Normothermic regional perfusion (NRP) has emerged as a transformative technique in organ transplantation, particularly in donation after circulatory death (DCD). This bibliometric analysis provides a comprehensive overview of research trends, key contributors, and evolving themes in NRP literature between 2014 and 2025. By analyzing 372 studies indexed in the Web of Science database, the authors offer valuable insight into how this technology is reshaping transplant medicine.
NRP is designed to reduce warm ischemic injury by restoring oxygenated blood flow to organs after circulatory arrest using extracorporeal membrane oxygenation. This process allows clinicians to assess organ viability, replenish cellular energy stores, and ultimately improve transplant outcomes. Compared with traditional rapid recovery methods, NRP has demonstrated significant advantages in preserving organ function and expanding the donor pool.
The study reveals a strong upward trend in NRP-related publications, with an annual growth rate of 22.35%. As shown in the publication trend graph on page 3, research output remained minimal until 2017, followed by sharp increases beginning in 2018 and peaking in 2024 with 87 publications and nearly 1890 citations. This growth reflects increasing global interest and clinical adoption of NRP.
Geographically, the United States led in total publications (146 studies), while the United Kingdom had the highest citation impact (2914 citations), indicating strong influence in shaping the field. The network visualization on page 4 highlights extensive international collaboration, with interconnected research clusters across Europe and North America. Spain, Italy, and France also played significant roles in early NRP research, while U.S. contributions surged after 2022.
Institutional contributions were dominated by leading academic centers such as the University of Cambridge and Royal Infirmary of Edinburgh, both of which demonstrated high citation counts and collaborative strength. Similarly, top journals publishing NRP research included the American Journal of Transplantation and the Journal of Heart and Lung Transplantation, underscoring the clinical importance of this field.
Keyword analysis provides insight into evolving research priorities. According to the network map on page 5, the most frequent keywords included “outcomes,” “donors,” “preservation,” and “liver transplantation.” Earlier studies focused on kidney transplantation, delayed graft function, and ischemia-reperfusion injury. Over time, the focus shifted toward broader clinical outcomes, heart transplantation, and procedural experience. This transition reflects maturation of the field from experimental application to clinical optimization.
Clinically, NRP has demonstrated benefits across multiple organ systems. In kidney transplantation, it reduces delayed graft function and ischemic injury. In liver transplantation, it improves graft survival and reduces complications such as ischemic cholangiopathy. For heart transplantation, NRP enables successful reconditioning of DCD hearts, achieving outcomes comparable to traditional donors. Emerging evidence also supports its use in lung and pancreas transplantation, although these areas require further study.
The analysis also highlights ethical considerations associated with NRP, particularly in thoracoabdominal applications. Concerns regarding potential restoration of cerebral circulation have been addressed through techniques such as aortic arch clamping, ensuring that brain perfusion does not occur. Professional organizations, including the American Society of Transplant Surgeons, have endorsed NRP as ethically acceptable due to its ability to improve organ utilization and patient outcomes.
Despite its strengths, the study has several limitations. As a bibliometric analysis, it focuses on publication trends rather than clinical outcomes or study quality. Additionally, reliance on a single database (Web of Science) may have excluded relevant research from other sources. Variability in terminology and the relatively recent adoption of NRP may also limit the completeness of the analysis.
Overall, this study demonstrates that NRP is rapidly evolving into a cornerstone of modern transplantation. The shift in research focus from complications to outcomes reflects growing confidence in the technique’s clinical utility. Continued research, particularly long-term outcome studies and ethical evaluations, will be essential to fully integrate NRP into standard transplant practice.
