Remarks: Recurrent VTE while on therapeutic-dose anticoagulant therapy is unusual and should prompt the following assessments: (1) reevaluation of whether there truly was a recurrent VTE; (2) evaluation of compliance with anticoagulant therapy; and (3) consideration of an underlying malignancy. CHEST has been developing and publishing guidelines for the treatment of DVT and PE, collectively referred to as VTE, for more than 30 years. CHEST published the last (9th) edition of these guidelines in February 2012 Since then, a substantial amount of new evidence relating to the treatment of VTE has been published, particularly in relation the use of non-vitamin K oral anticoagulants (NOACs). Moreover, several VTE treatment questions that were not addressed in the last edition have been highlighted. This article focuses on new developments and ongoing controversies in the treatment of VTE, updating recommendations for 12 topics that were included in AT9, and providing recommendations for 3 new topics. The target users of this guideline are clinicians. Methods Composition and Selection of Topic Panel Members The Guidelines Oversight Committee (GOC) at CHEST appointed the editor for the guideline update. Then, the editor nominated the project executive committee, the chair, and the remaining panelists (see Acknowledgments section). The GOC approved all panelists after review of their quali cations and con ict of interest (COI) disclosures. The 15 panelists include general internists, thrombosis specialists, pulmonologists, hematologists, and methodologists. Throughout guideline development, panelists were required to disclose any potential nancial or intellectual con icts of interest by topic.2 Financial and intellectual con icts of interest were classi ed as primary (more serious) or secondary (less serious) (e-Table 1). Panelists with primary COIs were required to abstain from voting on related topic areas, but could participate in discussions provided they refrained from strong advocacy. 