Reliability using the universal classification of acute myocardial infarction compared to ST-segment classification.

OBJECTIVES: To study the inter-physician reliability using the universal classification (UC) of acute myocardial infarction (AMI) compared to the ST-segment classification (STC). The UC is based on clinical, electrocardiographic (ECG), and pathophysiologic characteristics compared to the STC, which is mainly ECG based. METHODS: In this registry of consecutive patients with AMI presenting to a tertiary hospital, we studied the inter-physician reliability [weighted kappa (wK)] using the UC and the STC. Two physician investigators independently classified each patient with AMI according to the UC and STC, and a third senior physician investigator resolved any disagreement. RESULTS: The study included Type 1=226 (89.7%), Type 2=16 (6.3%), Type 3=3 (1.2%), Type 4a=1 (0.4%), Type 4b=4 (1.6%), Type 5=2 (0.8%), ST-segment-elevation AMI (STEMI)=140 (55.6%), and non-ST-segment-elevation AMI (NSTEMI)=112 (44.4%). Inter-physician reliability using the UC was very good (wK=0.84, 95% CI 0.68-0.99) and using the STC was good (wK=0.78, 95% CI 0.70-0.86). Of patients with Type 1 AMI, 57.1% were STEMI and 42.9% were NSTEMI. In contrast, of patients with Type 2 AMI, 18.8% were STEMI and 81.2% were NSTEMI. CONCLUSION: The UC is a reliable method to classify patients with AMI and performs better than the STC in this study. Validation of the two classifications should be performed in large prospective studies.

The universal classification is an independent predictor of long-term outcomes in acute myocardial infarction.

BACKGROUND: The long-term outcomes of patients with acute myocardial infarction (AMI) according to the universal classification (UC) are unknown. We investigated whether the outcome of these patients is better predicted by the UC than the ST-segment classification (STC). METHODS: We conducted a retrospective study of 348 consecutive patients with AMI with mean follow-up of 30.6 months. The primary outcome was major adverse cardiovascular events (MACE) [composite of all causes of death and AMI]. RESULTS: The study included ST-segment elevation (STEMI) = 168 (48%), non-ST-segment elevation (NSTEMI) = 180 (52%), Type 1 = 278 (80%), Type 2 = 55 (15.8%), Type 3 = 5 (1.4%), Type 4a = 2 (0.6%), Type 4b = 5 (1.4%), and Type 5 = 3 (0.9%). During follow-up, 102 (29.3%) patients had MACE, 80 (23%) patients died, and 31 (8.9%) had an AMI. The adjusted risk of MACE was similar for NSTEMI and STEMI (HR 1.26, 95% CI 0.77-2.03, P = .35) but was significantly lower for patients with Type 2 AMI as compared to Type 1 (HR 0.44, 95% CI 0.21-0.90, P= .02). The UC, peak troponin levels, discharge glomerular filtration rate <60 ml/min per 1.73 m(2), and thrombolysis in myocardial infarction risk score were independent predictors of MACE (all, P<.05). CONCLUSIONS: The UC is an independent predictor of long-term outcomes in AMI patients compared to the STC. Type 2 AMI has less than half the risk of MACE as Type 1 AMI. Future studies should report outcomes of AMI patients according to the UC types.

Quartiles of peak troponin are associated with long-term risk of death in type 1 and STEMI, but not in type 2 or NSTEMI patients.

BACKGROUND: The prognostic value of peak cardiac troponin (cTn) in different types of acute myocardial infarction (AMI) under the universal clinical classification is unknown. HYPOTHESIS: We tested the hypothesis that the prognostic value of cTn varies with its peak level and type of AMI. METHODS: We studied 345 consecutive patients with AMI with mean follow-up of 30.6 months according to quartiles of peak cTn level (QPTL) and the type of AMI. The study outcomes were the major adverse cardiovascular events (MACE; composite of all causes of mortality and recurrent AMI) and the individual components of MACE. RESULTS: The study included patients with AMI Type 1 (n = 276), type 2 (n = 54), ST-segment elevation myocardial infarction (STEMI; n = 159), and non-ST-segment elevation myocardial infarction (NSTEMI; n = 186). Overall, peak cTn level was an independent predictor of MACE (hazard ratio [HR]: 1.001, 95% confidence interval [CI]: 1.000-1.003, P = 0.01) and death (HR: 1.002, 95% CI: 1.001-1.004, P = 0.003), but not of recurrent AMI. The highest risk of MACE and death was in the highest QPTL (61.6%, P = .016 and 66.3%, P = 0.021, respectively) while the highest risk of recurrent AMI was in the lowest QPTL (83.7%, P = 0.04). Quartiles of peak cTn level were significantly associated with increased risk of MACE and death in patients with Type 1 (all P = 0.01) and STEMI (P = 0.01 and P = 0.02, respectively), but no association existed in type 2 or NSTEMI patients. CONCLUSIONS: Overall, peak cTn predicts the risk of MACE and death but not the risk of AMI. While in Type 1 and STEMI patients, QPTL are associated with risk of MACE and death, no association exists in type 2 or NSTEMI patients.