Abstract for presentation at The Australian and New Zealand Association of Neurologists Annual Scientific Meeting 2007

Stroke and cognitive decline in cardiac valve surgery

  • Dr Alan Barber, Auckland City Hospital and the University of Auckland, New Zealand
  • Ms Sylvia Hach, University of Auckland, New Zealand
  • Dr Paget Milsom, Auckland City Hospital, New Zealand
  • Linda Ross, Auckland City Hospital, New Zealand
  • Prof Alan Merry, University of Auckland, New Zealand
  • A/Prof Lynette Tippett, University of Auckland, New Zealand

    • Purpose: Coronary artery bypass graft (CABG) surgery is associated with fatal brain injury (2%), stroke (1-7%), new ischemic brain lesions (30%) and cognitive decline (40-80%). Our aims were to determine the frequency of these endpoints in patients with cardiac valve surgery and determine whether post-operative cognitive impairment is associated with new ischemic change on diffusion-weighted magnetic resonance imaging (DWI).
    Methods: Thirty five patients (24 men, mean age 60 (SD 13) years) had neurological and MRI studies 24 hours before, and again at 72 hours and 6 weeks after, elective cardiac valve surgery. Six patients also had CABG. Neuropsychological testing was performed pre-operatively and at 6-weeks.
    Results: Two of 35 (6%) patients had peri-operative strokes. Sixteen of 32 (50%) with post-operative imaging had new ischemic lesions including 5 of 6 with combined cardiac valve and CABG surgery. There were a range of 1–17 lesions, each <1 cm3 diameter except in 3 patients with large confluent areas of ischemia. Twenty of 29 (69%) patients with post-operative testing had significant cognitive declines in at least one domain (range 1-4), including all those with new ischemic lesions (p= 0.005).
    Conclusion: Brain injury is common following cardiac valve surgery: 6% have new neurological deficit and just over two thirds have measurable cognitive decline. Half of the patients had new post-operative ischemic lesions on DWI and these appeared embolic in nature. To our knowledge, this is the first study to link cognitive decline and cerebral ischemia. Cardiac surgery may be a useful model of human stroke in late phase IIB trials of putative neuroprotective therapies.

    Conference Organiser - ICMS Pty Ltd