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NCT Number: NCT06372730

Residual Pulmonary Vascular Obstruction Index Computed With Ventilation/Perfusion SPECT/CT Imaging to Predict the Risk of Venous Thromboembolism Recurrence in Patients With Pulmonary Embolism (PRONOSPECT)

Major risk after pulmonary embolism (PE) is recurrence, fatal in 10% of patients. Patients with PE can be stratified in 3 groups according to the risk of recurrence : very low risk, high risk or Intermediate risk. Little is known about this last group.

Anticoagulation is efficient to prevent recurrence but is currently not recommended for patient with an intermediate risk of recurrence.

Identifying risk factors of recurrent PE remains a major issue to identify sub-groups of patients who would require lifelong anticoagulation.

In 30-40% of cases, PE patients develop residual pulmonary vascular obstruction (RPVO), which has been found to be associated with an increased recurrence risk. This last observation was mostly reported in patients with unprovoked PE (patients with high risk of recurrence) and RPVO was measured using conventional planar lung scan.

In patients with an intermediate risk of recurrence, the impact of RPVO has been much less studied. In addition, the definition of RPVO was variable according to studies and correlation between RPVO burden and recurrence risk has not been clearly demonstrated. This might be explained by the inherent limitation of RPVO quantification using conventional planar imaging, which is only based on a visual estimation on 2-dimensional images.

Ventilation/Perfusion Single Photon Emission Computed Tomography (V/Q SPECT/CT) is a new method of scintigraphic image acquisition that offers the advantage of 3-dimensional imaging, enabling more accurate and reproducible quantification of RPVO.

The main hypothesis of this study is that in patients with PE at intermediate risk of recurrence, RPVO computed with V/Q SPECT/CT imaging may be an important predictor of recurrence.

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Key information

Conditions

Pulmonary Embolism Cardiovascular Diseases Embolism Embolism and Thrombosis Lung Diseases Respiratory Tract Diseases Thromboembolism Vascular Diseases Venous Thromboembolism

Age range

18 year and older

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

CHU Amiens, Amiens, France

Loading trial locations.

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Patients ≥ 18 years,
  • who experienced an objectively proven PE,
  • who have been treated initially with anticoagulant therapy for 3 to 6 uninterrupted months (180 - 210 days) and for whom anticoagulation will not be prolonged.

Exclusion criteria

  • Unwilling or unable to give written informed consent (protected adults, under tutorship or curatorship)
  • Patients deprived of their liberty by a judicial or administrative decision, patients undergoing psychiatric care by virtue of Articles L. 3212-1 and L. 3213-1 who are not covered by the provisions of Article L. 1121-8 and patients admitted to a health or social establishment for purposes other than research
  • No Social security affiliation
  • Isolated DVT
  • Pregnant women and parturients
  • Other indication for anticoagulant therapy (e.g. atrial fibrillation, mechanic valve)
  • Life expectancy < 6 months
  • Any patients for whom there is a strong indication to treat longer than 6 months:
  • PE provoked by a major persistent factor (e.g. cancer)
  • Recurrent unprovoked PE

PE provoked by a major transient risk factor (e.g. surgery with general anesthesia for greater than 30 min, confined to bed in hospital for at least 3 days with an acute illness, cesarean section)

AND none of the following persistent factors :

  • BMI ≥ 30
  • Chronic respiratory disease
  • Chronic inflammatory disease (e.g., ulcerative colitis, rheumatoid arthritis, etc.)
  • Hepatocellular insufficiency
  • Renal insufficiency with creatinine clearance < 60 mL/min
  • Chronic or persistent immobilization

Treatment and study plan

Ventilation/Perfusion Single Photon Emission Computed Tomography (V/Q SPECT/CT)

Other

All patients will undergo a V/Q SPECT/CT scan at inclusion.

Primary outcomes

  1. Symptomatic recurrent venous thromboembolism (VTE), including objectively confirmed nonfatal symptomatic PE or proximal deep vein thrombosis or fatal PE during a 24-month follow-up after inclusion in the study

    Time frame: From baseline to Month 24

    In case of a suspected VTE or death during follow-up, the study personnel will collect related clinical data on the electronic case report form, and prepare an adjudication file, including symptoms, clinical notes, hospital discharge summary, and results of all diagnostic tests. All suspicion of VTE recurrence will be adjudicated blindly by an independent central Clinical Events Committee.

    To assess the primary objective, RPVO will be defined by a perfusion mismatched defect of at least 5% of the whole lung, corresponding to a segmental defect. SPECT imaging should not be used at inclusion and should not result in proposing prolonged anticoagulation. SPECT images will be numerically stored and interpretation will be later performed independently by two nuclear medicine physicians who will be blinded to clinical history and the patient's outcome. Any difference in interpretation will be resolved by consensus.

Secondary outcomes

  1. Adjudicated symptomatic objectively confirmed recurrent VTE during the follow-up period.

    Time frame: From baseline to Month 24

  2. Percentage of patients with RPVO (as defined by a perfusion defect > 5%) on V/Q SPECT/CT imaging at inclusion in the study.

    Time frame: Inclusion

  3. Different cut-offs of pulmonary vascular obstruction index will be evaluated to predict the risk of VTE recurrence at 2 years, by generating ROC curves

    Time frame: Inclusion

  4. Other predictors of adjudicated symptomatic objectively confirmed recurrent VTE at 2 years including: age

    Time frame: Inclusion

  5. The following score will be computed : HERDOO2 (Hyperpigmentation, Edema, Redness, D-Dimer, Obesity, Old)

    Time frame: Inclusion

    Prediction score of recurrence in patients with unprovoked deep vein thrombosis or pulmonary embolism recurrence in patients with unprovoked PE, (test in patients at intermediate risk of recurrence in this trial). Patient with score of 0 to 1 have a low risk of recurrent VTE, whereas patient with a score of at least 2, have a high risk of recurrence

  6. Potential predictors of RPVO including : demographics

    Time frame: Inclusion

  7. Symptomatic recurrent VTE during a 3 Months follow-up period in patients with suspicion of PE recurrence who has been left untreated based on a negative V/Q SPECT/CT scan

    Time frame: 3 Months follow-up period after the suspicion of PE recurrence

    Symptomatic recurrent VTE including objectively confirmed nonfatal symptomatic PE or proximal DVT or fatal VTE

  8. Dyspnea index will be assessed using mMRC scale (Modified Medical Research Council)

    Time frame: Inclusion and Month 6

    The mMRC scale is a self-assessment tool used to measure the level of impairment caused by breathlessness during daily activities, rated on a scale from 0 to 4.[2] 0, no breathlessness except on strenuous exercise and 4, too breathless to leave the house, or breathless when dressing or undressing.

  9. Quality of life (QoL) will be assessed using PEmb-Qol (Pulmonary Embolism Quality of Life)

    Time frame: Inclusion and Month 6

    The PEmb-QoL is a validated 40-item questionnaire to quantify health-related quality of life in patients having experienced pulmonary embolism (PE). It covers six health dimensions: frequency of complaints, activities of daily living limitations, work-related problems, social limitations, intensity of complaints, and emotional complaints.The PEmb-QoL dimension scores are calculated by taking the mean of the constituting items. Dimension scores are then transformed to a scale from 0-100 to make them comparable across dimensions, with higher scores indicating worse outcome.

  10. Number of Participants with chronic thromboembolic pulmonary hypertension (CTEPH).

    Time frame: From baseline to Month 24

    CTEPH will be defined by a mean pulmonary artery pressure >20 mmHg.

  11. Mortality of all causes.

    Time frame: From baseline to Month 24

  12. Percentage of patients with RPVO (> 5%) on V/Q SPECT/CT imaging using Technegas and Krypton.

    Time frame: Inclusion

  13. The following score will be computed : PADIS-PE score.

    Time frame: Inclusion

    PADIS-PE (score derived from the PADIS study : Prolonged Anticoagulation During eighteen months versus placebo after Initial Six-month treatment for a first episode of idiopathic Pulmonary Embolism randomized trial).

    A higher score indicates a higher risk of recidive.

  14. Other predictors of adjudicated symptomatic objectively confirmed recurrent VTE at 2 years including: gender

    Time frame: Inclusion

  15. Other predictors of adjudicated symptomatic objectively confirmed recurrent VTE at 2 years including: obesity

    Time frame: Inclusion

    Body Mass Index > 30 kg/m2

  16. Other predictors of adjudicated symptomatic objectively confirmed recurrent VTE at 2 years including: D-Dimer

    Time frame: Inclusion

    Measurement of the concentration of plasma D-dimer

  17. Other predictors of adjudicated symptomatic objectively confirmed recurrent VTE at 2 years including: inherited or acquired thrombophilia

    Time frame: Inclusion

    Number of Participants with inherited or acquired thrombophilia

  18. Other predictors of adjudicated symptomatic objectively confirmed recurrent VTE at 2 years including: residual vein thrombosis

    Time frame: Inclusion

    Number of Participants with residual vein thrombosis

Study contacts

Contact information is provided by the study sponsor or research team.

Pierre-Yves LE ROUX, Pr

CONTACT

[email protected]

+33298223327

Sponsors and collaborators

Lead sponsor

University Hospital, Brest

Other

Registry information

Official study title

Residual Pulmonary Vascular Obstruction (RPVO) Index Computed With Ventilation/Perfusion SPECT/CT Imaging to Predict the Risk of Venous Thromboembolism (VTE) Recurrence in Patients With Pulmonary Embolism (PE)

Acronym: PRONOSPECT

Important dates

Study start
2024
Primary completion
2028
Study completion
2029
First posted
Apr 18, 2024
Registry last updated
Jun 15, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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