Prospective observational cohort study of time saved by prehospital thrombolysis for ST elevation myocardial infarction delivered by paramedics

Editor- Pedley et al provide welcome further evidence that paramedic
provision of prehospital thrombolysis for acute myocardial infarction
(AMI) is feasible and reduces the treatment delay.1 However, it is
disappointing that no cost data were presented. Their study was an ideal
opportunity to obtain estimates of cost-effectiveness for prehospital
thrombolysis, which is lacking for the United Kingdom.

The authors also state “we might expect two extra lives saved per
100 patients treated.” This is an important statement and more detail of
how this estimate was derived would have been helpful. We suspect this is
from the meta-analysis of the results from trials comparing prehospital
versus inhospital thrombolysis for AMI by Boersma et al.2 Importantly,
this health benefit of a one-hour reduction in the treatment delay must be
within three hours from symptom onset. The authors describe collecting
“times of onset of symptoms” but do not present their results. This is an
important omission as the mortality benefit of thrombolysis is directly
related to treatment delay from the time of the onset of symptoms. The
health benefit of a one-hour reduction in treatment delay will be
considerably smaller if the total delay is longer than three hours.2

It should be stressed that it is necessary to ensure through audit
that all aspects of the care pathway for AMI are being performed optimally
and therefore the maximum possible health benefit is being achieved prior
to the introduction of a prehospital thrombolysis service.

We believe that the emphasis of research in this area should now move
to establishing and evaluating cost effective models of care for
prehospital thrombolysis rather than feasibility studies. Such evaluations
should include consideration of the effects of different treatment
population characteristics for example age distribution and ambulance
travelling times. The recent Department of Health review of prehospital
thrombolysis is one step in this direction but more detail is needed to
assist implementation.3 It also needs to be acknowledged that proposals
for a prehospital thrombolysis service will be competing against other
forms of healthcare and interventions in the prioritisation process of
Primary Care Trusts. The costs and effectiveness of such a service will
need to be clear and robust in order to achieve long-term funding.

M Kroese

specialist registrar in public health medicine

Public Health Genetics Unit, Cambridge

markk@srl.cam.ac.uk

D Kanka

Director of Public Health

South Cambridgeshire Primary Care Trust

David.Kanka@southcambs-pct.nhs.uk

Competing interests: none

References

1 Pedley DK, Bissett K, Connolly EM, et al. Prospective observational
cohort study of time saved by prehospital thrombolysis for ST elevation
myocardial infarction delivered by paramedics. BMJ 2003. 327:22-26.

2 Boersma E, Maas AC, Deckers JW, Simoons ML. Early thrombolytic
treatment in acute myocardial infarction: reappraisal of the golden hour.
Lancet 1996;348:771-775.

3 Department of Health. Review of early thrombolysis Faster and
better treatment for heart attack patients. 1-16. 6-2003. London.

Competing interests:  
None declared