Mapping the global research landscape of ischemia–reperfusion injury in cardiac surgery and transplantation: a bibliometric analysis

Background Ischemia–reperfusion injury (IRI) is intrinsic to cardiac surgery and heart transplantation, where ischemia is inevitably followed by reperfusion that paradoxically aggravates myocardial damage. Despite decades of research, no universally accepted cardioprotective strategy exists, and the global structure of this literature has not been mapped. We aimed to characterize the scientific landscape of IRI and protective strategies in cardiac surgery and transplantation. Methods We retrieved documents (articles, reviews and proceedings papers) from the Web of Science Core Collection. No lower date limit was applied; the corpus covers the complete publication years 1979–2025. Performance indicators and science-mapping analyses (co-authorship, keyword co-occurrence, cited-reference analysis, thematic mapping and trend topics) were computed following the Bibliometrix methodology and reported per the BIBLIO guideline. Results The corpus spanned 1979–2025 across 905 journals and 18,312 authors, accruing 180,256 citations (mean 39.5 per document; h-index 162); 43% of documents appeared in 2015–2025. The United States and China led both production and impact, although roughly 93% of Chinese output postdates 2010; Harvard University, the Chinese Academy of Medical Sciences and Semmelweis University were the most productive institutions. By h-index, the most influential identifiable authors were Heusch, Hausenloy and Yellon. The Annals of Thoracic Surgery and the Journal of Thoracic and Cardiovascular Surgery were the leading journals, and a Bradford core of 23 journals concentrated one third of output. Cited-reference analysis identified the ischemic conditioning lineage as the dominant intellectual base. Ranking protective interventions showed that cardioplegia dominates by volume while the highest citation rates belong to recent, largely preclinical topics; thematic and trend analyses showed a shift from neutrophil- and nitric-oxide–centred inflammation toward mitochondria, regulated cell death and a more recent cluster of mesenchymal stem cells, exosomes, microRNA, melatonin, ferroptosis and donation after circulatory death. Conclusions Research on IRI in cardiac surgery has matured into a large, internationally collaborative field whose emphasis has been shifting from mechanistic description toward translational and regenerative cardioprotection, although the clinically oriented share of the literature has remained stable since 2010. This map identifies its intellectual foundations, leading contributors and emerging frontiers, offering a structured description that may help orient future cardioprotective research.