THE CONTEXT
Coronary artery bypass grafting (CABG) provides substantial initial relief of angina and improves survival in specified patterns of coronary disease. Long-term outcomes depend on graft patency, disease progression and preventive treatment.
Angina relief and recurrence
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Approximately 90% of patients are free of angina at 1 year, but fewer than 60% remain asymptomatic after 5 or more years.
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Early postoperative angina usually reflects graft failure from operative technical problems or poor run-off caused by disease in distal native coronary vessels.
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Late angina recurrence may result from progressive disease in native coronary arteries or graft degeneration.
Graft patency and preventive treatment
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Fewer than 50% of vein grafts remain patent at 10 years, compared with more than 80% of internal mammary artery grafts. Better arterial graft patency has encouraged consideration of total arterial revascularisation.
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Aspirin 75–150 mg daily and clopidogrel 75 mg daily both improve graft patency; one or the other should be prescribed indefinitely.
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Intensive lipid-lowering therapy slows disease progression in native coronary arteries and bypass grafts and reduces clinical cardiovascular events.
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Continued smoking is associated with excess cardiovascular morbidity and mortality. Persistent smokers are twice as likely to die during the 10 years after surgery as patients who stop smoking at surgery.
Patterns associated with survival benefit
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CABG improves survival in symptomatic patients with left main stem stenosis, three-vessel disease involving the LAD, CX and right coronary arteries, or two-vessel disease involving the proximal LAD coronary artery.
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The survival improvement is most marked with left main stem disease, impaired left ventricular function, positive preoperative stress testing or left internal mammary artery grafting.
Neurological complications
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The risk of perioperative stroke is 1%–2%.
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Short-term cognitive impairment develops in 30%–80% of patients and typically resolves within 6 months.
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Long-term cognitive decline has also been reported and may be evident in more than 30% of patients at 5 years.