Prognostic role of acute myocardial infarction diagnostic criteria in patients presenting with non-ST segment elevation myocardial infarction

Abstract

Abstract Background The Fourth Universal Definition of Myocardial Infarction (UDMI) defines acute myocardial infarction (AMI) as an acute myocardial injury associated with clinical evidence of acute myocardial ischemia. However, the prognostic role of each single diagnostic criteria has never been explored. Purpose To evaluate the prognostic role of the different diagnostic criteria of AMI according to the Fourth UDMI in patients with non-ST-segment elevation myocardial infarction. Methods We enrolled all consecutive patients with NSTEMI undergoing coronary angiography at our Centre. The admission diagnosis was performed according to the current guidelines criteria, namely the detection of an increase and/or decrease of high-sensitivity cardiac troponin I, with at least one value above the 99th percentile of the upper reference limit and at least one of the following: symptoms of ischemia, ECG changes (new ST depression or negative T-waves), echocardiographic evidence of new regional wall motion abnormality. Patients with very high-risk NSTEMI were excluded. Patients were then divided into different subgroups according to the combination of diagnostic criteria presented at admission. A composite endpoint of all-cause mortality, re-hospitalization for myocardial reinfarction or heart failure was collected. The predictive value of AMI diagnostic criteria alone and their combination were evaluated using Kaplan-Meier survival curves and subsequent Cox-regression analysis to find independent predictors of major adverse events. Results Our study population consisted of 2791 patients. The mean age was 68.3±13.4 and 31.5% were female. The mean follow-up time was 23.3±14.5 months. Depending on the AMI diagnostic criteria and their combination, patients were divided into three subgroups: 196 patients fulfilling only clinical criteria (group A), 187 with clinical and ECG-graphic criteria (group B) and 829 patients with clinical, ECG-graphic and echo-graphic criteria (group C). Baseline characteristics of the three groups were similar. At two-year follow-up, patients with clinical criteria alone exhibited the best outcome, whereas those with all three criteria fulfilled showed the worse prognosis (14.8% for group A vs 23.6% for group B vs 28.0% for group C; p-value <0.001). In multivariable Cox-regression model, the presence of clinical criteria alone was the independent predictor of better prognosis compared to the other diagnostic criteria combination (HR=0.48; CI 95% 0.31–0.74; p<0.001). Conclusions In non-very high-risk NSTEMI, not all diagnostic criteria have the same prognostic value. In fact, prognosis is significantly more favorable in patients exhibiting only the clinical criteria at admission. We hypothesize that the absence of ECG-graphic and echocardiographic alterations may indirectly indicate smaller infarct sizes that contribute to patients' outcomes. These findings could enhance the current risk stratification in patients admitted with NSTEMI. Funding Acknowledgement Type of funding sources: None.