Ann Thorac Surg 2000;70:S1-S2
© 2000 The Society of Thoracic Surgeons
Platelet inhibitors and cardiac surgery
Jerrold H. Levy, MDa,
Peter K. Smith, MDb
a Department of Anesthesiology, Emory University School of Medicine, Emory Healthcare, Atlanta, Georgia, USA
b Department of Cardiac Surgery, Duke University Medical Center, Durham, North Carolina, USA
Address reprint requests to Dr Levy, Department of Anesthesiology, Emory University Hospital, 1364 Clifton Rd, NE, Atlanta, GA 30322
e-mail: jerrold_levy{at}emory.org
Presented at the "Managing the Patient Receiving Platelet Inhibitors in Cardiac Surgery" Roundtable Discussion, San Antonio, TX, Jan 22–23, 1999.
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Introduction
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The treatment of coronary artery disease (CAD) has evolved rapidly over the past two decades. The gold standard of surgical revascularization was challenged by the development of angioplasty, which was popularized in the United States in the early 1980s in Atlanta, by Andreas Gruentzig, who invented the procedure when he was working in Europe. I (J.H.L.) was at Emory Healthcare in the early days of angioplasty, when emergency coronary artery bypass grafting was all too common for acute closure or dissection of coronary vessels. We would emergently bring patients to the operating room, sometimes performing cardiopulmonary resuscitation, for acute cardiogenic shock due to angioplasty or interventional complications. The need for emergency coronary revascularization has dramatically decreased, and rushing a patient in cardiogenic shock from the cardiac catheterization laboratory to the operating room is now a far less frequent occurrence because of the advent of the glycoprotein (GP) IIb/IIIa receptor antagonists, and intracoronary stents.
The GP IIb/IIIa receptor antagonists have assumed a pivotal role in cardiology and have had a major impact on the cardiac surgeon as well. Patients who have been treated with GP IIb/IIIa receptor antagonists pose a challenge, not only for the cardiac surgical team, but also for all the physicians and other health care personnel involved in their management. We are still learning how to manage these patients effectively for cardiac surgery and cardiopulmonary bypass. This supplement was developed to evaluate objectively the information regarding how to effectively manage patients receiving a potent antiplatelet agent. The published experience and information from abciximab patients provide critical data and perspectives indicating that patients receiving this agent can be managed effectively. The paper by Lincoff and associates in this month’s Annals of Thoracic Surgery also provides data to support this idea [1].
Even recently, in patients who were receiving aspirin, the aspirin was stopped and cardiac surgery was delayed because of the perceived risk of bleeding. The studies supporting this practice have provided variable results, and this provides a useful paradigm for our current practice with antiplatelet agents [2]. Another important factor to consider is the concomitant use of other anticoagulant and antiplatelet agents in our patients, including clopidogrel (Plavix) [3] and low-molecular-weight heparin (LMWH), agents that may significantly contribute to bleeding. LMWH has an enhanced anti-Xa:anti-IIa activity [4]. The LMWHs have been suggested to provide a therapeutic benefit because factor Xa generation occurs several steps earlier in the coagulation cascade than thrombin generation and inhibition of Xa has a profound effect on the later steps in coagulation [5, 6]. LMWH use is rapidly growing in cardiovascular medicine because of its long half-life and ease of dosing, yet its use may pose a potential problem for surgical patients because commonly used hemostatic tests are not affected by LMWH [5, 6]. Further, LMWH is not readily reversible with protamine and may potentially contribute to bleeding after cardiac surgery.
Bleeding after cardiac surgery has had major implications on our practice. The advent of pharmacologic approaches that we have studied to decrease bleeding in cardiac surgical patients has reduced the need for allogeneic blood transfusions and reexploration and provided the potential beneficial effect of antiinflammatory strategies [7–10]. The development of novel strategies advances our understanding of the complexities of bleeding after cardiac surgery. The ability to monitor platelet and hemostatic function better during cardiac surgery may also help us to treat bleeding due to platelet inhibitors more effectively when it occurs [11]. It is interesting to note, as Edmunds and his group have suggested, that platelet inhibitors may have theoretical benefit (to provide platelet anesthesia) and may preserve platelet function better postoperatively [12]. Whether this preservarion will occur in clinical trials remains to be seen, but the possibility poses an interesting consideration as we evaluate ways to reduce bleeding and hemostatic activation further during extracorporeal circulation.
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References
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Lincoff A.M., LeNarz L.A., Despotis G.J., et al. Abciximab and bleeding during coronary surgery. Ann Thorac Surg 2000;70:516-526.
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Levy J.H. Aspirin and bleeding following coronary artery bypass grafting. Anesth Analg 1994;79:1-3.
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Quinn M.J., Fitzgerald D.J. Ticlopidine and clopidogrel. Circulation 1999;100:1667-1672.
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Hirsh J., Raschke R., Warkentin T.E., Dalen J.E., Deykin D., Poller L. Heparin. Chest 1995;108(Suppl):258-275.
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Antman E.M., Handin R. Low-molecular-weight heparins. Circulation 1998;98:287-289.
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Weitz J.I. Low-molecular-weight heparins. N Engl J Med 1997;337:688-698.
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Levy J.H., Pifarre R., Schaff H., et al. A multicenter, placebo-controlled, double-blind trial of aprotinin to reduce blood loss and the requirement of donor blood transfusion in patients undergoing repeat coronary artery bypass grafting. Circulation 1995;92:2236-2244.
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Miller B.E., Bailey J.M., Levy J.H., et al. Predicting and treating coagulopathies after cardiopulmonary bypass in children. Anesth Analg 1997;85:1196-1202.
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Miller B.E., Tosone S.R., Tam V.K.H., et al. Hematologic and economic impact of aprotinin in reoperative pediatric cardiac surgery. Ann Thorac Surg 1998;66:535-540.
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Alderman E.L., Levy J.H., Rich J., et al. International multi-center aprotinin graft patency experience (IMAGE). J Thorac Cardiovasc Surg 1998;116:716-730.
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Despotis G.J., Filos K., Gravlee G., Levy J.H. Anticoagulation monitoring during cardiac surgery. Anesthesiology 1999;91:1122-1151.
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Hiramatsu Y., Gikakis N., Anderson H.L., III, et al. Tirofiban provides "platelet anesthesia" during cardiopulmonary bypass in baboons. J Thorac Cardiovasc Surg 1997;113:182-193.
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Introduction
References