The effect of leucocyte-depleting arterial line filters on cerebral microemboli and neuropsychological outcome following coronary artery bypass surgery

Abstract

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