Neurocognitive functioning in patients undergoing coronary artery bypass graft surgery or percutaneous coronary intervention: evidence of impairment before intervention compared with normal controls.

BACKGROUND: Cognitive deficits have been reported to occur in a significant proportion of patients undergoing coronary artery bypass grafting (CABG), but the extent to which these deficits were preexistent or related to the natural history of cognitive decline in this patient population remains poorly defined.
METHODS: After excluding patients with conditions known to cause brain dysfunction (eg, hepatic dysfunction, stroke), a group of patients referred for percutaneous coronary intervention (PCI) or CABG (n = 82) was compared with an age- and education-matched control group that did not have clinical evidence of coronary artery disease (n = 41). These subjects underwent a battery of neurocognitive and emotional testing.
RESULTS: Test score means for 5 of 14 different measures were significantly greater (impaired) in cardiac compared with control group subjects. Of cardiac subjects, 20% demonstrated clinical impairment (test result > or = 1 SD worse than mean for normative standards) in 6 of 14 tests, compared with 10% of the controls. By clinical standards, 46% of cardiac subjects would be considered to be impaired (score 1 SD or more below the control group mean) on 3 or more neuropsychologic measures, compared with 29% of the controls. By this (control group mean) standard, cardiac subjects demonstrated impaired scores on 3.06 +/- 2.6 tests compared with impairment in 2.0 +/- 2.35 tests for the control group (p = 0.01).
CONCLUSIONS: Even excluding patients at high risk for brain dysfunction, cognitive impairment is found in patients with coronary artery disease before interventional therapy. Baseline impairment must be considered when evaluating outcomes after intervention.