Perioperative Thrombotic Risk of Coronary Artery Stents: Possible Role for Intravenous Platelet Blockade

Abstract

Hospital of the University of Pennsylvania, Philadelphia, Pennsylvania. yiandoc@hotmail.comI read with great interest the recent science advisory by Dr. Grines et al. 1detailing their recommendations with respect to dual platelet therapy (aspirin and clopidogrel) after placement of a coronary stent. The advisory highlights the perioperative thrombotic risk for coronary stents. In the perioperative setting, they should be regarded as an unstable coronary syndrome.1–2Where possible, elective procedures should be postponed for at least 1 month (bare-metal stent) or up to 1 yr (drug-eluting stent). Furthermore, dual antiplatelet therapy should be continued throughout the perioperative period, with only temporary cessation of clopidogrel therapy where clinically indicated, e.g. , excessive bleeding risk.Even with protocol-based intensive perioperative treatment of these patients in the noncardiac surgical setting, there is still a 4.9% mortality rate and a staggering 44.7% complication rate.2The major etiology of perioperative stent thrombosis is the activated platelet, which may require multimodal blockade even in the setting of an overt bleeding risk.What about the adjunctive role of perioperative intravenous platelet blockade with IIa/IIIb blockers such as tirofiban? This would allow preoperative withdrawal of clopidogrel with ongoing precise control of platelet blockade. This application was recently successfully illustrated in the following integrated protocol involving three patients: clopidogrel discontinued 3 days before surgery; preoperative hospital admission for infusion of unfractionated heparin and tirofiban until 6 h before surgery; loading dose of clopidogrel on the first postoperative day, followed by maintenance therapy; aspirin therapy continued throughout the perioperative period.3This encouraging pilot experience awaits confirmation of efficacy and safety in further trials. Until then, the safety and efficacy of this perioperative approach are not conclusively established.It is imperative that aggressive anticoagulation, including dense platelet blockade, be maintained throughout the perioperative period to maintain coronary stent patency. This is particularly important if the stent has not endothelialized, as may be the case in emergency surgery. The coronary stent, whether bare metal or drug eluting, should be managed as a high-risk coronary lesion in the perioperative period. Intravenous IIa/IIIb platelet blockade has tremendous promise as an adjunct in the perioperative management of these iatrogenic unstable coronary artery syndromes.Hospital of the University of Pennsylvania, Philadelphia, Pennsylvania. yiandoc@hotmail.com