Evaluation of the vasoactive-inotropic score, mid-regional pro-adrenomedullin and cardiac troponin I as predictors of low cardiac output syndrome in children after congenital heart disease surgery

Abstract

Objective

To determine the predictive value of the inotropic score (IS) and vasoactive-inotropic score (VIS) in low cardiac output syndrome (LCOS) in children after congenital heart disease surgery involving cardiopulmonary bypass (CPB), and to establish whether mid-regional pro-adrenomedullin (MR-proADM) and cardiac troponin I (cTn-I), associated to the IS and VIS scores, increases the predictive capacity in LCOS.

Design

A prospective observational study was carried out.

Setting

A Paediatric Intensive Care Unit.

Patients

A total of 117children with congenital heart disease underwent CPB. Patients were divided into two groups: LCOS and non-LCOS.

Interventions

The clinical and analytical data were recorded at 2, 12, 24 and 48 h post-CPB. Logistic regression was used to develop a risk prediction model using LCOS as dependent variable.

Main outcome measures

LCOS, IS, VIS, MR-proADM, cTn-I, age, sex, CPB time, PIM-2, Aristotle score.

Results

While statistical significance was not recorded for IS in the multivariate analysis, VIS was seen to be independently associated to LCOS. On the other hand, VIS > 15.5 at 2 h post-CPB, adjusted for age and CPB timepoints, showed high specificity (92.87%; 95%CI: 86.75–98.96) and increased negative predictive value (75.59%, 95%CI: 71.1–88.08) for the diagnosis of LCOS at 48 h post-CPB. The predictive power for LCOS did not increase when VIS was combined with cTn-I >14 ng/ml at 2 h and MR-proADM >1.5 nmol/l at 24 h post-CPB.

Conclusions

The VIS score at 2 h post-CPB was identified as an independent early predictor of LCOS. This predictive value was not increased when associated with LCOS cardiac biomarkers. The VIS score was more useful than IS post-CPB in making early therapeutic decisions in clinical practice post-CPB.

Resumen

Objetivo

Estudiar el valor predictivo de la escala inotrópica (IS) y la escala vasoactiva-inotrópica (VIS) en el síndrome de bajo gasto cardiaco (SBGC) en niños poscirugía de cardiopatías congénitas mediante bypass cardiopulmonar (BCP). Determinar si adrenomedulina (MR-proADM) y troponina cardiaca-I (cTn-I) asociadas con IS y VIS incrementan su capacidad predictora de SBGC.

Diseño

Estudio prospectivo y observacional.

Ámbito

Cuidados intensivos pediátricos.

Pacientes

Ciento diecisiete pacientes pediátricos con cardiopatías congénitas corregidos mediante BCP, clasificados en función de la presencia o no de SBGC.

Intervenciones

Los datos analíticos y clínicos se midieron a las 2, 12, 24 y 48 h post-BCP. Las principales variables se analizaron mediante regresión logística multivariante, considerando SBGC como variable dependiente.

Variables de interés principales

SBGC, IS, VIS, MR-proADM, cTn-I, edad, sexo, BCP, PIM-2 y escala Aristóteles.

Resultados

El IS no alcanzó significación estadística en el estudio multivariante; sin embargo, el VIS se asoció independientemente a SBGC. El VIS > 15,5 a las 2 h del ingreso en CIP, ajustado por edad y tiempo de CEC, muestra alta especificidad (92,87%; IC 95%: 86,75-98,96%) y alto valor predictivo negativo (75,59%; IC 95%: 71,10-88,08) para predecir SBGC a las 48 h post-BCP. La capacidad predictora no se incrementa al incorporar cTn-I > 14 ng/ml a las 2 h y ADM > 1,5 nmol/l a las 24 h del postoperatorio.

Conclusiones

El VIS a las 2 h post-BCP es un predictor independiente precoz de SBGC. Este valor no se incrementa al asociarse biomarcadores cardiacos de LCOS. La escala de VIS fue más útil que la escala de IS en la toma de decisiones terapéuticas tras la cirugía cardiaca.

Introduction

Current research focuses on preventing mortality and reducing the risk of morbidity in children who undergo congenital heart disease (CHD) surgery with cardiopulmonary bypass (CPB). In order to accomplish these objectives, it is essential to monitor the diverse variables influencing these potential outcomes, such as the levels of inotrope score (IS) and/or of vasoactive-inotropic score (VIS), and their prognostic value in the post-operative period.1, 2, 3 Nevertheless, the association between VIS and the post-operative course of the patient remains controversial.

Wermousky et al.¹ have quantified the degree of inotrope support received by neonates after surgical repair of transposition of the great arteries, and have reported that the maximum IS within the first 48 h was an indicator of poor prognosis, of higher incidence of prolonged mechanical circulatory support, renal replacement therapy, neurological damage, of cardiac arrest and death. In addition to this, IS was also associated with longer duration of mechanical ventilation (MV), paediatric intensive care unit (PICU) and hospital stay.² On the other hand, other authors have been unable to establish an association between VIS and the early post-operative outcomes in neonates who underwent heart surgery with CPB.⁴ Therefore, elevated VIS levels could not be associated with prolonged MV duration and PICU stay. Likewise, these authors have found that low cardiac output syndrome (LCOS) was not associated with MV duration or length of PICU stay.

Neonates undergoing CPB are more likely to present increased risk of morbimortality compared with other age groups. Thereby they might be considered a special group. Gaies et at.⁵ have studied 391 children (only one-third were neonates) who underwent CHD surgical repair, in which VIS > 15 within the first 24 h post-operatively was considered empirically high. A high VIS level was strongly associated with mortality at 30 days following surgery, with incidence of cardiac arrest, need for mechanical circulatory support, dialysis, neurological damage, MV duration and length of PICU stay. In another work on VIS as a short-term outcome biomarker, a maximal VIS on the second post-operative day predicted adverse outcomes in adolescents following cardiac surgery.⁶

There are other studies regarding the paediatric population that centre on cardiac biomarkers, such as the β-type natriuretic peptide (BNP),⁷ mid-regional pro-atrial natriuretic peptide (MR-proANP),⁸ pro-adrenomedulina (MR-proADM),⁹ cardiac troponin-I (cTn-I)¹⁰ and copeptin¹¹ as early predictors of LCOS to monitor the post-operative period after CHD surgery with CPB. To date, there are no published studies that relate IS, VIS and cardiac biomarkers levels with the prediction of LCOS in children during the post-operative period after CHD surgery requiring CPB.

In order to address this knowledge gap, we have performed a study of CHD children to evaluate whether IS and VIS scores improve the predictive power for LCOS.IS and VIS have been estimated in the immediate post-operative period and during LCOS development and have been associated with the cardiac markers above mentioned predictors of LCOS in the paediatric population. These could be useful in aiding in therapeutic decision-making in clinical practice after CPB, and in improving the prognosis of the patient.