A prospective clinical study of cerebral microemboli and neuropsychological outcome comparing vent-line and auto-venting arterial line filters: both filters are equally safe

Abstract

Microemboli are the main implicated cause of neuropsychological (NP) impairment after cardiac surgery. This prospective clinical trial compared the effect of an auto-venting arterial line filter on intraoperative cerebral microemboli and NP outcome compared to an arterial line filter with a vent line, in patients undergoing elective coronary artery bypass graft (CABG) surgery. One hundred and ten patients received either an Avecor Affinity (n =73) or Pall AV-6 (n =37) control filter. Cerebral microemboli during cardiopulmonary bypass were recorded by transcranial Doppler monitoring of the right middle cerebral artery. Evidence of cerebral impairment was obtained by comparing patients' performance in a NP test battery (nine tests) administered 6-8 weeks postoperatively with their preoperative scores. During cardiopulmonary bypass, the median number and range of microemboli were 67 (5-846) and 55 (2-773) for the Avecor and AV-6 groups, respectively (p = 0.47). There was no difference in NP outcome. There is no difference in the filtering ability of vent-line and auto-vent filters as assessed by cerebral microemboli. This, together with the similar NP outcome, suggests that both types of filter are equally safe for clinical use.