Abstract Number: OC 52.4
Meeting: ISTH 2022 Congress
Background: Metallic Heart Valves (MHVs) pose a high risk of thrombotic complications in pregnancy. Recent UKOSS data report 5% mortality. Anticoagulation management remains controversial, lacking clear guidance. At Barts NHS trust most women opt for Low Molecular Weight Heparin (LMWH) with intensive anti-Xa monitoring with dose adjustment aiming for peak anti-Xa of 0.8-1.2iu/ml (valve dependant), trough >0.6iu/ml.
Aims: To evaluate the safety and efficacy of Barts’ anticoagulation regimes in pregnant women with MHVs.
Methods: A single centre retrospective audit of anticoagulation management of MHV during pregnancy 2010-2022
Results: We reviewed 19 pregnancies in 13 women. 15/19 (78.9%) anticoagulated with LMWH and aspirin; 2/19 (10.5%) LMWH and warfarin, 2/19 (10.5%) warfarin throughout pregnancy. The 2 pregnancies on warfarin throughout resulted in miscarriage at 12/40 and stillbirth at 24/40. 1/15 (6.67%) on LMWH experienced a miscarriage and there was one termination. 2/19 developed valve thrombus; one woman (incorrectly started on daily tinzaparin and aspirin without anti-Xa monitoring) presented with an embolic coronary event at 9/40 and opted for termination. The other woman on therapeutic LMWH developed valve thrombus at 33/40 provoking a switch to warfarin – the thrombus resolved and she was delivered safely at 37/40. On average there was a 24mgBD (0-35mg) increase in LMWH dose, anti-Xa levels were done every 11.6 days and 15.5% anti-Xa results were out of range during pregnancy. 5 women had scheduled caesarean sections, 5 had normal deliveries at mean gestation at 36/40 (30-41), mean birth weight 2456g (1795-3180g). Mean blood loss at delivery was 581mls with mean haemoglobin drop 22g/l. 3/19 (15.8%) patients required transfusion (1 placenta praevia, 1 pelvic subcutaneous haematoma).
Conclusion(s): An individualised MDT approach and tightly controlled LMWH dosing can result in good outcomes for women with MHV in pregnancy, but they remain high risk and require intensive medical surveillance and delivery planning.
To cite this abstract in AMA style:White K, Millar L, Vonklemperer K, Bowles L, Hogg M, Glesa O, Howard R, Khan R, Deaner A. A case series examining the safety and efficacy of anticoagulation management in pregnant women with metallic heart valves [abstract]. https://abstracts.isth.org/abstract/a-case-series-examining-the-safety-and-efficacy-of-anticoagulation-management-in-pregnant-women-with-metallic-heart-valves/. Accessed August 9, 2022.
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