Management of Heparin-Resistant Patients with Benefits? Maximizing Biocompatibility in Cardiopulmonary Bypass: Combining ATryn® Recombinant Antithrombin III and Carmeda® Heparin-Bonded Perfusion Circuits: A Case Series.

As many as 25% of our cardiopulmonary bypass (CPB) patients have a diminished heparin response and fail to reach a therapeutic activated clotting time (ACT). We treat a majority of these patients with antithrombin III (ATryn®, recombinant antithrombin III [rhAT], rEVO Biologics). Our current CPB circuit uses Medtronic Carmeda® coating. We observed less post-operative bleeding in a number of patients treated with rhAT. We theorized that adding rhAT would allow patients with diminished heparin response to safely achieve a therapeutic ACT. On the basis of our postoperative bleeding observations, we wondered if using rhAT with a heparin-bonded CPB circuit enhanced its biocompatibility and perhaps improved patient outcomes. Data were collected on 15 patients undergoing CPB who received antithrombin III (AT) replacement therapy for diminished heparin response. We used patient data from 2012, prior to rhAT usage for comparison. All patients achieved therapeutic ACT after rhAT administration. We also observed decreased postoperative atrial fibrillation rates, improved platelet preservation, decreased intensive care unit and ventilator times in patients receiving rhAT compared to rates commonly observed at our center. Heparin-resistant patients can be treated with rhAT to achieve therapeutic ACTs. Our observations suggest that the use of rhAT in conjunction with Carmeda® heparin-bonded circuits may also have a positive benefit on some of the well-established negative clinical consequences of CPB and improve patient outcomes.