Argatroban for Off-Pump Coronary Artery Bypass Surgery

To the Editor: Kieta et al. (1) described the use of argatroban anticoagulation for off-pump coronary artery bypass surgery in a patient with heparin-induced thrombocytopenia type II. While the case report and TEG data were interesting, based on our experience at Virginia Commonwealth University Health System, we believe that bivalirudin (Angiomax; The Medicines Company, Parsippany, NJ) offers a safer and more efficacious alternative for this case. At our institution we have experienced success using bivalirudin anticoagulation for cardiac surgery both with and without cardiopulmonary bypass. Results awaiting publication from a trial of bivalirudin at our institution for cardiopulmonary bypass cases demonstrate equal or less chest tube drainage and blood utilization than standard heparin anticoagulation for cardiac surgery. Bivalirudin has a plasma half-life of 25 min (2), which is substantially shorter than argatroban, and a unique elimination method (from cleavage by thrombin) relatively independent of specific organ function (3). In patients with normal renal function, only 20% of the drug is cleared by kidneys while the rest is cleared by proteolysis. In dialysis patients or patients with severe renal impairment, the half-life is increased; however, excessive concentrations of bivalirudin can be effectively reduced by hemofiltration or plasmapheresis (2). Argatroban, which requires hepatic elimination, has been safely used in patients with renal failure (4). In their report, Kieta et al. (1) stated, “no important clinical coagulopathy was noted.” However, chest tube drainage for 24 h was 1186 mL, which we consider moderately severe postoperative bleeding for an off-pump CABG. Furthermore, the laboratory studies reported suggest evidence of coagulopathy as all coagulation parameters measured, except fibrinogen and platelets, were significantly elevated above baseline at 3 h after infusion. The most significant finding in Kieta et al’s report is that at 3 h after infusion of argatroban, there remained marked prolongation of the ACT, aPTT, PT, and TEG R time, accompanied by a decrease in the TEG alpha angle and MA from baseline, suggesting a prolonged anticoagulant effect of argatroban. Given the relatively long half-life of argatroban (46 ± 10 min) and associated laboratory abnormalities, it appears likely that the excessive bleeding reported in the case was, at least in part, related to the residual effects of argatroban at the end of the case. In summary, bivalirudin may offer a safer alternative for anticoagulation during cardiac surgery. Jeffrey A. Green, MD Catherine L. Cooper, MD Octavio A. Falcucci, MD Amira Safwat, MD Thomas Slaughter, MD Bruce D. Spiess, MD