Identifying Patients at Risk for Prehospital Sudden Cardiac Arrest at the Early Phase of Myocardial Infarction: The e-MUST Study (Evaluation en Médecine d'Urgence des Stratégies Thérapeutiques des inf
Circulation. 2016 Dec 20;134(25):2074-2083. Epub 2016 Oct 28. Am Heart J. 2015 Aug;170(2):339-345.e1. doi: 10.1016/j.ahj.2015.03.022. Epub 2015 May 9. Karam N1, Bataille S2, Marijon E2, Giovannetti O2, Tafflet M2, Savary D2, Benamer H2, Caussin C2, Garot P2, Juliard JM2, Pires V2, Boche T2, Dupas F2, Le Bail G2, Lamhaut L2, Laborne F2, Lefort H2, Mapouata M2, Lapostolle F2, Spaulding C2, Empana JP2, Jouven X2, Lambert Y2; e-MUST Study Investigators.
In-hospital mortality of ST-segment-elevation myocardial infarction (STEMI) has decreased drastically. In contrast, prehospital mortality from sudden cardiac arrest (SCA) remains high and difficult to reduce. Identification of the patients with STEMI at higher risk for prehospital SCA could facilitate rapid triage and intervention in the field.
Using a prospective, population-based study evaluating all patients with STEMI managed by emergency medical services in the greater Paris area (11.7 million inhabitants) between 2006 and 2010, we identified characteristics associated with an increased risk of prehospital SCA and used these variables to build an SCA prediction score, which we validated internally and externally.
In the overall STEMI population (n=8112; median age, 60 years; 78% male), SCA occurred in 452 patients (5.6%). In multivariate analysis, younger age, absence of obesity, absence of diabetes mellitus, shortness of breath, and a short delay between pain onset and call to emergency medical services were the main predictors of SCA. A score built from these variables predicted SCA, with the risk increasing 2-fold in patients with a score between 10 and 19, 4-fold in those with a score between 20 and 29, and >18-fold in patients with a score ≥30 compared with those with scores <10. The SCA rate was 28.9% in patients with a score ≥30 compared with 1.6% in patients with a score ≤9 (P for trend <0.001). The area under the curve values were 0.7033 in the internal validation sample and 0.6031 in the external validation sample. Sensitivity and specificity varied between 96.9% and 10.5% for scores ≥10 and between 18.0% and 97.6% for scores ≥30, with scores between 20 and 29 achieving the best sensitivity and specificity (65.4% and 62.6%, respectively).
At the early phase of STEMI, the risk of prehospital SCA can be determined through a simple score of 5 routinely assessed predictors. This score might help optimize the dispatching and management of patients with STEMI by emergency medical services.