[Is troponin I useful for predicting in-hospital risk for unstable angina patients in a community hospital? Results of a prospective study]

Cardiac Troponin T (cTn T) and the Postmortem Diagnosis of Sudden Death

PURPOSE

To evaluate the effectiveness of the increase of postmortem cardiac troponin T (cTn T) in acute disease-related deaths.

METHODS

Peripheral venous blood was sampled from 39 autopsies performed. Thirty nonhemolyzed specimens were considered in the final analysis (n = 30).Only the calculation of the cTn T was performed using the Roche Diagnostics Elecsys 2010 Immunoassay System. The high limit and the cutoff are 25 ng/mL. Deaths were divided into 2 groups, according to sudden cardiac deaths (group 1, n = 15) and non-cardiac-related deaths without resuscitation (group 2, n = 15).

RESULTS

All the cases with visual myocardial infarction had elevated concentrations of cTn T. The difference of the postmortem cTn T concentrations between resuscitated and nonresuscitated is nonsignificant. In the non-cardiac-related deaths, the elevated concentrations of cTn T were only noted in all cases of electrocution.

CONCLUSION

In clinical practice, several biochemical markers are used for the diagnosis of myocardial infarction. Because of its extreme specificity for myocardial damage, cTn T and cardiac troponin I (cTn I) are frequently used. The results of these assays could then be used to facilitate selection for cases that may be released following histologic examinations.

[Prognostic markers of non-ST elevation acute coronary syndromes]

OBJECTIVES

We analyzed whether the study of systolic function by echocardiography adds independent information to that afforded by biochemical markers in predicting six-month major events after non-ST elevation acute coronary syndrome.

PATIENTS AND METHOD

Baseline clinical and electrocardiographic data as well as serum concentrations of troponin, myoglobin, C-reactive protein, fibrinogen and homocysteine were recorded prospectively in 515 consecutive patients admitted because of non-ST elevation acute coronary syndrome. Ejection fraction (echocardiogram) was determined in 248 cases (48%). Predictors of cardiac death or infarction within the following six months were analyzed.

RESULTS

In the 248 patients in whom ejection fraction was analyzed, 38 major events were recorded. Increased biochemical markers were related to major events (p < 0.05 for all markers). In the final multivariate model, which included clinical, electrocardiographic, serological and systolic function data, ejection fraction was the most powerful predictor of six-month major events: age > 70 years (p = 0,04), insulin-dependent diabetes (p = 0.03), C-reactive protein > 11 mg/l (p = 0.004) and ejection fraction < 50% (p < 0.0001); C-statistic = 0.80.

CONCLUSIONS

Apart from the clinical and biochemical profile, analysis of systolic function is advisable for correct risk stratification of patients with non-ST elevation acute coronary syndrome.

[Emergency room risk stratification of patients with chest pain without ST segment elevation]

OBJECTIVES

To investigate the prognostic factors in patients who come to the emergency room with chest pain but without ST segment elevation.

PATIENTS AND METHOD

743 consecutive patients were evaluated by recording clinical history, electrocardiogram and troponin I determination, and early (<24 h) exercise testing was done for the low-risk subgroup of patients (n=203). All patients were followed during 3 months for major events (acute myocardial infarction or death).

RESULTS

Major events occurred in 71 patients (9.6%). Multivariate analysis (C statistic=0.79; 95% CI 0.73-0.84; p=0.0001) identified the following predictors: age > or =72 years (OR=1.7; 95% CI, 1.0-2.9; p=0.05), insulin-dependent diabetes mellitus (OR=2.9; 95% CI, 1.5-5.4; p=0.001), previous ischemic heart disease (OR=1.9; 95% CI, 1.1-3.2; p=0.02), ST depression (OR=2.1; 95% CI, 1.2-3.8; p=0.01) and troponin I elevation (OR=2.9; 95% CI, 1.5-5.3; p=0.001). These five predictors were used to construct a risk score based on their odds ratios, which allowed event rate stratification by quartiles of the score: 0-2 points (1.6% events), 3-4 points (8.1% events), 5-7 points (11.9% events) and > or =8 points (26.2% events); p=0.0001. No patient with negative findings in the early exercise testing had major events.

CONCLUSIONS

In patients with chest pain, the combination of clinical, electrocardiographic and biochemical data available on admission to the emergency service allows rapid prognostic stratification. Early exercise testing is advisable for the final stratification of low risk patients.

[Usefulness of troponin I for predicting systolic dysfunction in acute coronary syndromes. Results of a prospective and quantitative study]

The relationship between troponin I and systolic function (quantitative contrast ventriculography) was evaluated in 137 consecutive patients with a first acute coronary syndrome (60 with and 77 without ST elevation). In general, a larger troponin I peak value was related with a more depressed ejection fraction and poorer regional systolic function (p < 0.0001). Nevertheless, this correlation was weaker than expected, especially in those cases without ST-segment elevation, suggesting that other factors apart from systolic dysfunction must be taken into account in order to explain the worse prognosis of those patients with increased serum levels of this marker of myocardial damage.

[Short-term prognosis of patients admitted for probable acute coronary syndrome without ST-segment elevation. Role of new myocardial damage markers and acute-phase reactants]

OBJECTIVES

The relative value of classic markers, myocardial damage variables, and levels of acute-phase reactants in establishing the pre-discharge prognosis of acute coronary syndrome without ST-segment elevation was analyzed.

METHOD

We prospectively studied 385 consecutive patients admitted from our chest pain unit with a high-probability diagnosis of acute coronary syndrome without ST-segment elevation. The clinical and electrocardiographic data, myocardial damage markers (troponin I, CK-Mb mass, myoglobin), and acute-phase reactants (high-sensitivity C-reactive protein, fibrinogen) were recorded.

RESULTS

During admission, 15 deaths (3.9%) and 16 complicative infarctions (4.2%) occurred, for a total of 31 major events (death and/or infarction: 8.1%). Age (p = 0.03), insulin-dependent diabetes (p = 0.009), and C-reactive protein (p = 0.05) were independently related to death. Fibrinogen was related to infarction (p = 0.01); by fibrinogen quartiles: 1.4%; 1.4%; 2.9%, and 11.7% (p = 0.02). Age (p = 0.01), insulin-dependent diabetes (p = 0.02), and C-reactive protein (p = 0.04) were independent predictors of major events; by C-reactive protein quartiles: 1.4%; 5.5%; 5.4%, and 16.7% (p = 0.004). Troponin I was related to major events (p = 0.03), but it was not an independent predictor.

CONCLUSIONS

Acute-phase reactants add independent information to clinical variables in the short-term risk stratification of patients with an acute coronary syndrome. The predictive power of troponins is lower than that of other variables.