Cognitive Problems After Bypass Surgery

Since the 1960s, coronary artery bypass grafting (CABG) has helped people with heart disease live healthier and longer lives. But some people are left with memory and focus problems. These problems can happen right after surgery and may be long-lasting.

What Happens?

CABG is done to treat coronary artery disease (CAD). CAD happens when fatty plaque builds up in the arteries that bring oxygen to the heart. This buildup blocks blood flow. CABG reroutes blood flow around a blockage using vessels from other parts of the body. During surgery, a person's heart may be stopped and a heart-lung machine may be used to bring oxygen to the body.

Some things that are thought to cause the cognitive problems that some people have are:

  • Tiny air bubbles or clots that break off and travel to the brain
  • Not enough oxygen coming from the heart-lung machine
  • Heart disease clogging the arteries to the brain

Some studies have also found that cognitive changes were the same in people with CAD who did not have CABG. This may mean that the changes do not have anything to do with the surgery and more to do with the disease it was treating. More studies may show that the risk of these problems may be due to CAD and not CABG. More research needs to be done.

Who May Be at Risk?

Researchers have found that age and having less formal education may raise a person’s risk. Older adults are more likely to have problems adjusting to decreases in brain blood flow during surgery. More education may raise a person’s ability to make up for the cognitive problems, but this is still being studied.

What Is Being Done?

Research is being done see if making small changes to the surgery will help prevent these problems. There are also other surgeries that can be used, such as angioplasty. It inserts a tube with a balloon into the blocked artery. The balloon is inflated and opens the artery. A mesh stent is often used to keep it open. However, this surgery is not right for everyone.

Until we know more, talk to your doctor if you need CABG and are worried about cognitive problems. Your doctor can talk about your risk based on your medical history, current health problems, and other factors.


American Psychological Association
National Heart, Lung, and Blood Institute



Beating heart CABG/Off-pump CABG surgery. Memorial Care Health System website. Available at:
...(Click grey area to select URL)
Accessed June 10, 2021.
Bronster DJ. Neurologic complications of cardiac surgery: current concepts and recent advances. Curr Cardiol Rep. 2006;8(1):9-16.
Coronary artery bypass graft (CABG) surgery. EBSCO DynaMed website. Available at: Accessed June 10, 2021.
Keith JR, Puente AE, et al. Assessing postoperative cognitive change after cardiopulmonary bypass surgery. Neuropsychology. 2002;16(3):411-421.
Newman MF, Kirchner JL, et al. Longitudinal assessment of neurocognitive function after coronary-artery bypass surgery. N Engl J Med. 2001;344(6):395-402.
Rudolph JL, Jones RN, et al. Derivation and validation of a preoperative prediction rule for delirium after cardiac surgery. Circulation. 2009;119(2):229-236.
Selnes OA, Grega MA, et al. Cognition 6 years after surgical or medical therapy for coronary artery disease. Ann Neurol. 2008;63(5):581-590.
Selnes OA, McKhann GM, et al. Cognitive and neurobehavioral dysfunction after cardiac bypass procedures. Neurol Clin. 2006;24(1):133-145
Last reviewed June 2021 by EBSCO Medical Review Board
Last Updated: 6/10/2021

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