CONCLUSIONS: Of 54 recommendations included in the 30 statements, 20 were strong and none was based on high-quality evidence, highlighting the need for further research. KEY WORDS: antithrombotic therapy; evidence-based medicine; GRADE approach; venous thromboembolism FOR EDITORIAL COMMENT SEE PAGE 293 ABBREVIATIONS: AT9 = 9th Edition of the Antithrombotic Guideline; AT10 = 10th Edition of the Antithrombotic Guideline; CHEST = American College of Chest Physicians; CDT = catheter-directed thrombolysis; COI = con ict of interest; CTEPH = chronic thrombo- embolic pulmonary hypertension; CTPA = CT pulmonary angiogram; GOC = Guidelines Oversight Committee; INR = International Normalized Ratio; IVC = inferior vena cava; LMWH = low-molecular- weight heparin; NOAC = non-vitamin K oral anticoagulant; PE = pulmonary embolism; PTS = postthrombotic syndrome; RCT = ran- domized controlled trial; UEDVT = upper extremity deep vein thrombosis; US = ultrasound; VKA = vitamin K antagonist AFFILIATIONS: From McMaster University (Drs Kearon and Akl), Hamilton, ON; American University of Beirut (Dr Akl), Beirut, Lebanon; CHEST (Dr Ornelas), Glenview, IL; VA New Jersey Health Care System (Dr Blaivas), Newark, NJ; Hospital Ram n y Cajal and Instituto Ram n y Cajal de Investigaci n Sanitaria, Universidad de Alcala (Dr Jimenez), Madrid, Spain; University of Geneva (Dr Bou- nameaux), Geneva, Switzerland; Leiden University Medical Center (Dr Huisman), Leiden, Netherlands; Virginia Commonwealth University (Dr King), Falls Church, VA; University of California (Dr Morris), San Diego, CA; The Ohio State University (D. Sood), Columbus, OH; Intermountain Medical Center and the University of Utah (Drs Stevens and Woller), Murray, UT; Harbor-UCLA Medical Center (Dr Vintch), Torrance, CA; The University of Ottawa and Ottawa Hospital Research Institute (Dr Wells), Ottawa, ON; Uniformed Services University of the Health Sciences (Dr Moores), Bethesda, MD. 