A while back I cited a study which showed a 3.8% rate of development of chronic thromboembolic pulmonary hypertension after PE. This was surprisingly high to me. The September issue of Medicine reports this study of patients with PE which looks at outcomes in relation to the degree of pulmonary vascular obstruction. The rate of chronic pulmonary hypertension was much lower, on the order of 1%. The study reported nearly complete resolution of emboli in most patients. I previously linked to this study reporting a high rate of persistence of perfusion defects long term.