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Comparing clinical surveillance to anticoagulation for low-risk patients with isolated pulmonary embolism

Clinical Surveillance vs. Anticoagulation for Low-risk Patients With Isolated Subsegmental Pulmonary Embolism: a Multicenter Randomized Placebo-controlled Non-inferiority Trial

Phase 4 Interventional Insel Gruppe AG, University Hospital Bern · NCT04263038

This study is testing whether low-risk patients with isolated pulmonary embolism can safely be monitored without blood thinners instead of taking them.

Quick facts

PhasePhase 4
Study typeInterventional
Enrollment276 (estimated)
Ages18 Years and up
SexAll
SponsorInsel Gruppe AG, University Hospital Bern Academic / other
Drugs / interventionschemotherapy
Locations39 sites (Liège and 38 other locations)
Trial IDNCT04263038 on ClinicalTrials.gov

What this trial studies

This trial aims to evaluate the efficacy and safety of clinical surveillance without anticoagulation versus anticoagulation treatment in low-risk patients diagnosed with isolated subsegmental pulmonary embolism (SSPE). The study will involve randomizing participants to receive either rivaroxaban or a placebo, assessing whether withholding anticoagulation is a safe option for selected patients. The trial addresses the uncertainty surrounding the clinical significance of isolated SSPE and aims to clarify the potential benefits and risks of anticoagulant treatment in this population.

Who should consider this trial

Good fit: Ideal candidates for this study are adults aged 18 and older with a documented diagnosis of isolated SSPE who are considered low-risk.

Not a fit: Patients with active cancer, deep vein thrombosis, or those requiring therapeutic anticoagulation for other reasons may not benefit from this study.

Why it matters

Potential benefit: If successful, this study could provide evidence that may reduce unnecessary anticoagulation treatment and its associated bleeding risks for patients with isolated SSPE.

How similar studies have performed: Other observational studies have suggested that withholding anticoagulation may be safe for selected patients with isolated SSPE, indicating potential for success in this approach.

Eligibility criteria

Show full inclusion / exclusion criteria 
Inclusion Criteria:

1. Informed Consent as documented by signature
2. Age ≥18 years
3. Objective diagnosis of symptomatic or asymptomatic isolated SSPE

Exclusion Criteria:

1. Presence of leg deep vein thrombosis (DVT) or upper extremity DVT (subclavian vein or above)
2. Active cancer, defined as cancer treated with surgery, chemotherapy, radiotherapy, or palliative care during the last 6 months
3. ≥1 prior episode of unprovoked VTE (absence of a transient or permanent risk factor)
4. Clinical instability (systolic blood pressure \<100 mm Hg or arterial Oxygen saturation \<92% at ambient air) at the time of presentation
5. Active bleeding or at high risk of bleeding
6. Severe renal failure (creatinine clearance \<30ml/min)
7. Severe liver insufficiency (Child-Pugh B or C)
8. Concomitant use of strong CYP3A4 inhibitors or strong CYP3A4 inducers
9. Known hypersensitivity to rivaroxaban
10. Need for therapeutic anticoagulation for another reason
11. Therapeutic anticoagulation for \>72 hours for any reason at the time of screening
12. Hospitalized for \>72 hours prior to the diagnosis of isolated SSP (hospital-acquired VTE)
13. Known pregnancy or breast feeding (pregnancy test to be performed for women of childbearing potential)
14. Lack of safe contraception in women of childbearing potential
15. Refusal or inability to provide informed consent
16. Prior enrolment in this trial

Where this trial is running

Liège and 38 other locations

Study contacts

How to participate

  1. Review the eligibility criteria above with your treating physician.
  2. Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
  3. Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.
View on ClinicalTrials.gov → Find more trials like this →
Conditions Pulmonary EmbolismEmbolismEmbolism and ThrombosisLung DiseasesCardiovascular DiseasesRespiratory Tract DiseasesVenous ThromboembolismAnticoagulant-induced Bleeding
Last reviewed 2026-06-13 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.