3296Clinical application of the fourth universal definition of myocardial infarction

Abstract

Abstract Background The recently released fourth version of the Universal Definition of Myocardial Infarction (UDMI) introduced substantial changes such as the implementation of the categories acute and chronic myocardial injury. It further recommends the use of sex-specific troponin cut-offs and consideration of absolute rather than relative changes of troponin concentrations for diagnosis of myocardial infarction (MI). Our aim was to apply the updated UDMI in patients with suspected MI to investigate its effect on diagnosis and prognosis. Methods We included 2'304 patients presenting to the emergency department with suspected MI. The final diagnosis was first adjudicated according to the 3rd UDMI by two physicians in a blinded fashion using all available medical records, laboratory findings including high-sensitivity troponin T results as well as clinical and imaging findings. Thereafter all patients were re-adjudicated based on the 4th UDMI, again all available information was used. Included patients were followed up to 4 years to assess all-cause mortality, incident nonfatal MI, revascularization and rehospitalization. Hazard ratios (HR) were calculated to investigate the effect of the diagnoses based on the 4th UDMI on prognosis. Results Out of 2'304 included patients, 708 got reclassified by the 4th UDMI. 442 (19.2%) were diagnosed as having MI compared to 504 (21.9%) based on the 3rd UDMI. Out of 1'862 non-MI patients, 74 (3.97%) patients had acute and 583 (31.3%) chronic myocardial injury (Figure 1). Patients with acute or chronic injury were older, more often female and had worse renal function than other non-MI patients. The most common causes for acute myocardial injury were heart failure, pulmonary embolism and takotsubo cardiomyopathy. For chronic myocardial injury hypertension, heart failure and non-obstructive coronary artery disease were the most frequent reasons. In cox regression analyses unadjusted HR for all-cause mortality in patients with acute or chronic myocardial injury was considerably higher when compared to patients with non-cardiac chest pain (HR 13.2 (confidence interval (CI) 6.7–26.3) (p<0.001) for acute myocardial injury and 7.2 (CI 4.2–12.5) (p<0.001) for chronic myocardial injury). After adjustment for age and gender, acute and chronic myocardial injury still strongly predicted a poorer outcome and higher rate of cardiovascular events compared to other non-MI patients. Patients with acute or chronic myocardial injury showed equally poor outcome as patients with MI. Figure 1. Re-adjudication Conclusion By introducing the categories of acute and chronic myocardial injury the 4th UDMI succeeds to identify non-MI patients with higher risk for cardiovascular events and poorer outcome and thus seems to improve risk assessment in this heterogeneous population. Prevention strategies for this specific population are yet to be investigated.