Optimizing Anticoagulation in Pregnancies With Mechanical Heart Valves

Sponsor
Mount Sinai Hospital, Canada
Study ID
NCT07658989
Status
Recruiting
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Conditions

  • Anticoagulant Therapy
  • Pregnancy
  • Prosthetic Heart Valve

Eligibility Criteria

Sex
FEMALE
Age
18 Years - 45 Years
Healthy Volunteers
Not accepted

Interventions

  • LMWH and LDA — DRUG
    1\) Therapeutic LMWH throughout pregnancy either using weight-based dosing or dosing according to anti-Xa levels. The initial dose will be a twice daily therapeutic dose of 1.35U/kg (pregnancy weight) of enoxaparin or 135 U/kg (pregnancy weight) of dalteparin using prefilled syringes titrated to the higher dose prefilled syringe (i.e., not below the pregnancy weight-based dosing). 1. The dose of therapeutic LMWH can be adjusted by anti-Xa (done at least after four days of the start of LMWH or change in LMWH dose) levels or by pregnancy weight however, weight and anti-Xa levels will be determined for all participants using LMWH. Pregnancy weight in kilograms is to be determined every month. 2. If therapeutic LMWH is adjusted according to anti-Xa levels, peak and trough anti-Xa levels (done at least after four days of the start of LMWH or change in LMWH dose) are to be sent every four weeks or weekly if there is a change in dose.
  • Vitamin K antagonists (e.g warfarin)+/- LDA — OTHER
    VKAs during pregnancy: VKA use will require INRs every two weeks or weekly (done at least 5 days after starting or changing the dose) if there is a change in doses to ensure an INR of 2.5 for a patient with an aortic MVR (INR of 2 for the On-X AVR) and 3 for mitral MVR or two MHVs is met. LDA 81 mg to be added once pregnancy is confirmed.
  • Sequential therapy +/- LDA — OTHER
    LMWH at 6 weeks gestation until 12 weeks gestation prescribed according to the regimens above then VKAs from 12 weeks gestation until 34-36 weeks gestation followed by twice daily LMWH according to doses above until delivery. LDA to be added when pregnancy is confirmed

Study Details

The purpose of this pilot study is to collect data on pregnancies with mechanical heart valves to see if using a blood thinner called low molecular weight heparin (LMWH) and low dose aspirin (LDA) is comparable to warfarin/vitamin K antagonist (VKA) to reduce the chance of clotting around the mechanical valve and improve survival. The study is a pilot study as the study investigators need to ensure that the blood levels needed for adequate amounts of LMWH and warfarin can be maintained during pregnancy to be able to compare LMWH and aspirin to warfarin. If this study shows that we can collect the tests that are needed for a larger study, the individuals' information who participated in this pilot study will be moved to the larger study. The larger study will compare survival, clot development and cardiac function as well as safety of these two common blood thinners.

Key Dates

First listed
Jun 22, 2026
Start date
May 26, 2026
Status verified
May 2026
Primary completion
Jan 31, 2030
Completion
Dec 31, 2030

Study Design

Enrollment
100 participants (estimated)
Allocation
NON_RANDOMIZED
Intervention model
PARALLEL
Primary purpose
TREATMENT

Arms

  • Experimental: LMWH and LDA
    Therapeutic LMWH throughout pregnancy either using weight-based dosing or dosing according to peak and/or trough anti-Xa levels (measured after at least 4 days of starting or change of dose) and LDA
  • Other: Vitamin K antagonists (e.g warfarin)+/- LDA
    VKA use will require INRs every two weeks or weekly (done at least 5 days after starting or changing the dose) if there is a change in doses to ensure an INR of 2.5 for and aortic MVR and 3 for a mitral MVR or two MHVs is met.
  • Other: Sequential therapy +/-LDA
    LMWH at 6 weeks gestation until 12 weeks gestation prescribed according to the regimens above then VKAs from 12 weeks gestation until 34-36 weeks gestation followed by twice daily LMWH. VKA use will require INRs every two weeks or weekly (done at least 5 days after starting or changing the dose) if there is a change in doses to ensure an INR of 2.5 for an aortic MVR (INR of 2 for the On-X AVR) and 3 for mitral MVR or two MHVs is met. LMWH will be administered twice daily according to pregnancy weight or anti-Xa level

Primary Outcome Measure

Primary outcome Measures [ Time Frame: At baseline ]

Central Contacts

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