A 36yo woman, G3P2, with no vascular risk factors, presented at 26 weeks’ gestation with nine days of claudication progressing to ischaemic rest pain. Bilateral femoral pulses were absent. Duplex doppler diagnosed infrarenal abdominal aortic thrombus with monophasic flow through external iliac and common femoral arteries.
This case report will discuss the urgent surgical and ongoing medical management. An axillo-bifemoral bypass graft allowed perfusion of both the uterus, retrograde via the internal iliac arteries, and lower limbs. Infusions of heparin and magnesium sulphate (for fetal neuroprotection) were followed by therapeutic enoxaparin and aspirin.
No cardiac cause, antiphospholipid antibodies nor vasculitis were found. However, Lipoprotein(a) was 234.7nmol/L (0.94 g/L). Lipoprotein(a) doubles in pregnancy to a median peak of 68nmol/L (0.27g/L), and increased risk of cardiovascular disease is at >100 nmol/L (>0.4g/L). Niacin 500mg/d was initiated. Lipoprotein apheresis was prepared if rapid reduction of lipoprotein(a) was required for arterial or graft occlusion.
The multidisciplinary management will be discussed, including monitoring of maternal perfusion, lipoprotein(a) response to niacin, fetal hypoperfusion injury, and planning of timing and mode of delivery. Key considerations were adequacy of bypass perfusion of the uterus with increased gestation and for delivery, graft stretch with increasing abdominal size, graft occlusion with hip flexion at vaginal delivery, and cutting the graft at caesarean delivery.
Conclusion: Timely bypass surgery with retrograde perfusion of the uterus allowed for early-term vaginal delivery of a healthy baby. Elevated lipoprotein(a), as a cause of arterial thrombus, should be considered.