PP-031 Prognostic significance of the ADAMTS-13/vWF axis during pregnancy

To compare the features of the functioning of the ADAMTS-13 /vWF system in pregnant women with physiologically occurring pregnancy in the I, II, III trimester and in pregnant women with a physiological course in the I and II trimester, who developed late preeclampsia in the III trimester.

At the first stage, we prospectively examined 167 women with a physiological course of pregnancy in the I, II, III trimester, however, 104 women (n=63; the main group) were excluded from the study (acute respiratory infections, premature birth, acute pyelonephritis, gestational diabetes mellitus, preeclampsia). In these women, we examined the levels of ADAMTS-13 antigen, vWF antigen and the ADAMTS-13/vWF axis and performed a comparative analysis of the indicators between pregnant women with a physiological course of pregnancy (n=63; the main group) in the I, II and III trimesters of gestation and healthy non-pregnant women (n=45; the control group). At the second stage of the study, a comparative analysis of ADAMTS-13 indicators was carried out ADAMTS-13:Ag, vWF:Ag and axis АDAMTS-13:Ag/vWF:Ag between patients with a physiological course of pregnancy in the I, II, III trimester (n= 63) and in patients with a physiological course of pregnancy in the I, II, trimester who developed preeclampsia after 34 weeks of gestation (n=15; the comparison group).

The average age in women with physiological pregnancy was 28.5±4.64 years (the main group), in patients with advanced late preeclampsia 29.2±6.24 years (comparison group)., in the control group 28.3±5.83 years. At the first stage of the study, we found out that starting from the second trimester of physiological pregnancy in the normal, the level of ADAMTS-13:Ag decreases and the level of vWF:Ag increases. The decrease in the level of ADAMTS-13:Ag in the second trimester was by 13% (0.855 [0.726; 0.92] U/ml), compared with the control group (0.909 [0.886; 1.00] U/ml) and by 17% in the third trimester (0.787 [0.72; 0.89]U/ml). We also revealed a decrease in the axis ADAMTS-13:Ag/vWF:Ag by 50% in the second trimester and by 59% in the third trimester. At the second stage of the study, when examining the ADAMTS-13:Ag/vWF:Ag, it was found that in the main group, the median of this indicator was 0.976 [0.895;1.09], and in the comparison group 0.573 [0.486;0.696] (p<0.01). A 13.3% decrease in the ADAMTS-13:Ag axis was revealed/vWF:Ag in the first trimester in patients who developed preeclampsia in the future. The area under the ROC curve corresponding to the relationship between the development of preeclampsia and the level of ADAMTS-13:Ag/vWF:Ag was 0.952. The threshold value of ADAMTS-13:Ag/vWF:Ag at the cut-off point equal to 0.587 U/ml. If the ADAMTS 13:Ag/vWF:Ag level is equal to or lower than this value, a high risk of developing preeclampsia is predicted in the first trimester. Median ADAMTS-13:Ag/vWF:Ag in patients with preeclampsia in the second trimester was 0.269 [0.218-0.356], and in the third trimester 0.154 [0.131-0.200] , compared with pregnant women whose pregnancy was physiologically 0.557 [0.475-0.631] (II trimester) and 0.447[0.394-0.48] (III trimester).

Our study shows the normal functioning of the ADAMTS-13:Ag/vWF:Ag in healthy pregnant women in the I, II, and III trimesters. This is important to know, since a violation of this axis may indicate the development of possible pregnancy complications. Further research on this subject should be a priority for the obstetrics.