The post-PE syndrome: a new concept for chronic complications of pulmonary embolism.

Long-term follow-up studies have consistently demonstrated that after an episode of acute pulmonary embolism (PE), half of patients report functional limitations and/or decreased quality of life up to many years after the acute event. Incomplete thrombus resolution occurs in one-fourth to one-third of patients. Further, pulmonary artery pressure and right ventricular function remain abnormal despite adequate anticoagulant treatment in 10-30% of patients, and 0.5-4% is diagnosed with chronic thromboembolic pulmonary hypertension (CTEPH) which represents the most severe long term complication of acute PE. From these numbers, it seems that CTEPH itself is the extreme manifestation of a much more common phenomenon of permanent changes in pulmonary artery flow, pulmonary gas exchange and/or cardiac function caused by the acute PE and associated with dyspnea and decreased exercise capacity, which in analogy to post-thrombotic syndrome after deep vein thrombosis could be referred to as the post-pulmonary embolism syndrome. The acknowledgement of this syndrome would both be relevant for daily clinical practice and also provide a concept that aids in further understanding of the pathophysiology of CTEPH. In this clinically oriented review, we discuss the established associations and hypotheses between the process of thrombus resolution or persistence, lasting hemodynamic changes following acute PE as well as the consequences of a PE diagnosis on long-term physical performance and quality of life.