A blood clot is a boon when you nick yourself while shaving or get a cut from the kitchen knife. Clotting stops you from bleeding out. But when a clot blocks arteries in major organs like the heart or lungs, it can quickly become life threatening. In Jan, actor Catherine O’Hara — famous for the ‘Beetlejuice’ and ‘Home Alone’ movies — was taken to a Los Angeles hospital with breathing difficulties and died of pulmonary embolism (PE), a blood clot that travelled up her legs and clogged an artery in her lungs.