Impact of Universal Definition of MI on Mortality
Impact of Universal Definition of MI on Mortality
Aims Redefinition of myocardial infarction (MI) based on specific cardiac troponins (cTn) was universally accepted in 2007. The new definition has been widely discussed for including a large spectrum of quantitative myocardial necrosis and their clinical implications remain under debate. Our aim was to assess the impact of the universal definition of MI on mortality at 10 years.
Methods and results We studied 676 consecutive patients (Pts) admitted to our intensive cardiac care unit for acute coronary syndrome (ACS) between January 1999 and December 2000. We calculated the relative risk of the total death at 10 years adjusted with the Cox proportional hazards model, between the presence and absence of MI following different definitions: (1), typical symptoms and persistent ST-segment elevation or left bundle branch block (ST-segment elevation definition); (2), typical symptoms and CK-MB activity rise and/or fall >ULN (old definition); and (3), typical symptoms and cTn I rise and/or fall >99th percentile (universal definition). The total mortality at 10 years was 23.8%. The proportion of Pts with AMI was 33.6% for ST-segment elevation definition, 55.8% for old definition, and 70.1% for universal definition. The adjusted hazard ratio of death at 10 years between the presence and absence of AMI was 0.71 (95% confidence interval (CI): 0.46–1.08; P = 0.11) for ST-segment elevation definition, 0.84 (95% CI: 0.55–1.27; P = 0.40) for old definition, and 1.58 (95% CI: 1.07–2.40; P = 0.03) for universal definition. Patients submitted to myocardial revascularization during the initial hospital stay (72%) presented a significantly lower mortality at 10 years, compared with patients not revascularized (adjusted hazard ratio: 0.63, 95% CI: 0.44–0.91; P = 0.014).
Conclusions In a population with the entire spectrum of ACSs, the universal definition of MI increased this diagnosis by one-quarter and was an independent predictor of mortality at 10 years. Furthermore, myocardial revascularization was associated with a significantly lower mortality at 10 years.
Myocardial infarction (MI) is one of the main causes of mortality and morbidity worldwide. The occurrence of MI has various major clinical, social, psychological, epidemiological, and research implications. Clinically, MI has a powerful impact on the quality of life and on patient prognosis. The existence of prior MI events has psychological and legal implications. The epidemiological impact of MI derives from the fact that its incidence is used as a health indicator and as an estimate of coronary disease prevalence within a population. Finally, MI represents a major clinical event in clinical trials and registries.
In this context, the precise definition of MI assumes a crucial relevance. MI may be defined according to different perspectives and clinical, electrocardiographic, biochemical, imaging, and pathological features. The development of biochemical markers of high sensitivity and specificity, such as cardiac troponins (cTn) I and T, has represented a remarkable evolution in MI diagnosis and risk stratification and it has led to the redefinition of MI by the European Society of Cardiology and the American College of Cardiology in 2000 and, later, to the universal definition of MI by the European Society of Cardiology, the American College of Cardiology Foundation, American Heart Association and the World Heart Federation. The criteria for spontaneous MI diagnosis (type 1) came to include cTn elevation, associated with myocardial ischaemia symptoms, above the 99th percentile with a variation coefficient of <10% in an apparently healthy adult population.
The MI definition based on cTn elevation above the 99th percentile has significantly increased MI incidence and it has led to an intense debate on the reclassification of small myocardial necrosis such as MI. Several trials have shown that the new universal definition of MI had implications in the short- and medium-term prognosis but there are no evidence regarding the impact on long-term prognosis. The objective of this study is to evaluate the impact of the universal definition of MI on mortality at 10 years.
Abstract and Introduction
Abstract
Aims Redefinition of myocardial infarction (MI) based on specific cardiac troponins (cTn) was universally accepted in 2007. The new definition has been widely discussed for including a large spectrum of quantitative myocardial necrosis and their clinical implications remain under debate. Our aim was to assess the impact of the universal definition of MI on mortality at 10 years.
Methods and results We studied 676 consecutive patients (Pts) admitted to our intensive cardiac care unit for acute coronary syndrome (ACS) between January 1999 and December 2000. We calculated the relative risk of the total death at 10 years adjusted with the Cox proportional hazards model, between the presence and absence of MI following different definitions: (1), typical symptoms and persistent ST-segment elevation or left bundle branch block (ST-segment elevation definition); (2), typical symptoms and CK-MB activity rise and/or fall >ULN (old definition); and (3), typical symptoms and cTn I rise and/or fall >99th percentile (universal definition). The total mortality at 10 years was 23.8%. The proportion of Pts with AMI was 33.6% for ST-segment elevation definition, 55.8% for old definition, and 70.1% for universal definition. The adjusted hazard ratio of death at 10 years between the presence and absence of AMI was 0.71 (95% confidence interval (CI): 0.46–1.08; P = 0.11) for ST-segment elevation definition, 0.84 (95% CI: 0.55–1.27; P = 0.40) for old definition, and 1.58 (95% CI: 1.07–2.40; P = 0.03) for universal definition. Patients submitted to myocardial revascularization during the initial hospital stay (72%) presented a significantly lower mortality at 10 years, compared with patients not revascularized (adjusted hazard ratio: 0.63, 95% CI: 0.44–0.91; P = 0.014).
Conclusions In a population with the entire spectrum of ACSs, the universal definition of MI increased this diagnosis by one-quarter and was an independent predictor of mortality at 10 years. Furthermore, myocardial revascularization was associated with a significantly lower mortality at 10 years.
Mortality at Follow-up
Myocardial infarction (MI) is one of the main causes of mortality and morbidity worldwide. The occurrence of MI has various major clinical, social, psychological, epidemiological, and research implications. Clinically, MI has a powerful impact on the quality of life and on patient prognosis. The existence of prior MI events has psychological and legal implications. The epidemiological impact of MI derives from the fact that its incidence is used as a health indicator and as an estimate of coronary disease prevalence within a population. Finally, MI represents a major clinical event in clinical trials and registries.
In this context, the precise definition of MI assumes a crucial relevance. MI may be defined according to different perspectives and clinical, electrocardiographic, biochemical, imaging, and pathological features. The development of biochemical markers of high sensitivity and specificity, such as cardiac troponins (cTn) I and T, has represented a remarkable evolution in MI diagnosis and risk stratification and it has led to the redefinition of MI by the European Society of Cardiology and the American College of Cardiology in 2000 and, later, to the universal definition of MI by the European Society of Cardiology, the American College of Cardiology Foundation, American Heart Association and the World Heart Federation. The criteria for spontaneous MI diagnosis (type 1) came to include cTn elevation, associated with myocardial ischaemia symptoms, above the 99th percentile with a variation coefficient of <10% in an apparently healthy adult population.
The MI definition based on cTn elevation above the 99th percentile has significantly increased MI incidence and it has led to an intense debate on the reclassification of small myocardial necrosis such as MI. Several trials have shown that the new universal definition of MI had implications in the short- and medium-term prognosis but there are no evidence regarding the impact on long-term prognosis. The objective of this study is to evaluate the impact of the universal definition of MI on mortality at 10 years.
