We evaluated the hypothesis that if hypotension or hypoperfusion is a major cause of border zone brain infarction, infarcts following cardiac surgery will be likely to be located in the vascular border zone areas, whereas cerebral perfusion would be lower compared with non-border zone infarcts. Ten of 37 patients with brain infarction following cardiac surgery had an infarct in one of the vascular border zones on CT. Haemodynamical characteristics and clinical features did not differ between border zone infarcts and remaining infarct subgroups. We conclude that compared with stroke series brain infarcts following cardiac surgery are more frequently located in one of the vascular border zone areas, but peri-operative haemodynamic compromise alone does not sufficiently explain this difference. Other possible mechanisms, such as showers of (micro-)emboli, should also be considered.