Pump Is Irrelevant to Cardiac or Cognitive Benefits After Five Years

February 20, 2007

UTRECHT, The Netherlands -- In low-risk patients undergoing CABG surgery, spurning the cardiopulmonary bypass pump had no effect on five-year cognitive or cardiac outcomes, according to Dutch researchers.

UTRECHT, The Netherlands, Feb. 20 -- In low-risk patients having CABG surgery, spurning the cardiopulmonary bypass pump had no effect on five-year cognitive or cardiac outcomes, according to Dutch researchers.

Earlier results from the Dutch Octopus Study, a multicenter controlled trial, which enrolled patients from 1998 to 2000, had found that off-pump CABG led to a trend toward better cognitive outcomes three months after the procedure.

However, the difference disappeared at 12 months, and was nonexistent at five years, Diederik van Dijk, M.D., Ph.D., of the University Medical Center Utrecht here, and colleagues, reported in the Feb. 21 issue of the Journal of the American Medical Association.

To compare five-year cardiac and cognitive outcomes, the researchers assessed 281 low-risk patients having CABG surgery in the Octopus Study.

Of the patients in whom an off-pump procedure was deemed technically feasible, 142 (mean age 61.7) were randomized to off-pump CABG and 139 (mean age 60.8) to on-pump surgery.

The patients were recruited from three centers in the Netherlands, and 16 surgeons participated. Five-year cognitive status was determined by a psychologist blinded to treatment allocation who administered 10 standardized validated neuropsychological tests.

After five years, 130 patients were alive in each group. Cognitive outcomes could be determined in 123 off-pump and 117 on-pump patients.

The standard definition of cognitive decline was a 20% performance decline in 20% of the neuropsychological test variables.

Using this definition, 62 (50.4%) of 123 in the off-pump group and 59 (50.4%) of 117 in the on-pump group had cognitive decline (absolute difference, 0%; 95% confidence interval [CI], ?12.7% to 12.6%; P

Cohort studies have indicated that off-pump CABG surgery may prevent strokes, but a sufficiently powered randomized study to confirm this would require a larger patient sample.

Finally, they said, because of the small number of participants in the present study, the absolute differences in the outcome measures were associated with wide confidence intervals. Therefore, significant differences in outcome may have been missed.

In conclusion, Dr. van Dijk and his colleagues wrote that in low-risk patients undergoing CABG surgery, avoiding the use of cardiopulmonary bypass did not benefit five-year cognitive or cardiac outcomes. These results, the researchers said, suggest that factors other than cardiopulmonary bypass may be responsible for cognitive decline, such as anesthesia and the generalized inflammatory response associated with major surgical procedures.

It is also possible, they said, that the cognitive decline observed at five years is not caused by the operation but reflects natural aging.