare the effects of IC administration of tenecteplase to that of abciximab on myocardial perfusion and infarct size in patients with acute STEMI of anterior location undergoing primary PCI. Methods: We conducted a pilot study consisting in a phase‐III, single‐center, prospective, randomised clinical trial. Seventy‐six patients with acute anterior STEMI were randomised to receive an IC infusion of reduced‐dose tenecteplase (one fifth part of systemic dose) or abciximab (standard dose) during primary PCI. All patients were pretreated with heparin, aspirin and clopidogrel. Two days after primary PCI, coronary angiography was repeated to obtain parameters of epicardial flow (corrected TIMI frame count) and myocardial perfusion (TIMI myocardial perfusion grade‐ TMPG‐, grades 0‐3) for an ulterior blinded assessment at an external independent core‐lab. Major adverse cardiac events included cardiac death, infarction, stroke and urgent target vessel revascularisation. A cardiac‐ MRI was performed at 4 months at an external institution blinded to the treatment groups in order to assess infarct size (the primary end‐point of study) and LV function. Results: Two days after primary PCI, patients in the IC‐abciximab group showed a lower corrected TIMI frame count than patients in the IC‐tenecteplase group (median 14.1 versus 18.2, p=0.02), and the incidence of TMPG grade 2/3 was higher in the IC‐abciximab group than in the IC‐tenecteplase group (90.3% versus 67.7%; p=0.03). The study was underpowered to detect substantial differences in 30‐day major cardiac events (13.2% versus 5.3% in the IC‐tenecteplase and ICabciximab groups, p=0.43) but, of note, 2 of 38 patients (5.3%) who had received IC‐tenecteplase experienced definite subacute stent thrombosis. Major bleeding events were similar in both groups. At 4 months, patients in the IC‐tenecteplase group showed a small non‐significant trend towards a lower infarct size than patients in the IC‐abciximab group (mean 19.3 grams vs 23.3 grams, p=0.29, or 15.9% vs 17.7% of LV‐mass respectively, p=0.51). Left‐ventricular size or systolic function on cardiac MRI did not significantly differ between study groups. Conclusions: In our pilot trial, the administration of IC tenecteplase during primary PCI in anterior STEMI patients did not significantly reduce infarct size as compared to IC abciximab. During the acute phase, IC abciximab showed to improve myocardial perfusion as compared to IC tenecteplase. It should also be noted a higher than expected rate of definite subacute stent thrombosis in patients treated with IC tenecteplase.