Trombolys och biokemiska markörer : I den prehospitala fasen av akuta koronara syndrom

Abstract: Efficacy of thrombolytic therapy among patients with ST-segment elevation myocardial infarction is time dependent. The earlier treatment can be started the more powerful are the effects on reducing infarct size, preservation of ventricular function and reducing long and short-term mortality. Therefore this treatment is used already before arrival in hospital, given by ambulance personal. Patients who call for ambulance due to chest pain are heterogeneous with respect to characteristics and prognosis. Riskevaluation of this population already before arrivals in hospital with regards to diagnosis and prognosis have so far been limited. To evaluate the feasibility of prehospital thrombolysis in Sweden in terms of safety and various components of delay between onset of symptoms and start of treatment. To evaluate the occurrence of elevation of serum biochemical markers for myocardial damagein the prehospital setting among patients how called for an ambulance due to suspicion of anacute coronary syndrome. To evaluate factors, which, prior to hospital admission, predict the development of acute coronary syndrome, acute myocardial infarction, short and long term risk of death among patients who called for an ambulance due to suspicion of an acute coronary syndrome. Sixteen hospitals in Sweden, including urban and less populated areas and the associated ambulance organisations were participating. This was a prospective evaluation of 154 patients with an ST-elevation infarction treated with reteplase in the prehospital phase.Patients who during January through November 2000 called for an ambulance due to suspicion of an acute coronary syndrome in the South Hospital catchment area in Stockholm and in the municipal of Gothenburg Sweden were included. In all 5 11 patients participated on 538 occasions. On arrival of the ambulance a blood sample was drawn for bedside analysis of serum myoglobin, kreatinaseMB and troponin-I. A 12-lead electrocardiogram (ECG) was simultaneous recorded. The implementation of prehospital thrombolysis on a national basis in Sweden appears to be safe. Six patients (4%) had cardiac arrest prior to hospital admission and 2 (1 %) died prior to arrival at hospital. One patient was given treatment despite an exclusion criterion (previous stroke) and died on the first day in hospital due to cerebral haemorrhage. More than half of the patients was given treatment less than two hours after the onset of symptoms. The median arrival time tended to be shorter in urban compare to rural areas and the median interval between arrival of the ambulance and start of thrombolysis was shorter in urban areas (27 minutes vs. 36 minutes: p<0.0001). Complications prior to hospital admission was low and similar in the two groups. Elevation of any biochemical marker was observed in 11% of all patients. Predictors can be defined prior to hospital admission as follows: Acute myocardial infarction: male gender (p=0.01 1), ECG changes with ST-elevation (p<0.0001) or ST-depression (p<0.0001) elevation of CKMB (p<0.000 1) short interval between the onset of symptoms and blood sampling (p=0.010). Acute coronary syndrome: history of myocardial infarction (p=0.006), angina pectoris (p=0.005) or hypertension (p=0.017), ECG changes with ST-elevation (p<0.0001) ST-depression (p<0.0001) or T-wave inversion (p=0.012), elevation of CKMB (p=0.005). Among patients with a clinical suspicion of acute coronary syndrome, those with a combination of ECG signs of myocardial ischemia or infarction and the elevation of any biochemical marker on arrival of the ambulance constitute a group with particularly high risk of death. Bedside analysis of biochemical markers in serum is feasible already prior to hospital admission among patients with a suspected acs. However, false positives were found and whether this strategy will improve the triage of these patients in the prehospital setting remains to be proven.