Abstract Number: PB0596
Meeting: ISTH 2021 Congress
Background: Emicizumab prophylaxis reduces bleeding in patients with hemophilia A and inhibitors (PwHA-I). A small number of cases have been reported describing global coagulation assays for monitoring hemostasis during concomitant treatment with bypassing agents in emicizumab-treated PwHA-I undergoing surgery. However, coagulation potential during the perioperative period in these circumstances remains to be assessed.
Aims: To assess global coagulation potential for the perioperative hemostatic management of emicizumab-treated PwHA-I.
Methods: Arthroscopic synovectomy in one pediatric PwHA-I receiving emicizumab prophylaxis was performed during concomitant treatment with recombinant factor VIIa (rFVIIa). Coagulation potential was assessed using modified-clot waveform analysis (CWA) triggered with a reagent-mixture containing tissue factor and ellagic acid, and thrombin generation assays (TGA) triggered by tissue factor were utilized. Maximum velocity (Ad|min1|) and clot time in CWA, and peak thrombin, endogenous thrombin potential (ETP) and time-to-peak in TGA were calculated.
Results: A bolus infusion of rFVIIa (80 μg/kg) was administered immediately before surgery, and continued at the same dose every 3 hours on day 1, every 4 hours on day 2, and 6 hours day 3, respectively. Treatment with rFVIIa was discontinued on day 4. No perioperative bleeding or thrombotic events were observed. Clot time in CWA and time-to-peak in TGA were shortened than the normal upper limits and ETP in TGA barely reached the lower normal limits, indicating that these parameters appeared unlikely to reflect coagulation potential in the patient. In contrast, measurements of Ad|min1| (5.26 at baseline level) were increased to 6.55-7.55, and remained within or near to the normal range (mean±SD; 6.7±0.6) during concomitant therapy with rFVIIa, suggesting good hemostatic management. Changes in peak thrombin in TGA paralleled the Ad|min1| results.
Conclusions: Ad|min1| in modified-CWA and peak thrombin in TGA provide useful data for assessing coagulation potential for the perioperative hemostatic management of emicizumab-treated PwHA-I.
To cite this abstract in AMA style:Mizumachi K, Tsumura Y, Nakajima Y, Ko K, Nogami K. Usefulness of Clot Waveform Analysis as a Perioperative Monitoring in Arthroscopic Synovectomy to a Pediatric Patient with Hemophilia A and Inhibitor Receiving Emicizumab [abstract]. Res Pract Thromb Haemost. 2021; 5 (Suppl 2). https://abstracts.isth.org/abstract/usefulness-of-clot-waveform-analysis-as-a-perioperative-monitoring-in-arthroscopic-synovectomy-to-a-pediatric-patient-with-hemophilia-a-and-inhibitor-receiving-emicizumab/. Accessed December 3, 2021.
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