Identifying promising lines of research

Heart disease is a major killer in developed countries, so research into preventative measures and cures is obviously very important, but what exactly should be researched? Quite a few years ago now, someone put together the fact that some heart attacks can be caused by blood clots in coronary arteries with the fact that aspirin reduces the effectiveness of platelets to form clots ("thinning of the blood") to suggest that perhaps regularly taking small doses of aspirin might reduce one's risk of having a heart attack, thus leading to "The Physicians Health Study I".