To screen or not to screen for chronic thromboembolic pulmonary hypertension after acute pulmonary embolism.

Chronic thromboembolic pulmonary hypertension (CTEPH) is the most severe long term complication of acute pulmonary embolism (PE). Untreated, CTEPH is associated with a very poor prognosis and high risk of mortality, although curation can be achieved by surgical removal of the obstructive endothelialised thromboemboli from the pulmonary arteries. Early CTEPH diagnosis may improve surgical possibilities and patients outcome. Currently, early diagnosis of CTEPH is a major challenge as demonstrated by an unacceptable median diagnostic delay of over a year and as a result, surgery is impossible in 40% of patients. Most important reasons for this delay are the non-specific clinical presentation of CTEPH and lack of guideline recommendations with regard to the optimal follow-up of patients with acute PE. Despite compelling reasons to diagnose CTEPH earlier, acute PE is not classified among the conditions that warrant screening for pulmonary hypertension. Meaningful screening programs improve the patients' prognosis, and screening tools should be simple, widely available, non-invasive and acceptable to patients. In this review, we discuss current knowledge of available screening instruments for CTEPH, provide recommendations for clinical practice and expand on future developments of this particular subject.