We then used an iterative approach that involved review by, and approval from, all panel members for the writing of this manuscript. Peer Review External reviewers who were not members of the expert panel reviewed the guideline before it was published. These reviewers included content experts, a methodological expert, and a practicing clinician. The nal manuscript was reviewed and approved by the CHEST GOC, the CHEST Board of Regents, and the CHEST journal. Choice of Long-Term (First 3 Months) and Extended (No Scheduled Stop Date) Anticoagulant Summary of the Evidence Phases of Anticoagulant Therapy for VTE: The need for anticoagulant therapy in patients with proximal DVT or PE is presented in AT9.1 The minimum duration of anticoagulant therapy for DVT or PE is usually 3 months; this period of treatment is referred to as long-term therapy. 1 A decision to treat patients for longer than 3 months, which we refer to as extended anticoagulant therapy, usually implies that anticoagulant therapy will be continued inde nitely.1 1. In patients with proximal DVT or pulmonary embolism (PE), we recommend long-term (3 months) anticoagulant therapy over no such therapy (Grade 1B). Choice of Anticoagulant for Acute and Long-Term (First 3 Months) Therapy AT9 recommendations on choice of anticoagulant therapy were based on comparisons of VKA with LMWH that were performed in the preceding two and with two of the NOACs (dabigatran,20 ) that had recently been published. 