Abstract Number: PB0339
Meeting: ISTH 2020 Congress
Background: With modern coagulation analyzers, single activated partial thromboplastin time (aPTT) result is not just a number but a collection of photo-optical data in the form of a reaction curve.
Aims: To investigate if aPTT reaction curve provides important additional information and whether it allows to predict the degree of FVIII/FIX deficiency from reaction curve in hemophilia patients.
Methods: The study examined plasma samples from 25 healthy, 89 hemophilia A and 17 hemophilia B subjects. aPTT (Actin FS, Atellica COAG360, Siemens, Germany) was determined with two evaluation modes: fixed absorbance (onset of coagulation, FA) and drifting baseline (DB) proposed by manufacturer. Moreover, aPTT at 50% coagulation (PI) was manually determined. We calculated DELTA-1 (aPTT-DB minus aPTT-FA) and DELTA-2 (aPTT-PI minus aPTT-DB). FVIII and FIX activities were measured by one-stage clotting assay and inhibitor using Nijmegen-Bethesda assay. Hemophilia A patients were further divided into HA1 (FVIII< 1IU/dL, N=20), HA2 (FVIII=1-5IU/dL, N=22) and HA3 (FVIII>5-40IU/dL, N=47) groups, hemophilia B into HB1 (FIX=< 1IU/dL, N=8) and HB2 (FIX≥1UI/dL, N=9) groups, and all hemophilia patients into 2 groups according to the presence (I2, N=29) or absence (I1, N=77) of an inhibitor.
Results: Results of DELTA-1 and DELTA-2 in all studied groups are presented in Table 1, whereas results of correlation between DELTA-1/DELTA-2 and FVIII/FIX activities are presented in Table 2. According to Receiver Operating Characteristic (ROC) analysis DELTA-1 >1.30 s allowed distinguishing between healthy and hemophilia subjects (sensitivity:100%, specificity:100%) and >3.64 s between patients with and without inhibitors (sensitivity:79.3%, specificity:53.2%). DELTA-2 values >5.90 s and >13.70 s allowed distinguishing between healthy and hemophilia subjects (sensitivity:93.4%, specificity:100%) and between patients with and without inhibitors (sensitivity:75.9%, specificity:74.0%).
|HA (N=89)||HB (N=17)||All hemophilia patients (N=106)|
|Parameter||Healthy subjects (N=25)||All hemophilia patients (N=106)||HA1 (N=20)||HA2 (N=22)||HA3 (N=47)||HB1 (N=8)||HB2 (N=9)||I1 (N=77)||I2 (N=29)|
|DELTA-1 (s)||0.9 (0.3-1.3)||4.0 (1.7-10.6)||6.1 (4.4-10.6)||4.7 (1.8-10.1)||2.7 (1.7-6.8)||6.1 (3.4-7.3)||2.8 (1.9-5.1)||3.5 (1.7-10.6)||5.0 (1.8-8.3)|
|DELTA-2 (s)||4.4 (3.7-5.9)||10.4 (3.9-47.7)||41.2 (22.0-45.9)||18.7 (8.0-45.4)||8.4 (4.7-36.3)||45.2 (7.0-47.7)||2.8 (1.9-5.1)||9.2 (3.9-45.9)||27.9 (6.7-47.7)|
[Table 1. Results of DELTA-1 and DELTA-2 in all studied groups (medians with ranges);*Mann-Whitney test; **Kruskal-Wallis test]
|PARAMETERS||HEMOPHILIA A (N=89)||HEMOPHILIA B (N=17)|
|HA group||HA1 group||HA2 group||HA3 group||HB group||HB1 group||HB2 group|
|FVIII:C 6.0* (0.9-39.0) IU/dL||FVIII:C <1.0 IU/dL||FVIII:C 3.0* (1.0-5.0) IU/dL||FVIII:C 13.0* (6.0-39.0) IU/dL||FIX:C 1.0* (0.9-23.0) IU/dL||FIX:C <1.0 IU/dL||FIX:C 8.0* (1.0-23.0) IU/dL|
|DELTA-1 (s)||r=0.815 P<0.001||not applicable||r=0.667 P=0.768||r=0.655 P<0.001||r=0.836 P<0.001||not applicable||r=0.882 P=0.002|
|DELTA-2 (s)||r=0.849 P<0.001||not applicable||r=0.520 P=0.013||r=0.587 P<0.001||r=0.845 P<0.001||not applicable||r=0.840 P=0.005|
[Table 2.Correlation of parameters DELTA-1/DELTA-2 with FVIII/FIX activities in all studied groups; *median with range;r- Spearman’s Rank coefficient]
Conclusions: aPTT reaction curve provides important additional information in hemophilia patients. Parameters DELTA-1 and DELTA-2 can be reliable used to distinguish healthy from hemophilia subjects, as well as hemophilia patients with and without inhibitors.
To cite this abstract in AMA style:Pavic J, Milos M, Coen Herak D, Zadro R. aPTT Reaction Curves Provide Important Additional Information in Hemophilia Patients [abstract]. Res Pract Thromb Haemost. 2020; 4 (Suppl 1). https://abstracts.isth.org/abstract/aptt-reaction-curves-provide-important-additional-information-in-hemophilia-patients/. Accessed January 28, 2022.
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