Background
Available data suggest worse cognitive performance and increased risk of cognitive decline in patients with coronary vascular disease in comparison to controls. However, a recent review showed that data were limited to a few case:control and cohort studies of stable coronary vascular disease and all but one study did not exclude co-existent stroke. Case:control studies may be subject to selection bias in that controls may be particularly healthy volunteers or be selected using inappropriately strict criteria, and cases may themselves be unrepresentative of the total population with the disease. Cohort studies may be similarly affected by volunteer bias. Furthermore, the high prevalence of vascular risk factors in patients with coronary vascular disease should result in an association between acute coronary syndrome (ACS) and cognitive dysfunction over and above any effects of the event itself since vascular risk factors are well recognised predictors of cognitive decline. None of the previous studies specifically matched cases and controls for vascular risk factors.
It might therefore be more informative to compare cognitive outcomes in ACS patients with transient ischaemic attack (TIA) and stroke patients in whom there is a similar high prevalence of vascular risk factors. Although ACS patients have been thought to be at risk of poor cognitive outcomes through indirect effects of cardiac dysfunction on the brain including hypoperfusion, cognition might be expected to be worse after TIA and stroke owing to the powerful effect of the direct brain insult and more cerebrovascular pathology.
We therefore performed a study of cognitive outcome including cognitive domain profile >1 year after ACS versus TIA and minor stroke in a population based study of all acute vascular events.