Two big trials will highlight this year's American College of Cardiology meeting in March in San Francisco. First is the PREVAIL trial testing Boston Scientific's long-anticipated Watchman left atrial appendage closure device for stroke prevention in patients with atrial fibrillation. Second is the detailed presentation of the controversial failed HPS2-THRIVE trial of extended-release niacin and laropiprant. The final list of trials has been posted on the ACC website.