The only one study scaling the tolerance of anticoagulants for this population found major hemorrhagic levels discording with the clinical practice : really high for connectives associated to pulmonary arterial hypertension (PAHT), and lower in "simple" pulmonary embolism in CTE-PHT. These discoveries could belong to methodological failures of this study: a retrospective, monocentric one, without adjudication of events by an independent committee. Furthermore, there were no information about the existence of a validated indication for anticoagulant treatments.