Coronary artery bypass graft (CABG) surgery often results in cognitive decline or even stroke. Such a decline can affect between 3 per cent of patients and up to half, depending on the patient and when the cognitive assessment takes place.

Overall, around 23 per cent of all CABG patients will suffer some decline in their mental faculties.

Surgeons believe that this mental decline after surgery is due to the use of CPB (cardiopulmonary bypass) or ‘on-pump procedures’, rather than the graft itself, although studies have produced conflicting findings.

A new Dutch study has looked at 248 patients who were undergoing their first CABG procedure. Patients were assigned to have surgery with either off- or on-pump assistance by the researchers, based at the University Medical Centre in Utrecht.

Cognitive decline occurred in 21 per cent of the ‘off-pump’ group and 29 per cent of the ‘on-pump’ group after three months.

However, by 12 months, the gap between the groups had narrowed to within 3 per cent, with 30.8 per cent of the ‘off-pumps’ and 33.6 per cent of the ‘on-pumps’ showing cognitive decline.

The study also found no significant differences between the two groups in terms of quality of life, or stroke rate or mortality (JAMA, 2002; 287: 1405-12).