Potential impact of interventions to reduce times to thrombolysis

Abstract

Objectives: To estimate the lifesaving potential of interventions to accelerate the administration of intravenous thrombolysis for myocardial infarction. Methods: Data were analysed from a prospective, observational study of all patients transported to hospital by ambulance, who subsequently received intravenous thrombolysis at 20 hospitals and two ambulance services in Victoria, Australia (n = 1147). Regression models estimated the association between predictor variables age, sex, route of referral, symptom onset to call time, ambulance pre-notification of the receiving hospital, emergency department thrombolysis, and the outcome, time to thrombolysis. Further modelling estimated the number needed to treat to save one life by several recommended interventions to reduce time delays. Results: Presentation via a rural hospital or general practitioner was associated with an approximate doubling of the onset to call time (2.08 and 2.30 respectively). Ambulance-hospital pre-notification and emergency department thrombolysis reduced door to needle times by 21% and 27% respectively. Modelling showed that each of the following interventions would be expected to save one life: 1069 hospital pre-notifications, 714 cases of emergency department thrombolysis, 184 cases of prehospital thrombolysis, 340 cases to bypass their rural hospital, or 50 cases to bypass their general practitioner. Conclusions: Hospital pre-notification and emergency department thrombolysis reduce time delays, although the mortality impact seems to be modest. Prehospital thrombolysis has the potential to save lives, although validation in real practice is required. Advising patients to call directly for an ambulance, rather than the general practitioner, has the greatest potential to save lives.

Does initiation of an ambulance pre-alert call reduce the door to needle time in acute myocardial infarct?

“…Previous studies have looked at various methods of reducing DTN, such as emergency department thrombolysis, 4 pre-alert calls for confirmed AMIs, 6 and pre-hospital thrombolysis. These have shown reductions in DTN times of between 21% and 51%.…”

“…[1][2] Other work has shown that paramedic electrocardiogram (ECG) interpretation and fast tracking of patients with myocardial infarction to a coronary care unit (CCU) reduces door to needle (DTN) times, [3][4][5] as does thrombolysis in the emergency department. 6 Currently our institution has a target of 30 minutes for DTN 7 in 75% of cases and that an ECG should be carried out within 10 minutes of arrival.…”

Delay factors on the administration of thrombolytic therapy in patients diagnosed with acute myocardial infarction in a general hospital

“…In the present study, 28.1% of the patients got to the hospital by ambulance, but the total time taken to start the therapy was not reduced (P=0.81). Studies have shown a reduction in mortality after thrombolytic therapy in patients that received pre-hospital care (8% versus 13%) (P = 0.04) (9)(10) .…”

Emergency Medical Services Management of ST-Elevation Myocardial Infarction

“…11 Once AMI patients decide to access medical care, a substantial number of them do not call EMS, even though the use of EMS and subsequent hospital prenotification have been shown to reduce time delay to reperfusion. [12][13][14] Once the patient has accessed the EMS system, it is important that EMS providers perform an appropriate history and physical examination to evaluate for acute coronary syndromes. EMS providers are often taught that the chief complaint for a patient having an AMI is chest pain.…”