title: Mapping cross-border collaboration and communication in cardiovascular research from 1992 to 2012.
abstract: OBJECTIVE
  The growing burden of cardiovascular disease requires growth in research and innovation. We examine world-wide participation and citation impact across the cardiovascular research landscape from 1992 to 2012; we investigate cross-fertilization between countries and examine whether cross-border collaboration affects impact.
  
  
  RESULTS
  State-of-the-art bibliometric methods and indicators are used to identify cardiovascular publications from the Web of Science, and to map trends over time in output, citation impact, and collaboration. The publication output in cardiovascular research has grown steadily from 1992 to 2012 with increased participation worldwide. China has the highest growth as relative share. The USA share initially predominated yet has reduced steadily. Over time, the EU-27 supra-national region has increased its participation above the USA, though on average it has not had greater citation impact than the USA. However, a number of European countries, as well as Australia and Canada, have improved their absolute and relative citation impact above that of the USA by 2006-2012. Europe is a hub of cross-fertilization with strengthening collaborations and strong citation links; the UK, Germany, and France remain central in this network. The USA has the highest number of strong citation links with other countries. All countries, but especially smaller, highly collaborative countries, have higher citation impact for their internationally collaborative research when compared with their domestic publications.
  
  
  CONCLUSIONS
  Participation in cardiovascular research is growing but growth and impact show wide variability between countries. Cross-border collaboration is increasing, in particular within the EU, and is associated with greater citation impact.
authors.affiliation: Department of Cardiovascular Sciences, KU Leuven, Leuven 3000, Belgium.
authors.forename: Diane
authors.initials: D
authors.lastname: Gal
authors.affiliation: ECOOM and Dept. MSI, KU Leuven, 3000, Leuven, Belgium and Library of the Hungarian Academy of Sciences, Dept. Science Policy & Scientometrics, Budapest, Hungary.
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Glänzel
authors.affiliation: Division of Experimental Cardiology, Department of Cardiovascular Sciences, KU Leuven, Campus Gasthuisberg O/N1 704, Herestraat 49, 3000 Leuven, Belgium.
authors.forename: Karin R
authors.initials: KR
authors.lastname: Sipido
mesh_terms: D015706:Bibliometrics; D035843:Biomedical Research / Q000639:trends*; D002309:Cardiology; D003142:Communication; D014943:Global Health; D006801:Humans; D007391:International Cooperation; D007400:Interprofessional Relations; D011642:Publications / Q000706:statistics & numerical data; D011643:Publishing / Q000706:statistics & numerical data
keywords: Bibliometrics; Cardiovascular diseases; Citation impact; International collaboration; Networks