Measurement of cognitive outcome and quality of life in congenital heart disease

Since the 1970s, the improvement of diagnostic tools and the success of cardiac surgery have dramatically changed the natural history of complex congenital heart diseases. The number of newborns who have survived through infancy, reaching adolescence and adult age, and becoming socially integrated has increased.1,2 Consequently, nowadays determinants of late surgical results are evaluated by not only using survival as a measure, which was of major importance for surgeons and cardiologists up until the 1980s, but also by freedom from negative clinical events together with improvements in quality of life. Various guidelines,3 based on long post-surgical follow-up and knowledge of sequelae and complications, codify clinical evaluation of adult patients with a congenital heart defect. It is more difficult to codify the assessment of cognitive performance and quality of life. This article reviews the mechanisms of cerebral damage in patients with congenital heart disease, the definition and measurement of quality of life, assessment of the psychological profile, and definition of cognitive functions and their measurement. The aetiological factors that modify the integrity of the brain can be related to the following: congenital heart defect, duration of haemodynamic and haematologic effects of the disease, hypoxic–ischaemic insult secondary to hypothermic cardiopulmonary bypass, and cardiac arrest during surgery.4 In patients with chromosomal abnormalities, particularly trisomy 21 and deletion on chromosome 22q11 (Di George syndrome), the neurodevelopmental outcome seems to be related more to genetic influence than to the associated cardiac defect. Congenital heart disease characterised by hypoxaemia and cyanosis with polycythemia and microcytosis are at risk of cerebral accident, particularly during blue spells (cyanosis) or when blood viscosity is increased. Severe metabolic acidosis secondary to hypoxaemia strengthens the negative effects of ischaemia on glial and cerebral vascular cells due to the action of free radicals on membrane lipids and proteins. …