Pre-Hospital Thrombolysis: Current Status and Future Prospects

The impact of thrombolytic therapy in acute myocardial infarction has been such that it now constitutes standard therapy for patients who present to hospital with acute myocardial infarction. In an attempt to minimise the duration of ischaemia, and subsequent impairment of contractile function, trials of pre-hospital thrombolysis have been initiated. These reveal time gains of up to 60 minutes but convincing evidence of clinical benefit has not yet been forthcoming. This review examines the rationale for very early thrombolysis, in the context of the underlying pathophysiological mechanisms. It examines the impact of recent small scale studies on coronary patency, left ventricular function and infarct size and examines the potential risks. Large scale studies of pre-hospital thrombolysis are in progress and their findings will need to be interpreted in comparison with optimal 'fast-track' in-hospital treatment. The review highlights the need for co-ordinated policies for acute management of myocardial infarction involving primary care, the emergency medical systems and cardiac units. Enthusiasm for wide scale administration of thrombolytics by general practitioners, without electrocardiographic confirmation of the diagnosis, must be tempered by a clear analysis of the potential risks and benefits. Current evidence does not support such widespread clinical application, outwith the current evaluation studies. An urgent re-evaluation of hospital triage of patients with acute myocardial infarction is merited.