ProC Global Assay in the Evaluation of Women at Risk for VTE While Using Hormonal Therapy

Abstract number: P1687

Sarig¹ G, Aberbach² I, Schliamser³ L, Blumenfeld^1,2 Z, Zlotzover^1,2 M, Brenner^1,2 B

^{1,2 11}Rambam Medical Center, Haifa, Israel ²²The Bruce Rappaport Faculty of Medicine, Technion-Israel Institute of Technology, Haifa, Israel ³³Bnai Zion Medical Center, Haifa, Israel

Use of oral contraceptives (OC) and hormonal replacement therapy (HRT) is associated with an increased risk of venous thromboembolism (VTE). ProC Global assay was developed for evaluation of protein C pathway abnormalities and could serve as a diagnostic tool in women at risk for VTE. The aim of this study was to determine the diagnostic value of ProC Global assay in women receiving hormonal therapy. Study group included 32 women who developed VTE (6 PE, 23 DVT, 3 PE and DVT) while using OC (23) or HRT (9). ProC Global assay was performed six month, at least, after the VTE event without anticoagulant or hormonal therapies. The two control groups included healthy women without history of VTE matched for ethnicity and age. The first included 40 women matched for hormonal therapy used by patients while developing VTE. The second included 56 women without hormonal therapy, matched for patients at blood sampling. Protein C activation time normalized ratio (PCAT-NR) in patients group (0.72 ± 0.1) was significantly lower than controls; matched for age (0.99 ± 0.2) and matched for hormonal therapy (0.94 ± 0.2) (P < 0.001 for both). PCAT-NR lower than cut off level of 0.8 were found in 23/32 (72%) of patients compared to 5/56 (9%) of age matched controls (OR = 26, 95% CI: 6.9–106, P < 0.001) and 9/40 (22.5%) of hormonal therapy matched controls (OR = 8.8, 95% CI: 2.7–30, P < 0.001). Any thrombophilic risk factor was found in 20/32 (62.5%) of patients compared to 12/56 (21.4%) of age matched controls (OR = 6, 95% CI: 2.1–10, P < 0.001) and 12/40 (30%) of hormonal matched controls (OR = 4, 95% CI: 1.3–11.8, P= 0.006). These results suggest that abnormal PCAT-NR is associated with VTE while using OC or HRT and that ProC Global assay can potencially serve as a diagnostic tool for evaluation of the risk for VTE in women, before administration of hormonal therapy.