Diagnostic Strategy for Suspected Pulmonary Embolism Based on 4PEPS

The increased use of diagnostic imaging and especially computed tomography pulmonary angiography in patients suspected of pulmonary embolism (PE) is an important point of concerns.

The goal of this pragmatic cluster-randomized trial is to compare the diagnostic strategy based on the four-level pulmonary embolism probability score (4PEPS) and current practices.

The main questions it aims to answer is: "Does the diagnostic strategy based on 4PEPS significantly reduce the use of thoracic imaging without increasing the risk of serious adverse events as compared to current diagnostic practices?" Patients suspected of having PE in the participating emergency departments will be included and followed for 90 days. In ten centers, the emergency physicians will apply the 4PEPS strategy and in ten other centers, the emergency physicians will be free to do as they see fit. Researchers will compare the two groups of patients to see if the rate of diagnostic thoracic imaging tests and the rate of adverse events related to diagnostic strategies will differ.

Several strategies have been devised to safely limit the use of thoracic imaging in patients suspected of pulmonary embolism (PE). However, they are based on different rules for clinical probability (CP) assessment, rendering their combination difficult. The four-level pulmonary embolism probability score (4PEPS) allows the combination of all other strategies using a single CP assessment. Methods and analysis: SPEED\&PEPS is a pragmatic cluster-randomized trial. After a preliminary period aimed to assess the possibility of inclusions and current practices in 23 Emergency Departments (ED), 20 EDs will be selected to participate to the active phase and randomization. Half of the centers will be allocated to the control group where physicians will be free to do as they see fit but they will be given the recommendation to apply a validated strategy. Half of the centers will be allocated to the interventional group where the physicians will be given the recommendation to apply the 4PEPS strategy. Patients with suspected PE will be included and followed for 90 days (anticipated number of patients to be included: 2560, 1280 in each arm). The primary objective will be to demonstrate that the application of the 4PEPS strategy by emergency physicians, in comparison to current practices, (i) does not increase the risk of serious events related to diagnostic strategies and (ii) significantly reduces the use of thoracic imaging. If successful, the SPEED\&PEPS trial will have an important impact for patients suspected of PE limiting their irradiation and for public health in substantial savings in terms of the direct cost of diagnostic investigations and the indirect cost of hospitalizations due to waiting times or delayed harmful effects. Funding: This work is funded by a French Public Health grant (PREPS-N 2019). The funding source plays no role in the study design, data collection, analysis, interpretation or the writing of the manuscript.

Eligibility Criteria:
Inclusion Criteria:

* Admission to an emergency department participating in the study.
* Suspected PE due to thoracic symptoms (dyspnea, chest pain, or hemoptysis) and/or syncope without any other obvious explanation after clinical examination and possible additional first-line tests (ECG, chest X-ray, or routine lab work-up not including D-dimer test).
* Free, prior, and informed consent to participate in the study.

Exclusion Criteria:

* Age \< 18 years.
* Known result of a specific diagnostic examination for PE (D-dimer test, thoracic CT angiography, pulmonary scintigraphy, or venous ultrasound of the lower limbs).
* Hemodynamic instability (systolic blood pressure \< 90 mmHg or more than 40 mmHg lower than usual for more than 15 min).
* Curative dose of anticoagulant in place for more than two days prior to inclusion.
* Pregnant or parturient patient.
* Patient in detention by judicial or administrative decision.
* Patient undergoing compulsory psychiatric treatment.
* Patient placed under a legal protection measure.
* Patient incapable of giving free and informed consent.