Abciximab Versus Tirofiban and Recovery of Left Ventricular Function - Abciximab Versus Tirofiban and Recovery of Left Ventricular Function

Description:

The goal of the trial was to evaluate adjunctive use of abciximab compared with high-dose tirofiban on left ventricular (LV) function in patients undergoing primary percutaneous coronary intervention (PCI) for acute myocardial infarction (MI).

Study Design

Study Design:

Patients Screened: 122
Patients Enrolled: 100
Mean Follow Up: 30 days

Patient Populations:

1) Presence of symptoms consistent with acute MI for ≥30 minutes and <6 hours and presence of ST-segment elevation in ≥2 contiguous leads or left bundle branch block
2) Suitability for percutaneous revascularization

Exclusions:

Age ≥75 years, cardiogenic shock, history of bleeding diathesis, major surgery during the previous six weeks, gastrointestinal or genitourinary bleeding in the preceding six months, cerebrovascular event in the previous year, and a platelet count <100,000/mm3

Primary Endpoints:

Difference in the infarct-zone wall motion score index between the initial and the 30-day echocardiographic studies

Secondary Endpoints:

Difference in global LV ejection fraction; TIMI grade flow, TIMI grade myocardial perfusion (“blush”), and corrected TIMI frame counts before and after the procedure; and major adverse cardiovascular event at 30 days, including death, reinfarction, or target lesion revascularization

Drug/Procedures Used:

Following baseline angiography, patients were randomized to the new high dose of tirofiban (n=50) (25 µg/kg bolus followed by an 18-hour infusion at 0.15 µg/kg/min) or abciximab (n=50) (0.25 mg/kg bolus followed by infusion at 0.125 µg/kg/min for 12 hours). Patients underwent a repeat echocardiography study at 30 days to assess LV function.

Concomitant Medications:

Before catheterization, all patients received aspirin (500 mg) and heparin (5000 U). Additional heparin was used to maintain an activated clotting time of 200-250 seconds.

Principal Findings:

Mean time from symptom onset to balloon was 206 minutes. Stents were used in 97% of patients. All patients received the assigned study drug. Culprit coronary artery was left anterior descending in 42% of patients in the tirofiban arm versus 32% in the abciximab arm and right coronary artery in 38% and 52%, respectively.

There was no difference in the secondary endpoints of post-PCI TIMI flow grade 3 (88% vs. 86%, p=1.0), corrected TIMI frame count (22.1 vs. 22.5 frames, p=0.37), or TIMI myocardial perfusion grade 3 (76% vs. 70%, p=0.65) for the comparisons of the tirofiban arm versus the abciximab arm, respectively. Paired baseline and 30-day echocardiograms were obtained in 87 patients. There was no difference between treatment groups in the primary endpoint of infarct-zone wall motion score index (p=0.67). Infarct-zone wall motion score index decreased from 2.18 to 1.95 in the tirofiban group and from 2.20 to 1.99 in the abciximab arm. Additionally, there was no difference between groups in the change in ejection fraction (p=0.25), from 47% to 55% in the tirofiban group and 47% to 54% in the abciximab group.

There were no major bleeds in either arm during the index hospitalization, and no significant difference in minor bleeding (4% in the tirofiban group vs. 8% in the abciximab arm, p=0.71). There was also no difference in major adverse cardiac events by 30 days (4% in the tirofiban group vs. 6% in the abciximab arm, p=0.74).

Interpretation:

Among patients with acute MI undergoing primary PCI, there was no difference in LV function or angiographic endpoints by treatment with high-dose tirofiban compared with abciximab.

Earlier studies of tirofiban in PCI such as the TARGET trial were conducted using a lower dose of 10 µg/kg bolus. TARGET showed that abciximab was associated with lower rates of death, MI, and urgent target vessel revascularization at 30 days compared to tirofiban in non-ST-elevation MI/unstable angina patients undergoing PCI. However, inhibition of glycoprotein IIb/IIIa binding activity was shown to be potentially subtherapeutic at the 10 µg/kg bolus dose. The present study used a higher dose bolus of 25 µg/kg, as did several other recent studies, including the ADVANCE trial.

The authors note that there was no increase in adverse safety and bleeding events in the present trial with the high-dose tirofiban bolus. However, larger studies are needed to validate these findings.

References:

Danzi GB, Sesana M, Capuano C, Mauri L, Berra Centurini P, Baglini R. Comparison in patients having primary coronary angioplasty of abciximab versus tirofiban on recovery of left ventricular function. Am J Cardiol 2004;94:35-9.

Clinical Topics: Arrhythmias and Clinical EP, Invasive Cardiovascular Angiography and Intervention, Noninvasive Imaging, EP Basic Science, Interventions and Imaging, Echocardiography/Ultrasound

Keywords: Myocardial Infarction, Platelet Aggregation Inhibitors, Coronary Disease, Immunoglobulin Fab Fragments, Fibrinolytic Agents, Tyrosine, Percutaneous Coronary Intervention, Bundle-Branch Block, Coronary Vessels, Echocardiography


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