Emergency room administration of eptifibatide before primary angioplasty for ST elevation acute myocardial infarction and its effect on baseline coronary flow and procedure outcomes

Abstract

S randomized trials and a meta-analysis have shown the superiority of primary angioplasty over thrombolytic therapy for treatment of ST elevation acute myocardial infarction (AMI).1–4 Two large registries representative of practice in a community setting, however, failed to confirm a significant benefit for primary angioplasty over thrombolytic therapy.5,6 It has been postulated that a major reason for the discrepancy in the randomized trial data and so-called “real-world” primary angioplasty is an increased delay in treatment in the less controlled settings.7 Furthermore, primary angioplasty is not available to many patients due to initial presentation to a hospital without angioplasty or cardiac catheterization facilities. Recently, there has been interest in facilitated primary angioplasty, where patients are treated with fibrinolytic agents, glycoprotein (GP) IIb/IIIa inhibitors, or a combination of these agents before baseline angiography. One potential advantage of these strategies is widening of the therapeutic window for revascularization by the provision of partial reperfusion. The present study evaluates the effects of emergency room administration of the GP IIb/IIIa inhibitor, eptifibatide, before primary angioplasty on baseline coronary flow, procedure results, and in-hospital outcomes. • • • The treatment group (group 1) consisted of 30 consecutive patients who presented to our institution with AMI within 6 hours of symptom onset, were referred for primary angioplasty, and provided informed consent from December 1999 to April 2000. The controls (group 2) included 30 patients who were treated with primary angioplasty, including GP IIb/ IIIa inhibitors at the time of angioplasty, at our institution from January 1999 to November 1999. Group 2 patients were matched 1:1 with group 1 patients for age, AMI location, diabetes, gender, and time from onset of symptoms to presentation in descending order of priority. Eptifibatide was administered as a bolus of 180 mg/kg followed by a 2 mg/kg/min infusion. Patients were then referred to the cardiac catheterization laboratory and the bolus dose of eptifibatide was repeated on arrival. Baseline quantitative angiography was performed using a computer edge detection system (Artrek, Quinton Imaging, Bothell, Washington), and Thrombolysis in Myocardial Infarction (TIMI) flow grade and corrected TIMI frame counts8 were assessed by independent review of the study angiograms by 1 investigator who was blinded to the type of treatment. The primary end point was the percentage of patients with TIMI 2 or TIMI 3 coronary flow at baseline angiography. Secondary end points included percentage of patients with TIMI 3 flow, mean corrected TIMI frame count, time from baseline angiography to first balloon inflation, total procedure time, total fluoroscopy time, and total stent length per lesion. Continuous variables were compared using Student’s t test. Frequencies were compared using the chi-square test or Fisher’s exact test. Mean age was 57 years and 25% of patients were women. Comparative baseline clinical and angiographic characteristics are listed in Tables 1 and 2, respectively. Baseline TIMI 2 or TIMI 3 flow was present in 57% (95% confidence intervals 39% to 74%) of group 1 patients compared with 13% (95% confidence intervals 1% to 26%) of group 2 patients (p ,0.01) (Figure 1). The mean time from baseline angiography to initial balloon inflation and total procedure times were significantly less for group 1 patients. This difference in time to first balloon inflation was also evident for patients with persistent total occlusion of the infarctrelated artery (TIMI grade 0 flow, 11.3% vs 21.6%, p ,0.01). Other procedural outcomes are listed in Table 3 and in-hospital outcomes are shown in Table 4.5 • • • The results of this study show that for patients undergoing primary angioplasty for ST elevation AMI, a strategy of administering the GP IIb/IIIa inhibitor, eptifibatide, early after presentation and before arrival in the cardiac catheterization laboratory provides partial reperfusion and may decrease procedure complexity. Of 30 patients who received eptifibatide administered as a double bolus of 180 mg/kg with the initial bolus given 51 6 27 minutes before baseline angiography, 17 (56.7%) had TIMI 2 or 3 flow. In addition, the time from baseline angiography to first balloon inflation was significantly less for these paFrom the Department of Medicine and Cardiology Unit, University of Rochester Medical Center, Rochester, New York. This study was supported by an educational grant from COR Therapeutics, South San Francisco, California. Dr. Cutlip’s address is: Cardiology Unit, Box 679, University of Rochester Medical Center, 601 Elmwood Avenue, Rochester, New York 14642. E-mail: donald_cutlip@urmc.rochester. edu. Manuscript received October 24, 2000; revised manuscript received and accepted February 1, 2001.