Original article
Development and External Validation of an Early Prognostic Model for Survivors of Out-of-hospital Cardiac ArrestDesarrollo y validación externa de un modelo pronóstico precoz para supervivientes de una parada cardiaca extrahospitalaria

https://doi.org/10.1016/j.rec.2018.05.022Get rights and content

Abstract

Introduction and objectives

Despite therapeutic hypothermia, unconscious survivors of out-of-hospital cardiac arrest have a high risk of death or poor neurologic function. Our objective was to assess the usefulness of the variables obtained in the early moments after resuscitation in the prediction of 6-month prognosis.

Methods

A multicenter study was performed in 3 intensive cardiac care units. The analysis was done in 153 consecutive survivors of out-of-hospital cardiac arrest who underwent targeted temperature management between January 2007 and July 2015. Significant neurological sequelae at 6 months were considered to be present in patients with Cerebral Performance Categories Scale > 2. An external validation was performed with data from 91 patients admitted to a third hospital in the same time interval.

Results

Among the 244 analyzed patients (median age, 60 years; 77.1% male; 50.0% in the context of acute myocardial ischemia), 107 patients (43.8%) survived with good neurological status at 6 months. The prediction model included 5 variables (Shockable rhythm, Age, Lactate levels, Time Elapsed to return of spontaneous circulation, and Diabetes – SALTED) and provided an area under the curve of 0.90 (95%CI, 0.85-0.95). When external validation was performed, the predictive model showed a sensitivity of 73.5%, specificity of 78.6%, and area under the curve of 0.82 (95%CI, 0.73-0.91).

Conclusions

A predictive model that includes 5 clinical and easily accessible variables at admission can help to predict the probability of survival without major neurological damage following out-of-hospital cardiac arrest.

Resumen

Introducción y objetivos

A pesar del uso de la hipotermia terapéutica, los pacientes recuperados tras sufrir una parada cardiaca extrahospitalaria tienen un elevado riesgo de muerte o deterioro neurológico grave. Se analizaron la utilidad de diversas variables disponibles al ingreso hospitalario para predecir su evolución a los 6 meses.

Métodos

Se desarrolló un estudio multicéntrico en 3 unidades de cuidados intensivos cardiacos. El análisis se realizó sobre 153 pacientes ingresados en dos centros tras sufrir una parada cardiaca extrahospitalaria recuperada y que se trataron con control de temperatura, entre enero de 2007 y julio de 2015. Se consideraron secuelas neurológicas significativas si la Cerebral Performance Categories Scale > 2 a los 6 meses. Los resultados se validaron externamente con los datos procedentes de otros 91 pacientes ingresados en un tercer hospital, durante el mismo periodo de tiempo.

Resultados

Del total de 244 pacientes (mediana de edad, 60 años; 77,1% varones; 50,0% en el contexto de isquemia miocárdica aguda), 107 (43,8%) sobrevivieron a los 6 meses con una evolución neurológica favorable. Se calculó un modelo predictivo que incluyó 5 variables (primer ritmo, edad, lactato al ingreso, tiempo hasta recuperación de circulación espontánea y diabetes), con un área bajo la curva de 0,90 (IC95%, 0,85-0,95). Cuando se realizó la validación externa del modelo, la sensibilidad fue de 73,5%, con una especificidad de 78,6% y un área bajo la curva de 0,82 (IC95%, 0,73-0,91).

Conclusiones

Un modelo predictivo que incluye cinco variables disponibles en el momento de ingreso de pacientes recuperados tras sufrir una parada cardiaca extrahospitalaria puede ayudar a predecir la probabilidad de supervivencia libre de secuelas neurológicas graves en el seguimiento.

Section snippets

INTRODUCTION

Out-of-hospital cardiac arrest (OHCA) is a major health problem, which affects between 76 and 110 patients per 100 000 inhabitants yearly. Despite the major efforts in treating these patients and the high costs involved,1 long-term prognosis remains poor, as two-thirds of resuscitated patients die before hospital discharge.2 Moreover, long-term mortality remains high after discharge, especially in patients > 65 years, of which nearly 1 in 3 die within the first year.3 In patients with OHCA due

Setting and Study Population

A multicenter prospective study was performed in 3 academic hospitals in Spain. We included consecutive adult survivors of nontraumatic OHCA admitted to the intensive cardiac care unit who underwent TTM between January 2007 and July 2015 (only patients who survived until hospital admission and who underwent TTM where analyzed). The overall population was divided into 2 groups: data from patients admitted at 2 hospitals (Hospital General Universitario Gregorio Marañón and Hospital Universitario

Study Population

Between January 2007 and July 2015, 300 patients were admitted to our institutions with a diagnosis of OHCA, persistent Glasgow Coma Scale score ≤ 8, and were treated with TTM. A total of 56 patients were excluded from the analysis: 33 had no lactate measurement at admission, 16 no information regarding time from collapse to ROSC, and 7 were lost to follow-up. Thus, 244 patients were available for analysis. As previously described, the population was divided into 2 groups: 153 patients in the

DISCUSSION

The present study, performed in comatose patients admitted after OHCA treated with therapeutic hypothermia, describes and validates a predictive model designed from variables obtained at admission to estimate the probability of survival without major neurological damage at 6 months. Overall survival to hospital discharge was 47%, whereas our cumulative survival with good neurological outcome at 6 months was 44%. These data are consistent with previous reported studies that include patients

CONCLUSIONS

A predictive model based on 5 clinical and easily accessible variables at admission (Shockable rhythm, Age, Lactate levels, Time Elapsed to ROSC, and Diabetes – SALTED) can help to predict the probability of survival without major neurological damage following OHCA.

FUNDING

Supported in partly by the Spanish Ministry of Science and Innovation (Red RIC, PLE2009-0152), the Spanish Health Research Fund (PI14/00857) and Spanish Society of Cardiology (Clinical Research Grants 2015).

CONFLICTS OF INTEREST

None declared.

WHAT IS KNOWN ABOUT THE TOPIC?

  • Unconscious survivors of OHCA have a high risk of death or poor neurologic function.

  • Neurological damage is frequent and plays a key role limiting the prognosis of these patients.

  • Although TTM is recommended to improve prognosis, it also limits the role of neurological examination and makes the determination of prognosis in the early moments after resuscitation a difficult task.

WHAT DOES THIS STUDY ADD?

  • The SALTED is a predictive model based on 5 clinical and easily accessible variables at admission

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