Argatroban for Anticoagulation during Cardiopulmonary Bypass.

The incidence of heparin-induced thrombocytopenia (HIT) with the use of heparin (H) might be higher in cardiac patient than other populations. Sometimes, these patients require surgery with the use of extracorporeal circulation (heart-lung machine or oxygenator). Anticoagulation during this surgery is essential, and almost always done with heparin. Knowledge in this setting about alternative anticoagulants, bleeding complications, monitoring problems, and drug elimination is limited. Here, we describe our experience with the direct thrombin inhibitor argatroban for anticoagulation during cardiac surgery.

CASE REPORT: A 48-year-old male presented with weakness. He was found to have new onset atrial fibrillation with rapid ventricular rate and congestive heart failure. Echocardiography and blood cultures revealed staphylococcus endocarditis affecting the mitral valve and he received antibiotics. The patient started heparin on admission, and developed thrombocytopenia six days later. HIT antibody was positive, heparin was stopped and argatroban was initiated. Platelet count normalized. After two weeks, he required the insertion of an intra-aortic balloon pump and mitral valve replacement for severe mitral regurgitation. On the day of surgery, a baseline celite activated clotting time (ACT) was 253 seconds (s). A loading dose of argatroban was given (10 mcg/kg) followed by continuous infusion of 3.0–6.0 mcg/kg/min. The ACT ranged from 423–755 s during the surgery. The patient received platelets and plasma products for adequate hemostasis of the surgical site, but had increase bleeding during the first post-operative day. Argatroban was held for 36 hours after surgery. During this period, his activated partial thromboplastin time (aPTT) ranged between 25.4 – 33.8 s. After that, argatroban was re-started and the aPTT kept between 48–55 s. On post-operative day (POD) 3, doppler studies revealed a venous thrombus in the right upper extremity. On POD 6 the patient started warfarin and continued to have a full recovery.

DISCUSSION: This case exemplifies the successful use of argatroban for anticoagulation during emergent cardiac surgery where heparin was contraindicated. The ACT monitoring was adequate and there were no unexpected complications. However, our patient suffered a venous thrombosis in the early post-operative period. In addition to the surgical complications, patients with HIT are at high risk for developing both venous and arterial thrombosis. Our case highlights the need for early anticoagulation with argatroban following surgery. We speculate that the delay in starting argatroban after surgery might have predisposed the patient to have a deep vein thrombosis. Yet, it is difficult to determine when to start anticoagulation in a highly thrombophilic patient who has significant post-operative bleed.

CONCLUSION: Argatroban, with ACT monitoring, can be safely used for emergent cardiac surgery in patients with HIT. The timing of post-operative anticoagulation may pose a challenge for the clinician.