Anticoagulation for mechanical heart valves during pregnancy: A case report and a literature review

Abstract

Rationale: Most previous treatment guidelines for pregnant women with mechanical heart valves recommend that low molecular weight heparin (LMWH) should be applied once every 12 hours and only as required to reach peak anti-Xa levels of approximately 1.0 to 1.2 IU/mL, but it is commonly associated with subtherapeutic trough levels, consequently with an inadequate level of anticoagulation. Our case report here together with a literature review suggests that dose-adjusted (Target trough anti-Xa levels of 0.6 to 0.7 IU/mL and with peak anti-Xa levels of around 1.0 to 1.2 IU/mL or < 1.5 IU/mL) LMWH should be given thrice daily throughout pregnancy. In addition, the findings of this rare case indicate that a combination of LMWH and warfarin is effective in the treatment of small thromboses in pregnancy. Patient concerns: In the 1 st trimester of pregnancy, a 28-year old pregnant female with a mechanical valve had a significant increase in the aortic valve flow rate and suspected mechanical valve thrombosis. Diagnoses: The peak velocity of the pregnant female aortic mechanical valve increased, and mechanical valve thrombosis was suspected. Interventions: We adjusted the enoxaparin sodium dose every 12 hours to 1 injection every 8 hours, with a total daily dose of 160 mL. Based on the original application of LMWH, warfarin (3 mg/day) was recommended. Outcomes: The pregnant woman delivered a live baby by cesarean section, and the peak flow velocity of the mechanical valve in the aortic position was reduced to nearly equivalent to the patient’s pre-pregnancy status. The mother and the baby were in good health at the time of discharge. Lessons: LMWH is administered twice daily, and anti-Xa trough levels are mostly in a subtherapeutic state, which may lead to insufficient anticoagulation and thrombosis. Dose-adjusted LMWH thrice daily throughout pregnancy is the recommended treatment for pregnant women with mechanical heart valves. The combination of LMWH and warfarin exhibited good efficacy for the treatment of small thromboses.

Enhancing transmission type frame structures: A BBO algorithm-based integrated design approach

“…Wang, J et al proposed a wind vulnerability framework with uncertainties in each line component, wind environment, and aerodynamic parameters of transmission towers [34]. Bai, JT et al innovatively investigated the three-point bending collapse of DRTWT by combining internal and external topological descriptor functions for structural optimization while optimizing numerical algorithms to validate the frame model [35][36][37]. Gui, CY et al proposed an integrated crashworthy design for a plastic frame model [38].…”

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“…In pregnant women with prosthetic mechanical valves, thromboembolism rates ranged from 7 -23 % per patient per year [4,5] . Despite recommendations that VKA should be the first-line antepartum therapy, low-molecularweight heparin (LMWH) is a significantly less effective anticoagulant, and various research indicate that the risk of embryopathy is low roughly 1 -2 % when the mother is on warfarin at 5 mg per day or less [6] . Recent recommendations classify warfarin as class I during the 2 nd & 3 rd trimesters, as the warfarin embryopathy risk is limited to weeks 6 to 12.…”

“…Recent recommendations classify warfarin as class I during the 2 nd & 3 rd trimesters, as the warfarin embryopathy risk is limited to weeks 6 to 12. During the 1 st trimester, warfarin doses of 5 7), [1][2][3][4][5][6] as class IIa, making it superior to unfractionated or LMWH [7,8] . Patients with mechanical heart valves have an elevated risk of maternal morbidity and mortality after delivery.…”