The Effect of Glycoprotein IIb/IIIa Receptor Inhibitor on the Microcirculation in Patients Undergoing High-Risk Coronary Stenting; A Prospective, Randomized Study

Abstract

Objectives: We evaluated the effect of the glycoprotein IIb/IIIa inhibitor, tirofiban, on the microcirculation measured by Doppler coronary flow reserve (CFR) in patients undergoing high-risk coronary stenting.

Background: The mechanisms by which glycoprotein IIb/IIIa inhibitors benefit patients undergoing high-risk angioplasty are not fully understood. This may be due to prevention of distal embolization of the coronary clot at the site of angioplasty.

Methods: Thirty two consecutive patients with acute coronary syndrome within 72 hours or with high-risk angiographic features were randomized into 2 groups. Group A (n = 17) received tirofiban (10 μg/kg bolus followed 0.15 μg/kg/min). Group B (n = 15) received placebo bolus and infusion. Coronary flow reserve was measured by Doppler wire technique at baseline, post balloon angioplasty and post-stenting. Platelet aggregation was measured at baseline, 10 minutes, 6 hours and 12 hours post bolus.

Results: There was no significant difference in CFR between the groups at baseline and after balloon angioplasty. Post-stenting CFR, however, was significantly higher in the group pretreated with tirofiban (2.94 vs. 2.25, p = 0.014). The inhibition of platelet aggregation was 94% at 10 minutes, 97% at 6 hours and 94% at 12 hours in the tirofiban group.

Conclusion: In patients undergoing high-risk coronary stenting, tirofiban protects and improves the microcirculation measured by Doppler wire technique. This may be due to prevention of distal embolization of clot by tirofiban and explain the clinical benefit.