Background: The coagulation function and clinical phenotype in acquired hemophilia A (AHA) often do not correlate with the levels of factor VIII activity (FVIII:C) and FVIII inhibitor.

Aims: To evaluate the coagulation potential in AHA by clot waveform analysis (CWA) and thrombin and plasmin generation assays (T/P-GA).

Methods: We analyzed the plasma samples from 59 AHA patients by CWA and T/P-GA.

Results: The medians (range) of FVIII:C and FVIII inhibitor titer at the admission were 3.3 (<1.0-12.5) IU/dL and 63.0 (2.4-3,872) BU/mL, respectively. The medians clot time and maximum coagulation velocity (|min1|) values calculated by CWA on the day of admission were 110 sec and 1.0, respectively, which were markedly less than those in the normal plasmas (30.2 sec, and 3.6, respectively). The peak thrombin and peak plasmin values calculated by T/P-GA on the day of admission were 24.7 nM and 9.5 nM, respectively, which were also markedly less than those in the normal plasmas (242 nM, and 15.3 nM, respectively). Furthermore, we evaluated the coagulation potentials during the clinical course in 39 cases (on the days 0, 14, 28, 56, and 93). The parameters of CWA were improving according to the elevation of FVIII:C and the decreasing of FVIII inhibitor. The peak thrombin was slowly improving on day 56 but still low comparing to the that of normal plasma. Peak plasmin was recovered to the same value as the congenital severe HA patients (12.7 nM) on day 14 and the values remained the same low level.  Peak plasmin was finally recovered to normal level on day 93.

Conclusions: The low values of peak thrombin and peak plasmin at the onset might show the severe bleeding symptom in AHA, and the quick improvement of peak plasmin would suggest the recovery symptom of coagulation potential.

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ISTH Congress Abstracts - https://abstracts.isth.org/abstract/hemostatic-evaluation-by-global-coagulation-assays-in-patients-with-acquired-hemophilia-a-analysis-of-multi-centers-in-japan/