New definition of myocardial infarction: impact on long-term mortality
Willibald Hochholzer1, Heinz J Buettner, Dietmar Trenk
1Herz-Zentrum, Bad Krozingen, Germany.
Insights
New cardiac troponin guidelines identify more myocardial infarction patients. These patients, identified by additional criteria, face higher long-term mortality than those meeting older World Health Organization (WHO) criteria.
Area of Science:
- Cardiology
- Biomarkers
- Clinical Outcomes
Background:
- Cardiac troponin use identifies myocardial necrosis in acute coronary syndrome (ACS).
- Novel guidelines recommend labeling troponin-identified events as myocardial infarction (MI).
- Older World Health Organization (WHO) criteria relied on creatine phosphokinase (CPK).
Purpose of the Study:
- To evaluate long-term mortality in non-ST segment elevation myocardial infarction (NSTEMI) patients.
- To compare outcomes between NSTEMI patients meeting older WHO criteria and those identified by novel cardiac troponin criteria.
Main Methods:
- A cohort study of 1024 consecutive NSTEMI patients.
- Patients classified into unstable angina, WHO criteria MI, and additional criteria MI.
- All patients underwent an early invasive strategy with up to 36 months of follow-up.
Main Results:
- Cumulative 3-year mortality rates were 5.6% (unstable angina), 9.1% (WHO criteria), and 17.5% (additional criteria).
- The "additional criteria" group showed significantly higher mortality (P <.001).
- Cox regression identified "additional criteria" as a significant predictor of mortality (HR 3.1, P <.001).
Conclusions:
- The new definition of MI using cardiac troponin identifies a high-risk ACS subgroup.
- Patients identified by "additional criteria" have higher long-term mortality than "WHO criteria" patients.
- This high-risk group should be appropriately classified as MI.
Background:
The use of cardiac troponin allows the identification of additional patients developing myocardial necrosis during an acute coronary syndrome. Novel guidelines of European and American cardiac societies recommend labeling these events as myocardial infarction. Our study evaluated the long-term mortality in the group of patients with non-ST segment elevation myocardial infarction not meeting the older World Health Organization (WHO) criteria (creatine phosphokinase) but additionally identified by the novel definition of myocardial infarction.
Methods:
This cohort study included 1024 consecutive patients with non-ST segment elevation acute coronary syndrome classified into "unstable angina," myocardial infarction according to the WHO definition ("WHO criteria"), and myocardial infarction additionally identified by the novel definition ("additional criteria"). All patients were treated with an early invasive strategy. The primary end point was all-cause mortality during follow-up of up to 36 months.
Results:
During long-term follow-up (median 16 months, interquartile range 6-29 months), 67 deaths occurred. Kaplan-Meier analysis showed cumulative 3-year mortality rates of 5.6% in patients with "unstable angina," 9.1% in patients identified by "WHO criteria," and 17.5% in patients identified by "additional criteria" (P <.001). Cox regression analysis confirmed the "additional criteria" as a significant predictor of mortality (hazard ratio 3.1; 95% confidence interval, 1.9-5.0; P <.001).
Conclusions:
The new definition of myocardial infarction based on cardiac troponin testing identifies a high-risk group of additional patients with acute coronary syndrome that is, therefore, appropriately classified as myocardial infarction. In fact, long-term mortality in "additional criteria" patients is higher than in "WHO criteria" patients.
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