Recruiting

LMWH & LDA

Sponsor:

Mount Sinai Hospital, Canada

Code:

NCT07658989

Conditions

Pregnancy

Prosthetic Heart Valve

Anticoagulant Therapy

Eligibility Criteria

Sex: Female

Age: 18 - 45

Healthy Volunteers: Not accepted

Interventions

LMWH and LDA

Vitamin K antagonists (e.g warfarin)+/- LDA

Sequential therapy +/- LDA

Study Details

Brief summary:

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.

Conditions

Pregnancy

Prosthetic Heart Valve

Anticoagulant Therapy

Study ID

NCT07658989

Start date

May 26, 2026

Status verified date

May, 2026

Completion date

Dec, 2030

Anticipated

Primary completion date

Jan, 2030

Anticipated

Eligibility Criteria

Eligibility Criteria

Sex: Female

Age: 18 - 45

Healthy Volunteers: Not accepted

Inclusion Criteria:

1. Pregnant individuals with one or more MHVs
2. Who consent to participate
3. Are 18 years or older and
4. Less than 12 weeks gestation

Exclusion Criteria:

1. Have a platelet count less than 50 x 10(9)/L as there is an increased risk of bleeding with thrombocytopenia, and/or
2. Have active bleeding defined as bleeding resulting in a hemoglobin reduction ≥10 g/L or in hemodynamic instability.
3. Have new valve thrombosis identified immediately prior to pregnancy

Study Design

Enrollment

100 participants

Anticipated

Allocation

Non randomized

Intervention Model

Parallel Assignment

Primary purpose

Treatment

Interventions and Outcome Measures

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

Interventions

LMWH and LDA

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

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

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

Primary outcome measure

  • Primary outcome Measures [ Time Frame: At baseline ]
  • Adherence rate [ Time Frame: From enrollment until birth. ]

Central Contacts and Locations

Central contacts

Nadine Shehata, MD

4165865133nadine.shehata@sinaihealth.ca

Locations

Mount Sinai Hospital

Recruiting

Toronto, Ontario, Canada, M5G1X5

Contacts

Nadine Shehata, MD

4165865133nadine.shehata@sinaihealth.ca

More Information

Sponsor

Mount Sinai Hospital, Canada

Last update posted

Jun 22, 2026

Last verified

May, 2026

Keywords

  • Pregnancy
  • Prosthetic heart valve
  • Anticoagulant therapy
  • Low molecular weight heparin
  • warfarin
  • vitamin K antagonist

Trial information was received from ClinicalTrials.gov and was last updated on 2026-09-10. This information was provided to ClinicalTrials.gov by Mount Sinai Hospital, Canada on 2026-06-22.