Furthermore, a low cardiopulmonary reserve or marked symptoms that cannot be attributed to another condition favor anticoagulant therapy, whereas a high risk of bleeding favors no anticoagulant therapy. The decision to anticoagulate or not is also expected to be sensitive to patient preferences. Patients who are not anticoagulated should be told to return for reevaluation if symptoms persist or worsen. The evidence supporting our recommendations is low quality because of indirectness and because there is limited ability to predict which patients will have VTE complications without anticoagulation. *19. In patients with subsegmental PE (no involvement of more proximal pulmonary arteries) and no proximal DVT in the legs who have a (i) low risk for recurrent VTE (see text), we suggest clinical surveillance over anticoagulation (Grade 2C), and (ii) high risk for recurrent VTE (see text), we suggest anticoagulation over clinical surveillance (Grade 2C). Remarks: US imaging of the deep veins of both legs should be done to exclude proximal DVT. Clinical surveillance can be supplemented by serial US imaging of the proximal deep veins of both legs to detect evolving DVT (see text). Patients and physicians are more likely to opt for clinical surveillance over anticoagulation if there is good cardiopulmonary reserve or a high risk of bleeding. Treatment of Acute PE Out of the Hospital Summary of the Evidence Our recommendation in AT9 was based on: (1) two trials that randomized patients with acute PE to receive LMWH for only 3 days in the hospital121 or entirely at compared with being treated with LMWH in the hospital for a longer period; (2) 15 observational studies, 9 of which were prospective, that evaluated treatment of acute PE out of the hospital1 ; and (3) longstanding experience treating DVT without admission to a hospital. 