Influences of pre-, peri- and postoperative risk factors in neonatal cardiac surgery on neurodevelopmental status in preschool-age children

Objective

Neurodevelopmental outcome in preschool-age after neonatal arterial switch operation, in relation to prospectively evaluated cerebral risk factors, including durations of the support strategies and serum levels of the marker enzyme neuron-specific enolase is assessed.

Methods

Thirty-three unselected children operated on as neonates with combined deep hypothermic circulatory arrest and low flow cardiopulmonary bypass were examined at an age of 3.0–4.6 years [3.6 ± 0.5 (mean ± standard deviation)]. The control group for developmental outcome consisted of 32 age-matched healthy children, who were 3.0–4.8 years [3.8 ± 0.6 (mean ± standard deviation)] of age. Evaluation of socioeconomic status and a standardised test comprising all areas of child development (Vienna developmental test), including scores of motor and cognitive functions, perception, language, learning and behaviour, were carried out in patients and controls, and clinical neurological status was assessed in patients. Results of patients were related to those of the control group and to pre-, peri-, and postoperative cerebral risk factors of the control group and to pre-, peri-, and postoperative cerebral risk factors as described in the context.

Results

Neurological impairment was more frequent (6.1%) than in the normal population. Compared with published norms, complete developmental score and the subtests for motor function, visual perception and visual motor integration, learning and memory, cognitive function, language, and socioemotional functions were not different. Compared with the control group, complete developmental score, cognitive score and language were reduced (P < 0.01), but socioeconomic status was significantly lower in the patient group (P = 0.0001). Motor function was weakly, but significantly inversely related to the duration of circulatory arrest (Pearson correlation coefficient -0.37; P = 0.049), but not to the duration of bypass. The other developmental parameters were not related to the duration of the support techniques. Serum levels of the biochemical marker neuron-specific enolase, although significantly elevated at the end of bypass (P = 0.0002) and 4 h after surgery (P = 0.0012) compared with preoperative values, were not correlated to developmental test results. No correlation was found between the test results and the following cerebral risk factors: protracted birth, perinatal asphyxia, peri- and postoperative cardiocirculatory insufficiency, enhanced cerebral echogenicity in the choroid plexus and ventricular system, and clinical seizures.

Conclusions

Neonatal arterial switch operation with combined circulatory arrest and low flow bypass is associated with increased neurological impairment. Developmental status, based on formal testing of motor, cognitive, language and behavioural functions, however, was not found to be different from a that in normal population. Outstanding results in our control group are probably related to differences in socioeconomic status. Perioperative serum levels of the neuron-specific enolase in neonates, in our experience, are not a valid marker with respect to later developmental outcome.