Long-Term Cognitive Decline After Coronary Artery Bypass Grafting: is Off-Pump Surgery Beneficial?

Background:

Coronary artery bypass surgery is associated with postoperative cognitive decline, which has largely been attributed to the use of cardiopulmonary bypass (CPB). A large recent study by Newman et al demonstrated that the incidence of cognitive decline was 24% at six months after surgery, but it increased to 42% at five years. In the recently conducted Octopus Randomized Trial, cognitive decline at three months after surgery was present in 29% of the patients operated with CPB. In the patients operated without CPB, the incidence was 21%, i.e. only slightly better.

Hypothesis:

Improvement of cognitive outcome by avoiding cardiopulmonary bypass will become more apparent five years after surgery, compared to three months after surgery.

Study objectives:

The objective of the present study is to compare the effect of coronary bypass surgery with and without cardiopulmonary bypass on cognitive and clinical outcome, five years after surgery.

Methods:

The 281 participants of the Octopus Study, who were operated on between March 1998 and August 2000 and randomized to off-pump or on-pump coronary bypass surgery, will be invited for an additional assessment of their cognitive and clinical status and quality of life, five years after surgery. Patients will undergo a battery of ten neuropsychologic tests to determine their cognitive status. Clinical status will be assessed by an interview. Questionnaires will be used to measure quality of life.

Inclusion criteria

• indication for (first-time) coronary artery bypass surgery
• off-pump CABG considered technically possible

Exclusion criteria

• concomitant valve surgery
• unable to complete neuropsychological testing
• life expectancy less than 1 year