Background: A multicenter study was conducted to assess the current medical management of unstable angina (UA) and non-ST-elevation acute coronary syndrome in Japan.
Methods and results: This study presents the results of a nationwide questionnaire survey of 770 sites and a case report investigation performed at 20 sites. The questionnaire survey revealed that the number of acute myocardial infarction (AMI) patients treated annually was 1.56-fold greater than the number of UA patients. Non-ST-elevation AMI accounted for 17% of all patients with AMI. Analysis of case reports for 885 UA patients showed extensive use of invasive treatment. In the UA patients, the cumulative incidence of a composite endpoint (all-cause mortality, AMI, and urgent coronary revascularization) was 2% at 1 month and 9% at 6 months. Stratified analysis with respect to the composite endpoint through 6 months showed a significantly lower incidence in patients treated with a calcium-channel blocker than in patients not treated with a calcium-channel blocker.
Conclusions: In Japan, fewer patients are hospitalized annually for treatment of UA than for AMI. The largest percentage of UA patients had Braunwald class III disease. Non-ST-elevation AMI is managed in Japan according to the principle of early invasive treatment, resembling the treatment for ST-elevation AMI. The outcome of treatment is better for Japanese UA patients than for Japanese AMI patients.