Prognostic value of biochemical markers, 12‐lead ECG and patient characteristics amongst patients calling for an ambulance due to a suspected acute coronary syndrome

. Objectives. To evaluate whether a 12‐lead ECG, together with a multi‐marker strategy that used point‐of‐care measurements of myoglobin, creatine kinase (CK‐MB) and troponin I, was able to predict patients at short‐ and long‐term risk of death, when simultaneously considering age, gender, previous history, symptoms and clinical findings on arrival of the ambulance. Design. Prospective observational study. Setting and subjects. Consecutive patients (n=511) in ambulances in Stockholm and Göteborg in Sweden who called for an ambulance due to chest pain or other symptoms raising a suspicion of acute coronary syndrome. Intervention. In almost all patients, a diagnostic ECG, patient baseline characteristics and measurements of CK‐MB, troponin I and myoglobin were recorded. Results. In univariate analysis, the highest 30‐day mortality (17%) was found amongst patients with the combination of ECG signs of myocardial ischaemia and the elevation of any biochemical marker. The highest 1‐year mortality (20%) was found amongst patients with ECG signs of myocardial ischaemia and the elevation of any biochemical marker. Increasing age (RR 1.07; 95 CI 1.02–1.13) lack of symptoms of chest pain and a previous history of hypertension (3.02; 1.08–8.79) were independent predictors of 30‐day mortality. Myoglobin was the only biochemical marker independently associated with 30‐day mortality (6.66; 1.83–22.3). Increasing age (1.11; 1.06–1.16), previous history of diabetes (3.42; 1.41–8.25) heart failure (2.64; 1.26–5.52) and other symptoms than chest pain and dyspnoea (5.23; 2.14–12.76) were independent predictors of 1‐year mortality. In many of the variables the confidence limits were wide. Conclusion. Amongst patients with a clinical suspicion of acute coronary syndrome, those with the combination of ECG signs of myocardial ischaemia and the elevation of any biochemical marker on arrival of the ambulance form a group with a particularly high risk of death. However, age as well as aspects of clinical history and type of symptoms independently contribute to prognostic information.