Comparison of 3 Diagnostic Strategies of PE: Planar V/Q Scan, CTPA, and V/Q SPECT.

Not Applicable

Terminated

• Conditions: Pulmonary Embolism
• Interventions: Device: V/Q SPECT-based strategy; Device: CTPA-based strategy; Device: Planar V/Q-based strategy

• Registration Number: NCT02983760
• Lead Sponsor: University Hospital, Brest

Brief Summary

Pulmonary embolism (PE) remains a diagnostic challenge. False negative testing exposes patient to the risk of potentially fatal recurrence. False positive testing exposes patients to potentially fatal unduly side effects of anticoagulants.

Current diagnostic strategies rely on the sequential use of pretest clinical probability, Ddimer test, and chest imaging. Two chest imaging modalities have been validated for PE diagnostic exclusion: Computed Tomography Pulmonary Angiography (CTPA) and planar V/Q scan. Main limitations of planar V/Q are the high proportion of non-conclusive results, therefore requiring additional testing and more complex diagnostic algorithms. Main limitations of CTPA are its higher radiation dose and contraindications (renal failure).

In a randomized trial that compared strategies based on CTPA and on planar V/Q scan, a 30% increase in the rate of PE diagnoses was found in the arm using CTPA, raising the hypothesis of over-diagnosing and over-treating PE when using CTPA.

V/Q Single Photon Emission CT (SPECT) is a new method of scintigraphic acquisition that has been reported to improve the diagnostic performances of the test, which could reduce the number of non-conclusive tests and allow simplified diagnostic algorithms.

The investigators hypothesize that a strategy based on V/Q SPECT could be an alternative to the two usual approaches responding rightly to the two mains issues and combining the advantages of CTPA (simplified diagnostic approach) and planar V/Q (no overdiagnosis, lower radiation exposure, no contraindication).

Although a recent survey showed that up to 70% of nuclear medicine centers perform SPECT rather than planar imaging for diagnosing PE, a diagnostic management outcome study, in which diagnostic decision would be made on the basis of a standardized algorithm based on the V/Q SPECT is lacking. Such a study needs to be conducted to ensure that the safety of diagnostic exclusion using a V/Q SPECT based strategy is non-inferior to that of previously validated strategies, and to verify that the use of V/Q SPECT does not lead to over-diagnosis.

Detailed Description

Not available

Study Timeline

• Study First Submitted: 2016-11-28
• Study First Submitted QC: 2016-12-02
• Study First Posted: 2016-12-06
• Study Start: 2017-04-10
• Primary Completion: 2024-12-17
• Study Completion: 2024-12-17
• Status Verified: 2025-02
• Last Update Submitted: 2025-02-03
• Last Update Posted: 2025-02-05

Recruitment & Eligibility

• Status: TERMINATED
• Sex: All
• Target Recruitment: 611

Inclusion Criteria

• Outpatients with a clinically suspected PE (defined as an acute onset of new or worsening shortness of breath, chest pain, hemoptysis, presyncope, or syncope) without another obvious apparent cause.
• High pretest clinical probability of PE or a non-high pretest clinical probability but a positive D-Dimer test.

Exclusion Criteria

• Age less than 18 years
• Patients with already confirmed PE
• Patients with a clinically suspected high-risk pulmonary embolism (hypotension or shock)
• Use of therapeutic doses of anticoagulants for more than 48 hours
• Other indication for long-term use of anticoagulants
• Contraindication to contrast media (including renal insufficiency with a creatinine clearance lower than 30 ml/min)
• Life expectancy less than 3 months
• Unable/unwilling to give informed consent
• Unlikely to comply with study follow-up
• Ongoing pregnancy or breastfeeding

Study & Design

• Study Type: INTERVENTIONAL
• Study Design: PARALLEL

Arm && Interventions

Group	Intervention	Description
V/Q SPECT-based strategy	V/Q SPECT-based strategy	Experimental arm
CTPA-based strategy	CTPA-based strategy	Control arm
Planar V/Q-based strategy	Planar V/Q-based strategy	Control arm

Primary Outcome Measures

Name	Time	Method
Thromboembolic events rate in a 3 month follow-up period in patients left untreated after a negative diagnostic strategy.	3 months	Rate of symptomatic objectively confirmed thromboembolic events during the 3-month follow-up period in patients left untreated after a negative diagnostic work-up in V/Q SPECT-based strategy in comparison with planar V/Q-based strategy and CTPA-based strategy.

Secondary Outcome Measures

Name	Time	Method
Proportion of PE diagnostic in each arm	3 months	Proportion of patients deemed to have PE according to the strategy in each arm.
Proportion of additionnal tests required in each arm	3 months	Proportion of patients for whom additional tests are requested in each arm.
Incidence and cause of death in each arm	3 months	Incidence and cause of death in each arm
Major bleeding incidence in each arm	3 months	Incidence of major bleeding episodes in each arm.

Trial Locations

Locations (11)

CH des Pays de Morlaix; 🇫🇷 Morlaix, France

Hegp - Ap-Hp; 🇫🇷 Paris, France

CHU la Réunion; 🇫🇷 Saint-Denis, France

CHU de Saint Etienne; 🇫🇷 Saint-Étienne, France

CH Toulon; 🇫🇷 Toulon, France

Geneva University Hospital; 🇨🇭 Genève, Switzerland

CHU Clermont Ferrand; 🇫🇷 Clermont-Ferrand, France

Ottawa; 🇨🇦 Ottawa, Canada

Hopital Saint Esprit; 🇫🇷 Agen, France

CHU d'ANGERS; 🇫🇷 Angers, France

CHRU de Brest; 🇫🇷 Brest, France