Discovered around 1979, coronary angioplasty has emerged to be one of the principal treatments for advanced coronary artery disease. This paper uses methods from social network analysis to understand how this mode of treatment developed. By using a bibiliographic database of over 11,000 medical journal articles related to coronary angioplasty spanning the 25 years of its history, a large citation network was constructed. The powerful but relatively unknown main path algorithm was then used to capture the underlying change in structure of this network and identify the major streams of events that define this specialised field of coronary medicine. This method was first used in the study of historiography of DNA theory (Hummon and Doreian, 1989) and later by Carley et al. (1993) to explore the social and intellectual factors in the then emerging field of conflict resolution. We believe that main path analysis enabled us to identify the problem sequence that is characteristic medical innovation. We have also identified from the network, periods of exploration by the medical community and periods of consolidation as the emerging field of coronary angioplasty took shape. In leading to this comparison we identify the issue of complementarity among methods and reflect upon the theorizing of knowledge in social science.