Clinical application of rapid quantitative determination of cardiac troponin-T in an emergency department setting.

OBJECTIVES: We analysed the clinical use of Troponin-T compared to creatine kinase MB in a non-trauma emergency department setting. BACKGROUND: A newly established single specimen quantitative Troponin T assay allows the clinical application of this parameter. METHODS. Five-hundred Troponin T tests were provided for use by emergency physicians who could combine them with the routine laboratory tests without restriction as to the indication or number of tests per patient. The number of tests per patient, time frame, final diagnosis and additional clinical information gained were recorded. All patients were followed for at least 6 months to verify the diagnosis and to assess the occurrence of cardiac events (nonfatal AMI or cardiac death). The ability of Troponin T and creatine kinase MB tests to predict cardiac events within 6 months were compared. RESULTS: The 500 Troponin T tests were used in 249 patients (median two tests per patient (range 1-5)) within 41 days. The final diagnosis revealed coronary heart disease in 85, non-coronary heart disease in 39, non-cardiac chest pain in 86 and other diagnoses in 39 of the patients. In 14 patients with an elevated creatine kinase MB, myocardial damage could safely be ruled out by a negative Troponin T, in six patients with a normal creatine kinase MB minor myocardial damage could be detected by a positive Troponin T. During follow up 28 cardiac events were recorded. Troponin T had a significantly higher specificity, positive predictive value and proportion of correct prediction for cardiac events within 6 months compared to creatine kinase MB. CONCLUSIONS: Troponin T has proved to be an useful method for diagnosing myocardial damage in routine clinical use in the non-trauma emergency department.

Out-of-hospital diagnosis of cerebral infarction versus intracranial hemorrhage.

OBJECTIVE: To establish a model based on clinical and anamnestic data easily available in the out-of-hospital setting, which facilitates the differential diagnosis between cerebral infarction and intracranial hemorrhage. DESIGN: Retrospective study that simulates a prospective approach. SETTING: Emergency Department of the University Hospital in Vienna, Austria. PATIENTS AND PARTICIPANTS: Data of 224 patients with either intracranial hemorrhage or cerebral infarction were prospectively collected. Uni-and multivariate analysis was performed to identify neurological symptoms and anamnestic data, which were associated with either intracranial hemorrhage or cerebral infarction. MEASUREMENTS AND RESULTS: Unilateral weakness or sensory loss was observed more frequently in patients with infarction compared to hemorrhage (69.8 % vs 11.9 %, P < 0.001). The frequency of patients with impaired level of consciousness was significantly higher in the hemorrhage group compared to the infarction group (59.3 % vs 3.8 %, P < 0.001). A multivariate logistic regression analysis showed that hypertension (OR = 0.31, 95 % CI = 0.12-0.76, P = 0.01), diabetes (OR = 0.17, 95% CI = 0.04-0.68, P = 0.01), and unilateral weakness or sensory loss (OR = 0.10, 95 % CI = 0.04-0.26, P < 0.001) were significantly associated with cerebral infarction. Impaired level of consciousness was significantly related to hemorrhage (OR = 13.41, 95 % CI = 3.92-45.91, P < 0.001). On the basis of the logistic regression analysis, we generated a scoring system for the out-of-hospital diagnosis between infarction and hemorrhage. The values of the score lay between -3 and +3. The probability of infarction increases when the score becomes negative, and the probability for hemorrhage increases when the score becomes positive. CONCLUSION: Our model is a useful guideline for the differential diagnosis between cerebral infarction and intracranial hemorrhage in the out-of-hospital setting, as it is based on easily available clinical and anamnestic parameters.

Evaluation of a point-of-care system for quantitative determination of troponin T and myoglobin.

We present the results of a multicenter evaluation of a new point-of-care system (Cardiac Reader) for the quantitative determination of cardiac troponin T (CARDIAC T Quantitative test) and myoglobin (CARDIAC M test) in whole blood samples. The Cardiac Reader is a CCD camera that optically reads the immunochemical test strips. The measuring range is 0.1 to 3 microg/l for CARDIAC T Quantitative and 30 to 700 microg/l for CARDIAC M. Both tests are calibrated by the manufacturer. The reaction times of the tests are 12 or 8 minutes, respectively. Method comparisons were performed with 281 heparinized blood samples from patients with suspected acute coronary syndromes. The results obtained with CARDIAC T Quantitative showed a good agreement compared with cardiac troponin T ELISA (r = 0.89; y = 0.93x + 0.02). The method comparison between CARDIAC M and Tina-quant Myoglobin also showed a good agreement between both assays (r = 0.98; y = 0.92x + 1.6). Test lot-to-lot comparisons yielded differences of 2% and 6% for CARDIAC T Quantitative and of 0 to 11% for CARDIAC M. The within-run imprecision with blood samples and control materials was acceptable for CARDIAC T Quantitative (CV 10 to 15%) and good for CARDIAC M (CV 5 to 10%). The between-instrument CV was below 7% for CARDIACT Quantitative and below 5% for CARDIAC M. The cross-reactivity of CARDIAC T Quantitative with skeletal troponin T was approximately 0.003%. No significant analytical interference was detected for any of the assays in investigations with biotin (up to 100 microg/l), hemoglobin (up to 0.125 mmol/l), hematocrit (26 to 52%), bilirubin (up to 340 micromol/l), triglycerides (up to 5.0 mmol/l), and 18 standard drugs. With the Cardiac Reader reliable quantitative results can be easily obtained for both cardiac markers. The system is, therefore, particularly suitable for use in emergency rooms, coronary care units and small hospitals.

Increased blood pressure response to the cold pressor test in pregnant women developing pre-eclampsia.

OBJECTIVES: Recent data indicate an increased vascular reactivity due to an overactivity of the sympathetic nervous system in women with pre-eclampsia. We therefore evaluated whether this increased vascular reactivity can be detected prior to the clinical manifestation of preeclampsia by the use of a physiological stimulus. DESIGN: Prospective data collection. SETTING: Clinic of Obstetrics and Gynecology in a 2000 bed tertiary care hospital. PARTICIPANTS: One hundred and twenty-three pregnant women between the 16th to 20th week of gestation. INTERVENTIONS: A cold pressor test was performed by positioning an ice-bag on the forehead of the woman for 3 min. Blood pressure and heart rate were monitored by a continuous, noninvasive blood pressure measurement device during the stimulus and after removal of the icebag. A clinical follow-up was carried out by review of the charts after delivery to identify those women who have developed pre-eclampsia. RESULTS: Ten (8%) out of 123 pregnant women developed pre-eclampsia. During the cold pressor test systolic as well as diastolic blood pressure increased significantly and was more pronounced in women developing pre-eclampsia compared with healthy pregnant women (systolic blood pressure: 14.2 +/- 5.5 versus 8.5 +/- 7.2 mmHg, P= 0.02; diastolic blood pressure: 7.3 +/- 4.9 versus 3.9 +/- 4.7 mmHg, P=0.03). The change in heart rate was similar between both groups (8 +/- 2.6 versus 10.4 +/- 6.4 beats/min, not significant). CONCLUSIONS: An increased vasoconstrictive response to a physiological stimulus is present in women with pre-eclampsia as a sign of an increased vascular reactivity prior to clinical manifestation of the disease. The cold pressor test may be a suitable diagnostic tool to identify women, who will develop pre-eclampsia. However, future studies in larger cohorts are required to establish the final value of this test.