Immature/total granulocyte ratio improves early prediction of neurological outcome after out-of-hospital cardiac arrest: the MyeloScore study

Abstract

Background: Elevation of the immature/total granulocyte (I/T-G) ratio has been reported after out-of-hospital cardiac arrest (OHCA). Our purpose here was to evaluate the prognostic significance of the I/T-G ratio and to investigate whether the I/T-G ratio improves neurological outcome prediction after OHCA.

Methods: This single-center prospective cohort study included consecutive immunocompetent patients admitted to our intensive care unit over a 3-year period (2012-2014) after successfully resuscitated OHCA. The I/T-G ratio was determined in blood samples collected at admission.

Results: We studied 204 patients (77 % male, median age, 58 [48-67] years), of whom 64 % had a suspected cardiac cause of OHCA, 62 % died in the unit, and 31.5 % survived with good cerebral function. Independent outcome predictors by multivariate analysis were age, first shockable rhythm, bystander-initiated resuscitation, and I/T-G ratio. Compared to the model computed without the I/T-G ratio, the model with the ratio performed significantly better [areas under the ROC curves (AUCs), 0.78 vs. 0.83, respectively; P = 0.04]. These items were used to develop the MyeloScore equation: ([0.47 × I/T-G ratio] + [0.023 × age in years]) - 1.26 if initial VF/VT - 1.1 if bystander-initiated CPR. The MyeloScore predicted neurological outcomes with similar accuracy to the previously reported OHCA score (0.83 and 0.85, respectively; P = 0.6). The ROC-AUC was 0.84, providing external validation of the MyeloScore.

Conclusions: The I/T-G ratio independently predicts neurological outcome after OHCA and, when added to other known risk factors, improves neurological outcome prediction. The clinical performance of the MyeloScore requires evaluation in a prospective study.

Keywords: Biological markers; Disability; Out-of-hospital cardiac arrest; Prognosis; Survival.

Fig. 1

Study flowchart. *6 died early after admission, 4 of them had cardiac arrest recurrence, and 2 of them presented a refractory postcardiac arrest shock (n = 2). All of them died at the admission to ICU, before blood samples were drawn. These patients were not included in the analysis

Fig. 2

a Receiver operating characteristics curves for MyeloScore model with and without I/T-G ratio. b Receiver operating characteristics curves for MyeloScore, OHCA score, and CAHP score calculated at ICU admission