Can Cognition Survive Heart Surgery?

Abstract

In this issue of Circulation , Jensen et al1 report that cognitive difficulties were no fewer when off-pump (OPCAB) versus conventional (CCAB) coronary artery bypass grafting was used. This important investigation, a substudy of the Best Bypass Surgery Trial, is a randomized prospective controlled trial that compares OPCAB with CCAB. Although the numbers seem relatively small (ie, 120 elderly patients with a men age of 76 years), the study was carefully powered to show differences in cognitive function at a mean of 103 days of follow-up. Although one could quibble with the details of the neuropsychological tests chosen (mini-mental state examination as a screening test for dementia after randomization but before inclusion, visual verbal learning, concept shifting, Stroop color word interference test, letter-digit coding), the main result is unequivocal. The incidence of cognitive decline was roughly 8%, and no difference between OPCAB and CCAB was found. This disappointing result raises important questions about the mechanisms of neurological injury caused by cardiac surgery and what future strategies might entail. Article p 2790 Early in the development of cardiac surgery, it was psychiatrists who first reported difficulties with thought content and process. Rizzo et al2 reported on 32 patients under the care of Lewis Dexter (cardiologist) and Dwight Harken (cardiac surgeon) who underwent “finger fracture” valvuloplasty surgery for rheumatic mitral valve disease at the Peter Bent Brigham Hospital in Boston. These psychiatrists applied analytical explanations (eg, hysterical fantasies as the heart as a sexual organ, transference to the surgeon, depersonalization, narcissism) to their findings of disordered thinking in many of their patients. Only 50 years later, these explanations sound amusingly antique, but they mark the first organized recognition that the brain could suffer serious damage as a result of cardiac surgery. The neurological complications of cardiac surgery fall into 2 …