[Acute subsegmental pulmonary embolism: could it sometimes be better not to treat?]

Diagnosis of 'subsegmental pulmonary embolism' has been on the rise since the introduction of modern CT scanners. The need to treat patients with these relatively small thrombi is under discussion. On the one hand, there is clear evidence of overdiagnosis. On the other hand, studies show that patients with subsegmental pulmonary embolisms have the same prognosis as patients with more proximal pulmonary embolisms. Based on currently available evidence, most patients with subsegmental pulmonary embolism should be treated with anticoagulation. A wait-and-see approach should only be considered in patients who are not at risk for new venous thromboembolism and in whom deep venous thrombosis has been ruled out. A European randomised study that starts in 2020 should determine whether it is indeed better not to treat this last group of patients.