Atherosclerosis does not develop overnight. The plaques that prevent blood from flowing in the arteries take years to form. But the heart attack occurs in an instant, often without warning. In order to understand this complex mechanism some researchers at Università Cattolica and Policlinico Gemelli carried out a survey, published in the New England Journal of Medicine. Filippo Crea, director of the Department of Cardiovascular and Respiratory Sciences of Università Cattolica, illustrates it.