The study is going to compare two different doses of aspirin for the treatment of heart disease in combination with the anticlotting medication ticagrelor. One of these doses of aspirin, 75 milligrams (mg) once a day, is the current standard treatment dose of aspirin used to treat heart attacks and angina. The other, 20 mg twice a day, is lower than the standard but there is growing scientific evidence that, when given with ticagrelor, this might offer advantages over the usual dose.