Blood thinners may be unnecessary for minor lung clots, new trial suggests

NCT ID NCT04263038

First seen Jun 27, 2026 · Last updated Jun 27, 2026

Summary

This study compares two approaches for low-risk patients with small blood clots in the lungs (isolated subsegmental pulmonary embolism). Half will receive standard blood-thinning medication (rivaroxaban), while the other half will get a placebo and be closely monitored. The goal is to see if simply watching and waiting is as safe as taking blood thinners, which can cause serious bleeding. The trial involves 276 adults and will track recurrent clots, bleeding events, and deaths.

What this could mean

Our plain-language read of the trial. This is informational only — not medical advice or a prediction.

Active substance

Rivaroxaban (blood thinner) or placebo (inactive pill)

What this could lead to

If successful, this could show that many patients with tiny lung clots can safely skip blood thinners, avoiding unnecessary bleeding risks.

What could go wrong

This is a relatively small Phase 4 trial (276 people), and the results may not apply to higher-risk patients. There is a chance that skipping blood thinners could lead to more clots.

Disclaimer Read more

This is a summary of the original study . Summaries may miss details or leave out important information. Before applying or accepting participation, make sure you have read and understood the full study. Curemydisease.com takes no responsibility whatsoever for anything missed, misunderstood, or acted upon as a result of our summary — we know it does not capture everything.

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Conditions

The condition(s) this trial relates to.

cardiovascular disorder Embolism Embolism and Thrombosis Hemorrhage hemorrhagic disease lung disorder pulmonary embolism respiratory system disorder venous thromboembolism

As listed by the trial registrant

The condition terms exactly as the trial's registrant entered them.

Contacts and locations

Study contacts

  • Contact

    Phone: •••-•••-•••• Email: •••••@•••••

  • Contact

    Phone: •••-•••-•••• Email: •••••@•••••

Locations

  • Albert Schweitzer Ziekenhuis Dordrecht

    RECRUITING

    Dordrecht, Netherlands

    Contact

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  • CHU De Rouen

    RECRUITING

    Rouen, France

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  • CHU Gabriel-Montpied

    RECRUITING

    Clermont-Ferrand, France

    Contact

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  • CHU ST Etienne - Hôpital Nord

    RECRUITING

    Saint-Priest-en-Jarez, France

    Contact

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  • Cantonal Hospital of Aarau

    RECRUITING

    Aarau, Canton of Aargau, Switzerland

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  • Cantonal Hospital of Baden

    RECRUITING

    Baden, Switzerland

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  • Cantonal Hospital of Frauenfeld

    RECRUITING

    Frauenfeld, Thurgau, Switzerland

    Contact

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  • Cantonal Hospital of Fribourg

    WITHDRAWN

    Fribourg, Canton of Fribourg, Switzerland

  • Cantonal Hospital of Liestal

    RECRUITING

    Liestal, Basel, Switzerland

    Contact

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  • Cantonal Hospital of Lucerne

    WITHDRAWN

    Lucerne, Canton of Lucerne, Switzerland

  • Cantonal Hospital of Olten

    WITHDRAWN

    Olten, Canton of Solothurn, Switzerland

  • Cantonal Hospital of St. Gallen

    RECRUITING

    Sankt Gallen, Canton of St. Gallen, Switzerland

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  • Cantonal Hospital of Uri

    WITHDRAWN

    Altdorf, Switzerland

  • Cantonal Hospital of Winterthur

    RECRUITING

    Winterthur, Canton of Zurich, Switzerland

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  • Centre Hospitalier Regional Et Universitaire De Brest

    RECRUITING

    Brest, France

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  • Centre Hospitalier Universitaire De Dijon

    RECRUITING

    Dijon, France

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  • Centre hospitalier universitaire de Liege

    RECRUITING

    Liège, Belgium

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  • Cliniques Universitaires Saint-Luc

    RECRUITING

    Woluwe-Saint-Lambert, Brussels Capital, 1200, Belgium

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  • Erasmus Universitair Medisch Centrum

    WITHDRAWN

    Rotterdam, Netherlands

  • Geneva University Hospital

    RECRUITING

    Geneva, Switzerland

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  • Haaglanden Medisch Centrum

    WITHDRAWN

    The Hague, Netherlands

  • Hospital Edouard Herriot

    RECRUITING

    Lyon, France

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  • Hospital of Bienne

    RECRUITING

    Biel/Bienne, Canton of Bern, Switzerland

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  • Hospital of Delémont

    TERMINATED

    Delémont, Switzerland

  • Hospital of Neuchâtel

    RECRUITING

    Neuchâtel, Switzerland

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  • Hospital of Nyon

    WITHDRAWN

    Nyon, Canton of Vaud, Switzerland

  • Hospital of Sion

    WITHDRAWN

    Sion, Valais, Switzerland

  • Hôpital Bicêtre - APHP

    RECRUITING

    Le Kremlin-Bicêtre, Le Kremlin-Bicêtre, 94270, France

    Contact Phone: •••-•••-•••• Email: •••••@•••••

    Contact

  • Hôpitaux universitaires de Marseille Timone AP-HM

    RECRUITING

    Marseille, France

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  • Isala Klinieken Zwolle

    RECRUITING

    Zwolle, Netherlands

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  • Leiden University Medical Center

    RECRUITING

    Leiden, Netherlands

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  • Medisch Spectrum Twente

    RECRUITING

    Enschede, Netherlands

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  • Regional Hospital of Emmental

    RECRUITING

    Burgdorf, Switzerland

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  • The Ottawa Hospital

    RECRUITING

    Ottawa, Canada

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  • Tiefenau Hospital

    COMPLETED

    Bern, Switzerland

  • Triemli Hospital

    RECRUITING

    Zurich, Canton of Zurich, Switzerland

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  • University Hospital Inselspital

    RECRUITING

    Bern, Canton of Bern, 3010, Switzerland

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  • University Hospital Zürich

    WITHDRAWN

    Zurich, Canton of Zurich, Switzerland

  • University Hospital of Basel

    RECRUITING

    Basel, Switzerland

    Contact

    Contact

  • University Hospital of Lausanne

    RECRUITING

    Lausanne, Canton of Vaud, Switzerland

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