Mapping evolutionary trajectories: Applications to the growth and transformation of medical knowledge

This paper is concerned with the mechanisms through which medical knowledge emerges, grows and transforms itself. It is a large-scale empirical analysis of the development of treatments for coronary artery disease, which is the most common cause of death in developed countries. We uncover the structure of medical understanding of the disease and the path-dependent co-evolution of scientific and technical knowledge in the search for solutions to the relevant set of problems. After reviewing a broad range of secondary sources and a number of interviews with leading clinicians, we use new tools recently developed for the longitudinal analysis of large citation networks. We apply them to a bibliographic database of 11,240 papers published in the area of coronary artery disease between 1979 and 2003 and to a patent dataset of 5136 US patents documents granted between 1976 and 2003 for angioplasty-related devices. The results are consistent maps, which we critically discuss, of the major scientific and technological trajectories associated with one of the most important medical procedures of the last 30 years.