Introduction to the ninth edition: antithrombotic therapy and prevention of thrombosis, 9th ed: American College of Chest Physicians evidence-based clinical practice guidelines / Introdução à nona edição: terapia antitrombótica e prevenção de trombose, 9ª ed: Diretrizes de prática clínica baseada em evidências do Colégio Americano de Médicos Torácicos

The Antithrombotic Therapy and Prevention of Thrombosis, 9th ed: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines differs substantially from the prior versions both in process and in content. In this introduction, we describe some of the differences and the rationale for the changes.