Background: There is continued debate as to whether a combined reperfusion regimen with platelet glycoprotein IIb/IIIa inhibitor-tirofiban provides additional benefit in optimal myocardial reperfusion for patients with acute ST-segment elevation myocardial infarction (STEMI). This study was conducted to investigate the clinical benefits of adjunctive tirofiban therapy combined with primary percutaneous coronary intervention (PCI) in patients with STEMI.
Methods: One hundred and seventy-two consecutive patients with STEMI presented within 12 h of symptoms were randomly allocated to primary PCI combined with early (upstream group, n=57) or late administration of tirofiban (downstream group, n=57) or primary PCI treatment alone (control group, n=58). Clinical characteristics, angiographic findings, and in-hospital outcomes were compared between groups, as well as left ventricular ejection fraction (LVEF) and major adverse cardiac events (MACE, including death, reinfarction and target vessel revascularization) at 30-day and 6-month clinical follow-up.
Results: Despite comparable baseline clinical features among three groups, angiographic and procedural characteristics and outcomes differed significantly between patients receiving tirofiban treatment and controls, with respect to preprocedural (upstream: 28.1%, downstream: 7.0%, control: 5.2%, P<0.001) and postprocedural thrombolysis in myocardial infarction (TIMI) grade 3 flow of infarct-related artery (98.2, 94.7, 86.2%, P=0.03), TIMI myocardial perfusion grade 3 (75.4, 70.2, 53.4%, P=0.03), corrected TIMI frame count (20.4+/-5.0, 23.1+/-5.3, 32.2+/-6.7, P<0.001), resolution of the sum of ST-segment elevation (6.16+/-1.21, 6.02+/-1.09, 4.53+/-2.65 mm, P<0.001), peak value of creatine kinase-MB (218.0+/-72.5, 224.2+/-69.4, 255.3+/-77.0 ng/ml, P=0.02) and troponin I (76.0+/-21.5, 79.8+/-18.7, 86.4+/-11.0 ng/ml, P=0.007), and average hospital stay (10.6+/-5.4, 12.6+/-4.7, 14.5+/-6.5 days, P=0.001). The MACE rate at 30 days (3.5, 5.3, 15.5%, P=0.04) was reduced and LVEF (0.51+/-0.07, 0.50+/-0.07, 0.47+/-0.08, P=0.008) was higher in upstream and downstream groups than in controls. At 6-month follow-up, the MACE rate was not significantly different among groups (7.0, 8.8, 17.2%, P=0.17), but LVEF in upstream and downstream groups was significantly improved (0.59+/-0.06, 0.57+/-0.07, 0.54+/-0.07, P<0.001). Subgroup analysis demonstrated a statistically significant difference between upstream and downstream groups in preprocedural TIMI grade 3 flow (P=0.003) and postprocedural corrected TIMI frame count (P=0.007), which resulted in a shortened hospital stay (P=0.04), reduction of MACE rate at 30-day and 6-month follow-up by 34 and 20%, respectively. Multivariate logistic analysis revealed that age more than 65 years [odds ratio (OR)=3.42, P<0.01], tirofiban therapy (OR=0.56, P<0.05) and LVEF less than 0.5 during hospitalization (OR=2.56, P<0.01) were major independent predictors of MACE at 6-month clinical follow-up. No significant difference in hemorrhagic complications among three groups was noted (upstream: 10.5%, downstream: 12.3%, control: 6.9%, P=0.61).
Conclusion: This prospective study indicates that adjunctive tirofiban therapy for patients with STEMI who undergo primary PCI can significantly improve reperfusion level in the infarct area, clinical outcomes at 30-day and 6-month follow-up, especially with upstream tirofiban therapy, and is safe.