Effect of procedural volume on the outcomes of congenital heart surgery in Japan

Naoki Yoshimura, Yasutaka Hirata, Ryo Inuzuka, Hisateru Tachimori, Akinori Hirano, Takahisa Sakurai, Shuichi Shiraishi, Hikoro Matsui, Mamoru Ayusawa, Toshihide Nakano, Shingo Kasahara, Yuji Hiramatsu, Masaaki Yamagishi, Hiroaki Miyata, Hiroyuki Yamagishi, Kisaburo Sakamoto

Research output: Contribution to journalArticlepeer-review

2 Citations (Scopus)


Objectives: The present study developed a new risk model for congenital heart surgery in Japan and determined the relationship between hospital procedural volume and mortality using the developed model. Methods: We analyzed 47,164 operations performed between 2013 and 2018 registered in the Japan Cardiovascular Surgery Database-Congenital and created a new risk model to predict the 90-day/in-hospital mortality using the Japanese congenital heart surgery mortality categories and patient characteristics. The observed/expected ratios of mortality were compared among 4 groups based on annual hospital procedural volume (group A [5539 procedures performed in 90 hospitals]: ≤50, group B [9322 procedures in 24 hospitals]: 51-100, group C [13,331 procedures in 21 hospitals]: 101-150, group D [18,972 procedures in 15 hospitals]: ≥151). Results: The overall mortality rate was 2.64%. The new risk model using the surgical mortality category, age-weight categories, urgency, and preoperative mechanical ventilation and inotropic use achieved a c-index of 0.81. The observed/expected ratios based on the new risk model were 1.37 (95% confidence interval, 1.18-1.58), 1.21 (1.08-1.33), 1.04 (0.94-1.14), and 0.78 (0.71-0.86) in groups A, B, C, and D, respectively. In the per-procedure analysis, the observed/expected ratios of the Rastelli, coarctation complex repair, and arterial switch procedures in group A were all more than 3.0. Conclusions: The risk-adjusted mortality rate for low-volume hospitals was high for not only high-risk but also medium-risk procedures. Although the overall mortality rate for congenital heart surgeries is low in Japan, the observed volume-mortality relationship suggests potential for improvement in surgical outcomes.

Original languageEnglish
Pages (from-to)1541-1550.e3
JournalJournal of Thoracic and Cardiovascular Surgery
Issue number4
Publication statusPublished - 2023 Apr


  • hospital procedural volume
  • national database
  • new risk model for congenital heart surgery
  • regionalization of congenital heart surgery programs

ASJC Scopus subject areas

  • Surgery
  • Pulmonary and Respiratory Medicine
  • Cardiology and Cardiovascular Medicine


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