A clinical study of the effect of leucocyte depleting arterial line filtration on cerebral microemboli and neuropsychological outcome after coronary artery bypass surgery

Abstract

OBJECTIVE: A randomised clinical trial sought evidence as to whether leucocyte depleting arterial line filters had any effect on intra- operative cerebral microemboli and post- operative neuropsychological outcome in non emergency patients undergoing coronary artery bypass (CABG) surgery.METHODS: One hundred and ninety -two patients were randomised to the use of a Pall LG -6 leucocyte depleting (test) filter or either an Avecor Affinity or Pall AV -6 control filter. Cerebral microemboli during surgery were recorded by transcranial Doppler monitor over the right middle cerebral artery. Evidence of cerebral impairment was obtained by comparing patients' performance in a neuropsychological test battery (9 tests) administered 6 -8 weeks post-operatively with their pre-operative scores.RESULTS: The groups proved well balanced in pre- operative variables. During cardiopulmonary bypass the median number and range of microemboli was 15 (3 -180) in the leucocyte depleting group compared to 67 (5 -846) and 55 (2 -773) for the Avecor and AV6 groups respectively (p <0.0001). One hundred and sixty -one patients completed all the neuropsychological tests. The leucocyte depleting group showed better post- operative performance in all but one of the nine tests although the difference in a total change score did not reach significance (p = 0.07, 1 tailed t test).CONCLUSION: Leucocyte depleting filtration during CABG reduced the number of cerebral microemboli recorded by transcranial Doppler and showed a strong trend towards improving neuropsychological performance post -operatively. These findings suggest that the use of such filters in CABG surgery may offer increased neuroprotection.