Abstract
Background
Treatment times for primary percutaneous coronary intervention frequently exceed the
recommended maximum delay. Automated “physicianless” systems of prehospital cardiac
catheterization laboratory (CCL) activation show promise, but have been met with resistance
over concerns regarding the potential for false positive and inappropriate activations
(IAs).
Methods
From 2010 to 2015, first responders performed electrocardiograms (ECGs) in the field
for all patients with a complaint of chest pain or dyspnea. An automated machine diagnosis
of “acute myocardial infarction” resulted in immediate CCL activation and direct transfer
without transmission or human reinterpretation of the ECG prior to patient arrival.
Any activation resulting from a nondiagnostic ECG (no ST-elevation) was deemed an
IA, whereas activations resulting from ECG's compatible with ST-elevation myocardial
infarction but without angiographic evidence of a coronary event were deemed false
positive. In 2012, the referral algorithm was modified to exclude supraventricular
tachycardia and left bundle branch block.
Results
There were 155 activations in the early cohort (2010-2012; prior to algorithm modification)
and 313 in the late cohort (2012-2015). Algorithm modification resulted in a 42% relative
decrease in the rate of IAs (12% vs 7%; P < 0.01) without a significant effect on treatment delay.
Conclusions
A combination of prehospital automated ST-elevation myocardial infarction diagnosis
and “physicianless” CCL activation is safe and effective in improving treatment delay
and these results are sustainable over time. The performance of the referral algorithm
in terms of IA and false positive is at least on par with systems that ensure real-time
human oversight.
Résumé
Contexte
Le délai d’intervention coronarienne percutanée (ICP) primaire dépasse souvent le
délai maximal recommandé pour ce type d’intervention. Les systèmes d’activation de
laboratoire de cathétérisme cardiaque (LCC) préhospitalier « sans médecin » semblent
prometteurs, mais font face à la résistance du milieu médical qui craint la possibilité
de « faux positifs » et d’activation inappropriée (AI).
Méthodes
Entre 2010 et 2015, les premiers répondants ont effectué un électrocardiogramme (ECG)
préhospitalier à tous les patients se plaignant de douleurs thoraciques ou de dyspnée.
Un diagnostic automatisé d'« infarctus aigu du myocarde » entraînait immédiatement
l'activation du LCC et le transfert direct du patient sans transmission de message
ou relecture de l'ECG par un humain. Toute activation consécutive à un ECG ne permettant
pas d'établir un diagnostic (sans sus-décalage du segment ST) était considérée être
une AI, tandis qu'une activation résultant d'un ECG indiquant possiblement un infarctus
du myocarde avec sus-décalage du segment ST, mais sans preuve angiographique d'événement
coronarien, était considérée être un « faux positif ». En 2012, l'algorithme de référence
a éé modifié pour exclure la tachycardie supraventriculaire et le bloc de branche
bilatéral.
Résultats
Il y a eu 155 activations dans la première cohorte (2010-2012; avant la modification
de l'algorithme) et 313 dans la dernière cohorte (2012-2015). La modification de l’algorithme
susmentionnée a entraîné une diminution relative du taux d’AI de l’ordre 42 % (12
% vs 7 %; p < 0,01), sans pour autant qu’il y ait d’incidence significative sur le délai d’intervention.
Conclusions
Il a été déterminé que la combinaison du diagnostic préhospitalier automatisé d’infarctus
du myocarde avec sus-décalage du segment ST et d’activation de LCC « sans médecin
» constituait un moyen à la fois sûr et efficace d’améliorer le délai d’intervention
chez les patients, les résultats obtenus ayant été durables au fil du temps. En ce
qui concerne les AI et les « faux positifs », le rendement du système automatisé a
été considéré au moins équivalent à celui des modalités d’intervention avec surveillance
humaine.
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Article info
Publication history
Published online: October 20, 2016
Accepted:
October 9,
2016
Received:
July 29,
2016
Footnotes
See page 153 for disclosure information.
Identification
Copyright
© 2016 Canadian Cardiovascular Society. Published by Elsevier Inc. All rights reserved.
