New Definition of Myocardial Infarction: Impact on Long-term Mortality
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.
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.
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).
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.
Available from: Ronald J Prineas
- "Troponin is the preferred biomarker due to its high specificity for cardiac muscle [1-4]. The risk for mortality and cardiovascular events is increased with even modest troponin elevations [5-9]; therefore, for several years, American and European cardiology societies, the National Heart, Lung and Blood Institute, the Centers for Disease Control and Prevention, and others have recommended defining abnormal troponin as any value above the 99th percentile for healthy individuals [1-4,10-14], culminating in the publication of the Universal Definition of MI in 2007 [1-3]. "
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International guidelines recommend that the decision threshold for troponin should be the 99th percentile of a normal population, or, if the laboratory assay is not sufficiently precise at this low level, the level at which the assay achieves a 10% or better coefficient of variation (CV). Our objectives were to examine US hospital laboratory troponin reports to determine whether either the 99th percentile or the 10% CV level were clearly indicated, and whether nonconcordance with these guidelines was a potential barrier to detecting clinically important microscopic or ‘microsize’ myocardial infarctions (MIs). To confirm past reports of the clinical importance of microsize MIs, we also contrasted in-hospital, 28-day and 1-year mortality among those with microsize and nonmicrosize MI.
In the REasons for Geographic And Racial Differences in Stroke national prospective cohort study (n=30,239), 1029 participants were hospitalized for acute coronary syndrome (ACS) between 2003–2009. For each case, we recorded all thresholds of abnormal troponin on the laboratory report and whether the 99th percentile or 10% CV value were clearly identified. All cases were expert adjudicated for presence of MI. Peak troponin values were used to classify MIs as microsize MI (< five times the lowest listed upper limit of normal) and nonmicrosize MI.
Participants were hospitalized at 649 acute care US hospitals, only 2% of whose lab reports clearly identified the 99th percentile or the 10% CV level; 52% of reports indicated an indeterminate range, a practice that is no longer recommended. There were 183 microsize MIs and 353 nonmicrosize MIs. In-hospital mortality tended to be lower in the microsize than in the nonmicrosize MI group (1.1 vs. 3.6%, p = 0.09), but 28-day and 1-year mortality were similar (2.5% vs. 2.7% [p = 0.93] and 5.2% vs. 4.3% [p = 0.64], respectively).
Current practices in many US hospitals created barriers to the clinical recognition of microsize MI, which was common and clinically important in our study. Improved hospital troponin reporting is warranted.
Available from: Yangsoo Jang
- "The questionnaire and survey were performed in cooperation with the KSC to improve the quality and rate of responses. To investigate the cardiovascular disease evidence reported in medical records, a structured questionnaire was drafted by a cardiologist using well-known diagnostic criteria by reviewing previous reports.8-10) The event validation committee of the KSC, consisting of 23 cardiologists in teaching hospitals, reviewed the questionnaire. "
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ABSTRACT: Medical insurance claims (MIC) data are one of the largest sources of outcome data in the form of International Classification of Diseases (ICD) codes. We evaluated the validity of the ICD codes from the Korean National MIC data with respect to the outcomes from acute myocardial infarction (AMI) in the Korean Heart Study.
Baseline information was obtained from health examinations conducted from 1994 to 2001. Outcome information regarding the incidence of AMI came from hospital admission discharge records from 1994 to 2007. Structured questionnaires were sent to 98 hospitals. In total, 107 cases of AMI with ICD codes of I21- (93 men, 26-73 years of age) were included in the final analyses. ICD code accuracy and reliability (kappa) for AMI were calculated.
A large number of AMI cases were from hospitals located in the Seoul area (75.9%). The accuracy of AMI was 71.4%, according to World Health Organization criteria (1997-2000, n=24, kappa=0.46) and 73.1% according to the European Society of Cardiology/American College of Cardiology (ESC/ACC) criteria (2001-2007, n=83, kappa=0.74). An age of 50 years or older was the only factor related to inaccuracy of codes for AMI (odds ratio, 4.6; 95% confidence interval, 1.2-17.7) in patients diagnosed since January 2001 using ESC/ACC criteria (n=83).
The accuracy for diagnosing AMI using the ICD-10 codes in Korean MIC data was >70%, and reliability was fair to good; however, more attention is required for recoding ICD codes in older patients.
Available from: Vipin Kumar
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ABSTRACT: Many parallel algorithm design models have been proposed for
abstracting a large class of parallel architectures. However, all of
these models potentially make inaccurate asymptotic performance
predictions that may be too optimistic or too pessimistic depending on
the circumstances. We propose a new, simpler parallel model called
A<sup>3</sup> (Approximate Model for Analysis of Aggregate Communication
Operations) that provides asymptotically accurate time estimates for a
wide class of parallel programs that are based on aggregate
communication operations. Accuracy is attained (1) by making the model
sensitive to the structure of aggregate data communication operations
and (2) by classifying these aggregate communication operations into
those that are cross-section bandwidth sensitive and those that are not.
We note that algorithms expressed exclusively using those aggregate
communication operations that are cross-section bandwidth insensitive
have the same time complexity across a wide range of architectures.
Other algorithms (using aggregate communication operations sensitive to
cross-section bandwidth) may have different time complexity but their
implementations may still be portable and possibly optimal across a wide
range of architectures as long as they use a library of aggregate
communication operations customized to each architecture. We note that
the simpler, asymptotically accurate algorithm analysis facilitated by A
<sup>3</sup> can make algorithm design much faster and simpler
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