Chronic thromboembolic pulmonary hypertension risk score evaluation and validation (CTEPH SOLUTION): proposal of a study protocol aimed to realize a validated risk score for early diagnosis

Background Chronic Thromboembolic Pulmonary Hypertension (CTEPH) is the most serious long-term complication of acute pulmonary embolism (PE) though it is the only potentially reversible form of Pulmonary Hypertension (PH). Its incidence is mainly limited to the first 2 years following the embolic event, however it is often underdiagnosed or misdiagnosed. Methods This is a multicenter observational cross-sectional and prospective study. Patients with a prior diagnosis of PE will be enrolled and undergo baseline evaluation for prevalent PH detection through a clinical examination and an echocardiogram as first screening exam. All cases of intermediate-high echocardiographic probability of PH will be confirmed by right heart catheterization and then identified as CTEPH through appropriate imaging and functional examinations in order to exclude other causes of PH. A CTEPH Risk Score will be created using retrospective data from this prevalent cohort of patients and will be then validated on an incident cohort of patients with acute PE. Results 1000 retrospective and 218 prospective patients are expected to be enrolled and the study is expected to be completed by the end of 2021. Up to now 841 patients (620 retrospective and 221 prospective) have been enrolled. Conclusions This study is the first large prospective study for the prediction of CTEPH development in patients with PE. It aims to create a comprehensive scoring tool that includes echocardiographic data which may allow early detection of CTEPH and the application of targeted follow up screening programs in patients with PE.