A 30-year analysis of National Institutes of Health–funded cardiac transplantation research: Surgeons lead the way

Objectives: Obtaining National Institutes of Health funding for heart transplant research is becoming increasingly difficult, especially for surgeons. We sought to determine the impact of National Institutes of Health–funded cardiac transplantation research over the past 30 years. Methods: National Institutes of Health Research Portfolio Online Reporting Tools Expenditures and Results was queried for R01s using 10 heart transplant–related terms. Principal Investigator, total grant funding amount, number of publications, and citations of manuscripts were collected. A citation-based Grant Impact Metric was assigned to each grant: sum of citations for each manuscript normalized by the funding of the respective grant (per $100K). The department and background degree(s) (MD, PhD, MD/PhD) for each funded Principal Investigator were identified from institutional faculty profiles. Results: A total of 321 cardiac transplantation R01s totaling $723 million and resulting in 6513 publications were analyzed. Surgery departments received more grants and more funding dollars to study cardiac transplantation than any other department (n = 115, $249 million; Medicine: n = 93, $208 million; Pathology: 26, $55 million). Surgeons performed equally well compared with all other Principal Investigators with respect to Grant Impact Metric (15.1 vs 20.6; P =.19) and publications per $1 million (7.5 vs 6.8; P =.75). Finally, all physician-scientists (MDs) have a significantly higher Grant Impact Metric compared with nonclinician researchers (non-MDs) (22.3 vs 16.3; P =.028). Conclusions: Surgeon-scientists are equally productive and impactful compared with nonsurgeons despite decreasing funding rates at the National Institutes of Health and greater pressure from administrators to increase clinical productivity.