Short term prognosis of patients with acute coronary syndromes: the level of cardiac troponin T elevation corresponding to the "old" WHO definition of myocardial infarction

Increasing serum troponin I and early prognosis in patients with chest pain or angina equivalent symptoms in the emergency department

BACKGROUND

The purpose of this research was to determine the relation between negative or positive qualitative troponin I test and the short term prognosis of patients presenting to emergency department with chest pain or angina equivalent symptoms.

METHODS

we assessed the qualitative rapid troponin I in patients with chest pain or angina equivalent symptoms after at least 4 hours and then we followed the patients in 72 hours after presentation for adverse events such as death, CCU admission, fatal arrhythmias and heart failure.

RESULTS

After comparing qualitative troponin I test results and adverse events, we concluded that the troponin I was significantly more positive in patients with adverse events (i.e. CCU admission, fatal arrhythmias and heart failure) (P=0.031).

CONCLUSION

A single measurement of rapid qualitative troponin I test can be used as a prognostic factor in patients with chest pain or angina equivalent symptoms and also as a device for risk stratification of moderate and high risk patients.

Interregional differences in the clinical, biological and electrical characteristics of first acute coronary events in France: results from the MONICA registries

BACKGROUND

In France, there is a large north-to-south, decreasing gradient in case fatality rates of hospitalized patients for an acute coronary event. This gradient may be explained by differences in the presenting patients' clinical, biological and electrocardiographic characteristics.

GOAL

To compare the characteristics of patients hospitalized for an acute episode of coronary insufficiency in three regions of France with contrasting fatality rates.

METHODS

We assessed all men and women (aged 35-74 years) covered by the MONICA registries in three geographical areas (north, east and south-west France) and hospitalized in 2006 for a first acute coronary event. The symptoms, electrocardiogram features, left ventricular ejection fraction (LVEF) and troponin levels were systematically transcribed from medical files. Vital status was followed up for one year.

RESULTS

Fatality rates at 28 days and 1 year were higher in the north (7% and 12%, respectively) than in the east (5% and 7%) and in the south-west (2% and 5%). Major symptoms (such as cardiac arrest, acute pulmonary oedema and cardiac shock), altered LVEF and ST+ myocardial infarction (STEMI) were more frequent in the north than in the south-west (all p < 0.0001) - pointing to marked inter-regional differences in the presentation of acute coronary syndromes (ACSs). In multivariate analyses, age, major symptoms, altered LVEF and STEMI remained strongly associated with 28-day lethality, whereas the relationship with geographical area was attenuated. Similar results were observed for 1-year outcomes.

CONCLUSIONS

The clinical, biological and electrocardiographic presentations of hospitalized incident ACSs differ from one region of France to another. These differences explain (at least in part) the 28-day and 1-year decreasing case fatality gradient in hospitalized patients from northern France to south-western France.

A lab-on-a-chip for rapid blood separation and quantification of hematocrit and serum analytes

In this work, a new lab-on-a-chip for rapid analysis of low volume blood samples was designed, fabricated and demonstrated for integration of serum separation, hematocrit evaluation, and protein quantitation. Blood separation was achieved using microchannel flow-based separation. A novel method for evaluating hematocrit from microfluidic flow-separated blood samples was developed using gray scale analysis of a point-and-shoot digital photograph of separated blood in a micochannel. Protein quantitation was subsequently performed in a high surface area-to-volume ratio microfluidic chemiluminescent immunoassay using cell depleted serum produced by microfluidic flow-based separation of whole blood samples. All three steps were achieved in a single microchannel with separation of blood samples and hematocrit evaluation in less than 1 min, and protein quantitation in 5 min.

Underuse of thrombolytic therapy in acute myocardial infarction and left bundle branch block

Thrombolytic therapy reduces mortality in patients with acute myocardial infarction (AMI) and left bundle branch block (LBBB). The difficulty in accurately diagnosing AMI in patients with LBBB, however, might result in their undertreatment. Among 3,890 patients hospitalized with chest pain, 241 (6.2%) had LBBB at presentation. The only variable independently associated with AMI among patients with LBBB was in-hospital left ventricular failure (odds ratio [OR]: 4.32, 95% confidence interval [CI]: 1.95-9.57, p < 0.0005). Only 16 (29%) of the LBBB patients with AMI received thrombolytic therapy compared with 583 (78%) of the 747 patients with ST-elevation AMI (p < 0.0005). A further 19 (10%) LBBB patients without AMI also received thrombolysis. Difficulty in making an accurate early diagnosis in patients with LBBB ensures that the majority of those with AMI fail to receive thrombolytic therapy while others without AMI are treated inappropriately. Improved diagnostic and therapeutic strategies are needed for patients with acute coronary syndromes and LBBB.

The determination of the 99th centile level for troponin assays in an Australian reference population

Background

Current guidelines for the diagnosis and risk assessment of patients presenting with myocardial infarction recommend a single decision cut-off point for cardiac troponin (cTn) based on the 99th centile of a reference population. The 99th centile level for eight troponin assays was determined in an apparently cardio-healthy Australian reference population.

Methods

Nine laboratories measured troponin in serum and plasma collected from 111 reference individuals. An imprecision profile was determined using up to 10 serum samples analysed on 10 separate days. Method comparison using 100 routinely tested plasma samples was performed to estimate method concordance.

Results

Generally 99th centile values determined in this study were lower than, or the same as manufacturers' levels, except for cTnI by Architect (0.020 vs. 0.012 μg/L), and imprecision at the 99th centile was 20% coefficient of variation (CV) or higher. Troponin concentrations at 10% CV were greater than those quoted in the manufacturer's package insert except by AxSYM, 0.06 vs. 0.16 μg/L cTnI, and by E-170, 0.02 vs. 0.03 μg/L cTnT. In the method comparison 74, 70, 65, 75, 58, 66, 58 and 77 samples measured by Access, Architect, AxSYM, Centaur, Dimension RxL, E-170, i-STAT and Vitros ECi assays, respectively, had troponin concentrations above the study 99th centile.

Conclusions

Depending on the selected reference population for troponin, there is likely to be variability in the 99th centile as shown in this study. Some differences in sample concordance at the 99th centile cut-off were observed between cTn methods and may result in different clinical classification.