People undergoing bypass surgery for heart disease are more likely to experience a drop in brainpower after the operation if they have a history of cigarette smoking – even if they quit decades ago.
In coronary artery bypass grafting (CABG), surgeons construct a detour around blocked heart arteries to restore proper blood circulation. Dr. James Slater, a cardiothoracic surgeon at Morristown Memorial Hospital in New Jersey, says fuzzy thinking after CABG is a well-known issue, with some studies reporting it occurs in up to 75 per cent of patients. However, the medical literature also suggests the problem tends to clear up after one year.
Slater and his colleagues assessed thinking power before surgery and at hospital discharge in 240 CABG patients, finding that those with a history of smoking had nearly double the risk of cognitive decline versus patients without a smoking history.
Past and current smokers were both at risk. For example, a 71-year-old woman who had quit smoking 20 years prior to surgery told Slater three weeks after successful CABG, "Your operation made me dumber." She said she had prided herself on being able to complete the Sunday New York Times crossword puzzle – the hardest of the week – but now could only get as far as Thursday's easier puzzle.
Slater speculates that the carbon monoxide and nicotine in cigarette smoke may permanently damage blood vessels over time. "Chances are you're not able to deliver as much blood and thereby oxygen to the brain during heart surgery or during other periods of stress."
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