A meta-analysis of cognitive outcome following coronary artery bypass graft surgery

A pilot study of cerebral tissue oxygenation and postoperative cognitive dysfunction among patients undergoing coronary artery bypass grafting randomised to surgery with or without cardiopulmonary bypass*

“…Different techniques may be used; however, the incidence among our patients is generally comparable with the range of 26-71% reported after major surgery in elderly patients [27], although there is some evidence that patients may recover more quickly after coronary artery surgery [28]. There is also some evidence that the incidence of cognitive dysfunction after coronary surgery may have been overestimated in the past [3,29,30].…”

“…However, a recent meta-analysis suggested that, despite early cognitive dysfunction, cognitive function might even improve in the first year after coronary artery surgery [30]. In the absence of a gold standard method of assessing cognitive function, it remains unclear whether the finding of a high incidence among our patients represents true neuronal dysfunction.…”

Fixing Hearts and Protecting Minds

“…92 Such diffuse and subtle damage, incorporating deep white matter, may lead to disconnection of neural networks and perhaps partly explains the presence of transient processing speed slowing demonstrated in a recent meta-analysis. 6 The effect on the brain of more generalized complications of CABG surgery, such as transient cerebral desaturations, neuroinflammation, and hemodilution, is far from clear, but would also be expected to result in variable deficit.…”

“…45 There is also little support for a group difference in POCD incidence according to a systematic review 46 and a recent meta-analysis. 6 However, another meta-analysis found that on-pump surgery increased the incidence of POCD at early (1-2 weeks and 3 months) but not later (6 months and 12 months) stages in recovery following CABG surgery 45 ; moreover there is evidence that this lack of a 'late' effect persists at 5 years. 47 The effect of cardiopulmonary bypass on POCD incidence is particularly well represented in the literature, and, on balance, the evidence suggests that this technique does not exert a major negative influence.…”

“…4 Despite significant methodological issues, it seems that the balance of interpretation has historically been in favor of CABG surgery as a cause of significant POCD. More recently, however, a review of a series of publications from a well-controlled longitudinal cohort study conducted at Johns Hopkins 5 and a meta-analysis 6 suggested that cognition is in fact stable or may even show some improvement after CABG surgery in the majority of patients, at least within the first year (Figures 1 and 2). There is little doubt that POCD affects some patients in the short term, but the pathophysiological mechanisms underlying this and the influence on longer-term cognitive function remain uncertain.…”