Risk Model of Valve Surgery in Japan Using the Japan Adult Cardiovascular Surgery Database

Background and aim of the study: Risk models of cardiac valve surgery using a large database are useful for improving surgical quality. In order to obtain accurate, high-quality assessments of surgical outcome, each geographic area should maintain its own database. The study aim was to collect Japanese data and to prepare a risk stratification of cardiac valve procedures, using the Japan Adult Cardiovascular Surgery Database (JACVSD). Methods: A total of 6,562 valve procedure records from 97 participating sites throughout Japan was analyzed, using a data entry form with 255 variables that was sent to the JACVSD office from a web-based data collection system. The statistical model was constructed using multiple logistic regression. Model discrimination was tested using the area under the receiver operating characteristic curve (C-index). The model calibration was tested using the Hosmer-Lemeshow (H-L) test. Results: Among 6,562 operated cases, 15% had diabetes mellitus, 5% were urgent, and 12% involved preoperative renal failure. The observed 30-day and operative mortality rates were 2.9% and 4.0%, respectively. Significant variables with high odds ratios included emergent or salvage status (3.83), reoperation (3.43), and left ventricular dysfunction (3.01). The H-L test and C-index values for 30-day mortality were satisfactory (0.44 and 0.80, respectively). Conclusion: The results obtained in Japan were at least as good as those reported elsewhere. The performance of this risk model also matched that of the STS National Adult Cardiac Database and the European Society Database.