Duration of thromboprophylaxis with low-molecular-weight heparin after abdominal delivery in Factor V Leiden carriers
Objective: To evaluate the efficacy of prolonged thromboprophylaxis based on the study of the laboratory phenotype after abdominal delivery in carriers of Factor V Leiden G1691A mutation. Materials and methods. We conducted a multicenter randomized clinical controlled trial that included 171 women with the Factor V Leiden G1691A mutation and had planned abdominal delivery. Depending on the resistance index of factor Va to activated protein C (APC-R), randomization was performed on the 10th day after delivery. In 17 women, the APC-R index according to NR was defined in the range of >0.5, derived from the study. 154 patients had the APC-R index according to NR defined as 0.49 or less and needed prolonged thromboprophylaxis. The main group included 99 recently delivered women who had calcium thromboprophylaxis with nadroparin in preventive doses prolonged to 42 days of the postpartum period. The control group consisted of 55 patients who received low molecular weight heparin (LMWH) 10 days after delivery and refused to use LMWH again. The efficacy of prolonged use of LMWH was evaluated by the number of venous thromboembolic events (VTE) registered during 42 days of the postpartum period in the main group compared to the control group. Results. In carriers of the factor V Leiden mutation with a manifested phenotype (APC-R according to NR <0.49), the use of LMWH 42 days after a cesarean section significantly reduces the risk of thrombotic events by 12.7% (p=0.0373). At the same time, it is necessary to treat 8 newly delivered women to prevent one episode of postpartum VTE. Conclusions: In carriers of the Factor V Leiden G1691A mutation with a laboratory phenotype manifested in the form of APC-R 0.49 according to NR after abdominal delivery, prolonged thromboprophylaxis with LMWH in preventive doses is justified for up to 42 days.