[Utility of the serum biochemical markers CPK, CPK MB mass, myoglobin, and cardiac troponin T in a chest pain unit. Which marker determinations should be requested and when?]. / Utilidad clínica de los distintos marcadores biológicos CPK, CPK MB masa, mioglobina y troponina T en una unidad de dolor torácico. Cuándo, cuáles y cómo pedirlos?

BACKGROUND: The prognostic value of biochemical markers in relation to time since onset of chest pain was evaluated in an emergency room with a chest pain unit. METHODS: In a single-center, prospective study we included 321 consecutive patients admitted to the emergency room with suspected unstable angina IIIB and an evolution of less than 12 hours. Blood samples were collected for CPK, CPK MB mass, myoglobin, and cardiac troponin T assays 6, 12, and 18 h after the onset of pain. ROC curve analysis was carried out to compare biochemical markers in terms of cutoff values and time since onset of pain. We determined the relation between prognosis and biochemical markers before and after adjustment for baseline characteristics. RESULTS: CPK mass and myoglobin showed the maximum sensitivity and specificity for new ischemic recurrences 6 hours after the onset of chest pain with laboratory cutoff values. We had to wait 12 h after the onset of pain for troponin T to be useful using the laboratory cutoff value (0.1 ng/ml). A single determination 6 hours after onset of chest pain of cardiac troponin T above 0.04 ng/ml was the most sensitive and specific marker for new ischemic recurrences. CONCLUSIONS: A single blood determination of cardiac troponin T 6 hours after the onset of chest pain complete the prognostic stratification in combination with clinical and ECG variables. The best cutoff point of cardiac troponin T, based on univariate and multivariate analysis, was 0.04 ng/ml 6 h after the onset of chest pain.

[Risk stratification using combined ECG, clinical, and biochemical assessment in patients with chest pain without ST-segment elevation. How long should we wait? ]. / Estratificación de riesgo en pacientes con dolor torácico sin ascenso persistente del segmento ST basado en variables clínicas, ECG y bioquímicas. ¿Cuánto tiempo debemos esperar?

INTRODUCTION: We use clinical, ECG, and biochemical data to stratify risk in patients with chest pain without ST segment elevation. However, the prognostic performance of these studies in relation to time from onset of symptoms is unknown. PATIENTS AND METHOD: In a single-center, prospective study, 321 consecutive patients who had been admitted in the emergency room with a suspected acute coronary syndrome without ST segment elevation were included in the study. Blood samples were collected for CK, CK-MB mass, myoglobin, and cardiac troponin T analysis 6, 12 and 18 hours after the onset of pain and other clinical and ECG data were recorded. Univariate and multivariate analysis was used to identify independent prognostic predictors 6 and 12 hours after the onset of chest pain. RESULTS: Five variables were independent predictors of the recurrence of ischemia. The model correctly classified 82% of the patients. Age, history of coronary artery disease, prolonged chest pain at rest in the preceding 15 days, pain, ST-segment changes with pain, and cardiac troponin T in excess of 0.1 ng/m 12 hours after the onset of chest pain were identified by logistic regression. A similar model was analyzed at 6 hours, after changing the cutoff point for cardiac troponin T. Cardiac troponin T was considered positive with values of 0.04 ng/ml 6 hours after the onset of chest pain. CONCLUSIONS: More than 80% of the patients admitted to the emergency room with chest pain without ST segment elevation can be correctly classified for new ischemic recurrences using clinical, ECG, and biochemical parameters 6 hours after the onset of pain.