Regional variations in the process of care for patients undergoing percutaneous coronary intervention in Japan.

Background: Measuring the quality of care has been central for improving the outcomes of patients undergoing percutaneous coronary intervention (PCI). This study described the performance rates and regional variations in quality metrics for PCI using a representative national Japanese registry. Methods: Overall, 760,854 patients across 714 institutions (2016-2018) were analysed. Quality metrics included preprocedural antiplatelet therapy use, door-to-balloon time ≤90 min for ST-elevation myocardial infarction, transradial approach, and preprocedural noninvasive stress testing for elective cases in 47 Japanese prefectures. Coronary computed tomography angiography (CCTA) and fractional flow reserve (FFR) were also evaluated. Factors associated with preprocedural testing rates were evaluated using multivariable linear regression. Findings: Rates of preprocedural antiplatelet therapy use were high with low variations (96·4% [94·7-97·2%]), but there was still substantial room for improvement in the rates of door-to-balloon time (74·7% [71·2-78·9%]) and transradial approach use (70·9% [65·1-73·4%]). Rates of preprocedural noninvasive stress testing were low with substantial variation (36·6% [27·1-49·7%]). Additionally, we found substantial variations in CCTA (50·0% [39·5-55·1%]) and FFR measurement (15·7% [113·-18·3%]) rates. The number of scintigraphy scanners/ prefecture was associated with the performance of noninvasive stress testing (13·4% [95% CI, 2·45-24·4%] increase for every 1/100,000 population increase in scanners). Interpretations: We observed substantial regional variation in the use of preprocedural testing, and its performance was directly related to nuclear-scanner availability. These findings suggest the need for targeted efforts in improving testing rates, whether by optimising resource allocation or additional education or feedback mechanisms. Funding: This study was funded by the Japan Society for the Promotion of Science (Grant Nos. 20H03915, 16H05215, 16KK0186, and 20K22883) and by the Ministry of Health, Labor and Welfare Grants-in-Aid for Scientific Research Program (Grant No. 21FA1015). The J-PCI registry is led and supported by the Japanese Association of Cardiovascular Intervention and Therapeutics.