Correspondence  |   May 2000
Does Perioperative Antithrombotic Therapy Increase the Likelihood of a Postoperative Coagulopathy After Cardiac Surgery?
Author Notes
  • Washington University School of Medicine
  • Assistant Professor of Anethesiology
  • Department of Anesthesiology
  • Associate Professor
  • of Anesthesiology and Pathology
  • Washington University School of Medicine
  • St. Louis, Missouri 63110
Article Information
Correspondence   |   May 2000
Does Perioperative Antithrombotic Therapy Increase the Likelihood of a Postoperative Coagulopathy After Cardiac Surgery?
Anesthesiology 5 2000, Vol.92, 1499. doi:
Anesthesiology 5 2000, Vol.92, 1499. doi:
In Reply:—
We agree with Drs. Lewis and Collard that measurement of anti-Xa activity and platelet function would have provided important information. Nevertheless, in the presence of normal ACT, no detectable heparin by heparin concentration assay (Hepcon, Medtronic Blood Management, Parker, CO), no identifiable surgical source, and a borderline platelet count, possible explanations for this patients’ excessive and protracted chest tube output that was unresponsive to hemostatic blood product transfusion, include either the persistent anticoagulant properties of low molecular weight heparin i.e., anti-Xa activity, or a platelet function abnormality that may be related to either of these agents, or a possible interaction between low molecular weight heparins and tirofiban. Previous anecdotal reports of increased bleeding when patients had received either low molecular weight heparin preparations 1,2 or platelet inhibitors 3–5 support our findings.
Furthermore, we are uncertain of the potential beneficial effects of hemofiltration, because we have previously shown that hemofiltration (using one specific filter) during cardiopulmonary bypass failed to remove the lower molecular weight fraction of unfractionated heparin (no anti-Xa activity in ultrafiltrate). 6 Factors related to the low molecular weight heparin molecule, such as, its linear shape, electrostatic charge, or binding to antithrombin III may account for these findings. Therefore, we would recommend that in patients receiving either enoxaparin or tirofiban, postponement of elective cardiac surgery should be considered for a period of time well over the five half-lives of either medication. Another alternative would be to switch patients from low molecular weight heparin to unfractionated heparin as soon as an operation is proposed. Further studies are needed to evaluate the efficacy of hemofiltration or plasma exchange filters with respect to removal of these agents.
Ganjoo AK, Harloff MG, Johnson WD: Cardiopulmonary bypass for heparin-induced thrombocytopenia: Management with a heparin-bonded circuit and enoxaparin. J Thorac Cardiovasc Surg 1996; 112:1390–2Ganjoo, AK Harloff, MG Johnson, WD
Robitaille D, Leclerc JR, Laberg R, Sahab P, Atkinson S, Cartier R: Cardiopulmonary bypass with a low-molecular-weight heparin fraction (enoxaparin) in a patient with a history of heparin-induced thrombocytopenia. J Thorac Cardiovasc Surg 1992; 103:597–8Robitaille, D Leclerc, JR Laberg, R Sahab, P Atkinson, S Cartier, R
Aguirre FV, Topol EJ, Ferguson JJ, Anderson K, Blankenship JC, Heuser RR, Sigmon K, Taylor M, Gottlieb R, Hanovich G, Rosenberg M, Donohue TJ, Weisman HF, Califf RM: Bleeding complications with the chimeric antibody to platelet glycoprotein IIb/IIIa integrin in patients undergoing percutaneous coronary intervention. Circulation 1995; 91:2882–90Aguirre, FV Topol, EJ Ferguson, JJ Anderson, K Blankenship, JC Heuser, RR Sigmon, K Taylor, M Gottlieb, R Hanovich, G Rosenberg, M Donohue, TJ Weisman, HF Califf, RM
Boehrer JD, Kereiakes DJ, Navetta FI, Califf RM, Topol EJ: Effects of profound platelet inhibition with c7E3 before coronary angioplastyon complications of coronary bypass surgery. Am J Cardiology 1994; 74:1166–70Boehrer, JD Kereiakes, DJ Navetta, FI Califf, RM Topol, EJ
Gammie JS, Zenati M, Kormos RL, Hatter BG, Wei LM, Pellegrini RV, Griffith BP, Dyke CM: Abciximab and excessive bleeding in patients undergoing emergency cardiac operations. Ann Thor Surg 1998; 65:465–9Gammie, JS Zenati, M Kormos, RL Hatter, BG Wei, LM Pellegrini, RV Griffith, BP Dyke, CM
Despotis GJ, Levine V, Filos KS, Joiner-Maier D, Joist, JH: Hemofiltration during cardiopulmonary bypass: the effect of anti-Xa and anti-IIa heparin activity. Anesth Analg 1997; 84:479–83Despotis, GJ Levine, V Filos, KS Joiner-Maier, D Joist, JH