Background: New criteria for diagnosis of acute myocardial infarction (AMI) were proposed in 2000 as a universal definition, in which cardiac troponin (cTn) was the preferred biomarker. A large number of patients formerly classified by creatine kinase (CK) as unstable angina are now ruled-in by cTn as non-ST-elevation myocardial infarction (NSTEMI).
Methods and results: The Japanese registry of acute Myocardial INfarction diagnosed by Universal dEfiniTion (J-MINUET) is a prospective and multicenter registry conducted in 28 institutions. We enrolled 3,283 consecutive patients with AMI diagnosed by cTn-based criteria who were admitted to participating institutions within 48 h of symptom onset. There were 2,262 patients (68.9%) with STEMI and 1,021 (31.1%) with NSTEMI. CK was not elevated more than twice the upper limit of normal in 458 patients (44.9%) with NSTEMI (NSTEMI-CK). Although there was no significant difference in the in-hospital mortality of STEMI and NSTEMI with CK elevation (NSTEMI+CK) patients (7.1% vs. 7.8%, P=0.57), it was significantly lower in patients with NSTEMI-CK than in those with STEMI or NSTEMI+CK (1.7%, P<0.001 for each).
Conclusions: J-MINUET revealed the clinical presentation, management and outcomes of Japanese patients with AMI in the current cTn era. We should be aware of the difference between AMI diagnosed by CK-based criteria and AMI diagnosed by cTn-based criteria when using universal definitions for the diagnosis of AMI.