Effect of High Bolus Dose Tirofiban on the Inflammatory Response Following Percutaneous Coronary Intervention

BACKGROUND: Tirofiban at the bolus dose of 10 microg/kg does not suppress the inflammatory response following percutaneous coronary intervention (PCI). This may be due to less than optimal inhibition of platelet aggregation. High bolus dose tirofiban (25 microg/kg) allows better inhibition of platelet aggregation but its anti-inflammatory effect remains unknown. HYPOTHESIS: High bolus dose tirofiban exhibits anti-inflammatory activity. METHODS: A total of 100 patients referred for PCI were randomized to receive high bolus dose tirofiban followed by a 24-h infusion or a bolus and an infusion of saline. Patients with elevated troponin or with thrombus in the culprit lesion were excluded. Inflammatory markers were measured at baseline and at 24 h. RESULTS: Levels of soluble CD40 ligand (sCD40L) were not affected by PCI while those of interleukin-6 (IL-6) and of high sensitivity C-reactive protein (hs-CRP) significantly increased. Despite inhibiting platelet's aggregation by > 90%, tirofiban did not suppress the rise of IL-6 and hs-CRP. Median (interquartile range) elevation of IL-6 was 0.6 pg/mL (-1.5-3.6) versus 0.4 pg/mL (-0.7-1.8) and that of hs-CRP was 2.1 mg/L (0.7-5.2) versus 2.4 mg/L (1-4.7) in the tirofiban and the control groups, respectively (p = ns). However, in patients with diabetes mellitus, tirofiban significantly suppressed the rise of hs-CRP by 65% (p = 0.01), but did not significantly affect the rise of IL-6. CONCLUSION: In low-risk patients undergoing PCI, tirofiban did not attenuate the rise of inflammatory markers. However, the significant effect in diabetics suggests that tirofiban may have anti-inflammatory activity in higher risk patients.