Abstract 18940: Efficacy and Safety of Tirofiban for Bridging Therapy in Patients at High-Risk for Stent Thrombosis Undergoing Surgery
Background: Patients with drug-eluting stent (DES) who need urgent surgery are at increased risk of surgical bleeding while on clopidogrel. However, preoperative clopidogrel discontinuation is associated with a high rate of adverse events due to stent thrombosis (ST).
Objective: A pilot study to evaluate whether perioperative administration of the short-acting antiplatelet agent, tirofiban, allows safe withdrawal of clopidogrel without increasing bleeding. The role of platelet function testing using VerifyNow® assay was also evaluated.
Methods: Bridging protocol involved withdrawing clopidogrel at least 5–7 days before surgery, starting tirofiban 48–72 hours later, continuing it until 10–12 hours before surgery, and resuming clopidogrel 24–36 hours after surgery. Aspirin use was left to the discretion of the surgeon. Adverse ischemic events related to ST and TIMI major bleeding and transfusion were assessed. VerifyNow® assay was used to measure P2Y12 receptor blockade (PRU) at baseline, and glycoprotein IIb/IIIa receptor blockade (PAU) at baseline (T1), 12 hrs after starting tirofiban (T2), and 12 hrs after discontinuing tirofiban (T3).
Results: Ten patients at high-risk for ST were enrolled at a mean of 18.4 mo (range 1–72 mo) after DES. There were no cases of death, MI, stent thrombosis, or surgical re-exploration due to bleeding, or TIMI major bleeding. Three patients received ≥3 PRBC transfusion during valve surgery. No significant difference in platelet count (156 vs 193K, p=0.1) or hemoglobin (12.6 vs 13 mg/dL, p=0.67) was observed postoperatively compared with baseline. P2Y12 assay revealed high residual platelet activity (defined as <20% platelet inhibition) in 5 out of 10 patients at a mean of 2.9 days post clopidogrel discontinuation. Platelet IIb/IIIa activity was reduced by 82% with tirofiban (205±66 PAU at T1 vs. 32±18 PAU at T2, p<0.001) and restored to 85% of baseline at T3 (174±53 PAU, p=0.31 vs T1).
Conclusions: Bridging protocol using tirofiban was effective in preventing ST without increasing the risk for perioperative bleeding. Larger studies are needed to further validate efficacy and safety of the bridging protocol and to evaluate the value of platelet function testing in tailoring perioperative antiplatelet therapy.
- Platelet receptor blockers
- Antiplatelet drugs
- Glycoprotein iib/iiia platelet inhibitors
- © 2010 by American Heart Association, Inc.