Figure 1.

Flow chart of subject selection. Almost all diagnostic procedure combination (DPC) hospitals with cardiovascular beds meet the Japanese Circulation Society (JCS) requirements. All training hospitals and hospitals associated with JCS must provide institutional data (hospital bed count, number of board-certified cardiologists etc.) and DPC hospitals must also provide patient data (age, gender, International Classification of Diseases and Injuries 10th revision codes etc.). JROAD, Japanese Registry of all Cardiac and Vascular Diseases.