Annual publication growth

A total of 558 publications were retrieved, including 356 articles, 12 reviews, and 190 publications of other types. Articles and reviews (n = 368) were included in further analysis. The growth of publications with respect to publication year is shown in Fig. 1A. The number of publications on TAPVC showed an overall increasing trend, suggesting increasing interest in the research field of TAPVC. Before 2016, the number of publications fluctuated with the publication year. In subsequent years, the number of publications grew rapidly (the significant reduction in 2023 is attributed to incomplete data). An S curve function was utilized to explore the relationship between the cumulative number of publications and the publication year, which fit the trend well (R2 = 0.940) (Fig. 1B). This strong correlation suggests that the field of TAPVC is still in a period of rapid growth and development.

Fig. 1

Number of publications per year (A) and the cumulative number of publications (B)

National production of publications

To study each country’s contribution to the TAPVC field, the number of publications for each country was examined. A total of 47 countries/regions worldwide have conducted research on TAPVC (Fig. 2A). The top 20 countries/regions with the most publications are displayed in Supplementary Fig. 1, Additional File 1. There was no doubt that the United States was the main impetus in the field of TAPVC, with 82 publications, followed by China (n = 72), Japan (n = 50), and India (n = 48). Each of the remaining countries/regions has fewer 30 publications. Pearson’s analysis revealed that there was a significant correlation between the number of publications and the GDP (R = 0.887, P < 0.001) (Fig. 2B), R&D expenditure (R = 0.375, P = 0.013) (Fig. 2C) and population (R = 0.694, P < 0.001) (Fig. 2D) of different countries.

Fig. 2

(A) Each country’s contribution to the field of total anomalous pulmonary venous connection; Pearson’s analysis revealed a significant correlation between the number of publications and gross domestic product (B), research and development (R&D) expenditure (C) and population (D) of different countries. (E) Collaborations between countries; (F) Network clustering of country co-authorship analysis; (G) Time-overlapping network of country co-authorship analysis

The collaborations between countries are displayed in Fig. 2E. The United States was the leader in international collaborations in the field of TAPVC. The most frequent collaborations were between the United States and the United Kingdom, the United States and China, the United States and Sweden, the United Kingdom and Sweden, the United Kingdom and India, and Egypt and Saudi Arabia, with a frequency of three each. To study the collaborations between countries, a co-authorship analysis of publications from these countries was performed (Fig. 2F). The circle size represents the number of publications, and the color represents the cluster. These 47 countries formed eight clusters, with the red and green clusters being the largest, each comprising four countries. The color of the circle in the time-overlapping network indicates the average year of publication for each country (Fig. 2G). Overall, there were very few connections between different clusters, indicating that international collaboration in the field of TAPVC needs to be better developed.

Institutional production of publications

To study each institution’s contribution to the TAPVC field, the number of publications for each institution was examined. A total of 457 institutions worldwide were involved in the research field of TAPVC. The top 20 institutions with the most publications are shown in Supplementary Fig. 2, Additional File 1. Seven of the top 20 institutions were from China, followed by the United States and Australia, with 6 and 3 institutions, respectively. In terms of the specific institution, Shanghai Jiao Tong University topped the list with 13 publications, followed by All India Institute of Medical Sciences, Capital Medical University, and Children’s Hospital of Philadelphia with 9, 8, and 8 publications, respectively.

To study the collaborations between institutions, a co-authorship analysis of publications from these institutions was performed (Fig. 3A). The circle size represents the number of publications, and the color represents the cluster. These 457 institutions formed five clusters, with the red cluster being the largest, which comprised 11 institutions, mainly from the United States. The time-overlapping network showed the average year of publication for each institution (Fig. 3B). Overall, there were very few connections between different clusters, indicating that institutional collaboration in the field of TAPVC was not well developed.

Fig. 3

(A) Network clustering of institutional co-authorship analysis; (B) Time-overlapping network of institutional co-authorship analysis

Author production of publications

To study each author’s contribution to the TAPVC field, the number of publications for each institution was examined. A total of 1 835 authors have been committed to the field of TAPVC, and most (88.1%) have published only one publication. Each core author (2.8%) has published at least three publications, and these authors collaborated as research teams. The top 20 authors with the most publications are displayed in Supplementary Fig. 3, Additional File 1. Huiwen Chen was the greatest contributor, with 9 publications, followed by Guocheng Shi, with 8 publications. Christopher A. Caldarone, Yves d’Udekem, Igor E. Konstantinov, and Zhongqun Zhu each had 7 publications.

To study the collaboration between authors, a co-authorship analysis was performed, and the results are displayed in Fig. 4A. The circle size represents the number of publications, and the color represents the cluster. These authors formed 9 clusters, with the red cluster being the largest, comprising 17 authors, mainly from Shanghai Jiao Tong University. The time-overlapping network showed the average year of publication for each author (Fig. 4B). Researchers from China have formed research networks in the field of TAPVC.

Fig. 4

(A) Network clustering of the results of the researcher co-authorship analysis; (B) Time-overlapping network of the researcher co-authorship analysis

Disciplinary distribution of publications

To study the disciplinary distribution in the field of TAPVC, the number of publications for each WOS category was examined. The four disciplines with the most publications were cardiac & cardiovascular systems (n = 244), surgery (n = 120), pediatrics (n = 81), and respiratory system (n = 72). Other disciplines included radiology, nuclear medicine & medical imaging (n = 28), medicine, general & internal (n = 24), obstetrics & gynecology (n = 15), acoustics (n = 15), genetics & heredity (n = 11), and peripheral vascular disease (n = 9). This indicated that the research performed in this field was broad and diverse and could attract the attention of researchers from different fields.

Journal production of publications

These 368 publications were published in 132 journals. The top 20 journals with the most publications are displayed in Supplementary Table 1, Additional File 1. Annals of Thoracic Surgery and Pediatric Cardiology topped the list with 29 publications each, followed by Journal of Cardiac Surgery with 24 publications. Each of the remaining journals had fewer than 20 publications. There were 48 journals from the United States, followed by the United Kingdom with 19 journals. China, Japan, and Switzerland each had eight journals. Pearson’s analysis revealed a significant correlation between the number of publications and the number of journals (R = 0.751, P < 0.001) in different countries (Fig. 5A). Bradford’s law showed that six core journals published 128 publications (Fig. 5B). These findings can aid researchers in selecting the most appropriate journals to publish their manuscripts.

Fig. 5

(A) Pearson’s analysis revealed a significant correlation between the number of publications and the number of journals in different countries; (B) Bradford’s law showed that six core journals published 128 publications

Most cited publications

Citation count is one of the indices used to judge the academic influence of a publication. Highly cited publications usually represent important research topics in a specific field. To study the influence of publications in the field of TAPVC, the number of citations each publication received was examined. The 20 most cited publications are displayed in Supplementary Table 2, Additional File 1, and all of them have been cited more than 40 times. Notably, nineteen of the 20 most-cited publications were published in JCR Q1 journals, and the remaining one was in JCR Q2 journal, indicating that these publications were published in high-level journals. Of these 20 publications, 15 focused on surgical treatment, two examined the application of echocardiography in prenatal diagnosis, two investigated the pathogenic mechanism of TAPVC, and the remaining one examined late neurodevelopmental problems after surgical repair of TAPVC. A publication published in Circulation in 2007 has received the most citations: “Factors associated with mortality and reoperation in 377 children with total anomalous pulmonary venous connection” [14]. This study involved a large single-institution cohort of patients whose mortality after surgical repair of TAPVC decreased but remained high in young patients and those with cardiac TAPVC or preoperative PVS. Despite improvements in perioperative care, unfavorable anatomic characteristics remain important risk factors for postoperative mortality. The second most cited publication was also published in Circulation: “Total anomalous pulmonary venous connection: morphology and outcome from an international population-based study” [15]. This international population-based study investigated the morphological characteristics of TAPVC and explored risk factors for postoperative mortality and PVS. The third most cited publication was published in Annals of Thoracic Surgery in 2005: “Total anomalous pulmonary venous connection: An analysis of current management strategies in a single institution” [16]. This study explored the impact of management strategies on postoperative mortality and PVS and revealed that the prognosis of patients with a single ventricle was still worse than that of patients with two ventricles.

National citations

To study the influence of each country in the field of TAPVC, the number of citations each country received was examined (Fig. 6A). The top 20 countries/regions with the most citations are displayed in Supplementary Fig. 4, Additional File 1. The United States ranked first (n = 1348), followed by Canada (n = 402). China (n = 384), Japan (n = 364), and the United Kingdom (n = 341). Each of the remaining countries had fewer than 300 citations. Pearson’s analysis revealed that there was a significant correlation between the number of citations and the GDP (R = 0.881, P < 0.001) (Fig. 6B), R&D expenditure (R = 0.446, P = 0.003) (Fig. 6C), and population (R = 0.305, P = 0.037) (Fig. 6D) of different countries.

Fig. 6

(A) The number of citations each country received in the field of total anomalous pulmonary venous connection; Pearson’s analysis revealed that there was a significant correlation between the number of citations and gross domestic product (B), research and development (R&D) expenditure (C), and population (D) of different countries

Institutional citations

To study the influence of each institution in the field of TAPVC, the number of citations each institution received was examined. The top 20 institutions with the most citations are shown in Supplementary Fig. 5, Additional File 1. Six of the top 20 institutions were from the United States, followed by the United Kingdom, which has four institutions. In terms of the specific institution, the University of Toronto topped the list with 250 citations, followed by Queen Silvia Children’s Hospital, University of London Imperial College of Science, Technology and Medicine, and Children’s Hospital of Philadelphia with 248, 248 and 233 citations, respectively. Each of the remaining institutions had fewer than 200 citations.

Author citations

To study the influence of each author in the field of TAPVC, the number of citations each author received was examined. The top 20 authors with the most citations are displayed in Supplementary Fig. 6, Additional File 1. Christopher A. Caldarone topped the list with 315 citations, followed by John G. Coles and Glen S. Van Arsdell with 271 citations each. Each of the remaining authors had fewer than 200 citations.

Journal citations

To study the influence of each journal in the field of TAPVC, the number of citations each journal received was examined. The top 20 journals with the most publications are displayed in Supplementary Table 3, Additional File 1. Annals of Thoracic Surgery topped the list with 746 citations, followed by Circulation and Journal of Thoracic and Cardiovascular Surgery with 402 and 401 citations, respectively. Each of the remaining journals had fewer than 300 citations. Pearson’s analysis revealed a significant correlation between the number of citations and the number of journals (R = 0.917, P < 0.001) in different countries (Fig. 7A). There was also a significant correlation between the number of citations and the IF of different journals (R = 0.398, P < 0.001) (Fig. 7B).

Fig. 7

(A) Pearson’s analysis revealed a significant correlation between the number of citations and the number of journals of different countries; (B)There was a significant correlation between the number of citations and the impact factor of different journals

Citation bursts of references

Citation burst detection was performed to capture the rapid increase in the popularity of references over a specific period. A total of 32 references with citation bursts from 2000 to 2023 were identified (Fig. 8). The blue line represents the time interval from 2000 to 2023, and the red line represents the period of citation bursts. The publication “Total Anomalous Pulmonary Venous Connection: The Current Management Strategies in a Pediatric Cohort of 768 Patients”, published in Circulation, had the highest citation burst value of 8.04 [5]. This multicenter study employed a large cohort of patients (768 individuals) to investigate the influence of current therapeutic regimens on the results of TAPVC. This study revealed that surgical treatment in patients with TAPVC could yield an acceptable outcome and investigated risk factors associated with mortality and postoperative PVS. This study explored the effects of the sutureless technique and revealed that this technique decreased the incidence of postoperative PVS in patients with preoperative PVS but not in patients without preoperative PVS. The publication “Repair of Total Anomalous Pulmonary Venous Connection: Risk Factors for Postoperative Obstruction” published in Annals of Thoracic Surgery, had the second highest citation burst value of 7.99 [17]. Because the definition of preoperative PVS has widely varied in prior studies, this research graded the severity of preoperative PVS to precisely examine the risk factors for postoperative PVS. This study may help in the risk stratification of patients with TAPVC. The publication “Surgical results of total anomalous pulmonary venous connection repair in 256 patients”, published in Interactive Cardiovascular and Thoracic Surgery, had the third highest citation burst value of 6.96 [18]. This study revealed that the long-term outcomes of surgical repair for TAPVC patients were satisfactory, and predictors of mortality and postoperative PVS were investigated. Postoperative PVS was strongly related to mortality, and close follow-up was needed, particularly within six months after surgery. The most recent burst occurred in 2021 and has lasted for three years. Seven references with ongoing citation bursts until 2023 deserve our further attention. Of these publications, six focused on the surgical treatment of TAPVC, and the remaining study focused on the classification of pulmonary venous malformations. One meta-analysis published by Wu et al. is worth noting [19]. This meta-analysis included 26 studies involving a total of 2702 patients and compared outcomes between the sutureless technique and conventional repair and revealed that the sutureless technique could reduce the incidence of postoperative PVS and re-operations, but could not reduce postoperative early, late, or overall mortality. The popularity of these research topics is likely to continue, and they could thus become potential frontiers in the future.

Fig. 8

Citation burst detection identified 32 references with citation bursts

Frequency of keywords

Keywords were the high condensation and summary of the main contents of a publication, which could indicate the research theme. Frequency analysis of keywords can help researchers quickly identify the main research hotspots in a research field. Supplementary Fig. 7, Additional File 1 shows the top 20 keywords with the greatest frequency. There was no doubt that “total anomalous pulmonary venous connection” topped the lists with a frequency of 181, followed by “congenital heart disease” (n = 60), “pulmonary vein stenosis” (n = 41), “echocardiography” (n = 20), “pulmonary vein” (n = 20), “sutureless technique” (n = 16), “prenatal diagnosis” (n = 13), “surgery” (n = 13), “fetal echocardiography” (n = 12), and “single ventricle” (n = 11).

Major research areas

Keyword co-occurrence analysis is an important approach for investigating the main research interests and hot issues in a specific research field. Among 546 keywords, 35 met the threshold of 5 occurrences. If keywords had the same meanings, they were merged. After merging duplicate keywords, 26 (threshold setting of 5) were displayed in the network visualization (Fig. 9A). The node size represents the frequency of the keywords, and the distance between them represents the strength of the association. Closely related keywords were grouped into one cluster, and each cluster represented one research domain. The 26 keywords were grouped into six clusters. The red cluster was the largest and included the keywords “congenital,” “heart defects,” “infant,” “mortality,” “outcome,” “pulmonary vein,” and “surgery” This indicates that the most important topic was surgical repair of TAPVC. The green cluster included the keywords such as “total anomalous pulmonary venous connection,” “pulmonary vein stenosis,” “pulmonary hypertension,” and “stent” and was mainly associated with postoperative PVS, an important complication after surgical repair of TAPVC. The blue cluster included the keywords such as “anomalous pulmonary venous connection,” “congenital heart surgery,” and “heterotaxy” and was mainly related to the surgical repair of TAPVC patients with heterotaxy. The yellow cluster included the keywords such as “congenital heart disease” and “echocardiography” and was mainly related to the application of echocardiography in diagnosing TAPVC. The purple cluster included the keywords such as “fetal echocardiography” and “prenatal diagnosis” and was mainly related to the application of echocardiography in the prenatal diagnosis of TAPVC. Finally, the light blue cluster included the keywords “right atrial isomerism,” “single ventricle,” and “sutureless technique” and was mainly related to the application of the sutureless technique in the surgical repair of TAPVC patients with right atrial isomerism or a single ventricle.

Fig. 9

(A) Network clustering of keyword co-occurrence analysis; (B) Time-overlapping co-occurrence network of keywords

Figure 9B shows the visualization of the time overlapping of keywords. Different nodes are marked with different colors based on the average occurrence year of these keywords. The keyword “case report” appeared most recently, with an average occurrence year of 2021.8.

Keyword bursts

Citation burst detection was conducted to explore the rapid increase in popularity of keywords over a specific period. In this study, there were no keywords with citation bursts. This suggests that research topics are relatively smooth in the field of TAPVC.