Pulmonary embolism in children: a French national multicentric retrospective cohort study

<bold>Rationale</bold>: Pulmonary embolism (PE) in children is a rare, life-threatening condition, whose incidence is increasing, and for which accurate timely diagnosis is crucial. The aim of this study is to describe the French pediatric PE cohort. <bold>Methods:</bold> Clinical, paraclinical, therapeutic and outcome data for children diagnosed between 2010 and 2020 were collected from the centers in the Respirare® network. Univariable and multivariable logistic regression were done. <bold>Results:</bold> 220 children presented with PE in 13 centers, with a median age of 15 years and a median diagnostic delay of 3 (IQR 0;7) days. The most common symptoms were tachycardia (39%), dyspnea (38%) and chest pain (35%). A risk factor or underlying pathology was present in 94% of cases. 170 patients (77%) presented at least one underlying pathology at risk of PE. The most common underlying pathologies were malignancy (20%), systemic infection (11%) and inherited cardiopathy (10.5%). For 42 patients, at least one underlying pathology was unknown prior to the PE even if 64% of them had already at least one obvious risk factor or other known underlying pathology that could explained the PE. 13% of patients had massive PE. The discovery of an inaugural underlying pathology (OR 6.1, p<0.001), the presence of thrombophilia (OR 4.2, p=0.006) or the use of oral contraception (OR 6.4, p<0.001) are associated with a shorter diagnostic delay. 20 patients (10%) died following their PE. 30-day mortality was associated with severity (OR 10.2, p=0.023) and with the cumulative impact of underlying pathologies (OR 98, p=0.029). <bold>Conclusions:</bold> This is one of the largest cohorts described in pediatrics. Etiological research must be as exhaustive as possible.