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.

Prevention of venous thrombosis after total hip arthroplasty. Antithrombin III and low-dose heparin compared with dextran 40.

The anticoagulant action of heparin is mediated through antithrombin III, and the postoperative decrease in the plasma concentration of antithrombin III may contribute to the relative ineffectiveness of prophylaxis with low-dose heparin in preventing venous thrombosis after total hip arthroplasty. We conducted a prospective, randomized trial to compare the effectiveness of a regimen of antithrombin III, given intravenously once daily, and low-dose heparin with a regimen of dextran 40, given intravenously, in preventing venographically documented venous thrombosis after total hip arthroplasty. The results demonstrated an incidence of venous thrombosis of 4.9 per cent in patients who received antithrombin III and heparin; this was significantly lower than the incidence (28.6 per cent) in patients who received dextran 40 (p less than 0.005). Venous thrombosis occurred only in patients who had total hip arthroplasty with a cemented prosthesis (fourteen of fifty-seven patients, or 24.6 per cent); none of the twenty-six patients in whom a non-cemented prosthesis was used had venous thrombosis (p less than 0.01). Of the patients in whom a cemented prosthesis had been inserted, the incidence of venous thrombosis was lower in those who were treated with antithrombin III and heparin (7.4 per cent) than in those who were treated with dextran 40 (40 per cent) (p less than 0.005). Postoperative levels of antithrombin III were maintained at more than 90 per cent of the baseline level in patients who received it; this was significantly higher than in patients who received dextran 40.(ABSTRACT TRUNCATED AT 250 WORDS)

Lower risk of thromboembolic disease after total hip replacement with non-cemented than with cemented prostheses.

During the course of a prospective, randomised trial comparing dextran 40 with antithrombin III plus heparin as prophylaxis against thrombosis after total hip replacement, an unexpectedly low incidence of postoperative thromboembolic disease was found in patients receiving non-cemented (0 of 23) rather than cemented prostheses (4 of 13, 31%). Despite the small number of patients, the difference was significant and necessitated modification of the protocol. These preliminary findings suggest that the type of hip replacement used was more important than the type of antithrombotic medication in preventing venous thrombosis and pulmonary embolism.